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Full-Text Articles in Physics

The Neutral Hydrogen Kinematics Of The Dwarf Galaxy Merger Ngc 3239, Robert N. Ford May 2019

The Neutral Hydrogen Kinematics Of The Dwarf Galaxy Merger Ngc 3239, Robert N. Ford

Macalester Journal of Physics and Astronomy

We present H I spectral line images of the nearby dwarf galaxy NGC 3239. The galaxy’s curious morphology suggests that it is a post-merger system. We propose that NGC 3239 is a merger because it has multiple tidal tails, an enhanced velocity dispersion throughout the disk, and widespread star formation. We have produced kinematic moment maps corresponding to the H I column density, radial velocity, and velocity dispersion. Further, position velocity (P-V) slices of the galaxy were taken and three-color images were made using the SDSS G, R, and I, filters for comparison with the moment maps. These slices ...


Search For Subsolar-Mass Ultracompact Binaries In Advanced Ligo's First Observing Run, B. P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Dec 2018

Search For Subsolar-Mass Ultracompact Binaries In Advanced Ligo's First Observing Run, B. P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

We present the first Advanced LIGO and Advanced Virgo search for ultracompact binary systems with component masses between 0.2 M-1.0 M using data taken between September 12, 2015 and January 19, 2016. We find no viable gravitational wave candidates. Our null result constrains the coalescence rate of monochromatic (delta function) distributions of nonspinning (0.2 M, 0.2 M) ultracompact binaries to be less than 1.0 x 106 Gpc-3 yr-1 and the coalescence rate of a similar distribution of (1.0 M, 1.0 M) ultracompact binaries to be less than 1.9 ...


The Radio Synchrotron Background: Conference Summary And Report, Jack Singal, J. Haider, M. Ajello, D. R. Ballantyne, Emory F. Bunn, J. Condon, J. Dowell, Et. Al. Mar 2018

The Radio Synchrotron Background: Conference Summary And Report, Jack Singal, J. Haider, M. Ajello, D. R. Ballantyne, Emory F. Bunn, J. Condon, J. Dowell, Et. Al.

Physics Faculty Publications

We summarize the radio synchrotron background workshop that took place 2017 July 19–21 at the University of Richmond. This first scientific meeting dedicated to the topic was convened because current measurements of the diffuse radio monopole reveal a surface brightness that is several times higher than can be straightforwardly explained by known Galactic and extragalactic sources and processes, rendering it by far the least well understood photon background at present. It was the conclusion of a majority of the participants that the radio monopole level is at or near that reported by the ARCADE 2 experiment and inferred from ...


Sdss-Iv Manga: Spatially Resolved Star Formation Main Sequence And Li(N)Er Sequence, B. C. Hsieh, Lihwai Lin, J. H. Lin, H. A. Pan, C. H. Hsu, S. F. Sánchez, M. Cano-Díaz, Kai Zhang, Renbin Yan, J. K. Barrera-Ballesteros, M. Boquien, R. Riffel, J. Brownstein, I. Cruz-González, A. Hagen, H. Ibarra, K. Pan, D. Bizyaev, D. Oravetz, A. Simmons Dec 2017

Sdss-Iv Manga: Spatially Resolved Star Formation Main Sequence And Li(N)Er Sequence, B. C. Hsieh, Lihwai Lin, J. H. Lin, H. A. Pan, C. H. Hsu, S. F. Sánchez, M. Cano-Díaz, Kai Zhang, Renbin Yan, J. K. Barrera-Ballesteros, M. Boquien, R. Riffel, J. Brownstein, I. Cruz-González, A. Hagen, H. Ibarra, K. Pan, D. Bizyaev, D. Oravetz, A. Simmons

Physics and Astronomy Faculty Publications

We present our study on the spatially resolved Hα and M* relation for 536 star-forming and 424 quiescent galaxies taken from the MaNGA survey. We show that the star formation rate surface density (ΣSFR), derived based on the Hα emissions, is strongly correlated with the M* surface density (Σ*) on kiloparsec scales for star-forming galaxies and can be directly connected to the global star-forming sequence. This suggests that the global main sequence may be a consequence of a more fundamental relation on small scales. On the other hand, our result suggests that ~20% of quiescent galaxies in ...


An Active Galactic Nucleus Caught In The Act Of Turning Off And On, Julia M. Comerford, R Scott Barrows, Francisco Müller Sánchez, Rebecca Nevin, Jenny E. Greene, David Pooley, Daniel Stern, Fiona A. Harrison Nov 2017

An Active Galactic Nucleus Caught In The Act Of Turning Off And On, Julia M. Comerford, R Scott Barrows, Francisco Müller Sánchez, Rebecca Nevin, Jenny E. Greene, David Pooley, Daniel Stern, Fiona A. Harrison

Physics and Astronomy Faculty Research

We present the discovery of an active galactic nucleus (AGN) that is turning off and then on again in the z = 0.06 galaxy SDSS J1354+1327. This episodic nuclear activity is the result of discrete accretion events that could have been triggered by a past interaction with the companion galaxy that is currently located 12.5 kpc away. We originally targeted SDSS J1354+1327 because its Sloan Digital Sky Survey spectrum has narrow AGN emission lines that exhibit a velocity offset of 69 km s−1 relative to systemic. To determine the nature of the galaxy and its velocity-offset ...


Molecular Tracers Of Star Formation Feedback In Nearby Galaxies, Mark Gorski Sep 2017

Molecular Tracers Of Star Formation Feedback In Nearby Galaxies, Mark Gorski

Physics & Astronomy ETDs

The energy and momentum injected into the ISM from stars has a drastic effect on the star formation history of a galaxy. This is called feedback. It is responsible for the inefficient collapse of the ISM into stars. The ``Survey of Water and Ammonia in Nearby Galaxies" (SWAN) is a survey of molecular line tracers in four nearby galaxies. By using molecular tracers of feedback, we provide insights into the star forming ecosystem of the galaxies NGC 253, IC 342, NGC 6946, and NGC 2146. These galaxies were chosen to span an order of magnitude in star formation rate and ...


Galactic Outflows And Their Correlations With Galaxy Properties At 0.8 < Z < 1.6, Lindsey Whiting Aug 2017

Galactic Outflows And Their Correlations With Galaxy Properties At 0.8 < Z < 1.6, Lindsey Whiting

Theses and Dissertations

Out

ows have been shown to be ubiquitous in galaxies between z = 1 and z=2,

and many models and observations have attempted to correlate the absorption line

properties of these out

ows with morphological characteristics of their host galaxies.

In this study, we examined the spectra of 71 galaxies with redshifts 1< z<2, paying

particular attention to the FeII and MgII absorption lines. We plotted the equivalent

width, velocity, and maximum velocity of the absorption features against various

physical properties of the galaxies, obtained from catalogues created by Skelton et

al., (2014) and van der Wel et al., (2012). We conrmed ...


The Validity Of 21 Cm Spin Temperature As A Kinetic Temperature Indicator In Atomic And Molecular Gas, Gargi Shaw, Gary J. Ferland, I. Hubeny Jul 2017

The Validity Of 21 Cm Spin Temperature As A Kinetic Temperature Indicator In Atomic And Molecular Gas, Gargi Shaw, Gary J. Ferland, I. Hubeny

Physics and Astronomy Faculty Publications

The gas kinetic temperature (TK) of various interstellar environments is often inferred from observations that can deduce level populations of atoms, ions, or molecules using spectral line observations; H I 21 cm is perhaps the most widely used, and has a long history. Usually the H I 21 cm line is assumed to be in thermal equilibrium and the populations are given by the Boltzmann distribution. A variety of processes, many involving Lyα, can affect the 21 cm line. Here we show how this is treated in the spectral simulation code Cloudy, and present numerical simulations of environments ...


Sloan Digital Sky Survey Iv: Mapping The Milky Way, Nearby Galaxies, And The Distant Universe, Michael R. Blanton, Matthew A. Bershady, Bela Abolfathi, Franco D. Albareti, Carlos Allende Prieto, Andres Almeida, Javier Alonso-García, Friedrich Anders, Scott F. Anderson, Brett Andrews, Erik Aquino-Ortíz, Alfonso Aragón-Salamanca, Maria Argudo-Fernández, Eric Armengaud, Eric Aubourg, Vladimir Avila-Reese, Carles Badenes, Stephen Bailey, Kathleen A. Barger, Jorge Barrera-Ballesteros, Curtis Bartosz, Dominic Bates, Falk Baumgarten, Julian Bautista, Rachael Beaton, Francesco Belfiore, Chad F. Bender, Andreas A. Berlind, Mariangela Bernardi, Florian Beutler, Renbin Yan, Daniel Lazarz, Kai Zhang Jun 2017

Sloan Digital Sky Survey Iv: Mapping The Milky Way, Nearby Galaxies, And The Distant Universe, Michael R. Blanton, Matthew A. Bershady, Bela Abolfathi, Franco D. Albareti, Carlos Allende Prieto, Andres Almeida, Javier Alonso-García, Friedrich Anders, Scott F. Anderson, Brett Andrews, Erik Aquino-Ortíz, Alfonso Aragón-Salamanca, Maria Argudo-Fernández, Eric Armengaud, Eric Aubourg, Vladimir Avila-Reese, Carles Badenes, Stephen Bailey, Kathleen A. Barger, Jorge Barrera-Ballesteros, Curtis Bartosz, Dominic Bates, Falk Baumgarten, Julian Bautista, Rachael Beaton, Francesco Belfiore, Chad F. Bender, Andreas A. Berlind, Mariangela Bernardi, Florian Beutler, Renbin Yan, Daniel Lazarz, Kai Zhang

Physics and Astronomy Faculty Publications

We describe the Sloan Digital Sky Survey IV (SDSS-IV), a project encompassing three major spectroscopic programs. The Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) is observing hundreds of thousands of Milky Way stars at high resolution and high signal-to-noise ratios in the near-infrared. The Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey is obtaining spatially resolved spectroscopy for thousands of nearby galaxies (median z ~ 0.03). The extended Baryon Oscillation Spectroscopic Survey (eBOSS) is mapping the galaxy, quasar, and neutral gas distributions between z ~ 0.6 and 3.5 to constrain cosmology using baryon acoustic oscillations, redshift space ...


Spatially Offset Active Galactic Nuclei. Ii. Triggering In Galaxy Mergers, R Scott Barrows, Julia M. Comerford, Jenny E. Greene, David Pooley Apr 2017

Spatially Offset Active Galactic Nuclei. Ii. Triggering In Galaxy Mergers, R Scott Barrows, Julia M. Comerford, Jenny E. Greene, David Pooley

Physics and Astronomy Faculty Research

Galaxy mergers are likely to play a role in triggering active galactic nuclei (AGNs), but the conditions under which this process occurs are poorly understood. In Paper I, we constructed a sample of spatially offset X-ray AGNs that represent galaxy mergers hosting a single AGN. In this paper, we use our offset AGN sample to constrain the parameters that affect AGN observability in galaxy mergers. We also construct dual-AGN samples with similar selection properties for comparison. We find that the offset AGN fraction shows no evidence for a dependence on AGN luminosity, while the dual-AGN fractions show stronger evidence for ...


The Mid-Infrared Luminosity Evolution And Luminosity Function Of Quasars With Wise And Sdss, Jack Singal Nov 2016

The Mid-Infrared Luminosity Evolution And Luminosity Function Of Quasars With Wise And Sdss, Jack Singal

Physics Faculty Publications

We determine the 22 μm luminosity evolution and luminosity function for quasars from a data set of over 20,000 objects obtained by combining flux-limited Sloan Digital Sky Survey optical and Wide field Infrared Survey Explorer mid-infrared data. We apply methods developed in previous works to access the intrinsic population distributions non-parametrically, taking into account the truncations and correlations inherent in the data. We find that the population of quasars exhibits positive luminosity evolution with redshift in the mid-infrared, but with considerably less mid-infrared evolution than in the optical or radio bands. With the luminosity evolutions accounted for, we ...


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 ...


Reconciling Ag-Star Formation, The Soltan Argument, And Meier's Paradox, David Garofalo, Matthew I. Kim, Damian J. Christian, Emily Hollingworth Jan 2016

Reconciling Ag-Star Formation, The Soltan Argument, And Meier's Paradox, David Garofalo, Matthew I. Kim, Damian J. Christian, Emily Hollingworth

Faculty Publications

We provide a theoretical context for understanding the recent work of Kalfountzou et al. showing that star formation is enhanced at lower optical luminosity in radio-loud quasars. Our proposal for coupling the assumption of collimated FRII quasar-jet-induced star formation with lower accretion optical luminosity also explains the observed jet power peak in active galaxies at higher redshift compared to the peak in accretion power, doing so in a way that predicts the existence of a family of radio-quiet active galactic nuclei associated with rapidly spinning supermassive black holes at low redshift, as mounting observations suggest. The relevance of this work ...


The Evolutionary Pathways Of Tidal Disruption Events: From Stars To Debris Streams, Accretion Disks, And Relativistic Jets, Eric Robert Coughlin Jan 2016

The Evolutionary Pathways Of Tidal Disruption Events: From Stars To Debris Streams, Accretion Disks, And Relativistic Jets, Eric Robert Coughlin

Astrophysical & Planetary Sciences Graduate Theses & Dissertations

Tidal disruption events, which occur when a star is destroyed by the gravitational field of a supermassive black hole, are unique probes of the inner regions of galaxies. In this thesis we explore various stages of the tidal disruption process, in an attempt to relate the observable signatures of tidal disruption events to the properties of the disrupted star and the black hole. We use numerical techniques to study the long-term evolution of the debris streams produced from tidal disruption events, showing that they can be gravitationally unstable and, as a result of the instability, fragment into small-scale, localized clumps ...


Strong Variability Of The Coronal Line Region In Ngc 5548, Hermine Landt, Martin J. Ward, Katrien C. Steenbrugge, Gary J. Ferland Dec 2015

Strong Variability Of The Coronal Line Region In Ngc 5548, Hermine Landt, Martin J. Ward, Katrien C. Steenbrugge, Gary J. Ferland

Physics and Astronomy Faculty Publications

We present the second extensive study of the coronal line variability in an active galaxy. Our data set for the well-studied Seyfert galaxy NGC 5548 consists of five epochs of quasi-simultaneous optical and near-infrared spectroscopy spanning a period of about five years and three epochs of X-ray spectroscopy overlapping in time with it. Whereas the broad emission lines and hot dust emission varied only moderately, the coronal lines varied strongly. However, the observed high variability is mainly due to a flux decrease. Using the optical [Fe vii] and X-ray O vii emission lines we estimate that the coronal line gas ...


A Deep Look At The Nuclear Region Of Ugc 5101 Through High Angular Resolution Mid-Ir Data With Gtc/Canaricam, M. Martínez-Paredes, Almudena Alonso-Herrero, Itziar Aretxaga, C. Ramos Almeida, A. Hernán-Caballero, O. González-Martín, M. Pereira-Santaella, Christopher Packham, A. Asensio Ramos, T. Díaz-Santos, Moshe Elitzur, P. Esquej, I. García-Bernete, Masatoshi Imanishi, Nancy A. Levenson, José Miguel Rodríguez Espinosa Dec 2015

A Deep Look At The Nuclear Region Of Ugc 5101 Through High Angular Resolution Mid-Ir Data With Gtc/Canaricam, M. Martínez-Paredes, Almudena Alonso-Herrero, Itziar Aretxaga, C. Ramos Almeida, A. Hernán-Caballero, O. González-Martín, M. Pereira-Santaella, Christopher Packham, A. Asensio Ramos, T. Díaz-Santos, Moshe Elitzur, P. Esquej, I. García-Bernete, Masatoshi Imanishi, Nancy A. Levenson, José Miguel Rodríguez Espinosa

Physics and Astronomy Faculty Publications

We present an analysis of the nuclear infrared (IR, 1.6–18 μm) emission of the ultraluminous IR galaxy UGC 5101 to derive the properties of its active galactic nucleus (AGN) and its obscuring material. We use new mid-IR high angular resolution (0.3–0.5 arcsec) imaging using the Si-2 filter (λC = 8.7 μm) and 7.5–13 μm spectroscopy taken with CanariCam (CC) on the 10.4 m Gran Telescopio CANARIAS. We also use archival Hubble Space Telescope/NICMOS and Subaru/COMICS imaging and Spitzer/IRS spectroscopy. We estimate the near- and mid-IR unresolved nuclear emission ...


Dark Matter Halo Concentration And The Evolution Of Spiral Structure In N-Body, Barred Spiral Galaxies, Jazmin Esmeralda Berlanga Medina Dec 2015

Dark Matter Halo Concentration And The Evolution Of Spiral Structure In N-Body, Barred Spiral Galaxies, Jazmin Esmeralda Berlanga Medina

Theses and Dissertations

Motivated by the evidence of relationships between pitch angle (the tightness of spiral arm structure in the disk), P, and various indicators of central mass concentration, as well as the theoretical relationship between halo mass concentration and the density of visible matter in the central part of the galaxy, we look at a possible relationship between P and cvir (the virial concentration of the dark matter halo) in N-body simulations of barred, spiral galaxies. We also look at the evolution of pitch angle over time in higher temporal resolution than any data currently available in the literature. We find that ...


The Inferred Evolution Of The Cold Gas Properties Of Candels Galaxies At 0.5 < Z < 3.0, G. Popping, K. Caputi, S. C. Trager, Rachel S. Somerville, Avishai Dekel, Susan A. Kassin, Dale D. Kocevski, Anton M. Koekemoer, Sandra M. Faber, Henry C. Ferguson, A. Galametz, Norman A. Grogin, Yicheng Guo, Y. Lu, Arjen Van Der Wel, Benjamin J. Weiner Dec 2015

The Inferred Evolution Of The Cold Gas Properties Of Candels Galaxies At 0.5 Z < 3.0, G. Popping, K. Caputi, S. C. Trager, Rachel S. Somerville, Avishai Dekel, Susan A. Kassin, Dale D. Kocevski, Anton M. Koekemoer, Sandra M. Faber, Henry C. Ferguson, A. Galametz, Norman A. Grogin, Yicheng Guo, Y. Lu, Arjen Van Der Wel, Benjamin J. Weiner

Physics and Astronomy Faculty Publications

We derive the total cold gas, atomic hydrogen, and molecular gas masses of approximately 24 000 galaxies covering four decades in stellar mass at redshifts 0.5 < z < 3.0, taken from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey survey. Our inferences are based on the inversion of a molecular hydrogen based star formation law, coupled with a prescription to separate atomic and molecular gas. We find that: (1) there is an increasing trend between the inferred cold gas (H i and H2), H i, and H2 mass and the stellar mass of galaxies down to stellar masses of 108 M already in place at z = 3; (2) the molecular fractions of cold gas increase with increasing stellar mass and look-back time; (3) there is hardly any evolution in the mean H i content of galaxies at fixed stellar mass; (4) the cold gas fraction and relative amount of molecular hydrogen in ...


A Determination Of The Gamma-Ray Flux And Photon Spectral Index Distributions Of Blazars From The Fermi-Lat 3lac, Jack Singal Nov 2015

A Determination Of The Gamma-Ray Flux And Photon Spectral Index Distributions Of Blazars From The Fermi-Lat 3lac, Jack Singal

Physics Faculty Publications

We present a determination of the distributions of gamma-ray photon flux – the so-called LogN–LogS relation – and photon spectral index for blazars, based on the third extragalactic source catalogue of the Fermi Gamma-ray Space Telescope's Large Area Telescope, and considering the photon energy range from 100 MeV to 100 GeV. The data set consists of the 774 blazars in the so-called Clean sample detected with a greater than approximately 7σ detection threshold and located above ±20° Galactic latitude. We use non-parametric methods verified in previous works to reconstruct the intrinsic distributions from the observed ones which account ...


Herschel Photometry Of Brightest Cluster Galaxies In Cooling Flow Clusters, A. C. Edge, J. B. R. Oonk, R. Mittal, S. W. Allen, S. A. Baum, H. Böhringer, J. N. Bregman, M. N. Bremer, F. Combes, C. S. Crawford, M. Donahue, E. Egami, A. C. Fabian, Gary J. Ferland, S. L. Hamer, N. A. Hatch, W. Jaffe, R. M. Johnstone, B. R. Mcnamara, C. P. O'Dea, P. Popesso, A. C. Quillen, P. Salomé, C. L. Sarazin, G. M. Voit, R. J. Wilman, M. W. Wise Oct 2015

Herschel Photometry Of Brightest Cluster Galaxies In Cooling Flow Clusters, A. C. Edge, J. B. R. Oonk, R. Mittal, S. W. Allen, S. A. Baum, H. Böhringer, J. N. Bregman, M. N. Bremer, F. Combes, C. S. Crawford, M. Donahue, E. Egami, A. C. Fabian, Gary J. Ferland, S. L. Hamer, N. A. Hatch, W. Jaffe, R. M. Johnstone, B. R. Mcnamara, C. P. O'Dea, P. Popesso, A. C. Quillen, P. Salomé, C. L. Sarazin, G. M. Voit, R. J. Wilman, M. W. Wise

Gary J. Ferland

The dust destruction timescales in the cores of clusters of galaxies are relatively short given their high central gas densities. However, substantial mid-infrared and sub-mm emission has been detected in many brightest cluster galaxies. In this letter we present Herschel PACS and SPIRE photometry of the brightest cluster galaxy in three strong cooling flow clusters, A1068, A2597 and Zw3146. This photometry indicates that a substantial mass of cold dust is present (> 3×107 M⊙) at temperatures significantly lower (20–28 K) than previously thought based on limited MIR and/or sub-mm results. The mass and temperature of the dust ...


A Critical Assessment Of Stellar Mass Measurement Methods, Bahram Mobasher, Tomas Dahlen, Henry C. Ferguson, Viviana Acquaviva, Guillermo Barro, Steven L. Finkelstein, Adriano Fontana, Ruth Gruetzbauch, Seth Johnson, Yu Lu, Casey Papovich, Janine Pforr, Mara Salvato, Rachel S. Somerville, Tommy Wiklind, Stijn Wuyts, Matthew L.N. Ashby, Eric Bell, Christopher J. Conselice, Mark E. Dickinson, Sandra M. Faber, Giovanni Fazio, Kristian Finlator, Audrey Galametz, Eric Gawiser, Mauro Giavalisco, Andrea Grazian, Norman A. Grogin, Yicheng Guo, Nimish Hathi, Dale Kocevski, Anton M. Koekemoer, David C. Koo, Jeffrey A. Newman, Naveen Reddy, Paola Santini, Risa H. Wechsler Jul 2015

A Critical Assessment Of Stellar Mass Measurement Methods, Bahram Mobasher, Tomas Dahlen, Henry C. Ferguson, Viviana Acquaviva, Guillermo Barro, Steven L. Finkelstein, Adriano Fontana, Ruth Gruetzbauch, Seth Johnson, Yu Lu, Casey Papovich, Janine Pforr, Mara Salvato, Rachel S. Somerville, Tommy Wiklind, Stijn Wuyts, Matthew L.N. Ashby, Eric Bell, Christopher J. Conselice, Mark E. Dickinson, Sandra M. Faber, Giovanni Fazio, Kristian Finlator, Audrey Galametz, Eric Gawiser, Mauro Giavalisco, Andrea Grazian, Norman A. Grogin, Yicheng Guo, Nimish Hathi, Dale Kocevski, Anton M. Koekemoer, David C. Koo, Jeffrey A. Newman, Naveen Reddy, Paola Santini, Risa H. Wechsler

Physics and Astronomy Faculty Publications

This is the second paper in a series aimed at investigating the main sources of uncertainty in measuring the observable parameters in galaxies from their spectral energy distributions (SEDs). In the first paper we presented a detailed account of the photometric redshift measurements and an error analysis of this process. In this paper we perform a comprehensive study of the main sources of random and systematic error in stellar mass estimates for galaxies, and their relative contributions to the associated error budget. Since there is no prior knowledge of the stellar mass of galaxies (unlike their photometric redshifts), we use ...


Observational Properties Of Simulated Galaxies In Overdense And Average Regions At Redshifts Z ≃ 6–12, Hidenobu Yajima, Isaac Shlosman, Emilio Romano-Díaz, Kentaro Nagamine Jul 2015

Observational Properties Of Simulated Galaxies In Overdense And Average Regions At Redshifts Z ≃ 6–12, Hidenobu Yajima, Isaac Shlosman, Emilio Romano-Díaz, Kentaro Nagamine

Physics and Astronomy Faculty Publications

We use high-resolution zoom-in cosmological simulations of galaxies of Romano-Díaz et al., post-processing them with a panchromatic three-dimensional radiation transfer code to obtain the galaxy UV luminosity function (LF) at z ≃ 6–12. The galaxies are followed in a rare, heavily overdense region within a ∼5σ density peak, which can host high-z quasars, and in an average density region, down to the stellar mass of Mstar ∼ 4 × 107 M. We find that the overdense regions evolve at a substantially accelerated pace – the most massive galaxy has grown to Mstar ∼ 8.4 × 1010 M by z ...


Stellar Metallicity Gradients In Sdss Galaxies, Benjamin Roig, Michael R. Blanton, Renbin Yan Jul 2015

Stellar Metallicity Gradients In Sdss Galaxies, Benjamin Roig, Michael R. Blanton, Renbin Yan

Physics and Astronomy Faculty Publications

We infer stellar metallicity and abundance ratio gradients for a sample of red galaxies in the Sloan Digital Sky Survey (SDSS) Main galaxy sample. Because this sample does not have multiple spectra at various radii in a single galaxy, we measure these gradients statistically. We separate galaxies into stellar mass bins, stack their spectra in redshift bins, and calculate the measured absorption-line indices in projected annuli by differencing spectra in neighboring redshift bins. After determining the line indices, we use stellar population modeling from the EZ_Ages software to calculate ages, metallicities, and abundance ratios within each annulus. Our data cover ...


Supermassive Black Hole Formation At High Redshifts Via Direct Collapse In A Cosmological Context, Jun-Hwan Choi, Isaac Shlosman, Mitchell C. Begelman Jul 2015

Supermassive Black Hole Formation At High Redshifts Via Direct Collapse In A Cosmological Context, Jun-Hwan Choi, Isaac Shlosman, Mitchell C. Begelman

Physics and Astronomy Faculty Publications

We study the early stage of the formation of seed supermassive black holes via direct collapse in dark matter (DM) haloes, in the cosmological context. We perform high-resolution zoom-in simulations of such collapse at high z. Using the adaptive mesh refinement code enzo, we resolve the formation and growth of a DM halo, until its virial temperature reaches ∼104 K, atomic cooling turns on, and collapse ensues. We demonstrate that direct collapse proceeds in two stages, although they are not well separated. The first stage is triggered by the onset of atomic cooling, and leads to rapidly increasing accretion ...


Star Formation And Quenching Among The Most Massive Galaxies At Z ∼ 1.7, C. Mancini, A. Renzini, E. Daddi, G. Rodighiero, S. Berta, N. Grogin, Dale D. Kocevski, A. Koekemoer Jun 2015

Star Formation And Quenching Among The Most Massive Galaxies At Z ∼ 1.7, C. Mancini, A. Renzini, E. Daddi, G. Rodighiero, S. Berta, N. Grogin, Dale D. Kocevski, A. Koekemoer

Physics and Astronomy Faculty Publications

We have conducted a detailed object-by-object study of a mass-complete (M* ≥ 1011 M) sample of 56 galaxies at 1.4 ≤ z ≤ 2 in the Great Observatories Origins Deep Survey-South field, showing that an accurate deblending in 24 μm images is essential to properly assign to each galaxy its own star formation rate (SFR), whereas an automatic procedure often fails. This applies especially to galaxies with SFRs below the main sequence (MS) value, which may be in their quenching phase. After that, the sample splits evenly between galaxies forming stars within a factor of 4 of the MS rate (∼45 ...


Variability Of The Coronal Line Region In Ngc 4151, Hermine Landt, Martin J. Ward, Katrien C. Steenbrugge, Gary J. Ferland Jun 2015

Variability Of The Coronal Line Region In Ngc 4151, Hermine Landt, Martin J. Ward, Katrien C. Steenbrugge, Gary J. Ferland

Physics and Astronomy Faculty Publications

We present the first extensive study of the coronal line variability in an active galaxy. Our data set for the nearby source NGC 4151 consists of six epochs of quasi-simultaneous optical and near-infrared spectroscopy spanning a period of about 8 yr and five epochs of X-ray spectroscopy overlapping in time with it. None of the coronal lines showed the variability behaviour observed for the broad emission lines and hot dust emission. In general, the coronal lines varied only weakly, if at all. Using the optical [Fe vii] and X-ray O vii emission lines we estimate that the coronal line gas ...


Metal-Poor, Strongly Star-Forming Galaxies In The Deep2 Survey: The Relationship Between Stellar Mass, Temperature-Based Metallicity, And Star Formation Rate, Chun Ly, Jane R. Rigby, Michael Cooper, Renbin Yan May 2015

Metal-Poor, Strongly Star-Forming Galaxies In The Deep2 Survey: The Relationship Between Stellar Mass, Temperature-Based Metallicity, And Star Formation Rate, Chun Ly, Jane R. Rigby, Michael Cooper, Renbin Yan

Physics and Astronomy Faculty Publications

We report on the discovery of 28 z ≈ 0.8 metal-poor galaxies in DEEP2.

For the remainder of the abstract, please download this article or visit https://doi.org/10.1088/0004-637X/805/1/45.


P-Manga: Gradients In Recent Star Formation Histories As Diagnostics For Galaxy Growth And Death, Cheng Li, Enci Wang, Lin Lin, Matthew A. Bershady, Kevin Bundy, Christy A. Tremonti, Ting Xiao, Renbin Yan, Dmitry Bizyaev, Michael Blanton, Sabrina Cales, Brian Cherinka, Edmond Cheung, Niv Drory, Eric Emsellem, Hai Fu, Joseph Gelfand, David R. Law, Lahwai Lin, Nick Macdonald, Claudia Maraston, Karen L. Masters, Michael R. Merrifield, Kaike Pan, S. F. Sánchez, Donald P. Schneider, Daniel Thomas, David Wake, Lixin Wang, Anne-Marie Weijmans, David Wilkinson, Peter Yoachim, Kai Zhang, Tiantian Zheng May 2015

P-Manga: Gradients In Recent Star Formation Histories As Diagnostics For Galaxy Growth And Death, Cheng Li, Enci Wang, Lin Lin, Matthew A. Bershady, Kevin Bundy, Christy A. Tremonti, Ting Xiao, Renbin Yan, Dmitry Bizyaev, Michael Blanton, Sabrina Cales, Brian Cherinka, Edmond Cheung, Niv Drory, Eric Emsellem, Hai Fu, Joseph Gelfand, David R. Law, Lahwai Lin, Nick Macdonald, Claudia Maraston, Karen L. Masters, Michael R. Merrifield, Kaike Pan, S. F. Sánchez, Donald P. Schneider, Daniel Thomas, David Wake, Lixin Wang, Anne-Marie Weijmans, David Wilkinson, Peter Yoachim, Kai Zhang, Tiantian Zheng

Physics and Astronomy Faculty Publications

We present an analysis of the data produced by the MaNGA prototype run (P-MaNGA), aiming to test how the radial gradients in recent star formation histories, as indicated by the 4000 Å break (Dn(4000)), Hδ absorption (EW(HδA)), and Hα emission (EW(Hα)) indices, can be useful for understanding disk growth and star formation cessation in local galaxies. We classify 12 galaxies observed on two P-MaNGA plates as either centrally quiescent (CQ) or centrally star-forming (CSF), according to whether Dn(4000) measured in the central spaxel of each datacube exceeds 1.6 ...


A Wfc3 Grism Emission Line Redshift Catalog In The Goods-South Field, Aaron M. Morris, Dale D. Kocevski, Jonathan R. Trump, Benjamin J. Weiner, Nimish P. Hathi, Guillermo Barro, Tomas Dahlen, Sandra M. Faber, Steven L. Finkelstein, Adriano Fontana, Henry C. Ferguson, Norman A. Grogin, Ruth Grützbauch, Yicheng Guo, Li-Ting Hsu, Anton M. Koekemoer, David C. Koo, Bahram Mobasher, Janine Pforr, Mara Salvato, Tommy Wiklind, Stijn Wuyts May 2015

A Wfc3 Grism Emission Line Redshift Catalog In The Goods-South Field, Aaron M. Morris, Dale D. Kocevski, Jonathan R. Trump, Benjamin J. Weiner, Nimish P. Hathi, Guillermo Barro, Tomas Dahlen, Sandra M. Faber, Steven L. Finkelstein, Adriano Fontana, Henry C. Ferguson, Norman A. Grogin, Ruth Grützbauch, Yicheng Guo, Li-Ting Hsu, Anton M. Koekemoer, David C. Koo, Bahram Mobasher, Janine Pforr, Mara Salvato, Tommy Wiklind, Stijn Wuyts

Physics and Astronomy Faculty Publications

We combine Hubble Space Telescope (HST)/Wide Field Camera3 (WFC3) imaging and G141 grism observations from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) and 3D-HST surveys to produce a catalog of grism spectroscopic redshifts for galaxies in the CANDELS/GOODS-South field. The WFC3/G141 grism spectra cover a wavelength range of 1.1 ≼ λ ≼ 1.7 μm with a resolving power of R ~ 130 for point sources, thus providing rest-frame optical spectra for galaxies out to z ~ 3.5. The catalog is selected in the H-band (F160W) and includes both galaxies with and without previously ...


Bootstrapping Dielectronic Recombination From Second-Row Elements And The Orion Nebula, N. R. Badnell, Gary J. Ferland, T. W. Gorczyca, D. Nikolić, Gururaj Anil Wagle May 2015

Bootstrapping Dielectronic Recombination From Second-Row Elements And The Orion Nebula, N. R. Badnell, Gary J. Ferland, T. W. Gorczyca, D. Nikolić, Gururaj Anil Wagle

Physics and Astronomy Faculty Publications

Dielectronic recombination (DR) is the dominant recombination process for most heavy elements in photoionized clouds. Accurate DR rates for a species can be predicted when the positions of autoionizing states are known. Unfortunately such data are not available for most third- and higher-row elements. This introduces an uncertainty that is especially acute for photoionized clouds, where the low temperatures mean that DR occurs energetically through very low-lying autoionizing states. This paper discusses S2+ → S+ DR, the process that is largely responsible for establishing the [S iii]/[S ii] ratio in nebulae. We derive an empirical rate coefficient using a ...