subject:(Astronomy)

University of Georgia

1. Maddox, James Mitchell. Cosmic poetics: a binary discourse.

Degree: MA, Comparative Literature, 2011, University of Georgia

URL: http://purl.galileo.usg.edu/uga_etd/maddox_james_m_201108_ma

► Poetry and astronomy seem to be very different in how they describe the world and our experience of it. But they are not in opposition.… (more)

Subjects/Keywords: Astronomy

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APA (6^th Edition):

Maddox, J. M. (2011). Cosmic poetics: a binary discourse. (Masters Thesis). University of Georgia. Retrieved from http://purl.galileo.usg.edu/uga_etd/maddox_james_m_201108_ma

Chicago Manual of Style (16^th Edition):

Maddox, James Mitchell. “Cosmic poetics: a binary discourse.” 2011. Masters Thesis, University of Georgia. Accessed February 25, 2020. http://purl.galileo.usg.edu/uga_etd/maddox_james_m_201108_ma.

MLA Handbook (7^th Edition):

Maddox, James Mitchell. “Cosmic poetics: a binary discourse.” 2011. Web. 25 Feb 2020.

Vancouver:

Maddox JM. Cosmic poetics: a binary discourse. [Internet] [Masters thesis]. University of Georgia; 2011. [cited 2020 Feb 25]. Available from: http://purl.galileo.usg.edu/uga_etd/maddox_james_m_201108_ma.

Council of Science Editors:

Maddox JM. Cosmic poetics: a binary discourse. [Masters Thesis]. University of Georgia; 2011. Available from: http://purl.galileo.usg.edu/uga_etd/maddox_james_m_201108_ma

UCLA

2. Mason, Charlotte. Galaxies at the Epoch of Reionization.

Degree: Astronomy, 2018, UCLA

URL: http://www.escholarship.org/uc/item/39t4d9qg

► The reionization of intergalactic hydrogen in the universe’s first billion years was likely driven by the first stars and galaxies, so its history encodes information… (more)

▼ The reionization of intergalactic hydrogen in the universe’s first billion years was likely driven by the first stars and galaxies, so its history encodes information about their prop- erties. But the timeline of reionization is not well-measured and it is still unclear whether galaxies alone can produce the required ionizing photons. In my thesis I have focused on two ways to use galaxies at our current observational frontiers to constrain reionization and high redshift galaxy evolution.One tool is the UV luminosity function (LF), which traces the evolution of star-forming galaxies and their ionizing photons. Accurately measuring LFs and understanding their evolution are important for understanding the connections between galaxies and their dark matter halos. I developed a simple, but powerful, semi-analytic model for LF evolution assuming star formation is driven by dark matter accretion. This has proved remarkably consistent with observations, and implies the majority of star formation at high redshifts occurs in low mass galaxies. I also developed a technique to improve the accuracy of LF by accounting for gravitational lensing magnification bias.Secondly, Lyman alpha (Lyα) emission from galaxies can probe the intergalactic medium (IGM) ionization state as Lyα photons are strongly attenuated by neutral hydrogen, but this requires disentangling physics on pc to Gpc scales. I developed a new forward-modeling Bayesian framework combining cosmological IGM simulations with interstellar medium models to infer the IGM neutral hydrogen fraction from observations of Lyα emission. My thesis presents new measurements of the neutral fraction at z ∼ 7 and z ∼ 8, which, along with other independent constraints, provide increasing evidence for the bulk of reionization occurring at z ∼ 6 − 8. This is consistent with reionization being driven by ultra-faint galaxies with a low average ionizing photon escape fraction. We also show that reionization impacts Lyα emission from different galaxy populations in different ways: UV bright galaxies living in overdense regions that reionize early have potentially visible Lyα even in a highly neutral IGM.The upcoming James Webb Space Telescope was designed to observe galaxies at Cosmic Dawn. Throughout this thesis I have made predictions for what JWST may observe in the context of high redshift galaxy evolution.

Subjects/Keywords: Astronomy

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APA (6^th Edition):

Mason, C. (2018). Galaxies at the Epoch of Reionization. (Thesis). UCLA. Retrieved from http://www.escholarship.org/uc/item/39t4d9qg

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Mason, Charlotte. “Galaxies at the Epoch of Reionization.” 2018. Thesis, UCLA. Accessed February 25, 2020. http://www.escholarship.org/uc/item/39t4d9qg.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Mason, Charlotte. “Galaxies at the Epoch of Reionization.” 2018. Web. 25 Feb 2020.

Vancouver:

Mason C. Galaxies at the Epoch of Reionization. [Internet] [Thesis]. UCLA; 2018. [cited 2020 Feb 25]. Available from: http://www.escholarship.org/uc/item/39t4d9qg.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Mason C. Galaxies at the Epoch of Reionization. [Thesis]. UCLA; 2018. Available from: http://www.escholarship.org/uc/item/39t4d9qg

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Oulu

3. Venhola, A. (Aku). Modeling galaxy interactions with Holmberg’s analog computer.

Degree: 2015, University of Oulu

URL: http://urn.fi/URN:NBN:fi:oulu-201504021286

► Galaxy dynamics using simulation models has been an important research field during the last 50 years. In the beginning of the 20th century there were… (more)

▼ Galaxy dynamics using simulation models has been an important research field during the last 50 years. In the beginning of the 20th century there were already extensive catalogs of galaxies which showed the large diversity of the galaxy shapes, although there was no theory to explain those. Nowadays, galaxy dynamics can be extensively studied by simulating the dark matter, star, and gas cloud orbits numerically, but before the era of modern computers constructing even a simple model was a considerable challenge. In the beginning of the 1940’s Erik Holmberg (University of Lund) introduced his new integration procedure for galaxy simulations (Holmberg, 1941) which can be considered as a pioneering study in galaxy dynamics. In his work, Holmberg replaced gravitation with light intensity, based on the fact that they both obey the same 1/r² attenuation with distance. He modeled the interaction of two galaxies with light bulbs and came out with the conclusion that some features of the galaxies, for example tails and intergalactic bridges, can be explained by gravitational tidal forces. Holmberg’s work was significant for being the first simulation of galaxy dynamics, which could be upgraded only 20 years later, when the first simulations with electronic computers were started. Despite the significance of the Holmberg’s simulations and the large number of citations they have received, there is no marks that the simulations would have been repeated. During the summer of 2013 I reconstructed the Holmberg’s experimental setting in the University of Oulu. The experiment was made two times: once using exactly the same parameters that Holmberg used, and another time with small changes in the initial parameters. In this thesis I introduce the Holmberg’s experiments and the theory behind that. In chapter 2, I give a brief overview of disk galaxies and methods used in galaxy simulations. In chapter 3, I present the theoretical basis of Holmberg’s analog simulation. Chapter 4 covers the hardware and the practical realization of the experiment. In chapter 4, I represent the results and compare them with the Holmberg’s results.

Subjects/Keywords: Astronomy

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APA (6^th Edition):

Venhola, A. (. (2015). Modeling galaxy interactions with Holmberg’s analog computer. (Masters Thesis). University of Oulu. Retrieved from http://urn.fi/URN:NBN:fi:oulu-201504021286

Chicago Manual of Style (16^th Edition):

Venhola, A (Aku). “Modeling galaxy interactions with Holmberg’s analog computer.” 2015. Masters Thesis, University of Oulu. Accessed February 25, 2020. http://urn.fi/URN:NBN:fi:oulu-201504021286.

MLA Handbook (7^th Edition):

Venhola, A (Aku). “Modeling galaxy interactions with Holmberg’s analog computer.” 2015. Web. 25 Feb 2020.

Vancouver:

Venhola A(. Modeling galaxy interactions with Holmberg’s analog computer. [Internet] [Masters thesis]. University of Oulu; 2015. [cited 2020 Feb 25]. Available from: http://urn.fi/URN:NBN:fi:oulu-201504021286.

Council of Science Editors:

Venhola A(. Modeling galaxy interactions with Holmberg’s analog computer. [Masters Thesis]. University of Oulu; 2015. Available from: http://urn.fi/URN:NBN:fi:oulu-201504021286

University of Central Lancashire

4. Sancho, Maider. The spatial distribution of metals in disc galaxies, via simulations and observations.

Degree: PhD, 2017, University of Central Lancashire

URL: http://clok.uclan.ac.uk/20925/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.733486

► In this thesis we are interested in the evoluNon of disc galaxies. One of the most common ways to study it is by a deep… (more)

▼ In this thesis we are interested in the evoluNon of disc galaxies. One of the most common ways to study it is by a deep analysis of the distribuNon of chemical abundances in the stellar populaNons of the disc component. Abundance gradients let us reconstruct the puzzle of the formaNon and evoluNon of this type of galaxies, once we learn about the diﬀerent elements that are released to the interstellar medium at each stage of the life of stars. In this work we pay special aaenNon to the so-‐called thick disc component of spiral galaxies, believing that it is a relic of the early galaxy and its understanding opens the door for a complete galaxy formaNon scenario. We analyse thick discs both with observaNonal data and simulaNons because we want to have a wider view of the situaNon and we think that such complementary approaches can help us maximise our knowledge and results. Our simulaNons with an enhanced feedback are the ones that best reproduce the measured data from the Milky Way. The trend for the variaNon of the mean metallicity with galacNc radius at diﬀerent heights from the plane matches that in the Galaxy. It is negaNve in the mid-‐plane of galaxies and then becomes posiNve at greatest heights. According to simulaNons, this behaviour is due to a populaNon of relaNvely young and metal-‐rich stars formed in situ in the outer galaxy, which is missing in the inner thick disc. When looking at the same magnitudes but via observaNons from the CALIFA local universe galaxy sample, we see that the external galaxies exhibit a variety of diﬀerent behaviours both for the metallicity and age radial gradients with height, in addiNon to the trend found in simulaNons and the Milky Way. We deduce that thick discs probably do not form through a unique mechanism but from a combinaNon of many of them. Finally we want to know the inﬂuence of the galacNc mass in the chemical evoluNon of a disc galaxy. By using a ﬁducial set of simulaNons and comparing the results to observaNonal data we conclude that the smallest systems in our set might have an incorrect feedback eﬃciency, and suggest that a mass-‐dependent modulaNon of feedback might improve the result.

Subjects/Keywords: Astronomy

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APA (6^th Edition):

Sancho, M. (2017). The spatial distribution of metals in disc galaxies, via simulations and observations. (Doctoral Dissertation). University of Central Lancashire. Retrieved from http://clok.uclan.ac.uk/20925/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.733486

Chicago Manual of Style (16^th Edition):

Sancho, Maider. “The spatial distribution of metals in disc galaxies, via simulations and observations.” 2017. Doctoral Dissertation, University of Central Lancashire. Accessed February 25, 2020. http://clok.uclan.ac.uk/20925/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.733486.

MLA Handbook (7^th Edition):

Sancho, Maider. “The spatial distribution of metals in disc galaxies, via simulations and observations.” 2017. Web. 25 Feb 2020.

Vancouver:

Sancho M. The spatial distribution of metals in disc galaxies, via simulations and observations. [Internet] [Doctoral dissertation]. University of Central Lancashire; 2017. [cited 2020 Feb 25]. Available from: http://clok.uclan.ac.uk/20925/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.733486.

Council of Science Editors:

Sancho M. The spatial distribution of metals in disc galaxies, via simulations and observations. [Doctoral Dissertation]. University of Central Lancashire; 2017. Available from: http://clok.uclan.ac.uk/20925/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.733486

University of Oulu

5. Mustonen, J. (Juha). Jäätikkömäiset muodostumat Moreux-kraatterin ja Protonilus Mensaen alueella.

Degree: 2015, University of Oulu

URL: http://urn.fi/URN:NBN:fi:oulu-201504021200

► Pro Gradu-tutkielmassa kartoitetaan Marsin Protonilus Mensaen ja Moreux-kraatterin alueelta löytyviä jäätikkömäisiä kohteita. Alue sijaitsee Marsin dikotomiarajalla, joka sisältää runsaasti merkkejä amatsoonisella aikakaudella tapahtuneesta jäätiköitymisestä. Protonilus… (more)

▼ Pro Gradu-tutkielmassa kartoitetaan Marsin Protonilus Mensaen ja Moreux-kraatterin alueelta löytyviä jäätikkömäisiä kohteita. Alue sijaitsee Marsin dikotomiarajalla, joka sisältää runsaasti merkkejä amatsoonisella aikakaudella tapahtuneesta jäätiköitymisestä. Protonilus Mensaen alueelta tehdyissä aiemmissa tutkimuksissa on löydetty paljon merkkejä jäätä sisältävistä laattamaisista LDA-muodostumista ja laaksojen pohjia täyttävistä LVF-muodostumista [Squyres 1978, 1979] ja [Levy et al. 2010]. Kyseistä aluetta ei ole kuitenkaan aiemmin kartoitettu laaja-alaisesti uuden sukupolven avaruusluotaimien tuottamaa kuvamateriaalia hyödyntäen. Tämän työn päämääränä on ollut kartoittaa Protonilus Mensaen alue uuden sukupolven Mars Global Surveyor-, Mars Express-, Mars Reconnaissance Orbiter- ja Mars Odyssey-luotaimien tuottaman kuvamateriaalin avulla. Työssä on etsitty merkkejä mahdollisesti eri aikakausina toimineista jäätiköitymisprosesseista. Toisen mielenkiintoisen tutkimusaiheen muodostavat merkit veden virtauksesta alueella. Lisäksi tutkielmassa käydään läpi veden ja jään historiaa, koska niiden merkitys Marsin historiassa on koko ajan kasvanut. Tämän vuoksi on tärkeää käydä läpi, kuinka nykyinen käsityksemme Marsin vedestä on muodostunut. Tämän tutkielman myötä lukija saa kattavan käsityksen Marsin veden historiasta sekä nykyhetkestä. Tutkimuksen aineistona käytetään erityisesti Mars Odyssey-luotaimen Mola-instrumentin tuottamaa topografiatietoja sekä muiden luotaimien CTX-, HiRISE- ja HRSC-kameroiden tuottamaa kuvamateriaalia. Mars Reconnaissance Orbiter-luotaimen CTX-kameran tarkat ja hyvälaatuiset kuvat ovat toimineet kartoituksen pohjamateriaalina. CTX-instrumentin avulla Protonilus Mensaen aluetta voidaan tutkia noin kuuden metrin resoluutiolla. HiRISE- ja HRSC-kameroiden tarkempia ja yksityiskohtaisempia kuvia on käytetty alueilta, joista niitä on ollut saatavilla. Topografiatiedon avulla on mahdollista ymmärtää alueen jäätikkömäisten muodostumien liikettä sekä merkkejä veden virtauksesta. Tutkielman historiaosuudessa on käytetty hyväksi aiempien tutkimusryhmien tuloksia 1970-luvulta 2010-luvulle. Kartoituksessa pääasiallisena työkaluna on käytetty ArcGis-kartoitusohjelmaa, jonka avulla voidaan kartoittaa tehokkaasti laajoja alueita. Pienempiä alueita kartoitettaessa on käytetty myös Photoshop-kuvankäsittelyohjelmaa. Kartoituksessa Marsin Protonilus Mensaen alueelta löytyi paljon jäätikkömäisiä muodostumia. Laattamaiset LDA-muodostumat keskittyvät sirpaloituneelle ylänköalueelle ja Moreux-kraatterin keskuskohouman ympärille. Protonilus Mensae-alueen vuorien ympärille on muodostunut vaihtelevan kokoisia LDA-muodostumia. Tutkitulta alueelta löydetyt LVF-muodostumat keskittyvät sirpaloituneen ylänköalueen laaksoihin ja noaakkisella ylänköalueella vanhoihin virtausuomiin. Kraattereiden täytteitä eli CCF-muodostumia löytyy jokaisen kraatterin pohjalta. Noaakkiselta ylänköalueelta löydettiin yksi muinainen kraatterijärvi, josta on lähtenyt uoma kohti alempana sijaitsevia alueita. Jäätikkömäiset muodostumat ovat…

Subjects/Keywords: Astronomy

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APA (6^th Edition):

Mustonen, J. (. (2015). Jäätikkömäiset muodostumat Moreux-kraatterin ja Protonilus Mensaen alueella. (Masters Thesis). University of Oulu. Retrieved from http://urn.fi/URN:NBN:fi:oulu-201504021200

Chicago Manual of Style (16^th Edition):

Mustonen, J (Juha). “Jäätikkömäiset muodostumat Moreux-kraatterin ja Protonilus Mensaen alueella.” 2015. Masters Thesis, University of Oulu. Accessed February 25, 2020. http://urn.fi/URN:NBN:fi:oulu-201504021200.

MLA Handbook (7^th Edition):

Mustonen, J (Juha). “Jäätikkömäiset muodostumat Moreux-kraatterin ja Protonilus Mensaen alueella.” 2015. Web. 25 Feb 2020.

Vancouver:

Mustonen J(. Jäätikkömäiset muodostumat Moreux-kraatterin ja Protonilus Mensaen alueella. [Internet] [Masters thesis]. University of Oulu; 2015. [cited 2020 Feb 25]. Available from: http://urn.fi/URN:NBN:fi:oulu-201504021200.

Council of Science Editors:

Mustonen J(. Jäätikkömäiset muodostumat Moreux-kraatterin ja Protonilus Mensaen alueella. [Masters Thesis]. University of Oulu; 2015. Available from: http://urn.fi/URN:NBN:fi:oulu-201504021200

Boston University

6. Sanhueza, Patricio. Characterizing molecular clouds in the earliest phases of high-mass star formation.

Degree: PhD, Astronomy, 2015, Boston University

URL: http://hdl.handle.net/2144/15420

► High-mass stars play a key role in the energetics and chemical evolution of molecular clouds and galaxies. However, the mechanisms that allow the formation of… (more)

▼ High-mass stars play a key role in the energetics and chemical evolution of molecular clouds and galaxies. However, the mechanisms that allow the formation of high-mass stars are far less clear than those of their low-mass counterparts. Most of the research on high-mass star formation has focused on regions currently undergoing star formation. In contrast, objects in the earlier prestellar stage have been more difficult to identify. Recently, it has been suggested that the cold, massive, and dense Infrared Dark Clouds (IRDCs) host the earliest stages of high-mass star formation. The chemistry of IRDCs remains poorly explored. In this dissertation, an observational program to search for chemical variations in IRDC clumps as a function of their age is described. An increase in N2H+ and HCO+ abundances is found from the quiescent, cold phase to the protostellar, warmer phases, reflecting chemical evolution. For HCO+ abundances, the observed trend is consistent with theoretical predictions. However, chemical models fail to explain the observed trend of increasing N2H+ abundances. Pristine high-mass prestellar clumps are ideal for testing and constraining theories of high-mass star formation because their predictions differ the most at the early stages of evolution. From the initial IRDC sample, a high-mass clump that is the best candidate to be in the prestellar phase was selected (IRDC G028.23-00.19 MM1). With a new set of observations, the prestellar nature of the clump is confirmed. High-angular resolution observations of IRDC G028.23-00.19 suggest that in order to form high-mass stars, the detected cores have to accrete a large amount of material, passing through a low- to intermediate-mass phase before having the necessary mass to form a high-mass star. The turbulent core accretion model is inconsistent with this observational result, but on the other hand, the observations support the competitive accretion model. Embedded cores have to grow in mass during the star-formation process itself; the mass is not set at early times as the turbulent core accretion model predicts. The observed gas velocity dispersion in the cores is transonic and mildly supersonic, resulting in low virial parameters (neglecting magnetic fields). The turbulent core accretion model assumes highly supersonic linewidths and virial parameters sim1, inconsistent with the observations, unless magnetic fields in the cores have strengths of the order of 1 mG.

Subjects/Keywords: Astronomy

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Sanhueza, P. (2015). Characterizing molecular clouds in the earliest phases of high-mass star formation. (Doctoral Dissertation). Boston University. Retrieved from http://hdl.handle.net/2144/15420

Chicago Manual of Style (16^th Edition):

Sanhueza, Patricio. “Characterizing molecular clouds in the earliest phases of high-mass star formation.” 2015. Doctoral Dissertation, Boston University. Accessed February 25, 2020. http://hdl.handle.net/2144/15420.

MLA Handbook (7^th Edition):

Sanhueza, Patricio. “Characterizing molecular clouds in the earliest phases of high-mass star formation.” 2015. Web. 25 Feb 2020.

Vancouver:

Sanhueza P. Characterizing molecular clouds in the earliest phases of high-mass star formation. [Internet] [Doctoral dissertation]. Boston University; 2015. [cited 2020 Feb 25]. Available from: http://hdl.handle.net/2144/15420.

Council of Science Editors:

Sanhueza P. Characterizing molecular clouds in the earliest phases of high-mass star formation. [Doctoral Dissertation]. Boston University; 2015. Available from: http://hdl.handle.net/2144/15420

The Ohio State University

7. Dong, Subo. Astrophysical Applications of Gravitational Microlensing.

Degree: PhD, Astronomy, 2009, The Ohio State University

URL: http://rave.ohiolink.edu/etdc/view?acc_num=osu1250546190

► In this thesis, I present several astrophysical applications of Galactic and cosmological microlensing. The first few topics are on searching and characterizing extrasolar planets… (more)

▼ In this thesis, I present several astrophysical applications of Galactic and cosmological microlensing. The first few topics are on searching and characterizing extrasolar planets by means of high-magnification microlensing events. The detection efficiency analysis of A_max ~ 3000 event OGLE-2004-BLG-343 is presented. Due to human error, intensive monitoring did not begin until 43 minutes after peak, at which point the magnification had fallen to A_max ~ 1200. It is shown that, had a similar event been well sampled over the peak, it would have been sensitive to almost all Neptune-mass planets over a factor of 5 in projected separation and even would have had some sensitivity to Earth-mass planets. New algorithms optimized for fast evaluation of binary-lens models with finite-sources effects have been developed. These algorithms have enabled efficient and thorough parameter-space searches in modeling planetary high-magnification events. The detection of the cool, Jovian-mass planet MOA-2007-BLG-400Lb, discovered from an A_max = 628 event with severe finite source effects, is reported. Detailed analysis yields a fairly precise planet/star mass ratio of q = (2.5 ± 0.4) x 10^-3, while the planet/star projected separation is subject to a strong close/wide degeneracy. Photometric and astrometric measurements from Hubble Space Telescope, as well as constraints from higher order effects extracted from the ground-based light curve (microlens parallax, planetary orbital motion and finite-source effects) are used to constrain the nature of planetary event OGLE-2005-BLG-071Lb. Our primary analysis leads to the conclusion that the host is an M = 0.46 ± 0.04 M_Sun M dwarf and that the planet has mass M_p = (3.8 ± 0.4) M_Jupiter, which is likely to be the most massive planet yet discovered that is hosted by an M dwarf. Next a spaced-based microlens parallax is determined for the first time using Spitzer and ground-based observations for binary-lens event OGLE-2005-SMC-001. The parallax measurement yields a projected velocity about 239 km/s, the typical value expected for halo lenses, but an order of magnitude smaller than would be expected for lenses lying in the Small Magellanic Cloud (SMC) itself. Finally, I propose using quasar microlensing to probe Mg II and otherabsorption "cloudlets" with sizes ~ 10^-4.0 - 10^-2.0 pc in the intergalactic medium. I show that significant spectral variability on timescales of months to years can be induced by such small-scale absorption "cloudlets" toward a microlensed quasar. With numerical simulations, I demonstrate the feasibility of applying this method to Q2237+0305, and I show that high-resolution spectra of this quasar in the near future would provide a clear test of the existence of such metal-line absorbing "cloudlets". Advisors/Committee Members: Gould, Andrew (Committee Chair).

Subjects/Keywords: Astronomy

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APA (6^th Edition):

Dong, S. (2009). Astrophysical Applications of Gravitational Microlensing. (Doctoral Dissertation). The Ohio State University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=osu1250546190

Chicago Manual of Style (16^th Edition):

Dong, Subo. “Astrophysical Applications of Gravitational Microlensing.” 2009. Doctoral Dissertation, The Ohio State University. Accessed February 25, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1250546190.

MLA Handbook (7^th Edition):

Dong, Subo. “Astrophysical Applications of Gravitational Microlensing.” 2009. Web. 25 Feb 2020.

Vancouver:

Dong S. Astrophysical Applications of Gravitational Microlensing. [Internet] [Doctoral dissertation]. The Ohio State University; 2009. [cited 2020 Feb 25]. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1250546190.

Council of Science Editors:

Dong S. Astrophysical Applications of Gravitational Microlensing. [Doctoral Dissertation]. The Ohio State University; 2009. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1250546190

The Ohio State University

8. Stoll, Rebecca A. Measuring and Extrapolating the Chemical Abundances of Normal and Superluminous Core-Collapse Supernovae.

Degree: PhD, Astronomy, 2013, The Ohio State University

URL: http://rave.ohiolink.edu/etdc/view?acc_num=osu1373284666

► Using the properties of star forming regions in the host galaxies of core-collapse supernovae (CCSNe), I extrapolate the properties of the progenitor stars of… (more)

▼ Using the properties of star forming regions in the host galaxies of core-collapse supernovae (CCSNe), I extrapolate the properties of the progenitor stars of these SNe. The goal is to determine what role progenitormetallicity plays in the luminosity of a supernova by comparing the environments of normal (average absolute magnitude of -17.5) and super-luminous (absolute magnitude brighter than -20) supernovae. First, I present spectroscopic oxygen abundance measurements of the hosts of two super-luminous CCSNe, and show that, together with three other measurements from the literature, a strong pattern emerges of super-luminous SNe occurring in host galaxies that are metal-poor compared to the overall galaxy population. Next, I present metallicity measurements, host photometry, and best-fit galaxy properties for a representative subsample of the Palomar Transient Factory's first-year type II SN sample. The purpose of the in-depth study of this sample is to serve as a reasonable standard of comparison for rare SN events. The secondary aim is to continue to press the discussion in the community about both the usefulness and the limitations of comparing SN hosts to samples of galaxies. Because iron is a key source of opacity for massive star winds, and at lower metallicity, α-elements like oxygen are enhanced relative to iron compared to the solar mixture, I present a conversion from gas-phase oxygen abundance measurements to implied iron abundances, and discuss the logic, uses, and limitations of this conversion. Finally, I present metallicity measurements for a sample of eight hosts of super-luminous CCSNe. Comparing them and four measurements from the literature, I find that super-luminous CCSNe come from much more metal-poor environments than normal type II SNe. This implies that the progenitors of super-luminous CCSNe are much poorer in iron than the progenitors of normal type II SNe, suggesting mass loss is a key factor for abnormally high luminosity. Advisors/Committee Members: Pogge, Richard (Advisor).

Subjects/Keywords: Astronomy

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APA (6^th Edition):

Stoll, R. A. (2013). Measuring and Extrapolating the Chemical Abundances of Normal and Superluminous Core-Collapse Supernovae. (Doctoral Dissertation). The Ohio State University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=osu1373284666

Chicago Manual of Style (16^th Edition):

Stoll, Rebecca A. “Measuring and Extrapolating the Chemical Abundances of Normal and Superluminous Core-Collapse Supernovae.” 2013. Doctoral Dissertation, The Ohio State University. Accessed February 25, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1373284666.

MLA Handbook (7^th Edition):

Stoll, Rebecca A. “Measuring and Extrapolating the Chemical Abundances of Normal and Superluminous Core-Collapse Supernovae.” 2013. Web. 25 Feb 2020.

Vancouver:

Stoll RA. Measuring and Extrapolating the Chemical Abundances of Normal and Superluminous Core-Collapse Supernovae. [Internet] [Doctoral dissertation]. The Ohio State University; 2013. [cited 2020 Feb 25]. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1373284666.

Council of Science Editors:

Stoll RA. Measuring and Extrapolating the Chemical Abundances of Normal and Superluminous Core-Collapse Supernovae. [Doctoral Dissertation]. The Ohio State University; 2013. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1373284666

UCLA

9. Boehle, Anna Lee. The Environments Around Nearby Supermassive Black Holes and the Upgrade of the OSIRIS Integral Field Spectrograph.

Degree: Astronomy, 2017, UCLA

URL: http://www.escholarship.org/uc/item/25p9r0nr

► In this thesis, I explore the environments around supermassive black holes (SMBHs) in the nearby universe. The thesis is divided into five chapters. I begin… (more)

▼ In this thesis, I explore the environments around supermassive black holes (SMBHs) in the nearby universe. The thesis is divided into five chapters. I begin with an introduction to SMBHs in general and to the astronomical instrumentation that is used to study their direct environments in the highest possible detail. The second chapter focuses on the closest galactic nucleus to Earth: the center of our own Milky Way galaxy. The orbits of stars around the Milky Way SMBH, Sgr A*, can be used to determine the black hole mass and distance. I present a new method of analyzing images of the Galactic center to increase the time baseline for faint, short-period stars that orbit Sgr A*. I use this new analysis method to improve the constraints on the mass of the SMBH and the distance to the Galactic center by a factor of 2. The second chapter discusses the upgrade of the detector in the OSIRIS instrument at W.M. Keck Observatory. This adaptive-optics-fed instrument uses an array of small lenses to sample a rectangular section of the focal plane, producing up to 3,000 spectra simultaneously with a spectral resolution of 3,800 and diffraction-limited spatial resolution. I helped to upgrade the original near-infrared (NIR) Hawaii-2 detector to a Hawaii-2RG, which improved the raw sensitivity of OSIRIS by a factor of 2 at J-band wavelengths (1.2 - 1.4 μm) and 1.6 at H- and K-band wavelengths (1.5 - 2.4 microns). The third and fourth chapters discuss a NIR integral field spectroscopic survey of nearby LINER (low ionization nuclear emission line) galaxies, the lowest luminosity class of active galactic nuclei. LINERs are found at the centers of ∼1/3 of galaxies within 40 Mpc, but it is unclear whether accretion onto a supermassive black hole or another mechanism such as shock excitation drives their emission. I use the OSIRIS instrument to map the strength and kinematics of singly ionized iron, molecular hydrogen, and hydrogen recombination lines at spatial scales of 1-10 pc in the nuclei of 11 nearby LINERs, in close proximity to their central SMBHs. The third chapter presents a detailed study of the closest LINER in the sample, NGC 404, in which I find that its LINER emission is likely excited by shocks, and the final chapter presents results from the survey sample as a whole.

Subjects/Keywords: Astronomy

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APA (6^th Edition):

Boehle, A. L. (2017). The Environments Around Nearby Supermassive Black Holes and the Upgrade of the OSIRIS Integral Field Spectrograph. (Thesis). UCLA. Retrieved from http://www.escholarship.org/uc/item/25p9r0nr

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Boehle, Anna Lee. “The Environments Around Nearby Supermassive Black Holes and the Upgrade of the OSIRIS Integral Field Spectrograph.” 2017. Thesis, UCLA. Accessed February 25, 2020. http://www.escholarship.org/uc/item/25p9r0nr.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Boehle, Anna Lee. “The Environments Around Nearby Supermassive Black Holes and the Upgrade of the OSIRIS Integral Field Spectrograph.” 2017. Web. 25 Feb 2020.

Vancouver:

Boehle AL. The Environments Around Nearby Supermassive Black Holes and the Upgrade of the OSIRIS Integral Field Spectrograph. [Internet] [Thesis]. UCLA; 2017. [cited 2020 Feb 25]. Available from: http://www.escholarship.org/uc/item/25p9r0nr.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Boehle AL. The Environments Around Nearby Supermassive Black Holes and the Upgrade of the OSIRIS Integral Field Spectrograph. [Thesis]. UCLA; 2017. Available from: http://www.escholarship.org/uc/item/25p9r0nr

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

10. MacLeod, Morgan Elowe. Social Stars: Modeling the Interactive Lives of Stars in Dense Clusters and Binary Systems in the Era of Time Domain Astronomy.

Degree: Astronomy & Astrophysics, 2016, University of California – Santa Cruz

URL: http://www.escholarship.org/uc/item/8p01x7b9

► This thesis uses computational modeling to study of phases of dramatic interaction that intersperse stellar lifetimes. In galactic centers stars trace dangerously wandering orbits dictated… (more)

▼ This thesis uses computational modeling to study of phases of dramatic interaction that intersperse stellar lifetimes. In galactic centers stars trace dangerously wandering orbits dictated by the combined gravitational force of a central, supermassive black hole and all of the surrounding stars. In binary systems, stars' evolution – which causes their radii to increase substantially – can bring initially non-interacting systems into contact. Moments of strong stellar interaction transform stars, their subsequent evolution, and the stellar environments they inhabit. In tidal disruption events, a star is partially or completely destroyed as tidal forces from a supermassive black hole overwhelm the star's self gravity. A portion of the stellar debris falls back to the black hole powering a luminous flare as it accretes. This thesis studies the relative event rates and properties of tidal disruption events for stars across the stellar evolutionary spectrum. Tidal disruptions of giant stars occur with high specific frequency; these objects' extended envelopes make them vulnerable to disruption. More-compact white dwarf stars are tidally disrupted relatively rarely. Their transients are also of very different duration and luminosity. Giant star disruptions power accretion flares with timescales of tens to hundreds of years; white dwarf disruption flares take hours to days. White dwarf tidal interactions can additionally trigger thermonuclear burning and lead to transients with signatures similar to type I supernovae. In binary star systems, a phase of hydrodynamic interaction called a common envelope episode occurs when one star evolves to swallow its companion. Dragged by the surrounding gas, the companion star spirals through the envelope to tighter orbits. This thesis studies accretion and flow morphologies during this phase. Density gradients across the gravitationally-focussed material lead to a strong angular momentum barrier to accretion during common envelope. Typical accretion efficiencies are in the range of 1 percent the Hoyle-Lyttleton accretion rate. This implies that compact objects embedded in common envelopes do not grow significantly during this phase, increasing their mass by at most a few percent. This thesis models the properties of a recent stellar-merger powered transient to derive constraints on this long-uncertain phase of binary star evolution.

Subjects/Keywords: Astronomy

11 more images…

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APA (6^th Edition):

MacLeod, M. E. (2016). Social Stars: Modeling the Interactive Lives of Stars in Dense Clusters and Binary Systems in the Era of Time Domain Astronomy. (Thesis). University of California – Santa Cruz. Retrieved from http://www.escholarship.org/uc/item/8p01x7b9

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

MacLeod, Morgan Elowe. “Social Stars: Modeling the Interactive Lives of Stars in Dense Clusters and Binary Systems in the Era of Time Domain Astronomy.” 2016. Thesis, University of California – Santa Cruz. Accessed February 25, 2020. http://www.escholarship.org/uc/item/8p01x7b9.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

MacLeod, Morgan Elowe. “Social Stars: Modeling the Interactive Lives of Stars in Dense Clusters and Binary Systems in the Era of Time Domain Astronomy.” 2016. Web. 25 Feb 2020.

Vancouver:

MacLeod ME. Social Stars: Modeling the Interactive Lives of Stars in Dense Clusters and Binary Systems in the Era of Time Domain Astronomy. [Internet] [Thesis]. University of California – Santa Cruz; 2016. [cited 2020 Feb 25]. Available from: http://www.escholarship.org/uc/item/8p01x7b9.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

MacLeod ME. Social Stars: Modeling the Interactive Lives of Stars in Dense Clusters and Binary Systems in the Era of Time Domain Astronomy. [Thesis]. University of California – Santa Cruz; 2016. Available from: http://www.escholarship.org/uc/item/8p01x7b9

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

UCLA

11. Mace, Gregory Nathan. Investigating Low-Mass Binary Stars And Brown Dwarfs with Near-Infrared Spectroscopy.

Degree: Astronomy, 2014, UCLA

URL: http://www.escholarship.org/uc/item/56q669xw

► The mass of a star at formation determines its subsequent evolution and demise. Low-mass stars are the most common products of star formation and their… (more)

Subjects/Keywords: Astronomy

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APA (6^th Edition):

Mace, G. N. (2014). Investigating Low-Mass Binary Stars And Brown Dwarfs with Near-Infrared Spectroscopy. (Thesis). UCLA. Retrieved from http://www.escholarship.org/uc/item/56q669xw

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Mace, Gregory Nathan. “Investigating Low-Mass Binary Stars And Brown Dwarfs with Near-Infrared Spectroscopy.” 2014. Thesis, UCLA. Accessed February 25, 2020. http://www.escholarship.org/uc/item/56q669xw.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Mace, Gregory Nathan. “Investigating Low-Mass Binary Stars And Brown Dwarfs with Near-Infrared Spectroscopy.” 2014. Web. 25 Feb 2020.

Vancouver:

Mace GN. Investigating Low-Mass Binary Stars And Brown Dwarfs with Near-Infrared Spectroscopy. [Internet] [Thesis]. UCLA; 2014. [cited 2020 Feb 25]. Available from: http://www.escholarship.org/uc/item/56q669xw.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Mace GN. Investigating Low-Mass Binary Stars And Brown Dwarfs with Near-Infrared Spectroscopy. [Thesis]. UCLA; 2014. Available from: http://www.escholarship.org/uc/item/56q669xw

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

12. Nayyeri, Hooshang. A Study of Massive and Evolved Galaxies at z>3.

Degree: Physics, 2014, University of California – Riverside

URL: http://www.escholarship.org/uc/item/7379d0g5

► I use deep data taken as part of the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) observations by the Cosmic Assembly Near-infrared Deep… (more)

Subjects/Keywords: Astronomy

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APA (6^th Edition):

Nayyeri, H. (2014). A Study of Massive and Evolved Galaxies at z>3. (Thesis). University of California – Riverside. Retrieved from http://www.escholarship.org/uc/item/7379d0g5

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Nayyeri, Hooshang. “A Study of Massive and Evolved Galaxies at z>3.” 2014. Thesis, University of California – Riverside. Accessed February 25, 2020. http://www.escholarship.org/uc/item/7379d0g5.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Nayyeri, Hooshang. “A Study of Massive and Evolved Galaxies at z>3.” 2014. Web. 25 Feb 2020.

Vancouver:

Nayyeri H. A Study of Massive and Evolved Galaxies at z>3. [Internet] [Thesis]. University of California – Riverside; 2014. [cited 2020 Feb 25]. Available from: http://www.escholarship.org/uc/item/7379d0g5.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Nayyeri H. A Study of Massive and Evolved Galaxies at z>3. [Thesis]. University of California – Riverside; 2014. Available from: http://www.escholarship.org/uc/item/7379d0g5

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of California – Berkeley

13. Newman, Sarah. Galactic Winds and Structure of z~2 Star-forming Galaxies.

Degree: Astrophysics, 2013, University of California – Berkeley

URL: http://www.escholarship.org/uc/item/93c8g0n1

► Galactic-scale outflows are a key driver of galaxy evolution through their feedback effect on star-formation and their ejection of metals and energy into the inter-galactic… (more)

▼ Galactic-scale outflows are a key driver of galaxy evolution through their feedback effect on star-formation and their ejection of metals and energy into the inter-galactic medium (IGM). While it is known that outflows likely play an important role in the quenching of star-formation - transforming actively star-forming, blue galaxies into their `red and dead' counterparts - this role is currently not well understood. In particular, at z~2, during the most active epoch of star-formation, the mass and energy in these outflows is poorly constrained, as is the mechanism for launching them. Furthermore, active-galactic nuclei (AGN) in the centers of massive star-forming galaxies (SFGs) likely play an important role in star-formation quenching, but we do not have a clear understanding of how this AGN feedback compares with that of star-formation driven feedback, and it is not known how many of these massive SFGs at z~2 even have AGN. This issue is complicated by the fact that many high-z AGN are likely highly obscured, and have strong nebular emission line contributions from both star-formation and the AGN.In this dissertation, I explore these issues using high-spatial and spectral resolution integral field unit spectroscopic data of z~2 SFGs. The observations are obtained with the instrument SINFONI on the European Southern Observatory (ESO) Very Large Telescope (VLT) at Cerro Paranal. These high-quality data allow spatially-resolved studies of the gas-phase kinematics of these galaxies, as well dynamical information on their outflows. In this work, I explore outflow properties in one galaxy with exceptionally deep data, allowing detailed examination of the outflow energetics, spatial extent and underlying ISM properties, as well those from a larger sample of galaxies. I also probe the fraction of SFGs in our sample which contain (possibly obscured) AGN, and study how this affects our determination of galaxy properties, such as gas-phase metallicity. Finally, I study a subsample of z~2 galaxies whose turbulent velocities dominate the kinematic signature, and examine the link between the overall evolution of z~2 galaxies and the systems we see today. Together this body of work explores how galactic-scale outflows in z~2 SFGs are launched, effect the IGM and eventually shape the evolution of their host galaxies.

Subjects/Keywords: Astronomy

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Newman, S. (2013). Galactic Winds and Structure of z~2 Star-forming Galaxies. (Thesis). University of California – Berkeley. Retrieved from http://www.escholarship.org/uc/item/93c8g0n1

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Newman, Sarah. “Galactic Winds and Structure of z~2 Star-forming Galaxies.” 2013. Thesis, University of California – Berkeley. Accessed February 25, 2020. http://www.escholarship.org/uc/item/93c8g0n1.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Newman, Sarah. “Galactic Winds and Structure of z~2 Star-forming Galaxies.” 2013. Web. 25 Feb 2020.

Vancouver:

Newman S. Galactic Winds and Structure of z~2 Star-forming Galaxies. [Internet] [Thesis]. University of California – Berkeley; 2013. [cited 2020 Feb 25]. Available from: http://www.escholarship.org/uc/item/93c8g0n1.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Newman S. Galactic Winds and Structure of z~2 Star-forming Galaxies. [Thesis]. University of California – Berkeley; 2013. Available from: http://www.escholarship.org/uc/item/93c8g0n1

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

14. McAdam, Margaret M. Water in the Early Solar System| Infrared Studies of Aqueously Altered and Minimally Processed Asteroids.

Degree: 2018, University of Maryland, College Park

URL: http://pqdtopen.proquest.com/#viewpdf?dispub=10623671

► This thesis investigates connections between low albedo asteroids and carbonaceous chondrite meteorites using spectroscopy. Meteorites and asteroids preserve information about the early solar system… (more)

▼ This thesis investigates connections between low albedo asteroids and carbonaceous chondrite meteorites using spectroscopy. Meteorites and asteroids preserve information about the early solar system including accretion processes and parent body processes active on asteroids at these early times. One process of interest is aqueous alteration. This is the chemical reaction between coaccreted water and silicates producing hydrated minerals. Some carbonaceous chondrites have experienced extensive interactions with water through this process. Since these meteorites and their parent bodies formed close to the beginning of the Solar System, these asteroids and meteorites may provide clues to the distribution, abundance and timing of water in the Solar nebula at these times. Chapter 2 of this thesis investigates the relationships between extensively aqueously altered meteorites and their visible, near and mid-infrared spectral features in a coordinated spectral-mineralogical study. Aqueous alteration is a parent body process where initially accreted anhydrous minerals are converted into hydrated minerals in the presence of coaccreted water. Using samples of meteorites with known bulk properties, it is possible to directly connect changes in mineralogy caused by aqueous alteration with spectral features. Spectral features in the mid-infrared are found to change continuously with increasing amount of hydrated minerals or degree of alteration. Building on this result, the degrees of alteration of asteroids are estimated in a survey of new asteroid data obtained from SOFIA and IRTF as well as archived the Spitzer Space Telescope data. 75 observations of 73 asteroids are analyzed and presented in Chapter 4. Asteroids with hydrated minerals are found throughout the main belt indicating that significant ice must have been present in the disk at the time of carbonaceous asteroid accretion. Finally, some carbonaceous chondrite meteorites preserve amorphous iron-bearing materials that formed through disequilibrium condensation in the disk. These materials are readily destroyed in parent body processes so their presence indicates the meteorite/asteroid has undergone minimal parent body processes since the time of accretion. Presented in Chapter 3 is the spectral signature of meteorites that preserve significant amorphous iron-bearing materials and the identification of an asteroid, (93) Minerva, that also appears to preserve these materials.

Subjects/Keywords: Astronomy

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APA (6^th Edition):

McAdam, M. M. (2018). Water in the Early Solar System| Infrared Studies of Aqueously Altered and Minimally Processed Asteroids. (Thesis). University of Maryland, College Park. Retrieved from http://pqdtopen.proquest.com/#viewpdf?dispub=10623671

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

McAdam, Margaret M. “Water in the Early Solar System| Infrared Studies of Aqueously Altered and Minimally Processed Asteroids.” 2018. Thesis, University of Maryland, College Park. Accessed February 25, 2020. http://pqdtopen.proquest.com/#viewpdf?dispub=10623671.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

McAdam, Margaret M. “Water in the Early Solar System| Infrared Studies of Aqueously Altered and Minimally Processed Asteroids.” 2018. Web. 25 Feb 2020.

Vancouver:

McAdam MM. Water in the Early Solar System| Infrared Studies of Aqueously Altered and Minimally Processed Asteroids. [Internet] [Thesis]. University of Maryland, College Park; 2018. [cited 2020 Feb 25]. Available from: http://pqdtopen.proquest.com/#viewpdf?dispub=10623671.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

McAdam MM. Water in the Early Solar System| Infrared Studies of Aqueously Altered and Minimally Processed Asteroids. [Thesis]. University of Maryland, College Park; 2018. Available from: http://pqdtopen.proquest.com/#viewpdf?dispub=10623671

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Oulu

15. Nättilä, J. (Joonas). Mass and radius constraints for neutron stars using the cooling tail method.

Degree: 2013, University of Oulu

URL: http://urn.fi/URN:NBN:fi:oulu-201312041966

► Neutron stars (NS) are the most compact objects that can be directly observed. They can be used to study properties of matter at supranuclear densities.… (more)

▼ Neutron stars (NS) are the most compact objects that can be directly observed. They can be used to study properties of matter at supranuclear densities. This in turn gives us information to separate between numerous theoretical equations of states of dense matter. Thermonuclear (type-I) X-ray bursts from low mass X-ray binaries can be used to address this issue. Some of these bursts can be so energetic that they cause the whole photosphere of the NS to expand. The cooling of these photospheric radius expansion bursts can be compared to theoretical atmosphere models to obtain the mass and radius measurements of the NS. These measurements can then be used to differentiate between the different equations of state. We present a set of differential equations needed to compute these atmospheric models. We introduce an exact treatment of Compton scattering via the relativistic integral equation and an angle-dependent redistribution function. Using these equations, we can construct a set of atmosphere models in plane-parallel approximation in a local thermodynamical equilibrium for hot NSs. The emergent spectra is then fitted by a diluted blackbody to obtain the dilution factor w and the colour-correction factor f_c. On the other hand, the observed spectra from X-ray bursting neutron stars are close to thermal and can be fitted with a blackbody with two free parameters: the observed blackbody temperature T_bb and the normalization K. By equating the dilution factor w and the normalization K, we obtain a relation between the theoretical atmosphere models and the observations. This connection is the main idea of the so called cooling tail method. We then introduce a small correction to this method and discuss the consequences. A common problem encountered using this method is that different bursts from a given system can yield completely different mass and radius measurements. This fact casts a doubt on the robustness of the entire method. We study the burst emission from 4U 1608 – 52 at various persistent fluxes. We find a strong dependence of the burst properties on the flux before the burst. Bursts that ignite during the hard state at a low accretion rate show strong evolution of the apparent blackbody radius which is consistent with the model predictions of the neutron star atmosphere models. On the other hand, bursts occurring during the soft state at a higher accretion rate show constant apparent radius, which is inconsistent with the models. We then use the hard state bursts only to constrain the neutron star mass and radius from our set of sources. By taking only the physically relevant results into account, we also get information of the chemical composition of the atmosphere. This then gives us a way to conclude if the atmosphere is hydrogen- or helium-rich. After we know the chemical composition, we constrain the NS radius to be between 12 and 16 km. This implies a stiff equation of state of neutron star matter.

Subjects/Keywords: Astronomy

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Nättilä, J. (. (2013). Mass and radius constraints for neutron stars using the cooling tail method. (Masters Thesis). University of Oulu. Retrieved from http://urn.fi/URN:NBN:fi:oulu-201312041966

Chicago Manual of Style (16^th Edition):

Nättilä, J (Joonas). “Mass and radius constraints for neutron stars using the cooling tail method.” 2013. Masters Thesis, University of Oulu. Accessed February 25, 2020. http://urn.fi/URN:NBN:fi:oulu-201312041966.

MLA Handbook (7^th Edition):

Nättilä, J (Joonas). “Mass and radius constraints for neutron stars using the cooling tail method.” 2013. Web. 25 Feb 2020.

Vancouver:

Nättilä J(. Mass and radius constraints for neutron stars using the cooling tail method. [Internet] [Masters thesis]. University of Oulu; 2013. [cited 2020 Feb 25]. Available from: http://urn.fi/URN:NBN:fi:oulu-201312041966.

Council of Science Editors:

Nättilä J(. Mass and radius constraints for neutron stars using the cooling tail method. [Masters Thesis]. University of Oulu; 2013. Available from: http://urn.fi/URN:NBN:fi:oulu-201312041966

University of Oulu

16. Lesonen, J.-P. (Juho-Petteri). Morphological study of 0.1 ≤ z ≤ 1.3 galaxies:comparison to artificially redshifted local galaxies.

Degree: 2017, University of Oulu

URL: http://urn.fi/URN:NBN:fi:oulu-201711043039

► In this thesis, the goal is to disentangle the real morphological evolution of galaxies from the observational effects, caused by redshift. This was done by… (more)

▼ In this thesis, the goal is to disentangle the real morphological evolution of galaxies from the observational effects, caused by redshift. This was done by taking a sample of ~1300 high-redshift (0.1 ≤ z ≤ 1.3) galaxies, observed with HST (Hubble Space telescope), from the GOODS-south field and then dividing them into six redshift bins of ∆z ≈ 0.2 and further into absolute magnitude bins of ∆M = 0.5. The sample was then matched to low-redshift (z ≤ 0.025) galaxies from the SDSS with the same comoving number density per ∆M-bin to create a sample of galaxies of the possible descendants of the high-redshift galaxies. Spectroscopic redshifts of the high-redshift sample were fetched from data provided by the 3DHST project. The low-redshift sample was then spatially scaled, dimmed and k-corrected to simulate redshift effects caused by the accelerating expansion of space. To appear as observed with the HST, the images were convolved with a new point-spread function (PSF), created by deconvolving the HST PSF with the SDSS PSF. This results in a change of the PSF 2D-distribution and a resolution change from 0.396”/pix (SDSS) to 0.03”/pix (HST). To achieve this the FERENGI and the KCORRECT codes were used. All three (low-redshift, high-redshift, redshifted) samples were then classified both visually and with CAS (concentration, asymmetry, smoothness) parameters. The results were compared between these samples. The redshifting process did not produce clumpy structures in the low-redshift galaxies as seen in real high-redshift galaxies. Visual classification becomes increasingly difficult for z ≥ 0.55. The concentration index hardly changes with redshift. The asymmetry of the high-redshift galaxies seem to be genuinely higher than that of the low-redshift galaxies. The smoothness parameter values increase with redshift, implying an increasing clumpiness, but some of the change could be due to the redshift effects. For the high-redshift sample, all the CAS parameters between redshift bins show very little evolution for a given morphological type and could be used to differentiate between them. We also note that we found a significant amount of “clumpy” galaxy types, already in the nearest redshift bin of 0.1 ≤ z ≤ 0.3, as opposed to previous studies.

Subjects/Keywords: Astronomy

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APA (6^th Edition):

Lesonen, J. -. (. (2017). Morphological study of 0.1 ≤ z ≤ 1.3 galaxies:comparison to artificially redshifted local galaxies. (Masters Thesis). University of Oulu. Retrieved from http://urn.fi/URN:NBN:fi:oulu-201711043039

Chicago Manual of Style (16^th Edition):

Lesonen, J -P (Juho-Petteri). “Morphological study of 0.1 ≤ z ≤ 1.3 galaxies:comparison to artificially redshifted local galaxies.” 2017. Masters Thesis, University of Oulu. Accessed February 25, 2020. http://urn.fi/URN:NBN:fi:oulu-201711043039.

MLA Handbook (7^th Edition):

Lesonen, J -P (Juho-Petteri). “Morphological study of 0.1 ≤ z ≤ 1.3 galaxies:comparison to artificially redshifted local galaxies.” 2017. Web. 25 Feb 2020.

Vancouver:

Lesonen J-(. Morphological study of 0.1 ≤ z ≤ 1.3 galaxies:comparison to artificially redshifted local galaxies. [Internet] [Masters thesis]. University of Oulu; 2017. [cited 2020 Feb 25]. Available from: http://urn.fi/URN:NBN:fi:oulu-201711043039.

Council of Science Editors:

Lesonen J-(. Morphological study of 0.1 ≤ z ≤ 1.3 galaxies:comparison to artificially redshifted local galaxies. [Masters Thesis]. University of Oulu; 2017. Available from: http://urn.fi/URN:NBN:fi:oulu-201711043039

University of Cape Town

17. Aydi, Elias. Multiwavelength studies of classical novae.

Degree: PhD, Astronomy, 2018, University of Cape Town

URL: http://hdl.handle.net/11427/29576

► Classical novae are transient astronomical events resulting from an eruption on the surface of an accreting white dwarf in interacting binary stars, namely cataclysmic variables.… (more)

▼ Classical novae are transient astronomical events resulting from an eruption on the surface of an accreting white dwarf in interacting binary stars, namely cataclysmic variables. These eruptions and their progenitors are ideal astronomical events/objects to study a variety of interesting topics, such as mass-transfer mechanisms, binary evolution, and thermonuclear and radiative emission processes. Novae share some general observational characteristics during their eruption phases, yet each nova is new and can show unique light-curve and spectral developments. Therefore, carrying out detailed multiwavelength studies of individual novae is important to provide an holistic picture of the eruption development with the ultimate aim of a general understanding of the physical mechanisms involved in nova eruptions, as well as the structure and evolutionary condition of their progenitors. This dissertation presents detailed multiwavelength studies of three nova events, namely V5852 Sgr, SMCN 2016-10, and V407 Lup, as a series of chapters (papers). Our data were collected using several ground-based and space telescopes including: high- and mediumresolution optical spectroscopy from SALT, SOAR, and FLOYDS, optical and near-infrared photometry from IRSF, OGLE and SMARTS, UV and X-ray data from Swift, Chandra, and XMM-Newton. In the second chapter, we present an optical and infrared study of the unusual nova V5852 Sgr. This nova is a moderately fast nova showing features of the Fe II spectroscopic type. The light-curve development is unique, showing a combination of several light-curve classes. Estimates of the distance and measurements of the line velocities suggest that the nova might be associated with the Sagittarius stream. If so, it would be the first nova to be discovered in a dwarf spheroidal galaxy. The third chapter presents a multiwavelength study of the very fast nova SMCN 2016-10a. The fast light-curve development suggests that the system hosts a massive white dwarf (& 1.25 M), in good agreement with the high temperature of the super-soft X-ray emission and the turn-on/turn-off time of the super-soft state. At the distance of the Small Magellanic Cloud our measurements suggest that SMCN 2016-10a is the brightest nova in the Small Magellanic Cloud and one of the brightest novae on record, with an absolute maximum magnitude of ∼ −10.5 in the V -band. Chapter four is a multiwavelength study of nova V407 Lup. With a light-curve decline time t2 ≤ 2.9 d, this is one of the fastest known examples and the white dwarf is possibly more massive than 1.25 M. Our set of optical, UV, and X-ray data suggest that this system is an intermediate-polar cataclysmic variable based essentially on the presence of two periodicities (3.57 h and 565 s) in the light-curves. These periodicities are attributed to the orbital period of the binary and rotational period of the white dwarf. The late optical spectra (taken from day 165 post-eruption) show narrow and moving lines of He II and O VI, possibly associated with accretion regions within the… Advisors/Committee Members: Mohamed, Shazrene (advisor), Whitelock, Patricia (advisor).

Subjects/Keywords: Astronomy

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APA (6^th Edition):

Aydi, E. (2018). Multiwavelength studies of classical novae. (Doctoral Dissertation). University of Cape Town. Retrieved from http://hdl.handle.net/11427/29576

Chicago Manual of Style (16^th Edition):

Aydi, Elias. “Multiwavelength studies of classical novae.” 2018. Doctoral Dissertation, University of Cape Town. Accessed February 25, 2020. http://hdl.handle.net/11427/29576.

MLA Handbook (7^th Edition):

Aydi, Elias. “Multiwavelength studies of classical novae.” 2018. Web. 25 Feb 2020.

Vancouver:

Aydi E. Multiwavelength studies of classical novae. [Internet] [Doctoral dissertation]. University of Cape Town; 2018. [cited 2020 Feb 25]. Available from: http://hdl.handle.net/11427/29576.

Council of Science Editors:

Aydi E. Multiwavelength studies of classical novae. [Doctoral Dissertation]. University of Cape Town; 2018. Available from: http://hdl.handle.net/11427/29576

University of Cape Town

18. Genade, Anja. Stellar occultations by bodies in the outer solar system at the South African Astronomical Observatory.

Degree: MSc, Astronomy, 2018, University of Cape Town

URL: http://hdl.handle.net/11427/29637

► Information on the origin and evolutionary processes of the Solar System is harbored by primitive bodies called trans-Neptunian objects (TNOs). Their preserved state is due… (more)

▼ Information on the origin and evolutionary processes of the Solar System is harbored by primitive bodies called trans-Neptunian objects (TNOs). Their preserved state is due to these bodies having orbits at and beyond that of Neptune, as this specific area is considered to be the least thermally modified in the Solar System and could contain a large population of primordial remnants. These archaic remnants not only provide us with information on our infant Solar System, but also improve our understanding of extrasolar planetary formation processes. Stellar occultations by TNOs enable the determination of sizes and shapes with kilometric accuracy (confining albedos, leading us to compositions and densities), the detection of atmospheres down to pressures of a few nanobars, as well as an investigation of the immediate vicinity of the target body (indicating the presence of rings, satellites, jets, comas). These TNOs roam the icy outskirts of our Solar System which, together with their small sizes, make them faint and their stellar occultations short-lived. With a duration ranging from a couple of seconds for small bodies up to a few hundreds of seconds for the larger TNOs, specific imaging cameras combined with Global Positioning devices and optical telescopes, ensure the fast-cadence capture of these events with microsecond timing accuracy. This high-time resolution observing in combination with the relative speed of the star and the occulting body ensures accurate results with resolutions down to the kilometriclevel, which overthrows the resolvability of ground-based telescopes and rivals that of space probes. Here, we present work done by the South African Astronomical Observatory (SAAO) stellar occultation observing program during the period of July 2016 - July 2017. Specifically, we describe the telescopes, instruments and data analysis pipelines that are used for the SAAO stellar occultation program. The stellar occultation results are obtained from the slightly modified, data reducing SHOC pipeline as originally developed by Dr. Marissa Kotze. The SHOC pipeline laid the groundwork for two additional pipelines to be developed and therefore the MORIS instrument on the 3-m IRTF as well as the FLI autoguider cameras mounted on multiple 1-m LCO telescopes are included to provide many opportunities to observe the predicted stellar occultations. These pipelines include reduction features, correct and accurate derivation of timing information, optimization of the signal-to-noise ratio (SNR) through aperture corrected photometry and most important, provide the user with light curve plots of the point sources. The light curves are normalized and individually analyzed for any signs of a positive stellar occultation detection while testing the effects of reduction on the SNR. This is followed by checking the statistical distribution of the data as well as determining a few values for the line-of-sight optical depth. Instrumental deadtimes for the LCO guider cameras are calculated to effectively determine and use time… Advisors/Committee Members: Sickafoose, Amanda A (advisor), Mohamed, Shazrene (advisor).

Subjects/Keywords: Astronomy

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APA (6^th Edition):

Genade, A. (2018). Stellar occultations by bodies in the outer solar system at the South African Astronomical Observatory. (Masters Thesis). University of Cape Town. Retrieved from http://hdl.handle.net/11427/29637

Chicago Manual of Style (16^th Edition):

Genade, Anja. “Stellar occultations by bodies in the outer solar system at the South African Astronomical Observatory.” 2018. Masters Thesis, University of Cape Town. Accessed February 25, 2020. http://hdl.handle.net/11427/29637.

MLA Handbook (7^th Edition):

Genade, Anja. “Stellar occultations by bodies in the outer solar system at the South African Astronomical Observatory.” 2018. Web. 25 Feb 2020.

Vancouver:

Genade A. Stellar occultations by bodies in the outer solar system at the South African Astronomical Observatory. [Internet] [Masters thesis]. University of Cape Town; 2018. [cited 2020 Feb 25]. Available from: http://hdl.handle.net/11427/29637.

Council of Science Editors:

Genade A. Stellar occultations by bodies in the outer solar system at the South African Astronomical Observatory. [Masters Thesis]. University of Cape Town; 2018. Available from: http://hdl.handle.net/11427/29637

Yale University

19. Merritt, Allison Taylor. Characterizing Assembly Histories in the Local Universe with the Dragonfly Telephoto Array.

Degree: 2018, Yale University

URL: http://pqdtopen.proquest.com/#viewpdf?dispub=10783454

► This thesis explores the ways in which observations of the low surface brightness universe can inform our views of galaxy evolution and, specifically, the… (more)

▼ This thesis explores the ways in which observations of the low surface brightness universe can inform our views of galaxy evolution and, specifically, the extent to which galaxies assemble stellar mass through mergers and accretion events. I first present a study of the variation in the stellar halos of galaxies, using data from the Dragonfly Nearby Galaxies Survey (DNGS). The survey consists of wide field, deep (μg > 31 mag aresec^-2) optical imaging of nearby galaxies using the Dragonfly Telephoto Array. The sample in question includes eight spiral galaxies with stellar masses similar to that of the Milky Way, inclinations of 16 – 90 degrees and distances between 7–18 Mpc. I construct stellar mass surface density profiles from the observed g-band surface brightness in combination with the g – r color as a function of radius, and compute the halo fractions from the excess stellar mass (relative to a disk+bulge fit) beyond 5 half-mass radii. I find a mean halo fraction of 0.009 ± 0.005 and a large RMS scatter of 1.01[special characters omitted] dex. The peak-to-peak scatter of the halo fraction is a factor of > 100 – while some galaxies feature strongly structured halos resembling that of M31, three of the eight have halos that are completely undetected in our data. I conclude from this sample that spiral galaxies as a class exhibit a rich variety in stellar halo properties, implying that their assembly histories have been highly non-uniform. I find no convincing evidence for an environmental or stellar mass dependence of the halo fraction in the sample. In addition to being the future building blocks of the stellar halos of galaxies, dwarf satellite galaxies are a key probe of dark matter and of galaxy formation on small scales and of the dark matter halo masses of their central galaxies. They have very low surface brightness, however, which makes it difficult to identify and study them outside of the Local Group. I used the Dragonfly Telephoto Array to search for dwarf galaxies in the field of the massive spiral galaxy M101, and identified seven large, low surface brightness objects in this field, with effective radii of 10-30 arcseconds and central surface brightnesses of μg,0 ~ 25.5 – 27.5 mag aresec^-2. Given their large apparent sizes and low surface brightnesses, these objects would likely be missed by standard galaxy searches in deep fields. Their radial surface brightness profiles are well fit by Sersic profiles with a very low Sersic index (n ~ 0.3 – 0.7). The properties of the sample are similar to those of well-studied dwarf galaxies in the Local Group, such as Sextans I and Phoenix. Finally, follow-up observations of these low surface brightness objects with the Hubble Space Telescope subsequently revealed that three of the seven objects were bonafide satellite galaxies of the M101 group. I show that, unexpectedly, the other four galaxies are ultra-diffuse galaxies in a…

Subjects/Keywords: Astronomy

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APA (6^th Edition):

Merritt, A. T. (2018). Characterizing Assembly Histories in the Local Universe with the Dragonfly Telephoto Array. (Thesis). Yale University. Retrieved from http://pqdtopen.proquest.com/#viewpdf?dispub=10783454

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Merritt, Allison Taylor. “Characterizing Assembly Histories in the Local Universe with the Dragonfly Telephoto Array.” 2018. Thesis, Yale University. Accessed February 25, 2020. http://pqdtopen.proquest.com/#viewpdf?dispub=10783454.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Merritt, Allison Taylor. “Characterizing Assembly Histories in the Local Universe with the Dragonfly Telephoto Array.” 2018. Web. 25 Feb 2020.

Vancouver:

Merritt AT. Characterizing Assembly Histories in the Local Universe with the Dragonfly Telephoto Array. [Internet] [Thesis]. Yale University; 2018. [cited 2020 Feb 25]. Available from: http://pqdtopen.proquest.com/#viewpdf?dispub=10783454.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Merritt AT. Characterizing Assembly Histories in the Local Universe with the Dragonfly Telephoto Array. [Thesis]. Yale University; 2018. Available from: http://pqdtopen.proquest.com/#viewpdf?dispub=10783454

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

20. Reiter, Megan Ruth. Measuring the Physical Properties of Protostellar Outflows from Intermediate-Mass Stars in Feedback-Dominated Regions .

Degree: 2015, University of Arizona

URL: http://hdl.handle.net/10150/560846

► We present new spectroscopy and Hubble Space Telescope imaging of protostellar jets discovered in an Hαsurvey of the Carina Nebula. Near-IR [Fe II] emission from… (more)

▼ We present new spectroscopy and Hubble Space Telescope imaging of protostellar jets discovered in an Hαsurvey of the Carina Nebula. Near-IR [Fe II] emission from these jets traces dense gas that is self-shielded from Lyman continuum photons from nearby O-type stars, but is excited by non-ionizing FUV photons that penetrate the ionization front within the jet. New near-IR [Fe II] images reveal a substantial mass of dense, neutral gas that is not seen in Hαemission from these jets. In some cases, [Fe II] emission traces the jet inside its natal dust pillar, connecting the larger Hαoutflow to the embedded IR source that drives it. New proper motion measurements reveal tangential velocities similar to those typically measured in lower-luminosity sources (100−200 km/s⁻¹). Combining high jet densities and fast outflow speeds leads to mass-loss rate estimates an order of magnitude higher than those derived from the Hαemission measure alone. Higher jet mass-loss rates require higher accretion rates, implying that these jets are driven by intermediate-mass (~ 2−8 M⊙) protostars. For some sources, the mid-IR luminosities of the driving sources are clearly consistent with intermediate-mass protostars; others remain deeply embedded and require long-wavelength, high-resolution images to confirm their luminosity. These outflows are all highly collimated, with opening angles of only a few degrees. With this new view of collimated jets from intermediate-mass protostars, we argue that these jets reflect essentially the same outflow phenomenon seen in low-mass protostars, but that the collimated atomic jet core and the material it sweeps up are irradiated and rendered observable. Thus, the jets in Carina offer strong additional evidence that stars up to ~ 8 M⊙ form by the same accretion mechanisms as low-mass stars. Advisors/Committee Members: Smith, Nathan (advisor), Shirley, Yancy (committeemember), Bieging, John (committeemember), Rieke, George (committeemember), Smith, Nathan (committeemember).

Subjects/Keywords: Astronomy

11 more images…

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APA (6^th Edition):

Reiter, M. R. (2015). Measuring the Physical Properties of Protostellar Outflows from Intermediate-Mass Stars in Feedback-Dominated Regions . (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/560846

Chicago Manual of Style (16^th Edition):

Reiter, Megan Ruth. “Measuring the Physical Properties of Protostellar Outflows from Intermediate-Mass Stars in Feedback-Dominated Regions .” 2015. Doctoral Dissertation, University of Arizona. Accessed February 25, 2020. http://hdl.handle.net/10150/560846.

MLA Handbook (7^th Edition):

Reiter, Megan Ruth. “Measuring the Physical Properties of Protostellar Outflows from Intermediate-Mass Stars in Feedback-Dominated Regions .” 2015. Web. 25 Feb 2020.

Vancouver:

Reiter MR. Measuring the Physical Properties of Protostellar Outflows from Intermediate-Mass Stars in Feedback-Dominated Regions . [Internet] [Doctoral dissertation]. University of Arizona; 2015. [cited 2020 Feb 25]. Available from: http://hdl.handle.net/10150/560846.

Council of Science Editors:

Reiter MR. Measuring the Physical Properties of Protostellar Outflows from Intermediate-Mass Stars in Feedback-Dominated Regions . [Doctoral Dissertation]. University of Arizona; 2015. Available from: http://hdl.handle.net/10150/560846

University of Arizona

21. Baubock, Michael. Effects of Spin on Neutron-Star Observations .

Degree: 2016, University of Arizona

URL: http://hdl.handle.net/10150/621065

► Measurements of neutron-star properties provide a natural way to test models of cold dense matter and theories of gravity. In order to correctly interpret these… (more)

Subjects/Keywords: Astronomy

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APA (6^th Edition):

Baubock, M. (2016). Effects of Spin on Neutron-Star Observations . (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/621065

Chicago Manual of Style (16^th Edition):

Baubock, Michael. “Effects of Spin on Neutron-Star Observations .” 2016. Doctoral Dissertation, University of Arizona. Accessed February 25, 2020. http://hdl.handle.net/10150/621065.

MLA Handbook (7^th Edition):

Baubock, Michael. “Effects of Spin on Neutron-Star Observations .” 2016. Web. 25 Feb 2020.

Vancouver:

Baubock M. Effects of Spin on Neutron-Star Observations . [Internet] [Doctoral dissertation]. University of Arizona; 2016. [cited 2020 Feb 25]. Available from: http://hdl.handle.net/10150/621065.

Council of Science Editors:

Baubock M. Effects of Spin on Neutron-Star Observations . [Doctoral Dissertation]. University of Arizona; 2016. Available from: http://hdl.handle.net/10150/621065

University of Arizona

22. Ballering, Nicholas. Measuring the Structure and Composition of Circumstellar Debris Disks .

Degree: 2016, University of Arizona

URL: http://hdl.handle.net/10150/621759

► In this dissertation, I measure the structure and composition of circumstellar debris disks to probe the underlying planetary systems. In Chapter 1, I provide an… (more)

▼ In this dissertation, I measure the structure and composition of circumstellar debris disks to probe the underlying planetary systems. In Chapter 1, I provide an introduction to the field of debris disks. I highlight our current observational and theoretical understanding of the field, rather than providing a detailed history. This is intended to give the reader context and motivation for the subsequent chapters. I also describe important developments in debris disk science that are not the focus of this dissertation, but are nevertheless vital for a complete overview. In Chapter 2, I describe my analysis of a large sample of cold (≲130 K) debris disks seen in Spitzer/IRS data. Previous work had suggested a common temperature for these disk components, regardless of spectral type. I find that there is trend with spectral type and argue that the locations of cold disks are not set by snow lines, but more likely by the formation/evolution of planets. This work was published in Ballering et al. (2013). In Chapter 3, I turn my focus to the warm (~190 K) debris components identified in Chapter 2 – specifically those exhibiting silicate emission features. I show that these features arise from exozodiacal dust in the habitable zones around these stars. This was published in Ballering et al. (2014). In Chapter 4, I examine the remainder of the warm disks to investigate what mechanism sets their location. I find that for many systems, the locations trace the water snow line in the primordial protoplanetary disk, rather than the current snow line. This favors the interpretation that warm debris components arise from asteroid belts in these systems. This study will be published soon. In Chapter 5, I analyze images of the debris disk around beta Pictoris at five different wavelengths, including in thermal emission and scattered light. I find that matching the disk brightness at all wavelengths constrains the composition of the dust, with a mixture of astronomical silicates and organic refractory material fitting the data well. This was published in Ballering et al. (2016). In Chapter 6, I conclude with a summary of this dissertation and prospects for future progress in these areas. Advisors/Committee Members: Rieke, George (advisor), Rieke, George (committeemember), Su, Kate (committeemember), Apai, Daniel (committeemember), Schneider, Glenn (committeemember), Hinz, Phil (committeemember).

Subjects/Keywords: Astronomy

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APA (6^th Edition):

Ballering, N. (2016). Measuring the Structure and Composition of Circumstellar Debris Disks . (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/621759

Chicago Manual of Style (16^th Edition):

Ballering, Nicholas. “Measuring the Structure and Composition of Circumstellar Debris Disks .” 2016. Doctoral Dissertation, University of Arizona. Accessed February 25, 2020. http://hdl.handle.net/10150/621759.

MLA Handbook (7^th Edition):

Ballering, Nicholas. “Measuring the Structure and Composition of Circumstellar Debris Disks .” 2016. Web. 25 Feb 2020.

Vancouver:

Ballering N. Measuring the Structure and Composition of Circumstellar Debris Disks . [Internet] [Doctoral dissertation]. University of Arizona; 2016. [cited 2020 Feb 25]. Available from: http://hdl.handle.net/10150/621759.

Council of Science Editors:

Ballering N. Measuring the Structure and Composition of Circumstellar Debris Disks . [Doctoral Dissertation]. University of Arizona; 2016. Available from: http://hdl.handle.net/10150/621759

University of Arizona

23. Males, Jared Robert. Towards the Habitable Zone: Direct Imaging of Extrasolar Planets with the Magellan AO System .

Degree: 2013, University of Arizona

URL: http://hdl.handle.net/10150/301763

► One of the most compelling scientific quests ever undertaken is the quest to find life in our Universe somewhere other than Earth. An important piece… (more)

Subjects/Keywords: Astronomy

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APA (6^th Edition):

Males, J. R. (2013). Towards the Habitable Zone: Direct Imaging of Extrasolar Planets with the Magellan AO System . (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/301763

Chicago Manual of Style (16^th Edition):

Males, Jared Robert. “Towards the Habitable Zone: Direct Imaging of Extrasolar Planets with the Magellan AO System .” 2013. Doctoral Dissertation, University of Arizona. Accessed February 25, 2020. http://hdl.handle.net/10150/301763.

MLA Handbook (7^th Edition):

Males, Jared Robert. “Towards the Habitable Zone: Direct Imaging of Extrasolar Planets with the Magellan AO System .” 2013. Web. 25 Feb 2020.

Vancouver:

Males JR. Towards the Habitable Zone: Direct Imaging of Extrasolar Planets with the Magellan AO System . [Internet] [Doctoral dissertation]. University of Arizona; 2013. [cited 2020 Feb 25]. Available from: http://hdl.handle.net/10150/301763.

Council of Science Editors:

Males JR. Towards the Habitable Zone: Direct Imaging of Extrasolar Planets with the Magellan AO System . [Doctoral Dissertation]. University of Arizona; 2013. Available from: http://hdl.handle.net/10150/301763

University of Arizona

24. Teske, Johanna Kavanagh. Connecting the Dots: Investigating Planet Formation and Composition Through Observations of Carbon and Oxygen Species in Stars, Disks, and Planets .

Degree: 2014, University of Arizona

URL: http://hdl.handle.net/10150/318831

► What physical processes and sources of material contribute to exoplanet compositions? Specifically, what roles do the protoplanetary disk composition and structure, and host star abundances… (more)

▼ What physical processes and sources of material contribute to exoplanet compositions? Specifically, what roles do the protoplanetary disk composition and structure, and host star abundances play in the different stages of planet formation? In this thesis, beginning with a brief literature review in Chapter 2, I trace oxygen and carbon species through these stages to inform how, when, and where planets form. In Chapter 3 I describe a study of the molecular emission from the warm inner disks of T Tauri stars, where terrestrial planets likely form. I report moderate correlations between HCN emission strength and both stellar accretion rate (measured from UV or optical excess emission associated with accretion) and X-ray luminosity. These correlations point towards accretion related processes being an important source of disk atmosphere heating, and suggests that efficient H₂O formation and/or UV dissociation of N₂ (both also associated with higher stellar accretion rates) may aid in the production of HCN. Studies following mine have further connected the abundance of HCN versus H₂O to the growth and migration of planetesimals in the disk, which helps control the formation of both giant and terrestrial planets. I shift to an already-formed exoplanet in Chapter 4, where I present optical photometry of the best-observed transiting super-Earth GJ 1214b with the goal of constraining the short-wavelength slope of its transmission spectrum. Most previous observations suggested a flat spectrum from the near-IR to the optical, corresponding to a low-scale-height, high-molecular-weight atmosphere. My observations are in general agreement with these findings, keeping the "door open" for a H₂O-rich atmosphere for GJ 1214b, which other published g-band observations appeared to contradict. Chapters 5-7 of my thesis focus on measuring stellar abundances, particularly C/O ratios, in transiting (mostly) hot Jupiter exoplanet host stars from high resolution optical spectroscopy. Host star abundances may indicate the precursor materials present in the disk and available for incorporation into planets. In hot Jupiters, the C/O ratio affects the partitioning of C in the major observable molecules, making C and O diagnostic of temperature structure and composition. I also demonstrate that extra caution is necessary in deriving carbon and oxygen abundances, especially for cool and metal-rich stars. Though exoplanetary C/O ratios are still uncertain, the more precise abundance analysis possible right now for their host stars can help constrain their formation environments and current compositions. I summarize my graduate school research in Chapter 8, and discuss the next steps I will take in my postdoctoral career. Advisors/Committee Members: Griffith, Caitlin A (advisor), Najita, Joan (advisor), Rieke, George (advisor), Schuler, Simon (advisor), Cunha, Katia (advisor), Griffith, Caitlin A. (committeemember), Rieke, George (committeemember), Cunha, Katia (committeemember), Schuler, Simon (committeemember), Apai, Daniel (committeemember).

Subjects/Keywords: Astronomy

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Teske, J. K. (2014). Connecting the Dots: Investigating Planet Formation and Composition Through Observations of Carbon and Oxygen Species in Stars, Disks, and Planets . (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/318831

Chicago Manual of Style (16^th Edition):

Teske, Johanna Kavanagh. “Connecting the Dots: Investigating Planet Formation and Composition Through Observations of Carbon and Oxygen Species in Stars, Disks, and Planets .” 2014. Doctoral Dissertation, University of Arizona. Accessed February 25, 2020. http://hdl.handle.net/10150/318831.

MLA Handbook (7^th Edition):

Teske, Johanna Kavanagh. “Connecting the Dots: Investigating Planet Formation and Composition Through Observations of Carbon and Oxygen Species in Stars, Disks, and Planets .” 2014. Web. 25 Feb 2020.

Vancouver:

Teske JK. Connecting the Dots: Investigating Planet Formation and Composition Through Observations of Carbon and Oxygen Species in Stars, Disks, and Planets . [Internet] [Doctoral dissertation]. University of Arizona; 2014. [cited 2020 Feb 25]. Available from: http://hdl.handle.net/10150/318831.

Council of Science Editors:

Teske JK. Connecting the Dots: Investigating Planet Formation and Composition Through Observations of Carbon and Oxygen Species in Stars, Disks, and Planets . [Doctoral Dissertation]. University of Arizona; 2014. Available from: http://hdl.handle.net/10150/318831

University of Arizona

25. Penner, Kyle. Haboobs in outer space: the when and where of dust storms in distant galaxies .

Degree: 2014, University of Arizona

URL: http://hdl.handle.net/10150/323445

► Dust grains are a minor component by mass of the interstellar medium of a galaxy. Yet they can be the dominant source of luminosity. At… (more)

▼ Dust grains are a minor component by mass of the interstellar medium of a galaxy. Yet they can be the dominant source of luminosity. At z ∼ 1, the luminosity density of the Universe in the IR is ∼ 10 times higher than it is at z ∼ 0; common high-redshift galaxies have IR luminosities and dust masses that surpass those of even rare low-redshift galaxies. Dusty galaxies must transition to dust-poor galaxies. In this thesis, we attempt to understand the When? and Where? of this transition. We examine the redshift distribution of the cosmic millimeter background and the spatial distributions of dust in high-redshift galaxies. The cosmic millimeter background is the flux surface density, across the entire sky, from dust emission from all galaxies in the Universe. We stack the 1.16mm flux densities of a sample of dusty galaxies to determine the evolution of their contribution to the background. We resolve ∼ 35% of the background at 1.16mm and ∼ 50% of the background at 850 μm. We make two unique predictions for the redshift origins of the total 1.16mm background. Dust is responsible for more than the IR emission from a galaxy. The existence of dust is a necessary but not sufficient condition for the attenuation of a galaxy's intrinsic UV emission; the IR- and emergent UV-emitting regions must be spatially coincident. We establish a relation between the ratio of infrared to UV luminosity and β for dusty galaxies at z ∼ 2, which implies that their regions are coincident. We also argue that the dust is spread on galactic scales. In dust-poor galaxies at low redshift, the amount of dust attenuating the emission from ionizing stars is greater than the amount attenuating the emission from massive but nonionizing stars. For dusty galaxies at z ∼ 1.3, the amounts may be unequal – though this result is subject to the assumption that high-redshift dusty galaxies have the same spatial and grain size distributions as low-redshift dust-poor galaxies. The dust properties of high-redshift galaxies may be more diverse than they are in low-redshift galaxies. Advisors/Committee Members: Dickinson, Mark E (advisor), Jannuzi, Buell T (advisor), Pope, Alexandra (advisor), Dickinson, Mark E. (committeemember), Jannuzi, Buell T. (committeemember), Pope, Alexandra (committeemember), Zaritsky, Dennis (committeemember), Fan, Xiaohui (committeemember).

Subjects/Keywords: Astronomy

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APA (6^th Edition):

Penner, K. (2014). Haboobs in outer space: the when and where of dust storms in distant galaxies . (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/323445

Chicago Manual of Style (16^th Edition):

Penner, Kyle. “Haboobs in outer space: the when and where of dust storms in distant galaxies .” 2014. Doctoral Dissertation, University of Arizona. Accessed February 25, 2020. http://hdl.handle.net/10150/323445.

MLA Handbook (7^th Edition):

Penner, Kyle. “Haboobs in outer space: the when and where of dust storms in distant galaxies .” 2014. Web. 25 Feb 2020.

Vancouver:

Penner K. Haboobs in outer space: the when and where of dust storms in distant galaxies . [Internet] [Doctoral dissertation]. University of Arizona; 2014. [cited 2020 Feb 25]. Available from: http://hdl.handle.net/10150/323445.

Council of Science Editors:

Penner K. Haboobs in outer space: the when and where of dust storms in distant galaxies . [Doctoral Dissertation]. University of Arizona; 2014. Available from: http://hdl.handle.net/10150/323445

University of Arizona

26. Gabor, Jared. Building a Red Sequence in Cosmological Hydrodynamic Simulations .

Degree: 2011, University of Arizona

URL: http://hdl.handle.net/10150/202937

► Despite years of study, the origins of red galaxies are not fully understood in a cosmological context. We develop new models for quenching star-formation and… (more)

▼ Despite years of study, the origins of red galaxies are not fully understood in a cosmological context. We develop new models for quenching star-formation and producing red galaxies in cosmological hydrodynamic simulations. We start with phenomenological models applied in post-processing to previously-run simulations. We focus separately on mergers and hot haloes – akin to “quasar mode” and “radio mode” feedback – as the drivers shutting down star-formation. With appropriate parameter choices, each model can produce a reasonably good match observed color-magnitude diagrams and red galaxy luminosity functions at redshift zero. We uncover some difficulties with these models in general, including red galaxy stellar populations that appear too blue by 0.1 magnitudes in g − r due to a metallicity deficit. Building on the post-processing models, we develop quenching models for simulations that run on-the-fly. Again, we test merger quenching and hot halo quenching separately. We model merger feedback as > 1000 km s⁻¹ winds motivated by observations of post-starburst galaxies, and wemodel hot halo feedback by continuously adding thermal energy to circum-galactic gas in haloes dominated by gas above 250, 000 K. Merger quenching temporarily shuts down starformation, butmerger-remnant galaxies typically resume star-formation with 1− 2 Gyrs thanks to accretion of newfuel fromthe IGM.Hot halo quenching successfully produces a realistic red sequence, providing a good match to the observed red galaxy luminosity function. Despite some minor difficulties with hot halo quenching, we examine its effects in more detail. Specifically, we study the evolution of the simulated red sequence over time. We find that galaxies with stellar mass ∼ 10¹¹M⊙ are the first to populate the red sequence at z ≳ 2, with significantly fewer red galaxies around 10¹⁰M⊙ until z ≈ 0. We show that massive galaxies grow substantially after moving onto the red sequence, primarily through minor mergers. We also examine the relationship between quenching and environment. Advisors/Committee Members: Dave, Romeel (advisor), Impey, Chris (committeemember), Narayanan, Desika (committeemember), Thompson, Rodger (committeemember), Zabludoff, Ann (committeemember), Dave, Romeel (committeemember).

Subjects/Keywords: Astronomy

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APA (6^th Edition):

Gabor, J. (2011). Building a Red Sequence in Cosmological Hydrodynamic Simulations . (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/202937

Chicago Manual of Style (16^th Edition):

Gabor, Jared. “Building a Red Sequence in Cosmological Hydrodynamic Simulations .” 2011. Doctoral Dissertation, University of Arizona. Accessed February 25, 2020. http://hdl.handle.net/10150/202937.

MLA Handbook (7^th Edition):

Gabor, Jared. “Building a Red Sequence in Cosmological Hydrodynamic Simulations .” 2011. Web. 25 Feb 2020.

Vancouver:

Gabor J. Building a Red Sequence in Cosmological Hydrodynamic Simulations . [Internet] [Doctoral dissertation]. University of Arizona; 2011. [cited 2020 Feb 25]. Available from: http://hdl.handle.net/10150/202937.

Council of Science Editors:

Gabor J. Building a Red Sequence in Cosmological Hydrodynamic Simulations . [Doctoral Dissertation]. University of Arizona; 2011. Available from: http://hdl.handle.net/10150/202937

University of Arizona

27. Skemer, Andrew. HIGH SPATIAL RESOLUTION MID-INFRARED STUDIES OF PLANETARY SYSTEMS .

Degree: 2011, University of Arizona

URL: http://hdl.handle.net/10150/202978

► I present the results of six papers related the formation and evolution of planets and planetary systems, all of which are based on high-resolution, ground-based,… (more)

▼ I present the results of six papers related the formation and evolution of planets and planetary systems, all of which are based on high-resolution, ground-based, mid-infrared observations.The first three chapters are studies of T Tauri binaries. T Tauri stars are young, low mass stars, whose disks form the building blocks of extrasolar planets. The first chapter is a study of the 0.68"/0.12" triple system, T Tauri. Our spatially resolved N-band photometry reveals silicate absorption towards one component, T Tau Sa, indicating the presence of an edge-on disk, which is in contrast to the other components. The second chapter is an adaptive optics fed N-band spectroscopy study of the 0.88" binary, UY Aur. We find that the dust grains around UY Aur A are ISM-like, while the mineralogy of the dust around UY Aur B is more uncertain, due to self-extinction. The third chapter presents a survey of spatially resolved silicate spectroscopy for nine T Tauri binaries. We find with 90%-95% confidence that the silicate features of the binaries are more similar than those of randomly paired single stars. This implies that a shared binary property, such as age or composition, is an important parameter in dust grain evolution.The fourth chapter is a study of the planetary system, 2MASS 1207. We explore the source of 2MASS 1207 b's under-luminosity, which has typically been explained as the result of an edge-on disk of large, grey-extincting dust grains. We find that the edge-on disk theory is incompatible with several lines of evidence, and suggest that 2MASS 1207 b's appearance can be explained by a thick cloudy atmosphere, which might be typical among young, planetary systems.The fifth chapter is a study of the white dwarf, Sirius B, which in the context of this thesis is being studied as a post-planetary system. Our N-band imaging demonstrates that Sirius B does not have an infrared excess, in contrast to previous results.The sixth chapter is a study of mid-infrared atmospheric dispersion, which in the context of this thesis is being studied as an effect that will limit the ability of ELTs to image planetary systems. We measure mid-infrared atmospheric dispersion, for the first time, and use our results to confirm theoretical models. Advisors/Committee Members: Close, Laird (advisor), Hinz, Phil (committeemember), Greene, Tom (committeemember), Rieke, George (committeemember), Eisner, Josh (committeemember), Close, Laird (committeemember).

Subjects/Keywords: Astronomy

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Skemer, A. (2011). HIGH SPATIAL RESOLUTION MID-INFRARED STUDIES OF PLANETARY SYSTEMS . (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/202978

Chicago Manual of Style (16^th Edition):

Skemer, Andrew. “HIGH SPATIAL RESOLUTION MID-INFRARED STUDIES OF PLANETARY SYSTEMS .” 2011. Doctoral Dissertation, University of Arizona. Accessed February 25, 2020. http://hdl.handle.net/10150/202978.

MLA Handbook (7^th Edition):

Skemer, Andrew. “HIGH SPATIAL RESOLUTION MID-INFRARED STUDIES OF PLANETARY SYSTEMS .” 2011. Web. 25 Feb 2020.

Vancouver:

Skemer A. HIGH SPATIAL RESOLUTION MID-INFRARED STUDIES OF PLANETARY SYSTEMS . [Internet] [Doctoral dissertation]. University of Arizona; 2011. [cited 2020 Feb 25]. Available from: http://hdl.handle.net/10150/202978.

Council of Science Editors:

Skemer A. HIGH SPATIAL RESOLUTION MID-INFRARED STUDIES OF PLANETARY SYSTEMS . [Doctoral Dissertation]. University of Arizona; 2011. Available from: http://hdl.handle.net/10150/202978

Columbia University

28. Zimmerman, Neil Thomas. High-Contrast Observations with an Integral Field Spectrograph.

Degree: 2011, Columbia University

URL: https://doi.org/10.7916/D8GM8F91

► This thesis is comprised of work carried out during the commissioning phase of Project 1640, a combined coronagraph – integral field spectrograph for Palomar Observatory's adaptive… (more)

Subjects/Keywords: Astronomy

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APA (6^th Edition):

Zimmerman, N. T. (2011). High-Contrast Observations with an Integral Field Spectrograph. (Doctoral Dissertation). Columbia University. Retrieved from https://doi.org/10.7916/D8GM8F91

Chicago Manual of Style (16^th Edition):

Zimmerman, Neil Thomas. “High-Contrast Observations with an Integral Field Spectrograph.” 2011. Doctoral Dissertation, Columbia University. Accessed February 25, 2020. https://doi.org/10.7916/D8GM8F91.

MLA Handbook (7^th Edition):

Zimmerman, Neil Thomas. “High-Contrast Observations with an Integral Field Spectrograph.” 2011. Web. 25 Feb 2020.

Vancouver:

Zimmerman NT. High-Contrast Observations with an Integral Field Spectrograph. [Internet] [Doctoral dissertation]. Columbia University; 2011. [cited 2020 Feb 25]. Available from: https://doi.org/10.7916/D8GM8F91.

Council of Science Editors:

Zimmerman NT. High-Contrast Observations with an Integral Field Spectrograph. [Doctoral Dissertation]. Columbia University; 2011. Available from: https://doi.org/10.7916/D8GM8F91

Columbia University

29. Kreckel, Kathryn Joyce. Gas in Void Galaxies.

Degree: 2011, Columbia University

URL: https://doi.org/10.7916/D8BV7PMR

► Void galaxies, residing within the deepest underdensities of the Cosmic Web, present an ideal population for the study of galaxy formation and evolution in an… (more)

▼ Void galaxies, residing within the deepest underdensities of the Cosmic Web, present an ideal population for the study of galaxy formation and evolution in an environment undisturbed by the complex processes modifying galaxies in clusters and groups, and provide an observational test for theories of cosmological structure formation. We investigate the neutral hydrogen properties (i.e. content, morphology, kinematics) of void galaxies, both individually and systematically, using a combination of observations and simulations, to form a more complete understanding of the nature of these systems. We investigate in detail the H I morphology and kinematics of two void galaxies. One is an isolated polar disk galaxy in a diffuse cosmological wall situated between two voids. The considerable gas mass and apparent lack of stars in the polar disk, coupled with the general underdensity of the environment, supports recent theories of cold flow accretion as an alternate formation mechanism for polar disk galaxies. We also examine KK 246, the only confirmed galaxy located within the nearby Tully Void. It is a dwarf galaxy with an extremely extended H I disk and signs of an H I cloud with anomalous velocity. It also exhibits clear misalignment between the kinematical major and minor axes, and a general misalignment between the H I and optical major axes. The relative isolation and extreme underdense environment make these both very interesting cases for examining the role of gas accretion in galaxy evolution. To study void galaxies as a population, we have carefully selected a sample of 60 galaxies that reside in the deepest underdensities of geometrically identified voids within the SDSS. We have imaged this new Void Galaxy Survey in H I at the Westerbork Synthesis Radio Telescope with a typical resolution of 8 kpc, probing a volume of 1.2 Mpc and 12,000 km s^-1 surrounding each galaxy. We reach H I mass limits of 2 x 10⁸ M_sun and column density sensitivities of 5 x 10¹⁹ cm^-2. We find that the void galaxies are generally gas rich, low luminosity, blue disk galaxies, but identify three as early type galaxies. The void galaxy optical and H I properties are not unusual for their luminosity and morphology. The small scale clustering in the void is similar to that in higher density regions, and we identify 18 H I rich neighboring galaxies in the voids. Two of these are systems of three galaxies linearly aligned and joined by a H I bridge, suggestive of filamentary formation within the void. We find no population of H I rich low luminosity galaxies within the observed voids that are not close companions of the targeted sample. Finally, to put these observations in a theoretical context, we analyze a (120 h^-1 Mpc)³ adaptive mesh refinement hydrodynamic simulation that contains a high resolution subvolume centered on a ~30 Mpc diameter void. We construct mock observations with ~1 kpc resolution of the stellar and gas properties of these systems which reproduce the range of colors and luminosities observed in the SDSS for nearby…

Subjects/Keywords: Astronomy

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APA (6^th Edition):

Kreckel, K. J. (2011). Gas in Void Galaxies. (Doctoral Dissertation). Columbia University. Retrieved from https://doi.org/10.7916/D8BV7PMR

Chicago Manual of Style (16^th Edition):

Kreckel, Kathryn Joyce. “Gas in Void Galaxies.” 2011. Doctoral Dissertation, Columbia University. Accessed February 25, 2020. https://doi.org/10.7916/D8BV7PMR.

MLA Handbook (7^th Edition):

Kreckel, Kathryn Joyce. “Gas in Void Galaxies.” 2011. Web. 25 Feb 2020.

Vancouver:

Kreckel KJ. Gas in Void Galaxies. [Internet] [Doctoral dissertation]. Columbia University; 2011. [cited 2020 Feb 25]. Available from: https://doi.org/10.7916/D8BV7PMR.

Council of Science Editors:

Kreckel KJ. Gas in Void Galaxies. [Doctoral Dissertation]. Columbia University; 2011. Available from: https://doi.org/10.7916/D8BV7PMR

Columbia University

30. Schroeder, Joshua. Observing and Modeling the Optical Counterparts of Short-Period Binary Millisecond Pulsars.

Degree: 2014, Columbia University

URL: https://doi.org/10.7916/D8BC3WRP

► In this dissertation, I explore the subject of short-period binary millisecond pulsars discovered by the Fermi Gamma-ray Space Telescope and radio follow-up teams, and present… (more)

▼ In this dissertation, I explore the subject of short-period binary millisecond pulsars discovered by the Fermi Gamma-ray Space Telescope and radio follow-up teams, and present observations of fields containing eight recently discovered short-period (Porb < 1 d) binary millisecond pulsars using the telescopes at MDM Observatory. The goal of these observations was to detect the optical counterparts of the binaries and, for the best-suited counterparts detected, to observe the photometric variation of the companion that happens over the course of the orbit in various filters. The hope was to then use the light curves to model the systems and obtain constraints on the mass of the neutron stars which are likely to be some of the most massive neutron stars in the galaxy. Optical counterparts to four of these systems are detected, one of which, PSR J2214+3000, is a novel detection. Additionally, I present the fully orbital phase-resolved B, V , and R light curves of the optical counterparts to two objects, PSR J1810+1744 and PSR J2215+5135, for which I employ the ELC model of Orosz & Hauschildt (2000) to measure the unknown system parameters. For PSR J1810+1744 I find that the system parameters cannot be fit even assuming that 100% of the spin-down luminosity of the pulsar is irradiating the secondary, and so radial velocity measurements of this object will be required for the complete solution. However, PSR J2215+5135 exhibits light curves that are extremely well constrained using the ELC model and we find that the mass of the neutron star is constrained by these and the radio observations to be MNS > 1.75 solar masses; at the 3-sigma level. I also find a discrepancy between the model temperature and the measured colors of this object which I interpret as possible evidence for an additional high-temperature source such as a quiescent disk. Given this and the fact that PSR J2215+5135 contains a relatively high mass companion (Mc > 0.1 solar masses), I propose that similar to the binary pulsar systems PSR J1023+0038 and IGR J18245-2452, the pulsar may transition between accretion- and rotation-powered modes.

Subjects/Keywords: Astronomy

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Schroeder, J. (2014). Observing and Modeling the Optical Counterparts of Short-Period Binary Millisecond Pulsars. (Doctoral Dissertation). Columbia University. Retrieved from https://doi.org/10.7916/D8BC3WRP

Chicago Manual of Style (16^th Edition):

Schroeder, Joshua. “Observing and Modeling the Optical Counterparts of Short-Period Binary Millisecond Pulsars.” 2014. Doctoral Dissertation, Columbia University. Accessed February 25, 2020. https://doi.org/10.7916/D8BC3WRP.

MLA Handbook (7^th Edition):

Schroeder, Joshua. “Observing and Modeling the Optical Counterparts of Short-Period Binary Millisecond Pulsars.” 2014. Web. 25 Feb 2020.

Vancouver:

Schroeder J. Observing and Modeling the Optical Counterparts of Short-Period Binary Millisecond Pulsars. [Internet] [Doctoral dissertation]. Columbia University; 2014. [cited 2020 Feb 25]. Available from: https://doi.org/10.7916/D8BC3WRP.

Council of Science Editors:

Schroeder J. Observing and Modeling the Optical Counterparts of Short-Period Binary Millisecond Pulsars. [Doctoral Dissertation]. Columbia University; 2014. Available from: https://doi.org/10.7916/D8BC3WRP

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