Results for "Anton M. Koekemoer"

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A new extensive catalog of optically variable AGN in the GOODS Fields and a new statistical approach to variability selectionAug 19 2010Aug 30 2010Variability is a property shared by practically all AGN. This makes variability selection a possible technique for identifying AGN. Given that variability selection makes no prior assumption about spectral properties, it is a powerful technique for detecting ... More
Non-parametric Star Formation History Reconstruction with Gaussian Processes I: Counting Major Episodes of Star FormationJan 09 2019The star formation histories (SFHs) of galaxies contain imprints of the physical processes responsible for regulating star formation during galaxy growth and quenching. We improve the Dense Basis SFH reconstruction method of Iyer & Gawiser (2017), introducing ... More
Physical properties of Herschel selected galaxies in a semi-analytic galaxy formation modelJan 11 2012[Abridged] We make use of a semi-analytic cosmological model that includes simple prescriptions for dust attenuation and emission to make predictions for the observable and physical properties of galaxies that may be detected by the recently launched ... More
Hubble Space Telescope Observations of the Associated Absorption Systems in Q0122+0338Oct 19 1999We have studied a spectrum of Q0122+0338 (z = 1.202) obtained by the FOS on board HST. We present the analysis of three associated absorption systems at z = 1.207, 1.199 and 1.166. The most complex of these at z = 1.207 shows strong absorption from the ... More
On the Stellar Populations and Evolution of Star-Forming Galaxies at 6.3 < z < 8.6Dec 08 2009Jun 21 2010We study the physical characteristics of galaxies at 6.3 < z < 8.6, selected from deep near-infrared imaging with the Wide Field Camera 3 (WFC3) on board the Hubble Space Telescope. Accounting for the photometric scatter using simulations, galaxies at ... More
Rapid Decline of Lyman-alpha Emission Toward the Reionization EraMay 19 2014Sep 24 2014The observed deficit of strongly Lyman-alpha emitting galaxies at z>6.5 is attributed to either increasing neutral hydrogen in the intergalactic medium (IGM) and/or to the evolving galaxy properties. To investigate this, we have performed very deep near-IR ... More
The Lyman Continuum escape fraction of emission line-selected $z\sim2.5$ galaxies is less than 15%May 17 2017Recent work suggests that strong emission line, star-forming galaxies may be significant Lyman Continuum leakers. We combine archival HST broadband ultraviolet and optical imaging (F275W and F606W, respectively) with emission line catalogs derived from ... More
Secular evolution and a non-evolving black hole to galaxy mass ratio in the last 7 GyrSep 21 2011We present new constraints on the ratio of black hole (BH) mass to total galaxy stellar mass at 0.3<z<0.9 for a sample of 32 type-1 active galactic nuclei (AGNs) from the XMM-COSMOS survey covering the range M_BH/M_sun~10^(7.2--8.7). Virial M_BH estimates ... More
3C236: Radio Source, Interrupted?Jan 24 2001We present new HST STIS/MAMA near-UV images and archival WFPC2 V and R band images which reveal the presence of four star forming regions in an arc along the edge of the dust lane in the giant (4 Mpc) radio galaxy 3C236. Two of the star forming regions ... More
Early-type galaxies in the PEARS survey: Probing the stellar populations at moderate redshiftAug 05 2009Aug 07 2009Using HST/ACS slitless grism spectra from the PEARS program, we study the stellar populations of morphologically selected early-type galaxies in the GOODS North and South fields. The sample - extracted from a visual classification of the (v2.0) HST/ACS ... More
Morphological Properties of Lyman Alpha Emitters at Redshift 4.86 in the COSMOS Field: Clumpy Star Formation or Merger?Jan 22 2016We investigate morphological properties of 61 Lyman-alpha emitters (LAEs) at z = 4.86 identified in the COSMOS field, based on Hubble Space Telescope Advanced Camera for Surveys (ACS) imaging data in the F814W-band. Out of the 61 LAEs, we find the ACS ... More
A Possible New Population of Sources with Extreme X-Ray / Optical RatiosJun 19 2003We describe a possible new class of X-ray sources that have robust detections in ultra-deep Chandra data, yet have no detections at all in our deep multi-band GOODS Hubble Space Telescope (HST) ACS images, which represent the highest quality optical imaging ... More
UVI colour gradients of 0.4<z<1.4 star-forming main sequence galaxies in CANDELS: dust extinction and star formation profilesMay 15 2017This paper uses radial colour profiles to infer the distributions of dust, gas and star formation in z=0.4-1.4 star-forming main sequence galaxies. We start with the standard UVJ-based method to estimate dust extinction and specific star formation rate ... More
Evolution of the Gas Mass Fraction of Progenitors to Today's Massive Galaxies: ALMA Observations in the CANDELS GOODS-S FieldMar 16 2019We present an ALMA survey of dust continuum emission in a sample of 70 galaxies in the redshift range z=2-5 selected from the CANDELS GOODS-S field. Multi-Epoch Abundance Matching (MEAM) is used to define potential progenitors of a z = 0 galaxy of stellar ... More
The UV Continuum of z > 1 Star-forming Galaxies in the Hubble Ultraviolet UltraDeep FieldJul 14 2014Aug 06 2014We estimate the UV continuum slope, beta, for 923 galaxies in the range 1 < z < 8 in the Hubble Ultradeep Field (HUDF). These data include 460 galaxies at 1 < z < 2 down to an absolute magnitude M_{UV} = -14 (~0.006 L*_{z=1}; 0.02 L*_{z=0}), comparable ... More
Are Compton-Thick AGN the Missing Link Between Mergers and Black Hole Growth?Sep 11 2015We examine the host morphologies of heavily obscured active galactic nuclei (AGN) at $z\sim1$ to test whether obscured supermassive black hole growth at this epoch is preferentially linked to galaxy mergers. Our sample consists of 154 obscured AGN with ... More
Pathways to quiescence: SHARDS view on the Star Formation Histories of massive quiescent galaxies at 1.0 < z < 1.5Jul 28 2015Jan 21 2016We present Star Formation Histories (SFHs) for a sample of 104 massive (stellar mass M > 10$^{10}$ M$_{\odot}$) quiescent galaxies (MQGs) at $z$=1.0-1.5 from the analysis of spectro-photometric data from the SHARDS and HST/WFC3 G102 and G141 surveys of ... More
Probing Very Bright End of Galaxy Luminosity Function at z >~ 7 Using Hubble Space Telescope Pure Parallel ObservationsOct 11 2010Jan 09 2011We report the first results from the Hubble Infrared Pure Parallel Imaging Extragalactic Survey, which utilizes the pure parallel orbits of the Hubble Space Telescope to do deep imaging along a large number of random sightlines. To date, our analysis ... More
Kinematic Downsizing at z~2May 31 2016We present results from a survey of the internal kinematics of 49 star-forming galaxies at z$\,\sim\,$2 in the CANDELS fields with the Keck/MOSFIRE spectrograph (SIGMA, Survey in the near-Infrared of Galaxies with Multiple position Angles). Kinematics ... More
Emission-Line Galaxies from the PEARS Hubble Ultra Deep Field: A 2-D Detection Method and First ResultsFeb 20 2008The Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) grism PEARS (Probing Evolution And Reionization Spectroscopically) survey provides a large dataset of low-resolution spectra from thousands of galaxies in the GOODS North and South fields. ... More
Unveiling the Phase Transition of the Universe During the Reionization Epoch with Lyman-alphaMar 11 2019The epoch of reionization (6 < z < 10) marks the period in our universe when the first large galaxies grew to fruition, and began to affect the universe around them. Massive stars, and potentially accreting supermassive black holes, filled the universe ... More
Hot-Dust-Poor Type 1 Active Galactic Nuclei in the COSMOS SurveySep 16 2010Nov 01 2010We report a sizable class of type 1 active galactic nuclei (AGNs) with unusually weak near-infrared (1-3{\mu}m) emission in the XMM-COSMOS type 1 AGN sample. The fraction of these "hot-dust-poor" AGNs increases with redshift from 6% at lowredshift (z ... More
The Hubble Ultra Deep FieldJul 27 2006This paper presents the Hubble Ultra Deep Field (HUDF), a one million second exposure of an 11 square minute-of-arc region in the southern sky with the Hubble Space Telescope. The exposure time was divided among four filters, F435W (B435), F606W (V606), ... More
An Increasing Stellar Baryon Fraction in Bright Galaxies at High RedshiftMar 31 2015Nov 18 2015Recent observations have shown that the characteristic luminosity of the rest-frame ultraviolet (UV) luminosity function does not significantly evolve at 4 < z < 7 and is approximately M*_UV ~ -21. We investigate this apparent non-evolution by examining ... More
The star formation history of mass-selected galaxies in the COSMOS fieldNov 29 2010Jan 18 2011We explore the evolution of the specific star formation rate (SSFR) for 3.6um-selected galaxies of different M_* in the COSMOS field. The average SFR for sub-sets of these galaxies is estimated with stacked 1.4GHz radio continuum emission. We separately ... More
The intrinsic characteristics of galaxies on the SFR-stellar mass plane at 1.2<z<4: I. the correlation between stellar age, central density and position relative to the main sequenceJun 07 2017Dec 28 2017We use the deep CANDELS observations in the GOODS North and South fields to revisit the correlations between stellar mass ($M_*$), star--formation rate (SFR) and morphology, and to introduce a fourth dimension, the mass-weighted stellar age, in galaxies ... More
Cross-correlation between X-ray and optical/near-infrared background intensity fluctuationsOct 06 2016Angular power spectra of optical and infrared background anisotropies at wavelengths between 0.5 to 5 $\mu$m are a useful probe of faint sources present during reionization, in addition to faint galaxies and diffuse signals at low redshift. The cross-correlation ... More
Breaking the Curve with CANDELS: A Bayesian Approach to Reveal the Non-Universality of the Dust-Attenuation Law at High RedshiftDec 16 2015May 25 2016Dust attenuation affects nearly all observational aspects of galaxy evolution, yet very little is known about the form of the dust-attenuation law in the distant Universe. Here, we model the spectral energy distributions (SEDs) of galaxies at z = 1.5--3 ... More
Near-Infrared Imaging of a z=6.42 Quasar Host Galaxy With the Hubble Space Telescope Wide Field Camera 3Jul 13 2012Aug 09 2012We report on deep near-infrared F125W (J) and F160W (H) Hubble Space Telescope Wide Field Camera 3 images of the z=6.42 quasar J1148+5251 to attempt to detect rest-frame near-ultraviolet emission from the host galaxy. These observations included contemporaneous ... More
The FMOS-COSMOS survey of star-forming galaxies at $z\sim1.6$ VI: Redshift and emission-line catalog and basic properties of star-forming galaxiesDec 04 2018Dec 13 2018We present a new data release from the Fiber Multi-Object Spectrograph (FMOS)-COSMOS survey, which contains the measurements of spectroscopic redshift and flux of rest-frame optical emission lines (H$\alpha$, [NII], [SII], H$\beta$, [OIII]) for 1931 galaxies ... More
Measuring the Geometry of the Universe from Weak Gravitational Lensing behind Galaxy Groups in the HST COSMOS surveyNov 14 2011Gravitational lensing can provide pure geometric tests of the structure of space-time, for instance by determining empirically the angular diameter distance-redshift relation. This geometric test has been demonstrated several times using massive clusters ... More
CANDELS: The correlation between galaxy morphology and star formation activity at z~2Jun 20 2013Jul 02 2013We discuss the state of the assembly of the Hubble Sequence in the mix of bright galaxies at redshift 1.4< z \le 2.5 with a large sample of 1,671 galaxies down to H_{AB}~26, selected from the HST/ACS and WFC3 images of the GOODS--South field obtained ... More
Extended X-ray emission from non-thermal sources in the COSMOS field: A detailed study of a large radio galaxy at z=1.168Apr 11 2012X-ray selected galaxy group samples are usually generated by searching for extended X- ray sources that reflect the thermal radiation of the intragroup medium. On the other hand, large radio galaxies that regularly occupy galaxy groups also emit in the ... More
Studying Relation Between Star Formation and Molecular Clumps on Subparsec Scales in 30 DoradusAug 18 2016We present $\mathrm{^{12}CO}$ and $\mathrm{^{13}CO}$ molecular gas data observed by ALMA, massive early stage young stellar objects identified by applying color-magnitude cuts to \textit{Spitzer} and \textit{Herschel} photometry, and low-mass late stage ... More
Astro2020 Science White Paper: Assembly of the Most Massive Clusters at Cosmic NoonMar 12 2019Galaxy evolution is driven by many complex interrelated processes as galaxies accrete gas, form new stars, grow their stellar masses and central black holes, and subsequently quench. The processes that drive these transformations is poorly understood, ... More
AGN and quasar science with aperture masking interferometry on the James Webb Space TelescopeJan 02 2014Mar 20 2014Due to feedback from accretion onto supermassive black holes (SMBHs), Active Galactic Nuclei (AGNs) are believed to play a key role in LambdaCDM cosmology and galaxy formation. However, AGNs' extreme luminosities and the small angular size of their accretion ... More
Superluminous supernovae at high redshiftFeb 08 2017Superluminous supernovae are beginning to be discovered at redshifts as early as the epoch of reionization. A number of candidate mechanisms is reviewed, together with the discovery programs.
A Very Large ($θ_{E}\gtrsim40$") Strong Gravitational Lens Selected with the Sunyaev-Zel'dovich Effect: PLCK G287.0+32.9 ($z$ = 0.38)Feb 16 2017May 03 2017Since galaxy clusters sit at the high-end of the mass function, the number of galaxy clusters both massive and concentrated enough to yield particularly large Einstein radii poses useful constraints on cosmological and structure formation models. To date, ... More
Dominant Nuclear Outflow Driving Mechanisms in Powerful Radio GalaxiesFeb 20 2007In order to identify the dominant nuclear outflow mechanisms in Active Galactic Nuclei, we have undertaken deep, high resolution observations of two compact radio sources (PKS 1549-79 and PKS 1345+12) with the Advanced Camera for Surveys (ACS) aboard ... More
On the Transition of the Galaxy Quenching Mode at 0.5<z<1 in CANDELSMay 02 2018We investigate the galaxy quenching process at intermediate redshift using a sample of $\sim4400$ galaxies with $M_{\ast} > 10^{9}M_{\odot}$ between redshift 0.5 and 1.0 in all five CANDELS fields. We divide this sample, using the integrated specific ... More
Clumpy Galaxies in CANDELS. I. The Definition of UV Clumps and the Fraction of Clumpy Galaxies at 0.5<z<3Oct 27 2014Feb 11 2015Although giant clumps of stars are crucial to galaxy formation and evolution, the most basic demographics of clumps are still uncertain, mainly because the definition of clumps has not been thoroughly discussed. In this paper, we study the basic demographics ... More
A CANDELS - 3D-HST Synergy: Resolved Star Formation Patterns at 0.7 < z < 1.5Oct 21 2013We analyze the resolved stellar populations of 473 massive star-forming galaxies at 0.7 < z < 1.5, with multi-wavelength broad-band imaging from CANDELS and Halpha surface brightness profiles at the same kiloparsec resolution from 3D-HST. Together, this ... More
Constraints on the Mass, Concentration, and Nonthermal Pressure Support of Six CLASH Clusters from a Joint Analysis of X-ray, SZ, and Lensing DataDec 16 2016We present a joint analysis of Chandra X-ray observations, Bolocam thermal Sunyaev-Zel'dovich (SZ) effect observations, Hubble Space Telescope (HST) strong lensing data, and HST and Subaru Suprime-Cam weak lensing data. The multiwavelength dataset is ... More
The Isophotal Structure of Star-forming Galaxies at $0.5< z <1.8$ in CANDELS: Implications for the Evolution of Galaxy StructureFeb 22 2018We have measured the radial profiles of isophotal ellipticity ($\varepsilon$) and disky/boxy parameter A$_4$ out to radii of about three times the semi-major axes for $\sim4,600$ star-forming galaxies (SFGs) at intermediate redshifts $0.5<z<1.8$ in the ... More
Bulge Growth and Quenching since z = 2.5 in CANDELS/3D-HSTFeb 04 2014Apr 17 2014Exploiting 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, ... More
AEGIS: Demographics of X-ray and Optically Selected AGNsJul 20 2010Jan 20 2011We develop a new diagnostic method to classify galaxies into AGN hosts, star-forming galaxies, and absorption-dominated galaxies by combining the [O III]/Hbeta ratio with rest-frame U-B color. This can be used to robustly select AGNs in galaxy samples ... More
Clumpy Galaxies in CANDELS. II. Physical Properties of UV-bright Clumps at $0.5\leq z<3$Dec 05 2017Studying giant star-forming clumps in distant galaxies is important to understand galaxy formation and evolution. At present, however, observers and theorists have not reached a consensus on whether the observed "clumps" in distant galaxies are the same ... More
The Nature of Extremely Red H-[4.5]>4 Galaxies revealed with SEDS and CANDELSFeb 02 2012Mar 29 2012We have analysed a sample of 25 extremely red H-[4.5]>4 galaxies, selected using 4.5 micron data from the Spitzer SEDS survey and deep H-band data from the Hubble Space Telescope (HST) CANDELS survey, over ~180 square arcmin of the UKIDSS Ultra Deep Survey ... More
A catalog of polychromatic bulge-disk decompositions of ~ 17.600 galaxies in CANDELSMar 27 2018Mar 30 2018Understanding how bulges grow in galaxies is critical step towards unveiling the link between galaxy morphology and star-formation. To do so, it is necessary to decompose large sample of galaxies at different epochs into their main components (bulges ... More
CANDELS Sheds Light on the Environmental Quenching of Low-mass GalaxiesMay 04 2017May 16 2017We investigate the environmental quenching of galaxies, especially those with stellar masses (M*)$<10^{9.5} M_\odot$, beyond the local universe. Essentially all local low-mass quenched galaxies (QGs) are believed to live close to massive central galaxies, ... More
The structural properties of classical bulges and discs from z~2Feb 11 2019Feb 13 2019We study the rest-frame optical mass-size relation of bulges and discs from z~2 to z~0 for a complete sample of massive galaxies in the CANDELS fields using 2 component S\'ersic models (Dimauro et a. 2018). Discs and star forming galaxies follow similar ... More
X-UDS: The Chandra Legacy Survey of the UKIDSS Ultra Deep Survey FieldSep 21 2018We present the X-UDS survey, a set of wide and deep Chandra observations of the Subaru-XMM Deep/UKIDSS Ultra Deep Survey (SXDS/UDS) field. The survey consists of 25 observations that cover a total area of 0.33 deg$^{2}$. The observations are combined ... More
The evolution of star formation histories of quiescent galaxiesSep 12 2016Although there has been much progress in understanding how galaxies evolve, we still do not understand how and when they stop forming stars and become quiescent. We address this by applying our galaxy spectral energy distribution models, which incorporate ... More
The Bursty Star Formation Histories of Low-mass Galaxies at $0.4<z<1$ Revealed by Star Formation Rates Measured from H$β$ and FUVApr 18 2016Nov 16 2016We investigate the burstiness of star formation histories (SFHs) of galaxies at $0.4<z<1$ by using the ratio of star formation rates (SFRs) measured from H$\beta$ and FUV (1500 \AA) (H$\beta$--to--FUV ratio). Our sample contains 164 galaxies down to stellar ... More
The Redshift and Mass Dependence on the Formation of The Hubble Sequence at z>1 from CANDELS/UDSMay 09 2013May 24 2013In this paper we present a detailed study of the structures and morphologies of a sample of 1188 massive galaxies with Mstar>10^10Msun between redshifts z=1-3 within the Ultra Deep Survey (UDS) region of the Cosmic Assembly Near-infrared Deep Extragalactic ... More
The Herschel view of the dominant mode of galaxy growth from z=4 to the present daySep 18 2014Jan 07 2015We present an analysis of the deepest Herschel images in four major extragalactic fields GOODS-North, GOODS-South, UDS and COSMOS obtained within the GOODS-Herschel and CANDELS-Herschel key programs. The picture provided by 10497 individual far-infrared ... More
Structural Evolution of Early-type Galaxies to z=2.5 in CANDELSMay 29 2013Jul 31 2013Projected axis ratio measurements of 880 early-type galaxies at redshifts 1<z<2.5 selected from CANDELS are used to reconstruct and model their intrinsic shapes. The sample is selected on the basis of multiple rest-frame colors to reflect low star-formation ... More
Deconstructing the Galaxy Stellar Mass Function with UKIDSS and CANDELS: the Impact of Colour, Structure and EnvironmentNov 12 2014We combine photometry from the UDS, and CANDELS UDS and CANDELS GOODS-S surveys to construct the galaxy stellar mass function probing both the low and high mass end accurately in the redshift range 0.3<z<3. The advantages of using a homogeneous concatenation ... More
Effect of local environment and stellar mass on galaxy quenching and morphology at $0.5<z<2.0$Jun 12 2017Sep 20 2017We study galactic star-formation activity as a function of environment and stellar mass over 0.5<z<2.0 using the FourStar Galaxy Evolution (ZFOURGE) survey. We estimate the galaxy environment using a Bayesian-motivated measure of the distance to the third ... More
On Star Formation Rates and Star Formation Histories of Galaxies out to z ~ 3Jun 27 2011We 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 ... More
Stellar Mass--Gas-phase Metallicity Relation at $0.5\leq z\leq0.7$: A Power Law with Increasing Scatter toward the Low-mass RegimeMar 15 2016Apr 14 2016We present the stellar mass ($M_{*}$)--gas-phase metallicity relation (MZR) and its scatter at intermediate redshifts ($0.5\leq z\leq0.7$) for 1381 field galaxies collected from deep spectroscopic surveys. The star formation rate (SFR) and color at a ... More
Evidence for a correlation between the sizes of quiescent galaxies and local environment to z ~ 2Jul 11 2013Jul 15 2013We present evidence for a strong relationship between galaxy size and environment for the quiescent population in the redshift range 1 < z < 2. Environments were measured using projected galaxy overdensities on a scale of 400 kpc, as determined from ~ ... More
Lyman-alpha Forest Tomography from Background Galaxies: The First Megaparsec-Resolution Large-Scale Structure Map at z>2Sep 19 2014We present the first observations of foreground Lyman-$\alpha$ forest absorption from high-redshift galaxies, targeting 24 star-forming galaxies (SFGs) with $z\sim 2.3-2.8$ within a $5' \times 15'$ region of the COSMOS field. The transverse sightline ... More
The Progenitors of the Compact Early-Type Galaxies at High-RedshiftOct 14 2013We use GOODS and CANDELS images to identify progenitors of massive (log M > 10 Msun) compact "early-type" galaxies (ETGs) at z~1.6. Since merging and accretion increase the size of the stellar component of galaxies, if the progenitors are among known ... More
The bulk of the black hole growth since z~1 occurs in a secular universe: No major merger-AGN connectionSep 16 2010Nov 11 2010What is the relevance of major mergers and interactions as triggering mechanisms for active galactic nuclei (AGN) activity? To answer this longstanding question, we analyze 140 XMM-selected AGN host galaxies and a matched control sample of 1264 inactive ... More
Inter-comparison of Radio-Loudness Criteria for Type 1 AGNs in the XMM-COSMOS SurveyAug 05 2014Limited studies have been performed on the radio-loud fraction in X-ray selected type 1 AGN samples. The consistency between various radio-loudness definitions also needs to be checked. We measure the radio-loudness of the 407 type 1 AGNs in the XMM-COSMOS ... More
Spectral Energy Distributions of Type 1 AGN in XMM-COSMOS Survey II - Shape EvolutionOct 10 2012Nov 22 2013The mid-infrared to ultraviolet (0.1 -- 10 $\mu m$) spectral energy distribution (SED) shapes of 407 X-ray-selected radio-quiet type 1 AGN in the wide-field ``Cosmic Evolution Survey" (COSMOS) have been studied for signs of evolution. For a sub-sample ... More
Evolution of Intrinsic Scatter in the SFR-Stellar Mass Correlation at 0.5<z<3Feb 11 2016We present estimates of intrinsic scatter in the Star Formation Rate (SFR) - Stellar Mass (M*) correlation in the redshift range 0.5 < z < 3.0 and in the mass range 10^7 < M* < 10^11 Msun. We utilize photometry in the Hubble Ultradeep Field (HUDF12), ... More
Galaxies in X-ray Groups I: Robust Membership Assignment and the Impact of Group Environments on QuenchingSep 27 2011Understanding the mechanisms that lead dense environments to host galaxies with redder colors, more spheroidal morphologies, and lower star formation rates than field populations remains an important problem. As most candidate processes ultimately depend ... More
X-ray spectral analyses of AGNs from the 7Ms Chandra Deep Field-South survey: the distribution, variability, and evolution of AGN's obscurationMar 02 2017Jun 09 2017We present a detailed spectral analysis of the brightest Active Galactic Nuclei (AGN) identified in the 7Ms Chandra Deep Field South (CDF-S) survey over a time span of 16 years. Using a model of an intrinsically absorbed power-law plus reflection, with ... More
NICMOS StatusApr 19 2006We provide an overview of the most important calibration aspects of the NICMOS instrument on board of HST. We describe the performance of the instrument after the installation of the NICMOS Cooling System, and show that the behavior of the instrument ... More
The Relationship Between Star-formation Activity and Galaxy Structural Properties in CANDELS and a Semi-analytic ModelJul 20 2016Oct 18 2016We study the correlation of galaxy structural properties with their location relative to the SFR-M* correlation, also known as the star formation "main sequence" (SFMS), in the CANDELS and GAMA surveys and in a semi-analytic model (SAM) of galaxy formation. ... More
Dynamics and Excitation of Radio Galaxy Emission-Line Regions - I. PKS 2356-61Nov 19 1997Results are presented from a programme of detailed longslit spectroscopic observations of the extended emission-line region (EELR) associated with the powerful radio galaxy PKS 2356-61. The observations have been used to construct spectroscopic datacubes, ... More
Redshifts of Emission Line Objects in the Hubble Ultra Deep FieldJan 30 2007We present redshifts for 115 emission line objects in the Hubble Ultra Deep Field (HUDF) identified through the GRism ACS Program for Extragalactic Science (GRAPES) project using the slitless grism spectroscopy mode of the ACS Camera on the Hubble Space ... More
Rest-frame UV--Optically Selected Galaxies at 2.3<z<3.5: Searching for Dusty Star-forming and Passively-Evolving GalaxiesOct 17 2011Apr 04 2012A new set of color selection criteria (VJL) analogous with the BzK method is designed to select both star-forming galaxies (SFGs) and passively-evolving galaxies (PEGs) at 2.3<z<3.5 by using rest-frame UV--optical (V-J vs. J-L) colors. The criteria are ... More
Discovery of a z = 7.452 High Equivalent Width Lyman-α Emitter from the Hubble Space Telescope Faint Infrared Grism SurveyDec 15 2017We present the results of an unbiased search for Ly{\alpha} emission from continuum-selected 6 < z < 8 galaxies. Our dataset consists of 160 orbits of G102 slitless grism spectroscopy obtained with the Hubble Space Telescope (HST) Wide Field Camera 3 ... More
The Dependence of Quenching upon the Inner Structure of Galaxies at 0.5<z< 0.8 in the DEEP2/AEGIS SurveyOct 15 2012Nov 16 2012The 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 ... More
Relations Between the Sizes of Galaxies and their Dark Matter Halos at Redshifts $0 < z < 3$Jan 15 2017Mar 22 2017We derive relations between the effective radii $R_{\rm{eff}}$ of galaxies and the virial radii $R_{200c}$ of their dark matter halos over the redshift range $0 < z < 3$. For galaxies, we use the measured sizes from deep images taken with \emph{Hubble ... More
Morphologies of low-redshift AGN host galaxies: what role does AGN luminosity play?Mar 08 2013Mergers 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 ... More
The Detection and Statistics of Giant Arcs Behind CLASH ClustersNov 12 2015We developed an algorithm to find and characterize gravitationally lensed galaxies (arcs) to perform a comparison of the observed and simulated arc abundance. Observations are from the Cluster Lensing And Supernova survey with Hubble (CLASH). Simulated ... More
Ultraviolet Morphologies and Star-Formation Rates of CLASH Brightest Cluster GalaxiesApr 02 2015Brightest cluster galaxies (BCGs) are usually quiescent, but many exhibit star formation. Here we exploit the opportunity provided by rest-frame UV imaging of galaxy clusters in the CLASH (Cluster Lensing and Supernovae with Hubble) Multi-Cycle Treasury ... More
Ultraviolet HST Snapshot Survey of 3CR Radio Source Counterparts at Low RedshiftDec 10 2001We present ultraviolet images of 27 3CR radio galaxies with redshifts z<0.1 that have been imaged with the Space Telescope Imaging Spectrograph (STIS) on board the Hubble Space Telescope (HST). The observations employed the NUV-MAMA and broad-band filters ... More
Ultraviolet Luminosity Density of the Universe During the Epoch of ReionizationSep 09 2015The spatial fluctuations of the extragalactic background light trace the total emission from all stars and galaxies in the Universe. A multi-wavelength study can be used to measure the integrated emission from first galaxies during reionization when the ... More
Comparison of optical observational capabilities for the coming decades: ground versus spaceSep 24 2009Ground-based adaptive optics (AO) in the infrared has made exceptional advances in approaching space-like image quality at higher collecting area. Optical-wavelength applications are now also growing in scope. We therefore provide here a comparison of ... More
The Nature of Massive Transition Galaxies in CANDELS, GAMA, and Cosmological SimulationsNov 11 2016Jul 14 2017We explore observational and theoretical constraints on how galaxies might transition between the "star-forming main sequence" (SFMS) and varying "degrees of quiescence" out to $z=3$. Our analysis is focused on galaxies with stellar mass $M_*>10^{10}M_{\odot}$, ... More
SHARDS: A global view of the star formation activity at z~0.84 and z~1.23Jul 28 2015Oct 21 2015In this paper, we present a comprehensive analysis of star-forming galaxies (SFGs) at intermediate redshifts (z~1). We combine the ultra-deep optical spectro-photometric data from the Survey for High-z Absorption Red and Dead Sources (SHARDS) with deep ... More
Smooth(er) Stellar Mass Maps in CANDELS: Constraints on the Longevity of Clumps in High-redshift Star-forming GalaxiesMar 12 2012May 10 2012We perform a detailed analysis of the resolved colors and stellar populations of a complete sample of 323 star-forming galaxies at 0.5 < z < 1.5, and 326 star-forming galaxies at 1.5 < z < 2.5 in the ERS and CANDELS-Deep region of GOODS-South. Galaxies ... More
The Evolution of the Galaxy Rest-Frame Ultraviolet Luminosity Function Over the First Two Billion YearsOct 20 2014Jun 06 2015We present a robust measurement and analysis of the rest-frame ultraviolet (UV) luminosity function at z=4-8. We use deep Hubble Space Telescope imaging over the CANDELS/GOODS fields, the Hubble Ultra Deep Field and the Year 1 Hubble Frontier Field deep ... More
Luminous and High Stellar Mass Candidate Galaxies at z ~ 8 Discovered in CANDELSDec 29 2011Nov 28 2012One key goal of the Hubble Space Telescope Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey is to track galaxy evolution back to z ~ 8. Its two-tiered "wide and deep" strategy bridges significant gaps in existing near-infrared surveys. Here ... More
Quantum Group as Semi-infinite CohomologyDec 09 2008Apr 15 2010We obtain the quantum group $SL_q(2)$ as semi-infinite cohomology of the Virasoro algebra with values in a tensor product of two braided vertex operator algebras with complementary central charges $c+\bar{c}=26$. Each braided VOA is constructed from the ... More
The distribution of satellites around massive galaxies at 1<z<3 in ZFOURGE/CANDELS: dependence on star formation activityJun 23 2014Jul 07 2014We study the statistical distribution of satellites around star-forming and quiescent central galaxies at 1<z<3 using imaging from the FourStar Galaxy Evolution Survey (ZFOURGE) and the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS). ... More
UVUDF: Ultraviolet Through Near-infrared Catalog and Photometric Redshifts of Galaxies in the Hubble Ultra Deep FieldMay 05 2015We 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 ... More
CANDELS/GOODS-S, CDFS, ECDFS: Photometric Redshifts For Normal and for X-Ray-Detected GalaxiesSep 24 2014We 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) ... More
Galaxy Structure and Mode of Star Formation in the SFR-Mass Plane from z ~ 2.5 to z ~ 0.1Jul 01 2011Oct 11 2011We analyze the dependence of galaxy structure (size and Sersic index) and mode of star formation (\Sigma_SFR and SFR_IR/SFR_UV) on the position of galaxies in the SFR versus Mass diagram. Our sample comprises roughly 640000 galaxies at z~0.1, 130000 galaxies ... More
No More Active Galactic Nuclei in Clumpy Disks Than in Smooth Galaxies at z~2 in CANDELS / 3D-HSTJul 28 2014We use CANDELS imaging, 3D-HST spectroscopy, and Chandra X-ray data to investigate if active galactic nuclei (AGNs) are preferentially fueled by violent disk instabilities funneling gas into galaxy centers at 1.3<z<2.4. We select galaxies undergoing gravitational ... More
Studying Large and Small Scale Environments of Ultraviolet Luminous GalaxiesJun 04 2009Studying the environments of 0.4<z<1.2 UV-selected galaxies, as examples of extreme star-forming galaxies (with star formation rates in the range of 3-30 M_sol/yr), we explore the relationship between high rates of star-formation, host halo mass and pair ... More
Completeness property of one-dimensional perturbations of normal and spectral operators generated by first order systemsJul 14 2018The paper is concerned with completeness property of rank one perturbations of unperturbed operators generated by special boundary value problems (BVP) for the following $2 \times 2$ system \begin{equation} L y = -i B^{-1} y' + Q(x) y = \lambda y , \quad ... More
Properties of Submillimeter Galaxies in the CANDELS GOODS-S FieldFeb 13 2014We 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 ... More
FIGS -- Faint Infrared Grism Survey: Description and Data ReductionJun 08 2017Jun 17 2017The Faint Infrared Grism Survey (FIGS) is a deep Hubble Space Telescope (HST) WFC3/IR (Wide Field Camera 3 Infrared) slitless spectroscopic survey of four deep fields. Two fields are located in the Great Observatories Origins Deep Survey-North (GOODS-N) ... More
A Two-Dimensional Spectroscopic Study of Emission Line Galaxies in the Faint Infrared Grism Survey (FIGS) I: Detection Method and CatalogJun 05 2018Nov 09 2018We present the results from the application of a two-dimensional emission line detection method, EMission-line two-Dimensional (EM2D), to the near-infrared G102 grism observations obtained with the Wide-Field Camera 3 (WFC3) as part of the Cycle 22 {\em ... More