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Series

2016

University of Kentucky

Astrophysics and Astronomy

Articles 1 - 30 of 45

Full-Text Articles in Physical Sciences and Mathematics

Sdss-Iv Manga: Spatially Resolved Star Formation Histories In Galaxies As A Function Of Galaxy Mass And Type, D. Goddard, D. Thomas, C. Maraston, K. Westfall, J. Etherington, R. Riffel, M. D. Mallmann, Z. Zheng, M. Argudo-Fernández, J. Lian, M. Bershady, K. Bundy, N. Drory, D. Law, Renbin Yan, D. Wake, A. Weijmans, D. Bizyaev, J. Brownstein, R. R. Lane, R. Maiolino, K. Masters, M. Merrifield, C. Nitschelm, K. Pan, A. Roman-Lopes, T. Storchi-Bergmann, D. P. Schneider Dec 2016

Sdss-Iv Manga: Spatially Resolved Star Formation Histories In Galaxies As A Function Of Galaxy Mass And Type, D. Goddard, D. Thomas, C. Maraston, K. Westfall, J. Etherington, R. Riffel, M. D. Mallmann, Z. Zheng, M. Argudo-Fernández, J. Lian, M. Bershady, K. Bundy, N. Drory, D. Law, Renbin Yan, D. Wake, A. Weijmans, D. Bizyaev, J. Brownstein, R. R. Lane, R. Maiolino, K. Masters, M. Merrifield, C. Nitschelm, K. Pan, A. Roman-Lopes, T. Storchi-Bergmann, D. P. Schneider

Physics and Astronomy Faculty Publications

We study the internal gradients of stellar population properties within 1.5 Re for a representative sample of 721 galaxies, with stellar masses ranging between 109 M⊙ and 1011.5 M⊙ from the SDSS-IV MaNGA Integral-Field-Unit survey. Through the use of our full spectral fitting code firefly, we derive light- and mass-weighted stellar population properties and their radial gradients, as well as full star formation and metal enrichment histories. We also quantify the impact that different stellar population models and full spectral fitting routines have on the derived stellar population properties and the radial gradient measurements. In …

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Sdss-Iv Manga: The Impact Of Diffuse Ionized Gas On Emission-Line Ratios, Interpretation Of Diagnostic Diagrams And Gas Metallicity Measurements, Kai Zhang, Renbin Yan, Kevin Bundy, Matthew Bershady, L. Matthew Haffner, René Walterbos, Roberto Maiolino, Christy Tremonti, Daniel Thomas, Niv Drory, Amy Jones, Francesco Belfiore, Sebastian F. Sánchez, Aleksandar M. Diamond-Stanic, Dmitry Bizyaev, Christian Nitschelm, Brett Andrews, Jon Brinkmann, Joel R. Brownstein, Edmond Cheung, Cheng Li, David R. Law, Alexandre Roman Lopes, Daniel Oravetz, Kaike Pan, Thaisa Storchi Bergmann, Audrey Simmons Dec 2016

Sdss-Iv Manga: The Impact Of Diffuse Ionized Gas On Emission-Line Ratios, Interpretation Of Diagnostic Diagrams And Gas Metallicity Measurements, Kai Zhang, Renbin Yan, Kevin Bundy, Matthew Bershady, L. Matthew Haffner, René Walterbos, Roberto Maiolino, Christy Tremonti, Daniel Thomas, Niv Drory, Amy Jones, Francesco Belfiore, Sebastian F. Sánchez, Aleksandar M. Diamond-Stanic, Dmitry Bizyaev, Christian Nitschelm, Brett Andrews, Jon Brinkmann, Joel R. Brownstein, Edmond Cheung, Cheng Li, David R. Law, Alexandre Roman Lopes, Daniel Oravetz, Kaike Pan, Thaisa Storchi Bergmann, Audrey Simmons

Physics and Astronomy Faculty Publications

Diffuse ionized gas (DIG) is prevalent in star-forming galaxies. Using a sample of 365 nearly face-on star-forming galaxies observed by Mapping Nearby Galaxies at APO, we demonstrate how DIG in star-forming galaxies impacts the measurements of emission-line ratios, hence the interpretation of diagnostic diagrams and gas-phase metallicity measurements. At fixed metallicity, DIG-dominated low ΣHα regions display enhanced [S II]/Hα, [N II]/Hα, [O II]/Hβ and [O I]/Hα. The gradients in these line ratios are determined by metallicity gradients and ΣHα. In line ratio diagnostic diagrams, contamination by DIG moves H II …

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Sdss-Iv Manga – The Spatially Resolved Transition From Star Formation To Quiescence, Francesco Belfiore, Roberto Maiolino, Claudia Maraston, Eric Emsellem, Matthew A. Bershady, Karen L. Masters, Dmitry Bizyaev, Médéric Boquien, Joel R. Brownstein, Kevin Bundy, Aleksandar M. Diamond-Stanic, Niv Drory, Timothy M. Heckman, David R. Law, Olena Malanushenko, Audrey Oravetz, Kaike Pan, Alexandre Roman-Lopes, Daniel Thomas, Anne-Marie Weijmans, Kyle B. Westfall, Renbin Yan Dec 2016

Sdss-Iv Manga – The Spatially Resolved Transition From Star Formation To Quiescence, Francesco Belfiore, Roberto Maiolino, Claudia Maraston, Eric Emsellem, Matthew A. Bershady, Karen L. Masters, Dmitry Bizyaev, Médéric Boquien, Joel R. Brownstein, Kevin Bundy, Aleksandar M. Diamond-Stanic, Niv Drory, Timothy M. Heckman, David R. Law, Olena Malanushenko, Audrey Oravetz, Kaike Pan, Alexandre Roman-Lopes, Daniel Thomas, Anne-Marie Weijmans, Kyle B. Westfall, Renbin Yan

Physics and Astronomy Faculty Publications

Using spatially resolved spectroscopy from SDSS-IV MaNGA we have demonstrated that low ionization emission-line regions (LIERs) in local galaxies result from photoionization by hot evolved stars, not active galactic nuclei, hence tracing galactic region hosting old stellar population where, despite the presence of ionized gas, star formation is no longer occurring. LIERs are ubiquitous in both quiescent galaxies and in the central regions of galaxies where star formation takes place at larger radii. We refer to these two classes of galaxies as extended LIER (eLIER) and central LIER (cLIER) galaxies, respectively. cLIERs are late-type galaxies primarily spread across the green …

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Sdss-Iv Manga: A Serendipitous Observation Of A Potential Gas Accretion Event, Edmond Cheung, David V. Stark, Song Huang, Kate H. R. Rubin, Lihwai Lin, Christy Tremonti, Kai Zhang, Renbin Yan, Dmitry Bizyaev, Médéric Boquien Nov 2016

Sdss-Iv Manga: A Serendipitous Observation Of A Potential Gas Accretion Event, Edmond Cheung, David V. Stark, Song Huang, Kate H. R. Rubin, Lihwai Lin, Christy Tremonti, Kai Zhang, Renbin Yan, Dmitry Bizyaev, Médéric Boquien

Physics and Astronomy Faculty Publications

The nature of warm, ionized gas outside of galaxies may illuminate several key galaxy evolutionary processes. A serendipitous observation by the MaNGA survey has revealed a large, asymmetric Hα complex with no optical counterpart that extends ≈8'' (≈6.3 kpc) beyond the effective radius of a dusty, starbursting galaxy. This Hα extension is approximately three times the effective radius of the host galaxy and displays a tail-like morphology. We analyze its gas-phase metallicities, gaseous kinematics, and emission-line ratios and discuss whether this Hα extension could be diffuse ionized gas, a gas accretion event, or something else. We find …

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Sdss-Iv Manga Ifs Galaxy Survey—Survey Design, Execution, And Initial Data Quality, Renbin Yan, Kevin Bundy, David R. Law, Matthew A. Bershady, Brett Andrews, Brian Cherinka, Aleksandar M. Diamond-Stanic, Niv Drory, Nicholas Macdonald, José R. Sánchez-Gallego, Daniel Thomas, David A. Wake, Anne-Marie Weijmans, Kyle B. Westfall, Kai Zhang, Alfonso Aragón-Salamanca, Francesco Belfiore, Dmitry Bizyaev, Guillermo A. Blanc, Michael R. Blanton, Joel Brownstein, Michele Cappellari, Richard D'Souza, Eric Emsellem, Hai Fu, Patrick Gaulme, Mark T. Graham, Daniel Goddard, James E. Gunn, Paul Harding Nov 2016

Sdss-Iv Manga Ifs Galaxy Survey—Survey Design, Execution, And Initial Data Quality, Renbin Yan, Kevin Bundy, David R. Law, Matthew A. Bershady, Brett Andrews, Brian Cherinka, Aleksandar M. Diamond-Stanic, Niv Drory, Nicholas Macdonald, José R. Sánchez-Gallego, Daniel Thomas, David A. Wake, Anne-Marie Weijmans, Kyle B. Westfall, Kai Zhang, Alfonso Aragón-Salamanca, Francesco Belfiore, Dmitry Bizyaev, Guillermo A. Blanc, Michael R. Blanton, Joel Brownstein, Michele Cappellari, Richard D'Souza, Eric Emsellem, Hai Fu, Patrick Gaulme, Mark T. Graham, Daniel Goddard, James E. Gunn, Paul Harding

Physics and Astronomy Faculty Publications

The MaNGA Survey (Mapping Nearby Galaxies at Apache Point Observatory) is one of three core programs in the Sloan Digital Sky Survey IV. It is obtaining integral field spectroscopy for 10,000 nearby galaxies at a spectral resolution of R ~ 2000 from 3622 to 10354 Å. The design of the survey is driven by a set of science requirements on the precision of estimates of the following properties: star formation rate surface density, gas metallicity, stellar population age, metallicity, and abundance ratio, and their gradients; stellar and gas kinematics; and enclosed gravitational mass as a function of radius. We describe …

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The Quenching Timescale And Quenching Rate Of Galaxies, Jianhui Lian, Renbin Yan, Kai Zhang, Xu Kong Nov 2016

The Quenching Timescale And Quenching Rate Of Galaxies, Jianhui Lian, Renbin Yan, Kai Zhang, Xu Kong

Physics and Astronomy Faculty Publications

The average star formation rate (SFR) in galaxies has been declining since the redshift of 2. A fraction of galaxies quench and become quiescent. We constrain two key properties of the quenching process: the quenching timescale and the quenching rate among galaxies. We achieve this by analyzing the galaxy number density profile in NUV−u color space and the distribution in NUV−u versus u − i color–color diagram with a simple toy-model framework. We focus on galaxies in three mass bins between 1010 and 1010.6 M ⊙. In the NUV−u versus u − i color–color …

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Holographic Renormalization Of Einstein-Maxwell-Dilaton Theories, Bom Soo Kim Nov 2016

Holographic Renormalization Of Einstein-Maxwell-Dilaton Theories, Bom Soo Kim

Physics and Astronomy Faculty Publications

We generalize the boundary value problem with a mixed boundary condition that involves the gauge and scalar fields in the context of Einstein-Maxwell-Dilaton theories. In particular, the expectation value of the dual scalar operator can be a function of the expectation value of the current operator. The properties are prevalent in a fixed charge ensemble because the conserved charge is shared by both fields through the dilaton coupling, which is also responsible for non-Fermi liquid properties. We study the on-shell action and the stress energy tensor to note practical importances of the boundary value problem. In the presence of the …

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The Intermediate-Line Region In Active Galactic Nuclei, T. P. Adhikari, A. Różańska, B. Czerny, K. Hryniewicz, Gary J. Ferland Oct 2016

The Intermediate-Line Region In Active Galactic Nuclei, T. P. Adhikari, A. Różańska, B. Czerny, K. Hryniewicz, Gary J. Ferland

Physics and Astronomy Faculty Publications

We show that the recently observed suppression of the gap between the broad-line region (BLR) and the narrow-line region (NLR) in some active galactic nuclei (AGNs) can be fully explained by an increase of the gas density in the emitting region. Our model predicts the formation of the intermediate-line region (ILR) that is observed in some Seyfert galaxies by the detection of emission lines with intermediate-velocity FWHM ~ 700–1200 km s−1. These lines are believed to be originating from an ILR located somewhere between the BLR and NLR. As was previously proved, the apparent gap is assumed to …

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Structure And Physical Conditions In The Huygens Region Of The Orion Nebula, C. R. O'Dell, Gary J. Ferland, M. Peimbert Oct 2016

Structure And Physical Conditions In The Huygens Region Of The Orion Nebula, C. R. O'Dell, Gary J. Ferland, M. Peimbert

Physics and Astronomy Faculty Publications

Hubble Space Telescope images, MUSE maps of emission lines, and an atlas of high velocity resolution emission-line spectra have been used to establish for the first time correlations of the electron temperature, electron density, radial velocity, turbulence, and orientation within the main ionization front of the nebula. From the study of the combined properties of multiple features, it is established that variations in the radial velocity are primarily caused by the photoevaporating ionization front being viewed at different angles. There is a progressive increase of the electron temperature and density with decreasing distance from the dominant ionizing star θ1 …

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Sdss-Iv Manga: Stellar Population Gradients As A Function Of Galaxy Environment, D. Goddard, D. Thomas, C. Maraston, K. Westfall, J. Etherington, R. Riffel, M. D. Mallmann, Z. Zheng, M. Argudo-Fernández, M. A. Bershady, K. Bundy, N. Drory, D. Law, Renbin Yan, D. Wake, A. Weijmans, D. Bizyaev, J. Brownstein, R. R. Lane, R. Maiolino, K. Masters, M. Merrifield, C. Nitschelm, K. Pan, A. Roman-Lopes, T. Storchi-Bergmann Oct 2016

Sdss-Iv Manga: Stellar Population Gradients As A Function Of Galaxy Environment, D. Goddard, D. Thomas, C. Maraston, K. Westfall, J. Etherington, R. Riffel, M. D. Mallmann, Z. Zheng, M. Argudo-Fernández, M. A. Bershady, K. Bundy, N. Drory, D. Law, Renbin Yan, D. Wake, A. Weijmans, D. Bizyaev, J. Brownstein, R. R. Lane, R. Maiolino, K. Masters, M. Merrifield, C. Nitschelm, K. Pan, A. Roman-Lopes, T. Storchi-Bergmann

Physics and Astronomy Faculty Publications

We study the internal radial gradients of stellar population properties within 1.5 Re and analyse the impact of galaxy environment. We use a representative sample of 721 galaxies with masses ranging between 109 M⊙ and 1011.5 M⊙ from the SDSS-IV survey MaNGA. We split this sample by morphology into early-type and late-type galaxies. Using the full spectral fitting code firefly, we derive the light and mass-weighted stellar population properties, age and metallicity, and calculate the gradients of these properties. We use three independent methods to quantify galaxy environment, namely the Nth nearest neighbour, the …

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The Growth Of The Central Region By Acquisition Of Counterrotating Gas In Star-Forming Galaxies, Yan-Mei Chen, Yong Shi, Christy A. Tremonti, Matt Bershady, Michael Merrifield, Eric Emsellem, Yi-Fei Jin, Song Huang, Hai Fu, David A. Wake, Kevin Bundy, David Stark, Lihwai Lin, Maria Argudo-Fernandez, Thaisa Storchi Bergmann, Dmitry Bizyaev, Joel Brownstein, Martin Bureau, John Chisholm, Niv Drory, Qi Guo, Lei Hao, Jian Hu, Cheng Li, Ran Li, Alexandre Roman Lopes, Kai-Ke Pan, Rogemar A Riffel, Daniel Thomas, Lan Wang, Renbin Yan Oct 2016

The Growth Of The Central Region By Acquisition Of Counterrotating Gas In Star-Forming Galaxies, Yan-Mei Chen, Yong Shi, Christy A. Tremonti, Matt Bershady, Michael Merrifield, Eric Emsellem, Yi-Fei Jin, Song Huang, Hai Fu, David A. Wake, Kevin Bundy, David Stark, Lihwai Lin, Maria Argudo-Fernandez, Thaisa Storchi Bergmann, Dmitry Bizyaev, Joel Brownstein, Martin Bureau, John Chisholm, Niv Drory, Qi Guo, Lei Hao, Jian Hu, Cheng Li, Ran Li, Alexandre Roman Lopes, Kai-Ke Pan, Rogemar A Riffel, Daniel Thomas, Lan Wang, Renbin Yan

Physics and Astronomy Faculty Publications

Galaxies grow through both internal and external processes. In about 10% of nearby red galaxies with little star formation, gas and stars are counter-rotating, demonstrating the importance of external gas acquisition in these galaxies. However, systematic studies of such phenomena in blue, star-forming galaxies are rare, leaving uncertain the role of external gas acquisition in driving evolution of blue galaxies. Here, based on new measurements with integral field spectroscopy of a large representative galaxy sample, we find an appreciable fraction of counter-rotators among blue galaxies (9 out of 489 galaxies). The central regions of blue counter-rotators show younger stellar populations …

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Fluctuations In A Cosmology With A Spacelike Singularity And Their Gauge Theory Dual Description, Robert H. Brandenberger, Elisa G. M. Ferreira, Ian A. Morrison, Yi-Fu Cai, Sumit R. Das, Yi Wang Oct 2016

Fluctuations In A Cosmology With A Spacelike Singularity And Their Gauge Theory Dual Description, Robert H. Brandenberger, Elisa G. M. Ferreira, Ian A. Morrison, Yi-Fu Cai, Sumit R. Das, Yi Wang

Physics and Astronomy Faculty Publications

We consider a time-dependent deformation of anti–de Sitter (AdS) space-time which contains a spacelike “singularity”—a spacelike region of high curvature. Making use of the AdS/CFT correspondence we can map the bulk dynamics onto the boundary. The boundary theory has a time dependent coupling constant which becomes small at times when the bulk space-time is highly curved. We investigate the propagation of small fluctuations of a test scalar field from early times before the bulk singularity to late times after the singularity. Under the assumption that the AdS/CFT correspondence extends to deformed AdS space-times, we can map the bulk evolution of …

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Large Linear Magnetoresistance In Heavily-Doped Nb:Srtio3 Epitaxial Thin Films, Hyunwoo Jin, Keundong Lee, Seung-Hyub Baek, Jin-Sang Kim, Byung-Ki Cheong, Bae Ho Park, Sungwon Yoon, B. J. Suh, Changyoung Kim, Sung S. Ambrose Seo, Suyoun Lee Oct 2016

Large Linear Magnetoresistance In Heavily-Doped Nb:Srtio3 Epitaxial Thin Films, Hyunwoo Jin, Keundong Lee, Seung-Hyub Baek, Jin-Sang Kim, Byung-Ki Cheong, Bae Ho Park, Sungwon Yoon, B. J. Suh, Changyoung Kim, Sung S. Ambrose Seo, Suyoun Lee

Physics and Astronomy Faculty Publications

Interaction between electrons has long been a focused topic in condensed-matter physics since it has led to the discoveries of astonishing phenomena, for example, high-Tc superconductivity and colossal magnetoresistance (CMR) in strongly-correlated materials. In the study of strongly-correlated perovskite oxides, Nb-doped SrTiO3 (Nb:SrTiO3) has been a workhorse not only as a conducting substrate, but also as a host possessing high carrier mobility. In this work, we report the observations of large linear magnetoresistance (LMR) and the metal-to-insulator transition (MIT) induced by magnetic field in heavily-doped Nb:STO (SrNb0.2Ti0.8O3) epitaxial thin …

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The Abundance Discrepancy Factor And T2 In Nebulae: Are Non-Thermal Electrons The Culprits?, Gary J. Ferland, W. J. Henney, C. R. O'Dell, M. Peimbert Oct 2016

The Abundance Discrepancy Factor And T2 In Nebulae: Are Non-Thermal Electrons The Culprits?, Gary J. Ferland, W. J. Henney, C. R. O'Dell, M. Peimbert

Physics and Astronomy Faculty Publications

We discuss recent claims that the free electrons in ionized nebulae may not have a significantly Maxwellian velocity distribution. Supra-thermal electrons, electrons with much more energy than is encountered at electron temperatures found in nebulae, may solve the t2/ADF puzzle, the observations that abundances obtained from recombination and collisionally excited lines do not agree, and that different temperature indicators give different results. These non-Maxwellian electrons can be designated by the kappa formalism. We show that the distance over which heating rates change are much longer than the distance supra-thermal electrons can travel, and that the timescale to thermalize …

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The Baryon Cycle At High Redshifts: Effects Of Galactic Winds On Galaxy Evolution In Overdense And Average Regions, Raphael Sadoun, Isaac Shlosman, Jun-Hwan Choi, Emilio Romano-Díaz Sep 2016

The Baryon Cycle At High Redshifts: Effects Of Galactic Winds On Galaxy Evolution In Overdense And Average Regions, Raphael Sadoun, Isaac Shlosman, Jun-Hwan Choi, Emilio Romano-Díaz

Physics and Astronomy Faculty Publications

We employ high-resolution cosmological zoom-in simulations focusing on a high-sigma peak and an average cosmological field at z ~ 6–12 in order to investigate the influence of environment and baryonic feedback on galaxy evolution in the reionization epoch. Strong feedback, e.g., galactic winds, caused by elevated star formation rates (SFRs) is expected to play an important role in this evolution. We compare different outflow prescriptions: (i) constant wind velocity (CW), (ii) variable wind scaling with galaxy properties (VW), and (iii) no outflows (NW). The overdensity leads to accelerated evolution of dark matter and baryonic structures, absent from the "normal" region, …

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High-Velocity Bipolar Molecular Emission From An Agn Torus, Jack F. Gallimore, Moshe Elitzur, Robert Maiolino, Alessandro Marconi, Christopher P. O'Dea, Dieter Lutz, Stefi A. Baum, Robert Nikutta, C. M. V. Impellizzeri, Richard Davies, Amy E. Kimball, Eleonora Sani Sep 2016

High-Velocity Bipolar Molecular Emission From An Agn Torus, Jack F. Gallimore, Moshe Elitzur, Robert Maiolino, Alessandro Marconi, Christopher P. O'Dea, Dieter Lutz, Stefi A. Baum, Robert Nikutta, C. M. V. Impellizzeri, Richard Davies, Amy E. Kimball, Eleonora Sani

Physics and Astronomy Faculty Publications

We have detected in ALMA observations CO J = 6 → 5 emission from the nucleus of the Seyfert galaxy NGC 1068. The low-velocity (up to ±70 km s−1 relative to systemic) CO emission resolves into a 12 × 7 pc structure, roughly aligned with the nuclear radio source. Higher-velocity emission (up to ±400 km s−1) is consistent with a bipolar outflow in a direction nearly perpendicular (≃80°) to the nuclear disk. The position–velocity diagram shows that in addition to the outflow, the velocity field may also contain rotation about the disk axis. These observations provide compelling …

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H-, He-Like Recombination Spectra ‒ Ii. L-Changing Collisions For He Rydberg States, Francisco Guzmán, N. R. Badnell, R. J. R. Williams, P. A. M. Van Hoof, Marios Chatzikos, Gary J. Ferland Sep 2016

H-, He-Like Recombination Spectra ‒ Ii. L-Changing Collisions For He Rydberg States, Francisco Guzmán, N. R. Badnell, R. J. R. Williams, P. A. M. Van Hoof, Marios Chatzikos, Gary J. Ferland

Physics and Astronomy Faculty Publications

Cosmological models can be constrained by determining primordial abundances. Accurate predictions of the He i spectrum are needed to determine the primordial helium abundance to a precision of < 1 per cent in order to constrain big bang nucleosynthesis models. Theoretical line emissivities at least this accurate are needed if this precision is to be achieved. In the first paper of this series, which focused on H ι, we showed that differences in l-changing collisional rate coefficients predicted by three different theories can translate into 10 per cent changes in predictions for H ι spectra. Here, we consider the more complicated case of He atoms, where low-l subshells are not energy degenerate. A criterion for deciding when the energy separation between l subshells is small enough to apply energy-degenerate collisional theories is given. Moreover, for certain conditions, the Bethe approximation originally proposed by …

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The Data Reduction Pipeline For The Sdss-Iv Manga Ifu Galaxy Survey, David R. Law, Brian Cherinka, Renbin Yan, Brett H. Andrews, Matthew A. Bershady, Dmitry Bizyaev, Guillermo A. Blanc, Michael R. Blanton, Adam S. Bolton, Joel R. Brownstein, Kevin Bundy, Yanmei Chen, Niv Drory, Richard D'Souza, Hai Fu, Amy Jones, Guinevere Kauffmann, Nicholas Macdonald, Karen L. Masters, Jeffrey A. Newman, John K. Parejko, José R. Sánchez-Gallego, Sebastian F. Sánchez, David J. Schlegel, Daniel Thomas, David A. Wake, Anne-Marie Weijmans, Kyle B. Westfall, Kai Zhang Sep 2016

The Data Reduction Pipeline For The Sdss-Iv Manga Ifu Galaxy Survey, David R. Law, Brian Cherinka, Renbin Yan, Brett H. Andrews, Matthew A. Bershady, Dmitry Bizyaev, Guillermo A. Blanc, Michael R. Blanton, Adam S. Bolton, Joel R. Brownstein, Kevin Bundy, Yanmei Chen, Niv Drory, Richard D'Souza, Hai Fu, Amy Jones, Guinevere Kauffmann, Nicholas Macdonald, Karen L. Masters, Jeffrey A. Newman, John K. Parejko, José R. Sánchez-Gallego, Sebastian F. Sánchez, David J. Schlegel, Daniel Thomas, David A. Wake, Anne-Marie Weijmans, Kyle B. Westfall, Kai Zhang

Physics and Astronomy Faculty Publications

Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) is an optical fiber-bundle integral-field unit (IFU) spectroscopic survey that is one of three core programs in the fourth-generation Sloan Digital Sky Survey (SDSS-IV). With a spectral coverage of 3622–10354 Å and an average footprint of ~500 arcsec2 per IFU the scientific data products derived from MaNGA will permit exploration of the internal structure of a statistically large sample of 10,000 low-redshift galaxies in unprecedented detail. Comprising 174 individually pluggable science and calibration IFUs with a near-constant data stream, MaNGA is expected to obtain ~100 million raw-frame spectra and ~10 million …

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Jet-Like Correlations With Direct-Photon And Neutral-Pion Triggers At √SNn = 200 Gev, L. Adamczyk, James K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, D. M. Anderson, A. Aparin, D. Arkhipkin, E. C. Aschenauer, Renee H. Fatemi, Suvarna Ramachandran Sep 2016

Jet-Like Correlations With Direct-Photon And Neutral-Pion Triggers At √SNn = 200 Gev, L. Adamczyk, James K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, D. M. Anderson, A. Aparin, D. Arkhipkin, E. C. Aschenauer, Renee H. Fatemi, Suvarna Ramachandran

Physics and Astronomy Faculty Publications

Azimuthal correlations of charged hadrons with direct-photon (γdir) and neutral-pion (π0) trigger particles are analyzed in central Au+Au and minimum-bias p+p collisions at in the STAR experiment. The charged-hadron per-trigger yields at mid-rapidity from central Au+Au collisions are compared with p+p collisions to quantify the suppression in Au+Au collisions. The suppression of the away-side associated-particle yields per γdir trigger is independent of the transverse momentum of the trigger particle (ptrigT), whereas the suppression is smaller at low transverse momentum of the associated charged hadrons ( …

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Sdss-Iv Manga: Properties Of Galaxies With Kinematically Decoupled Stellar And Gaseous Components, Yifei Jin, Yanmei Chen, Yong Shi, C. A. Tremonti, M. A. Bershady, M. Merrifield, E. Emsellem, Hai Fu, D. Wake, K. Bundy, Lihwai Lin, M. Argudo-Fernandez, Song Huang, D. V. Stark, T. Storchi-Bergmann, D. Bizyaev, J. Brownstein, J. Chisholm, Qi Guo, Lei Hao, Jian Hu, Cheng Li, Ran Li, K. L. Masters, E. Malanushenko, Kaike Pan, R. A. Riffel, A. Roman-Lopes, A. Simmons, D. Thomas, Renbin Yan Aug 2016

Sdss-Iv Manga: Properties Of Galaxies With Kinematically Decoupled Stellar And Gaseous Components, Yifei Jin, Yanmei Chen, Yong Shi, C. A. Tremonti, M. A. Bershady, M. Merrifield, E. Emsellem, Hai Fu, D. Wake, K. Bundy, Lihwai Lin, M. Argudo-Fernandez, Song Huang, D. V. Stark, T. Storchi-Bergmann, D. Bizyaev, J. Brownstein, J. Chisholm, Qi Guo, Lei Hao, Jian Hu, Cheng Li, Ran Li, K. L. Masters, E. Malanushenko, Kaike Pan, R. A. Riffel, A. Roman-Lopes, A. Simmons, D. Thomas, Renbin Yan

Physics and Astronomy Faculty Publications

We study the properties of 66 galaxies with kinematically misaligned gas and stars from MaNGA survey. The fraction of kinematically misaligned galaxies varies with galaxy physical parameters, i.e. M*, SFR and sSFR. According to their sSFR, we further classify these 66 galaxies into three categories, 10 star-forming, 26 ‘Green Valley’ and 30 quiescent ones. The properties of different types of kinematically misaligned galaxies are different in that the star-forming ones have positive gradient in Dn4000 and higher gas-phase metallicity, while the green valley/quiescent ones have negative Dn4000 gradients and lower gas-phase metallicity on average. …

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Crystallographically-Oriented Carbon Nanotubes Grown On Few-Layer Graphene Films, Douglas R. Strachan, David P. Hunley Jul 2016

Crystallographically-Oriented Carbon Nanotubes Grown On Few-Layer Graphene Films, Douglas R. Strachan, David P. Hunley

Physics and Astronomy Faculty Patents

A thermal and electrical conducting apparatus includes a few-layer graphene film having a thickness D where D≦1.5 nm and a plurality of carbon nanotubes crystallographically aligned with the few-layer graphene film.

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Crystallographically-Oriented Carbon Nanotubes Grown On Few-Layer Graphene Films, David P. Hunley, Douglas R. Strachan Jul 2016

Crystallographically-Oriented Carbon Nanotubes Grown On Few-Layer Graphene Films, David P. Hunley, Douglas R. Strachan

Physics and Astronomy Faculty Patents

A thermal and electrical conducting apparatus includes a few-layer graphene film having a thickness D where D≦1.5 nm and a plurality of carbon nanotubes crystallographically aligned with the few-layer graphene film.

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Galaxy Zoo: Comparing The Demographics Of Spiral Arm Number And A New Method For Correcting Redshift Bias, Ross E. Hart, Steven P. Bamford, Kyle W. Willett, Karen L. Masters, Carolin Cardamone, Chris J. Lintott, Robert J. Mackay, Robert C. Nichol, Christopher K. Rosslowe, Brooke D. Simmons, Rebecca J. Smethurst Jul 2016

Galaxy Zoo: Comparing The Demographics Of Spiral Arm Number And A New Method For Correcting Redshift Bias, Ross E. Hart, Steven P. Bamford, Kyle W. Willett, Karen L. Masters, Carolin Cardamone, Chris J. Lintott, Robert J. Mackay, Robert C. Nichol, Christopher K. Rosslowe, Brooke D. Simmons, Rebecca J. Smethurst

Physics and Astronomy Faculty Publications

The majority of galaxies in the local Universe exhibit spiral structure with a variety of forms. Many galaxies possess two prominent spiral arms, some have more, while others display a many-armed flocculent appearance. Spiral arms are associated with enhanced gas content and star formation in the discs of low-redshift galaxies, so are important in the understanding of star formation in the local universe. As both the visual appearance of spiral structure, and the mechanisms responsible for it vary from galaxy to galaxy, a reliable method for defining spiral samples with different visual morphologies is required. In this paper, we develop …

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Holographic Chern-Simons Defects, Mitsutoshi Fujita, Charles M. Melby-Thompson, René Meyer, Shigeki Sugimoto Jun 2016

Holographic Chern-Simons Defects, Mitsutoshi Fujita, Charles M. Melby-Thompson, René Meyer, Shigeki Sugimoto

Physics and Astronomy Faculty Publications

We study SU(N ) Yang-Mills-Chern-Simons theory in the presence of defects that shift the Chern-Simons level from a holographic point of view by embedding the system in string theory. The model is a D3-D7 system in Type IIB string theory, whose gravity dual is given by the AdS soliton background with probe D7 branes attaching to the AdS boundary along the defects. We holographically renormalize the free energy of the defect system with sources, from which we obtain the correlation functions for certain operators naturally associated to these defects. We find interesting phase transitions when the separation of the …

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Ultraviolet Emission Lines Of Si Ii In Quasars—Investigating The "Si Ii Disaster", Sibasish Laha, Francis P. Keenan, Gary J. Ferland, Catherine A. Ramsbottom, Kanti M. Aggarwal Jun 2016

Ultraviolet Emission Lines Of Si Ii In Quasars—Investigating The "Si Ii Disaster", Sibasish Laha, Francis P. Keenan, Gary J. Ferland, Catherine A. Ramsbottom, Kanti M. Aggarwal

Physics and Astronomy Faculty Publications

The observed line intensity ratios of the Si II λ1263 and λ1307 multiplets to that of Si II λ1814 in the broad-line region (BLR) of quasars are both an order of magnitude larger than the theoretical values. This was first pointed out by Baldwin et al., who termed it the "Si II disaster," and it has remained unresolved. We investigate the problem in the light of newly published atomic data for Si II. Specifically, we perform BLR calculations using several different atomic data sets within the CLOUDY modeling code under optically thick quasar cloud conditions. In addition, …

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Orion's Veil: Magnetic Field Strengths And Other Properties Of A Pdr In Front Of The Trapezium Cluster, Thomas H. Troland, W. M. Goss, C. L. Brogan, R. M. Crutcher, D. A. Roberts Jun 2016

Orion's Veil: Magnetic Field Strengths And Other Properties Of A Pdr In Front Of The Trapezium Cluster, Thomas H. Troland, W. M. Goss, C. L. Brogan, R. M. Crutcher, D. A. Roberts

Physics and Astronomy Faculty Publications

We present an analysis of physical conditions in the Orion Veil, an atomic photon-dominated region (PDR) that lies just in front (≈2 pc) of the Trapezium stars of Orion. This region offers an unusual opportunity to study the properties of PDRs, including the magnetic field. We have obtained 21 cm H i and 18 cm (1665 and 1667 MHz) OH Zeeman effect data that yield images of the line-of-sight magnetic field strength B los in atomic and molecular regions of the Veil. We find B los ≈ −50 to −75 μG in the atomic gas across much of the …

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Evidence For Fluorescent Fe Ii Emission From Extended Low Ionization Outflows In Obscured Quasars, Tinggui Wang, Gary J. Ferland, Chenwei Yang, Huiyuan Wang, Shaohua Zhang Jun 2016

Evidence For Fluorescent Fe Ii Emission From Extended Low Ionization Outflows In Obscured Quasars, Tinggui Wang, Gary J. Ferland, Chenwei Yang, Huiyuan Wang, Shaohua Zhang

Physics and Astronomy Faculty Publications

Recent studies have shown that outflows in at least some broad absorption line (BAL) quasars are extended well beyond the putative dusty torus. Such outflows should be detectable in obscured quasars. We present four WISE selected infrared red quasars with very strong and peculiar ultraviolet Fe II emission lines: strong UV Fe II UV arising from transitions to ground/low excitation levels, and very weak Fe II at wavelengths longer than 2800 Å. The spectra of these quasars display strong resonant emission lines, such as C IV, Al III and Mg II but sometimes, a lack of non-resonant lines such as …

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Hst Imaging Of The Dusty Filaments And Nucleus Swirl In Ngc4696 At The Centre Of The Centaurus Cluster, A. C. Fabian, S. A. Walker, H. R. Russell, C. Pinto, R. E. A. Canning, P. Salome, J. S. Sanders, G. B. Taylor, E. G. Zweibel, C. J. Conselice, F. Combes, C. S. Crawford, Gary J. Ferland, J. S. Gallagher Iii, N. A. Hatch, R. M. Johnstone, C. S. Reynolds Jun 2016

Hst Imaging Of The Dusty Filaments And Nucleus Swirl In Ngc4696 At The Centre Of The Centaurus Cluster, A. C. Fabian, S. A. Walker, H. R. Russell, C. Pinto, R. E. A. Canning, P. Salome, J. S. Sanders, G. B. Taylor, E. G. Zweibel, C. J. Conselice, F. Combes, C. S. Crawford, Gary J. Ferland, J. S. Gallagher Iii, N. A. Hatch, R. M. Johnstone, C. S. Reynolds

Physics and Astronomy Faculty Publications

Narrow-band HST imaging has resolved the detailed internal structure of the 10 kpc diameter H α+[N II] emission line nebulosity in NGC4696, the central galaxy in the nearby Centaurus cluster, showing that the dusty, molecular, filaments have a width of about 60 pc. Optical morphology and velocity measurements indicate that the filaments are dragged out by the bubbling action of the radio source as part of the active galactic nucleus feedback cycle. Using the drag force we find that the magnetic field in the filaments is in approximate pressure equipartition with the hot gas. The filamentary nature of the …

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Space Telescope And Optical Reverberation Mapping Project. Iv. Anomalous Behavior Of The Broad Ultraviolet Emission Lines In Ngc 5548, M. R. Goad, K. T. Korista, G. De Grosa, G. A. Kriss, R. Edelson, A. J. Barth, Gary J. Ferland, C. S. Kochanek, H. Netzer, B. M. Peterson, M. C. Bentz, S. Bisogni, D. M. Crenshaw, K. D. Denney, J. Ely, M. M. Fausnaugh, C. J. Grier, A. Gupta, K. D. Horne, J. Kaastra, A. Pancoast, L. Pei, R. W. Pogge, A. Skielboe, D. Starkey, M. Vestergaard, Y. Zu, M. D. Anderson, P. Arévalo, C. Bazhaw Jun 2016

Space Telescope And Optical Reverberation Mapping Project. Iv. Anomalous Behavior Of The Broad Ultraviolet Emission Lines In Ngc 5548, M. R. Goad, K. T. Korista, G. De Grosa, G. A. Kriss, R. Edelson, A. J. Barth, Gary J. Ferland, C. S. Kochanek, H. Netzer, B. M. Peterson, M. C. Bentz, S. Bisogni, D. M. Crenshaw, K. D. Denney, J. Ely, M. M. Fausnaugh, C. J. Grier, A. Gupta, K. D. Horne, J. Kaastra, A. Pancoast, L. Pei, R. W. Pogge, A. Skielboe, D. Starkey, M. Vestergaard, Y. Zu, M. D. Anderson, P. Arévalo, C. Bazhaw

Physics and Astronomy Faculty Publications

During an intensive Hubble Space Telescope (HST) Cosmic Origins Spectrograph (COS) UV monitoring campaign of the Seyfert 1 galaxy NGC 5548 performed from 2014 February to July, the normally highly correlated far UV continuum and broad emission line variations decorrelated for ~60–70 days, starting ~75 days after the first HST/COS observation. Following this anomalous state, the flux and variability of the broad emission lines returned to a more normal state. This transient behavior, characterized by significant deficits in flux and equivalent width of the strong broad UV emission lines, is the first of its kind to be unambiguously identified …

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Sdss Iv Manga – Spatially Resolved Diagnostic Diagrams: A Proof That Many Galaxies Are Liers, Francesco Belfiore, Roberto Maiolino, Claudia Maraston, Eric Emsellem, Matthew A. Bershady, Karen L. Masters, Renbin Yan, Dmitry Bizyaev, Médéric Boquien, Joel R. Brownstein, Kevin Bundy, Niv Drory, Timothy M. Heckman, David R. Law, Alexandre Roman-Lopes, Kaike Pan, Letizia Stanghellini, Daniel Thomas, Anne-Marie Weijmans, Kyle B. Westfall May 2016

Sdss Iv Manga – Spatially Resolved Diagnostic Diagrams: A Proof That Many Galaxies Are Liers, Francesco Belfiore, Roberto Maiolino, Claudia Maraston, Eric Emsellem, Matthew A. Bershady, Karen L. Masters, Renbin Yan, Dmitry Bizyaev, Médéric Boquien, Joel R. Brownstein, Kevin Bundy, Niv Drory, Timothy M. Heckman, David R. Law, Alexandre Roman-Lopes, Kaike Pan, Letizia Stanghellini, Daniel Thomas, Anne-Marie Weijmans, Kyle B. Westfall

Physics and Astronomy Faculty Publications

We study the spatially resolved excitation properties of the ionized gas in a sample of 646 galaxies using integral field spectroscopy data from the Sloan Digital Sky Survey IV Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) programme. Making use of Baldwin–Philips–Terlevich diagnostic diagrams we demonstrate the ubiquitous presence of extended (kpc scale) low-ionization emission-line regions (LIERs) in both star-forming and quiescent galaxies. In star-forming galaxies LIER emission can be associated with diffuse ionized gas, most evident as extraplanar emission in edge-on systems. In addition, we identify two main classes of galaxies displaying LIER emission: ‘central LIER’ (cLIER) galaxies, where …

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