E. McGrath - UCO/Lick

E. McGrath
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Name
E. McGrath
Affiliation
UCO/Lick
City
Santa Cruz
Country
United States

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Cosmology and Nongalactic Astrophysics (40)
 
Astrophysics of Galaxies (20)
 
Instrumentation and Methods for Astrophysics (2)
 
Nuclear Experiment (2)
 
Physics - Physics Education (1)
 
High Energy Physics - Experiment (1)

Publications Authored By E. McGrath

We present quantified visual morphologies of approximately 48,000 galaxies observed in three Hubble Space Telescope legacy fields by the Cosmic And Near-infrared Deep Extragalactic Legacy Survey (CANDELS) and classified by participants in the Galaxy Zoo project. 90% of galaxies have z < 3 and are observed in rest-frame optical wavelengths by CANDELS. Each galaxy received an average of 40 independent classifications, which we combine into detailed morphological information on galaxy features such as clumpiness, bar instabilities, spiral structure, and merger and tidal signatures. Read More

Structure functions, as measured in lepton-nucleon scattering, have proven to be very useful in studying the quark dynamics within the nucleon. However, it is experimentally difficult to separately determine the longitudinal and transverse structure functions, and consequently there are substantially less data available for the longitudinal structure function in particular. Here we present separated structure functions for hydrogen and deuterium at low four--momentum transfer squared, Q^2< 1 GeV^2, and compare these with parton distribution parameterizations and a k_T factorization approach. Read More

We present the results from a study of the morphologies of moderate luminosity X-ray selected AGN host galaxies in comparison to a carefully mass-matched control sample at 0.5 < z < 3 in the CANDELS GOODS-S field. We apply a multi-wavelength morphological decomposition analysis to these two samples and report on the differences between the morphologies as fitted from single Sersic and multiple Sersic models, and models which include an additional nuclear point-source component. Read More

We present photometry and derived redshifts from up to eleven bandpasses for 9927 galaxies in the Hubble Ultra Deep field (UDF), covering an observed wavelength range from the near-ultraviolet (NUV) to the near-infrared (NIR) with Hubble Space Telescope observations. Our Wide Field Camera 3 (WFC3)/UV F225W, F275W, and F336W image mosaics from the ultra-violet UDF (UVUDF) imaging campaign are newly calibrated to correct for charge transfer inefficiency, and use new dark calibrations to minimize background gradients and pattern noise. Our NIR WFC3/IR image mosaics combine the imaging from the UDF09 and UDF12 campaigns with CANDELS data to provide NIR coverage for the entire UDF field of view. Read More

We present Keck-I MOSFIRE spectroscopy in the Y and H bands of GDN-8231, a massive, compact, star-forming galaxy (SFG) at a redshift $z\sim1.7$. Its spectrum reveals both H$_{\alpha}$ and [NII] emission lines and strong Balmer absorption lines. Read More

We present photometric redshifts and associated probability distributions for all detected sources in the Extended Chandra Deep Field South (ECDFS). The work makes use of the most up-to-date data from the Cosmic Assembly Near-IR Deep Legacy Survey (CANDELS) and the Taiwan ECDFS Near-Infrared Survey (TENIS) in addition to other data. We also revisit multi-wavelength counterparts for published X-ray sources from the 4Ms-CDFS and 250ks-ECDFS surveys, finding reliable counterparts for 1207 out of 1259 sources ($\sim 96\%$). Read More

We study the relationship between the structure and star-formation rate (SFR) of X-ray selected low and moderate luminosity active galactic nuclei (AGNs) in the two Chandra Deep Fields, using Hubble Space Telescope imaging from the Cosmic Assembly Near Infrared Extragalactic Legacy Survey (CANDELS) and deep far-infrared maps from the PEP+GOODS-Herschel survey. We derive detailed distributions of structural parameters and FIR luminosities from carefully constructed control samples of galaxies, which we then compare to those of the AGNs. At z~1, AGNs show slightly diskier light profiles than massive inactive (non-AGN) galaxies, as well as modestly higher levels of gross galaxy disturbance (as measured by visual signatures of interactions and clumpy structure). Read More

We present the results of a new and improved study of the morphological and spectral evolution of massive galaxies over the redshift range 110^11 Msolar from the CANDELS WFC3/IR imaging within the COSMOS and UKIDSS UDS survey fields. We find that, by modelling the H(160) image of each galaxy with a combination of a de Vaucouleurs bulge (Sersic index n=4) and an exponential disk (n=1), we can then lock all derived morphological parameters for the bulge and disk components, and successfully reproduce the shorter-wavelength J(125), i(814), v(606) HST images simply by floating the magnitudes of the two components. Read More

We derive physical properties of 10 submillimeter galaxies located in the CANDELS coverage of the GOODS-S field. The galaxies were first identified as submillimeter sources with the LABOCA bolometer and subsequently targeted for 870um continuum observation with ALMA. The high angular resolution of the ALMA imaging allows secure counterparts to be identified in the CANDELS multiband dataset. Read More

Exploiting the deep high-resolution imaging of all 5 CANDELS fields, and accurate redshift information provided by 3D-HST, we investigate the relation between structure and stellar populations for a mass-selected sample of 6764 galaxies above 10^10 Msun, spanning the redshift range 0.5 < z < 2.5. Read More

The processes that trigger Active Galactic Nuclei (AGN) remain poorly understood. While lower luminosity AGN may be triggered by minor disturbances to the host galaxy, stronger disturbances are likely required to trigger luminous AGN. Major wet mergers of galaxies are ideal environments for AGN triggering since they provide large gas supplies and galaxy scale torques. Read More

We present results from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) photometric redshift methods investigation. In this investigation, the results from eleven participants, each using a different combination of photometric redshift code, template spectral energy distributions (SEDs) and priors, are used to examine the properties of photometric redshifts applied to deep fields with broad-band multi-wavelength coverage. The photometry used includes U-band through mid-infrared filters and was derived using the TFIT method. Read More

We present the multiwavelength - ultraviolet to mid-infrared - catalog of the UKIDSS Ultra-Deep Survey (UDS) field observed as part of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS). Based on publicly available data, the catalog includes: the CANDELS data from the Hubble Space Telescope (near-infrared WFC3 F125W and F160W data and visible ACS F606W and F814W data), u-band data from CFHT/Megacam, B, V, Rc, i' and z' band data from Subaru/Suprime-Cam, Y and Ks band data from VLT/HAWK-I, J, H and K bands data from UKIDSS (Data Release 8), and Spitzer/IRAC data (3.6, 4. Read More

We study the environmental dependence of color, stellar mass, and morphology by comparing galaxies in a forming cluster to those in the field at z = 1:6 with Hubble Space Telescope near-infrared imaging in the CANDELS/UDS field. We quantify the morphology of the galaxies using the effective radius, reff, and S\'ersic index, n. In both the cluster and field, approximately half of the bulge-dominated galaxies (n > 2) reside on the red sequence of the color-magnitude diagram, and most disk-dominated galaxies (n < 2) have colors expected for star-forming galaxies. Read More

Mergers of galaxies have been suspected to be a major trigger of AGN activity for many years. However, when compared to carefully matched control samples, AGN host galaxies often show no enhanced signs of interaction. A common explanation for this lack of observed association between AGN and mergers has often been that while mergers are of importance for triggering AGN, they only dominate at the very high luminosity end of the AGN population. Read More

We have used high-resolution, HST WFC3/IR, near-infrared imaging to conduct a detailed bulge-disk decomposition of the morphologies of ~200 of the most massive (M_star > 10^11 M_solar) galaxies at 12 they are mostly disk-dominated. Interestingly, we find that while most of the quiescent galaxies are bulge-dominated, a significant fraction (25-40%) of the most quiescent galaxies, have disk-dominated morphologies. Read More

We present global structural parameter measurements of 109,533 unique, H_F160W-selected objects from the CANDELS multi-cycle treasury program. Sersic model fits for these objects are produced with GALFIT in all available near-infrared filters (H_F160W, J_F125W and, for a subset, Y_F105W). The parameters of the best-fitting Sersic models (total magnitude, half-light radius, Sersic index, axis ratio, and position angle) are made public, along with newly constructed point spread functions for each field and filter. Read More

The shutdown of star formation in galaxies is generally termed `quenching'. Although quenching may occur through a variety of processes, the exact mechanism(s) that is in fact responsible for quenching is still in question. This paper addresses quenching by searching for traces of possible quenching processes through their effects on galaxy structural parameters such as surface stellar mass density and Sersic index (n). Read More

2012Jun
Affiliations: 1UCO/Lick, 2UCO/Lick, 3UCM, 4UCO/Lick, 5Umass, 6UCO/Lick, 7UCO/Lick, 8UCO/Lick, 9UCO/Lick, 10MPIA, 11MPIE, 12Michigan, 13Swinburne, 14Hebrew University, 15CfA, 16STScI, 17INAF, 18Umass, 19STScI, 20Umass, 21Carnegie, 22Berkeley, 23STScI, 24STScI, 25NOAO, 26Purdue, 27Pitt, 28UCO/Lick, 29UCO/Lick, 30STScI, 31MPIE, 32STScI

We combine high-resolution HST/WFC3 images with multi-wavelength photometry to track the evolution of structure and activity of massive (log(M*) > 10) galaxies at redshifts z = 1.4 - 3 in two fields of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS). We detect compact, star-forming galaxies (cSFGs) whose number densities, masses, sizes, and star formation rates qualify them as likely progenitors of compact, quiescent, massive galaxies (cQGs) at z = 1. Read More

We have used deep, HST, near-IR imaging to study the morphological properties of the most massive galaxies at high z, modelling the WFC3/IR H-band images of the ~200 galaxies in the CANDELS-UDS field with 1 < z_phot < 3, and stellar masses M_star > 10^11 M_sun. We have used both single-Sersic and bulge+disk models, have investigated the errors/biases introduced by uncertainties in the background and the PSF, and have obtained formally-acceptable model fits to >90% of the galaxies. Our results indicate that these massive galaxies at 1 < z < 3 lie both on and below the local size-mass relation, with a median R_e~2. Read More

We present a study on Spectral Energy Distributions, Morphologies, and star formation for an IRAC-selected extremely red object sample in the GOODS Chandra Deep Field-South. This work was enabled by new HST/WFC3 near-IR imaging from the CANDELS survey as well as the deepest available X-ray data from Chandra 4 Ms observations. This sample consists of 133 objects with the 3. Read More

We use HST/WFC3 imaging from the CANDELS Multicycle Treasury Survey, in conjunction with the Sloan Digital Sky Survey, to explore the evolution of galactic structure for galaxies with stellar masses >3e10M_sun from z=2.2 to the present epoch, a time span of 10Gyr. We explore the relationship between rest-frame optical color, stellar mass, star formation activity and galaxy structure. Read More

2011Oct
Affiliations: 1Texas A&M, 2Texas A&M, 3STScI, 4MPIA-Heidelberg, 5Texas A&M, 6Texas A&M, 7Michigan, 8Nottingham, 9Hebrew Univ, 10ROE, 11UMass, 12UC Santa Cruz, 13Sussex, 14STScI, 15Texas A&M, 16Nottingham, 17UC Santa Cruz, 18STScI, 19UC Santa Cruz, 20ROE, 21UC Santa Cruz, 22UMKC, 23OCIW, 24Pitt, 25Kansas, 26Arizona, 27Arizona, 28MPE Garching

We discuss the structural and morphological properties of galaxies in a z=1.62 proto-cluster using near-IR imaging data from Hubble Space Telescope Wide Field Camera 3 data of the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS). The cluster galaxies exhibit a clear color-morphology relation: galaxies with colors of quiescent stellar populations generally have morphologies consistent with spheroids, and galaxies with colors consistent with ongoing star formation have disk-like and irregular morphologies. Read More

2011Oct
Affiliations: 1MPE, 2UCSC, 3MPE, 4MPE, 5STScI, 6UCSC, 7OCI, 8Hebrew U., 9STScI, 10Edinburgh, 11UCSC, 12STScI, 13UMass., 14STScI, 15UMass., 16UPitt., 17UCSC, 18UCSC, 19Imperial, 20Imperial, 21STScI

We use multi-band spatially resolved photometry from the Cosmic Assembly Near-IR Deep Legacy Survey (CANDELS) in the 4 MSec Chandra Deep Field-South (CDF-S) to explore the nuclear and extended colors, color gradients and stellar populations of X-ray selected AGN host galaxies out to z=3. Based on a study of their central light, we develop X-ray based criteria to exclude objects with strong AGN contamination. We use stellar masses from the FIREWORKS database to understand and account for stellar mass selection effects, and carefully study, for the first time, the resolved host galaxy properties of AGNs at z~2 in their rest-frame optical light without substantial nuclear contamination. Read More

We use deep Chandra imaging and an extensive optical spectroscopy campaign on the Keck 10-m telescopes to study the properties of X-ray point sources in five large-scale structures at redshifts of z ~ 0.7-0.9. Read More

2011Aug
Affiliations: 1UCO/Lick, 2Arizona, 3Minnesota, 4UCO/Lick, 5Michigan, 6UCO/Lick, 7UCO/Lick, 8UCO/Lick, 9Imperial, 10UCO/Lick, 11Imperial, 12NYU, 13UCO/Lick, 14Spitzer, 15NOAO, 16STScI, 17Edinburgh, 18STScI, 19Texas A&M, 20STScI, 21Carnegie, 22Arizona, 23NOAO, 24STScI, 25MPE, 26Pitt, 27JHU, 28Goddard, 29Spitzer

We present Hubble Space Telescope Wide Field Camera 3 slitless grism spectroscopy of 28 emission-line galaxies at z~2, in the GOODS-S region of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS). The high sensitivity of these grism observations, with 1-sigma detections of emission lines to f > 2.5x10^{-18} erg/s/cm^2, means that the galaxies in the sample are typically ~7 times less massive (median M_* = 10^{9. Read More

We investigate the properties of the 525 spectroscopically confirmed members of the Cl1604 supercluster at z~0.9 as part of the Observations of Redshift Evolution in Large Scale Environments (ORELSE) survey. Using extensive Keck LRIS/DEIMOS spectroscopy in conjunction with ten-band ground-based, Spitzer, and HST imaging, we investigate the buildup of the red sequence in groups and clusters at high redshift. Read More

We identify an abundant population of extreme emission line galaxies (EELGs) at redshift z~1.7 in the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS) imaging from Hubble Space Telescope/Wide Field Camera 3 (HST/WFC3). 69 EELG candidates are selected by the large contribution of exceptionally bright emission lines to their near-infrared broad-band magnitudes. Read More

2011Jul
Affiliations: 1University of Arizona, 2MPE, 3UCSC, 4University of Victoria, 5Caltech, 6UCSC, 7UCSC, 8UCSC, 9UCSC, 10Leiden Observatory, 11UCSC

We present uncontaminated rest-frame u - R colors of 78 X-ray-selected AGN hosts at 0.5 < z < 1.5 in the Chandra Deep Fields measured with HST/ACS/NICMOS and VLT/ISAAC imaging. Read More

We compare multi-wavelength SFR indicators out to z~3 in GOODS-South. Our analysis uniquely combines U-to-8um photometry from FIREWORKS, MIPS 24um and PACS 70, 100, and 160um photometry from the PEP survey, and Ha spectroscopy from the SINS survey. We describe a set of conversions that lead to a continuity across SFR indicators. Read More

2011May
Authors: Norman A. Grogin, Dale D. Kocevski, S. M. Faber, Henry C. Ferguson, Anton M. Koekemoer, Adam G. Riess, Viviana Acquaviva, David M. Alexander, Omar Almaini, Matthew L. N. Ashby, Marco Barden, Eric F. Bell, Frédéric Bournaud, Thomas M. Brown, Karina I. Caputi, Stefano Casertano, Paolo Cassata, Marco Castellano, Peter Challis, Ranga-Ram Chary, Edmond Cheung, Michele Cirasuolo, Christopher J. Conselice, Asantha Roshan Cooray, Darren J. Croton, Emanuele Daddi, Tomas Dahlen, Romeel Davé, Duília F. de Mello, Avishai Dekel, Mark Dickinson, Timothy Dolch, Jennifer L. Donley, James S. Dunlop, Aaron A. Dutton, David Elbaz, Giovanni G. Fazio, Alexei V. Filippenko, Steven L. Finkelstein, Adriano Fontana, Jonathan P. Gardner, Peter M. Garnavich, Eric Gawiser, Mauro Giavalisco, Andrea Grazian, Yicheng Guo, Nimish P. Hathi, Boris Häussler, Philip F. Hopkins, Jia-Sheng Huang, Kuang-Han Huang, Saurabh W. Jha, Jeyhan S. Kartaltepe, Robert P. Kirshner, David C. Koo, Kamson Lai, Kyoung-Soo Lee, Weidong Li, Jennifer M. Lotz, Ray A. Lucas, Piero Madau, Patrick J. McCarthy, Elizabeth J. McGrath, Daniel H. McIntosh, Ross J. McLure, Bahram Mobasher, Leonidas A. Moustakas, Mark Mozena, Kirpal Nandra, Jeffrey A. Newman, Sami-Matias Niemi, Kai G. Noeske, Casey J. Papovich, Laura Pentericci, Alexandra Pope, Joel R. Primack, Abhijith Rajan, Swara Ravindranath, Naveen A. Reddy, Alvio Renzini, Hans-Walter Rix, Aday R. Robaina, Steven A. Rodney, David J. Rosario, Piero Rosati, Sara Salimbeni, Claudia Scarlata, Brian Siana, Luc Simard, Joseph Smidt, Rachel S. Somerville, Hyron Spinrad, Amber N. Straughn, Louis-Gregory Strolger, Olivia Telford, Harry I. Teplitz, Jonathan R. Trump, Arjen van der Wel, Carolin Villforth, Risa H. Wechsler, Benjamin J. Weiner, Tommy Wiklind, Vivienne Wild, Grant Wilson, Stijn Wuyts, Hao-Jing Yan, Min S. Yun

The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) is designed to document the first third of galactic evolution, over the approximate redshift (z) range 8--1.5. It will image >250,000 distant galaxies using three separate cameras on the Hubble Space Telescope, from the mid-ultraviolet to the near-infrared, and will find and measure Type Ia supernovae at z>1. Read More

2011May
Authors: Anton M. Koekemoer, S. M. Faber, Henry C. Ferguson, Norman A. Grogin, Dale D. Kocevski, David C. Koo, Kamson Lai, Jennifer M. Lotz, Ray A. Lucas, Elizabeth J. McGrath, Sara Ogaz, Abhijith Rajan, Adam G. Riess, Steve A. Rodney, Louis Strolger, Stefano Casertano, Marco Castellano, Tomas Dahlen, Mark Dickinson, Timothy Dolch, Adriano Fontana, Mauro Giavalisco, Andrea Grazian, Yicheng Guo, Nimish P. Hathi, Kuang-Han Huang, Arjen van der Wel, Hao-Jing Yan, Viviana Acquaviva, David M. Alexander Omar Almaini, Matthew L. N. Ashby, Marco Barden, Eric F. Bell, Frédéric Bournaud, Thomas M. Brown, Karina I. Caputi, Paolo Cassata, Peter Challis, Ranga-Ram Chary, Edmond Cheung, Michele Cirasuolo, Christopher J. Conselice, Asantha Roshan Cooray, Darren J. Croton, Emanuele Daddi, Romeel Davé, Duilia F. de Mello, Loic de Ravel, Avishai Dekel, Jennifer L. Donley, James S. Dunlop, Aaron A. Dutton, David Elbaz, Giovanni G. Fazio, Alex V. Filippenko, Steven L. Finkelstein, Chris Frazer, Jonathan P. Gardner, Peter M. Garnavich, Eric Gawiser, Ruth Gruetzbauch, Will G. Hartley, Boris Häussler, Jessica Herrington, Philip F. Hopkins, Jia-Sheng Huang, Saurabh Jha, Andrew Johnson, Jeyhan S. Kartaltepe, Ali Ahmad Khostovan, Robert P. Kirshner, Caterina Lani, Kyoung-Soo Lee, Weidong Li, Piero Madau, Patrick J. McCarthy, Daniel H. McIntosh, Ross J. McLure, Conor McPartland, Bahram Mobasher, Heidi Moreira, Alice Mortlock, Leonidas A. Moustakas, Mark Mozena, Kirpal Nandra, Jeffrey A. Newman, Jennifer L. Nielsen, Sami Niemi, Kai G. Noeske, Casey J. Papovich, Laura Pentericci, Alexandra Pope, Joel R. Primack, Swara Ravindranath, Naveen A. Reddy, Alvio Renzini, Hans-Walter Rix, Aday R. Robaina, David J. Rosario, Piero Rosati, Sara Salimbeni, Claudia Scarlata, Brian Siana, Luc Simard, Joseph Smidt, Diana Snyder, Rachel S. Somerville, Hyron Spinrad, Amber N. Straughn, Olivia Telford, Harry I. Teplitz, Jonathan R. Trump, Carlos Vargas, Carolin Villforth, Cory R. Wagner, Pat Wandro, Risa H. Wechsler, Benjamin J. Weiner, Tommy Wiklind, Vivienne Wild, Grant Wilson, Stijn Wuyts, Min S. Yun

This paper describes the Hubble Space Telescope imaging data products and data reduction procedures for the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS). This survey is designed to document the evolution of galaxies and black holes at $z\sim1.5-8$, and to study Type Ia SNe beyond $z>1. Read More

A large set of cross sections for semi-inclusive electroproduction of charged pions ($\pi^\pm$) from both proton and deuteron targets was measured. The data are in the deep-inelastic scattering region with invariant mass squared $W^2$ > 4 GeV$^2$ and range in four-momentum transfer squared $2 < Q^2 < 4$ (GeV/c)$^2$, and cover a range in the Bjorken scaling variable 0.2 < x < 0. Read More

We investigate the stellar structure of massive, quiescent galaxies at z~2, based on Hubble Space Telescope/WFC3 imaging from the Early Release Science program. Our sample of 14 galaxies has stellar masses of M* > 10^{10.8} Msol and photometric redshifts of 1. Read More

We describe a three hour inquiry activity involving converging lenses and telescopes as part of a semester-long astronomy lab course for non-science majors at Hartnell Community College in Salinas, CA. Students were shown several short demonstrations and given the chance to experiment with the materials, after which there was a class discussion about the phenomena they observed. Students worked in groups of 2-4 to design their own experiments to address a particular question of interest to them and then presented their findings to the class. Read More

Using Spitzer-MIPS 24um imaging and Keck spectroscopy we examine the nature of the obscured star forming population in three clusters and three groups at z~0.9. These six systems are components of the Cl1604 supercluster, the largest structure imaged by Spitzer at redshifts near unity. Read More