Results for "P. Capak"

total 118586took 0.18s
Near-Infrared Survey of the GOODS-North Field: Search for Luminous Galaxy Candidates at z=>6.5Jul 24 2012Aug 13 2012We present near-infrared (NIR; J & Ks) survey of the Great Observatories Origins Deep Survey-North (GOODS-N) field. The publicly available imaging data were obtained using the MOIRCS instrument on the 8.2m Subaru and the WIRCam instrument on the 3.6m ... More
The Evolution of the Ultraluminous Infrared Galaxy Population from Redshift 0 to 1.5Feb 10 2004We use redshift observations of two deep 1.4GHz fields to probe the evolution of the bright end of the radio galaxy luminosity function to z=1.5. We show that the number of galaxies with radio power that would correspond locally to an ultraluminous infrared ... More
A large sample of spectroscopic redshifts in the ACS-GOODS region of the HDF-NJan 18 2004We report the results of an extensive spectroscopic survey of galaxies in the roughly 160 square arcminute ACS-GOODS region surrounding the HDF-N. We have identified 787 galaxies or stars with z'<24, R<24.5, or B<25 lying in the region. The spectra were ... More
An Optical Catalog of the Chandra Large Area Synoptic X-ray Survey SourcesSep 03 2004We present photometric and spectroscopic observations of the X-ray sources detected in the wide-area, moderately deep Chandra Large Area Synoptic X-ray Survey of the Lockman Hole-Northwest field. We have B, V, R, I, and z' photometry for 521 (99%) of ... More
Deep+Wide Lensing Surveys will Provide Exquisite Measurements of the Dark Matter Halos of Dwarf GalaxiesMay 04 2019May 16 2019The advent of new deep+wide photometric lensing surveys will open up the possibility of direct measurements of the dark matter halos of dwarf galaxies. The HSC wide survey will be the first with the statistical capability of measuring the lensing signal ... More
Very High Redshift X-ray Selected AGN in the Chandra Deep Field-NorthJan 13 2003Deep Chandra X-ray exposures provide an efficient route for locating optically faint active galactic nuclei (AGN) at high redshifts. We use deep multicolor optical data to search for z>5 AGN in the 2 Ms X-ray exposure of the Chandra Deep Field-North. ... More
On the evolution of environmental and mass properties of strong lens galaxies in COSMOSSep 08 2010Feb 10 2011Among the 100 strong lens candidates found in the COSMOS field, 20 with redshifts in the range [0.34,1.13], feature multiple images of background sources. Using the multi-wavelength coverage of the field and its spectroscopic follow-up, we characterize ... More
The IRAM/GISMO two-millimeter survey in the COSMOS fieldApr 22 2019We present deep continuum observations at a wavelength of 2mm centered on the COSMOS field using the Goddard IRAM Superconducting Millimeter Observer (GISMO) at the IRAM 30m-telescope. These data constitute the widest deep 2mm survey to-date, reaching ... More
A Dark Core in Abell 520Jun 21 2007The rich cluster Abell 520 (z=0.201) exhibits truly extreme and puzzling multi-wavelength characteristics. It may best be described as a "cosmic train wreck." It is a major merger showing abundant evidence for ram pressure stripping, with a clear offset ... More
Horizon-AGN virtual observatory - 1. SED-fitting performance and forecasts for future imaging surveysMar 26 2019Using the ligthcone from the cosmological hydrodynamical simulation Horizon-AGN, we produced a photometric catalogue over $0<z<4$ with apparent magnitudes in COSMOS, DES, LSST-like, and Euclid-like filters at depths comparable to these surveys. The virtual ... More
Spectroscopic Studies of z~5.7 and z~6.5 Galaxies: Implications for ReionizationSep 21 2005The recent development of large, complete samples which identify high-redshift galaxies at z~5.7 and z~6.5 from deep, wide-field surveys provides detailed information on the earliest galaxies, their numbers, spatial and kinematic distributions, and implications ... More
Rainbow Cosmic Shear: Optimisation of Tomographic BinsJan 19 2019In this paper we address the problem of finding optimal cosmic shear tomographic bins. We generalise the definition of a cosmic shear tomographic bin to be a set of commonly labelled voxels in photometric colour space; rather than bins defined directly ... More
Mini-survey of the northern sky to Dec <+30Apr 23 2019We propose an extension of the LSST survey to cover the northern sky to DEC < +30 (accessible at airmass <1.8). This survey will increase the LSST sky coverage by ~9,600 square degrees from 18,900 to 28,500 square degrees (a 50% increase) but use only ... More
CARS: The CFHTLS-Archive-Research Survey II. Weighing dark matter halos of Lyman-break galaxies at z=3-5Mar 23 2009Aims: We measure the clustering properties for a large samples of u- (z~3), g- (z~4), and r- (z~5) dropouts from the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) Deep fields. Methods: Photometric redshift distributions along with simulations ... More
A Study of the Dark Core in A520 with Hubble Space Telescope: The Mystery DeepensFeb 28 2012We present a Hubble Space Telescope/Wide Field Planetary Camera 2 weak-lensing study of A520, where a previous analysis of ground-based data suggested the presence of a dark mass concentration. We map the complex mass structure in much greater detail ... More
Keck-I MOSFIRE spectroscopy of the z~12 candidate galaxy UDFj-39546284Jul 15 2013We report the results of deep (4.6h) H band spectroscopy of the well studied z~12 H-band dropout galaxy candidate UDFj-39546284 with MOSFIRE on Keck-I. These data reach a sensitivity of 5-10 x 10^-19 erg s^-1 cm^-2 per 4.4 Angstrom resolution element ... More
Galaxy Pairs in COSMOS -- Merger Rate Evolution Since z=1Sep 16 2011Nov 26 2011We present results of a statistical study of the cosmic evolution of the mass dependent major-merger rate since z=1. A stellar mass limited sample of close major-merger pairs (the CPAIR sample) was selected from the archive of the COSMOS survey. Pair ... More
Photo-z for weak lensing tomography from space: the role of optical and near-IR photometryMay 10 2007Apr 08 2008We study in detail the photometric redshift requirements needed for tomographic weak gravitational lensing in order to measure accurately the Dark Energy equation of state. In particular, we examine how ground-based photometry (u,g,r,i,z,y) can be complemented ... More
An Atlas of z=5.7 and z=6.5 Ly alpha EmittersSep 06 2010We present an atlas of 88 z~5.7 and 30 z~6.5 Ly alpha emitters obtained from a wide-field narrowband survey. We combined deep narrowband imaging in 120A bandpass filters centered at 8150A and 9140A with deep BVRIz broadband imaging to select high-redshift ... More
Spectroscopic observation of Ly$α$ emitters at z~7.7 and implications on re-ionizationFeb 14 2014May 05 2014We present spectroscopic follow-up observations on two bright Ly$\alpha$ emitter (LAE) candidates originally found by Krug et al. (2012) at a redshift of z~7.7 using the Multi-Object Spectrometer for Infra-Red Exploration (MOSFIRE) at Keck. We rule out ... More
Simulating the COSMOS: The fraction of merging galaxies at high redshiftNov 06 2006Simulations of nearby (0.015 < z < 0.025) SDSS galaxies have been used to reproduce as accurately as possible the appearance that they would have on COSMOS ACS images if they had been observed at z ~ 0.7 and z ~ 1.2. By adding the SDSS galaxies to random ... More
The ASTRODEEP Frontier Fields Catalogues: II - Photometric redshifts and rest-frame properties in Abell-2744 and MACS-J0416Mar 08 2016Mar 14 2016We present the first public release of photometric redshifts, galaxy rest-frame properties and associated magnification values in the cluster and parallel pointings of the first two Frontier Fields, Abell-2744 and MACS-J0416. We exploit a multi-wavelength ... More
The Distribution of Dark Matter Over 3 Decades in Radius in the Lensing Cluster Abell 611Sep 18 2009We present a detailed analysis of the baryonic and dark matter distribution in the lensing cluster Abell 611 (z=0.288), with the goal of determining the dark matter profile over an unprecedented range of cluster-centric distance. By combining three complementary ... More
The XMM-Newton wide-field survey in the COSMOS field: VI. Statistical properties of clusters of galaxiesDec 14 2006We present the results of a search for galaxy clusters in the first 36 XMM-Newton pointings on the COSMOS field. We reach a depth for a total cluster flux in the 0.5-2 keV band of 3x10-15 ergs cm-2 s-1, having one of the widest XMM-Newton contiguous raster ... More
The ASTRODEEP Frontier Fields Catalogues: I - Multiwavelength photometry of Abell-2744 and MACS-J0416Mar 08 2016Mar 14 2016We present multiwavelength photometric catalogues (HST, Spitzer and Hawk-I K band) for the first two of the Frontier Fields, Abell2744 and MACSJ0416 (plus their parallel fields). To detect faint sources even in the central regions of the clusters, we ... More
The effects of environment on morphological evolution between 0<z<1.2 in the COSMOS SurveyMar 26 2007We explore the evolution of the morphology density relation using the COSMOS-ACS survey and previous cluster studies. The Gini parameter measured in a Petrosian aperture is found to be an effective way of selecting early-type galaxies free from systematic ... More
Identification of two bright z>3 submillimeter galaxy candidates in the COSMOS fieldJul 01 2010We present high-resolution interferometric Submillimeter Array (SMA) imaging at 890 microns (~2" resolution) of two millimeter selected galaxies -- MMJ100015+021549 and MMJ100047+021021 -- discovered with the Max-Planck Millimeter Bolometer (MAMBO) on ... More
A proto-cluster at z=2.45Nov 03 2014Nov 06 2014We present the spectroscopic confirmation of a $z=2.45$ proto-cluster. Its member galaxies lie within a radius of 1.4Mpc (physical) on the sky and within $\Delta v \pm 700$km/s along the line of sight. We estimate an overdensity of 10, suggesting that ... More
Deep+Wide Lensing Surveys will Provide Exquisite Measurements of the Dark Matter Halos of Dwarf GalaxiesMay 04 2019The advent of new deep+wide photometric lensing surveys will open up the possibility of direct measurements of the dark matter halos of dwarf galaxies. The HSC wide survey will be the first with the statistical capability of measuring the lensing signal ... More
The Cosmic Evolution of Hard X-ray Selected Active Galactic NucleiOct 22 2004We use highly spectroscopically complete deep and wide-area Chandra surveys to determine the cosmic evolution of hard X-ray-selected AGNs. We determine hard X-ray luminosity functions (HXLFs) for all spectral types and for broad-line AGNs (BLAGNs) alone. ... More
Remarks on the Woods-Saxon PotentialJul 10 2016More recently, comprehensive application results of approximate analytical solutions of the Woods-Saxon potential in closed form for the 5-dimensional Bohr Hamiltonian have been appeared [14] and its comparison to the data for many different nuclei has ... More
SpecPro: An Interactive IDL Program for Viewing and Analyzing Astronomical SpectraMar 16 2011We present an interactive IDL program for viewing and analyzing astronomical spectra in the context of modern imaging surveys. SpecPro's interactive design lets the user simultaneously view spectroscopic, photometric, and imaging data, allowing for rapid ... More
The Evolution of ISM Mass Probed by Dust Emission -- ALMA Observations at z = 0.3 to 2Jan 13 2014Feb 07 2014The use of submm dust continuum emission to probe the mass of interstellar dust and gas in galaxies is empirically calibrated using samples of local star forming galaxies, Planck observations of the Milky Way and high redshift submm galaxies (SMGs). All ... More
X-ray, Optical, and Infrared Imaging and Spectral Properties of the 1 Ms Chandra Deep Field North SourcesJun 20 2002We present the optical, near-infrared, submillimeter, and radio follow-up catalog of the X-ray selected sources from the 1 Ms Chandra observation of the Hubble Deep Field North region. We have B, V, R, I, and z' magnitudes for the 370 X-ray point sources, ... More
A Redshift z = 6.56 Galaxy Behind the Cluster Abell 370Mar 06 2002We report the discovery of a redshift z=6.56 galaxy lying behind the cluster Abell 370. The object HCM 6A was found in a narrowband imaging survey using a 118 Angstrom bandpass filter centered at 9152 Ang in the LRIS camera on the 10 m Keck II Telescope. ... More
Optical and Infrared Properties of the 2 Ms Chandra Deep Field-North X-ray SourcesJun 10 2003We present an optical and NIR catalog for the X-ray sources in the 2 Ms Chandra observation of the Hubble Deep Field-North region. We have high-quality multicolor images of all 503 X-ray point sources and reliable spectroscopic redshifts for 284. We spectroscopically ... More
Dust-obscured star formation and the contribution of galaxies escaping UV/optical color selections at z~2Jun 02 2011A substantial fraction of the stellar mass growth across cosmic time occurred within dust-enshrouded environments. Yet, the exact amount of star-forming activity that took place in high-redshift dusty galaxies currently missed by optical surveys has been ... More
The Dark Matter Halos of Moderate Luminosity X-ray AGN as Determined from Weak Gravitational Lensing and Host Stellar MassesOct 21 2014Understanding the relationship between galaxies hosting active galactic nuclei (AGN) and the dark matter halos in which they reside is key to constraining how black-hole fueling is triggered and regulated. Previous efforts have relied on simple halo mass ... More
Molecular Gas in a Submillimeter Galaxy at z=4.5: Evidence for a Major Merger at 1 Billion Years after the Big BangOct 19 2008We report the detection of CO molecular line emission in the z=4.5 millimeter-detected galaxy COSMOS_J100054+023436 (hereafter: J100+0234) using the IRAM Plateau de Bure interferometer (PdBI) and NRAO's Very Large Array (VLA). The CO(4-3) line as observed ... More
ISM excitation and metallicity of star-forming galaxies at z~3.3 from near-IR spectroscopyFeb 08 2016We study the relationship between stellar mass, star formation rate (SFR),ionization state, and gas-phase metallicity for a sample of 41 normal star-forming galaxies at $3 \lesssim z \lesssim 3.7$. The gas-phase oxygen abundance, ionization parameter, ... More
Obscured star-formation and environment in the COSMOS fieldJul 12 2010We investigate the effects of the environment on star-formation in a sample of massive luminous and ultra-luminous infrared galaxies (LIRGs and ULIRGs) with S(24 micron)>80 uJy and i+<24 in the COSMOS field. We exploit the accurate photometric redshifts ... More
Spitzer bright, UltraVISTA faint sources in COSMOS: the contribution to the overall population of massive galaxies at z=3-7May 21 2015Aug 25 2015We have analysed a sample of 574 Spitzer 4.5 micron-selected galaxies with [4.5]<23 and Ks_auto>24 (AB) over the UltraVISTA ultra-deep COSMOS field. Our aim is to investigate whether these mid-IR bright, near-IR faint sources contribute significantly ... More
Evolution of the Fraction of Clumpy Galaxies at 0.2<z<1.0 in the COSMOS fieldMar 06 2014Using the Hubble Space Telescope/Advanced Camera for Surveys data in the COSMOS field, we systematically searched clumpy galaxies at 0.2<z<1.0 and investigated the fraction of clumpy galaxies and its evolution as a function of stellar mass, star formation ... More
Evolution of the Frequency of Luminous (\geq L_V*) Close Galaxy Pairs at z < 1.2 in the COSMOS FieldMay 16 2007We measure the fraction of luminous galaxies in pairs at projected separations of 5-20 kpc out to z=1.2 in the COSMOS field using ACS images and photometric redshifts derived from an extensive multiwavelength dataset. Analysis of a complete sample of ... More
Lyα Emission from High Redshift Sources in COSMOSAug 29 2012We investigate spectroscopically measured Ly{\alpha} equivalent widths and escape fractions of 244 sources of which 95 are Lyman Break Galaxies (LBGs) and 106 Lyman Alpha Emitters (LAEs) at z~4.2, z~4.8, and z~5.6 selected from intermediate and narrow ... More
Scientific Synergy Between LSST and EuclidOct 23 2017Nov 29 2017Euclid and the Large Synoptic Survey Telescope (LSST) are poised to dramatically change the astronomy landscape early in the next decade. The combination of high cadence, deep, wide-field optical photometry from LSST with high resolution, wide-field optical ... More
Optical Selection of Faint AGN in the COSMOS FieldFeb 20 2008We outline a strategy to select faint (i<24.5) type 1 AGN candidates down to the Seyfert/QSO boundary for spectroscopic targeting in the COSMOS field, picking candidates by their nonstellar colors in broadband ground-based photometry and morphological ... More
Relation Between Stellar Mass and Star Formation Activity in GalaxiesAug 20 2008For a mass-selected sample of 66544 galaxies with photometric redshifts from the Cosmic Evolution Survey (COSMOS), we examine the evolution of star formation activity as a function of stellar mass in galaxies. We estimate the cosmic star formation rates ... More
A massive, distant proto-cluster at z=2.47 caught in a phase of rapid formation?Jun 04 2015Jun 18 2015Numerical simulations of cosmological structure formation show that the Universe's most massive clusters, and the galaxies living in those clusters, assemble rapidly at early times (2.5 < z < 4). While more than twenty proto-clusters have been observed ... More
Near-Infrared MOSFIRE Spectra of Dusty Star-Forming Galaxies at 0.2<z<4Mar 29 2017We present near-infrared and optical spectroscopic observations of a sample of 450$\mu$m and 850$\mu$m-selected dusty star-forming galaxies (DSFGs) identified in a 400 arcmin$^2$ area in the COSMOS field. Thirty-one sources of the 102 targets were spectroscopically ... More
Unveiling a population of galaxies harboring low-mass black holes with X-raysMay 16 2013We report the discovery of three low-mass black hole candidates residing in the centers of low-mass galaxies at z<0.3 in the Chandra Deep Field - South Survey. These black holes are initially identified as candidate active galactic nuclei based on their ... More
Magellan Spectroscopy of AGN Candidates in the COSMOS FieldJun 01 2006We present spectroscopic redshifts for the first 466 X-ray and radio-selected AGN targets in the 2 deg^2 COSMOS field. Spectra were obtained with the IMACS instrument on the Magellan (Baade) telescope, using the nod-and-shuffle technique. We identify ... More
Dynamical Characterization of Galaxies at z~4-6 via Tilted Ring Fitting to ALMA [CII] ObservationsSep 14 2017Until recently, determining the rotational properties of galaxies in the early universe (z>4, Universe age <1.5Gyr) was impractical, with the exception of a few strongly lensed systems. Combining the high resolution and sensitivity of ALMA at (sub-) millimeter ... More
Characterisation of SCUBA-2 450um and 850um-selected Galaxies in the COSMOS FieldFeb 11 2013Sep 04 2013We present deep 450um and 850um observations of a large, uniformly covered 394arcmin^2 area in the COSMOS field obtained with the SCUBA-2 instrument on the James Clerk Maxwell Telescope (JCMT). We achieve root-mean-square noise values of 4.13mJy at 450um ... More
The Radio/Optical Catalog of the SSA13 FieldJul 04 2006We present a 1.4-GHz catalog of 810 radio sources (560 sources in the complete sample) with 1.8" resolution found within a 17' radius in the SSA13 field (RA=13h12m,DEC=42d38'). The radio image from the VLA has an rms noise level of 4.82 microJy/beam at ... More
WFIRST: The Essential Cosmology Space Observatory for the Coming DecadeApr 02 2019Two decades after its discovery, cosmic acceleration remains the most profound mystery in cosmology and arguably in all of physics. Either the Universe is dominated by a form of dark energy with exotic physical properties not predicted by standard model ... More
The Rise and Fall of Passive Disk Galaxies: Morphological Evolution Along the Red Sequence Revealed by COSMOSDec 06 2009Jul 21 2010The increasing abundance of passive "red-sequence" galaxies since z=1-2 is mirrored by a coincident rise in the number of galaxies with spheroidal morphologies. In this paper, however, we show that in detail the correspondence between galaxy morphology ... More
The Opacity of Galactic Disks at z~0.7Mar 17 2010We compare the surface brightness-inclination relation for a sample of COSMOS pure disk galaxies at z~0.7 with an artificially redshifted sample of SDSS disks well matched to the COSMOS sample in terms of rest-frame photometry and morphology, as well ... More
The COSMOS Survey: Hubble Space Telescope / Advanced Camera for Surveys (HST/ACS) Observations and Data ProcessingMar 05 2007We describe the details of the Hubble Space Telescope (HST) Advanced Camera for Surveys / Wide Field Channel (ACS/WFC) observations of the COSMOS field, including the data calibration and processing procedures. We obtained a total of 583 orbits of HST ... More
A robust morphological classification of high-redshift galaxies using support vector machines on seeing limited images. II. Quantifying morphological k-correction in the COSMOS field at 1<z<2: Ks band vs. I bandNov 06 2008Feb 24 2009We quantify the effects of \emph{morphological k-correction} at $1<z<2$ by comparing morphologies measured in the K and I-bands in the COSMOS area. Ks-band data have indeed the advantage of probing old stellar populations for $z<2$, enabling a determination ... More
Designing Future Dark Energy Space Mission: I. Building Realistic Galaxy Spectro-Photometric Catalogs and their first applicationsFeb 04 2009Jul 13 2009Future dark energy space missions such as JDEM and EUCLID are being designed to survey the galaxy population to trace the geometry of the universe and the growth of structure, which both depend on the cosmological model. To reach the goal of high precision ... More
Late-stage galaxy mergers in COSMOS to z~1Jun 09 2014The role of major mergers in galaxy and black hole formation is not well constrained. To help address this, we develop an automated method to identify late-stage galaxy mergers before coalescence of the galactic cores. The resulting sample of mergers ... More
The Bimodal Galaxy Stellar Mass Function in the COSMOS Survey to z~1: A Steep Faint End and a New Galaxy DichotomyOct 29 2009We present a new analysis of stellar mass functions (MF) in the COSMOS field to fainter limits than has been previously probed to z~1. Neither the total nor the passive or star-forming MF can be well fit with a single Schechter function once one probes ... More
Detecting high redshift evolved galaxies as the hosts of optically faint hard X-ray sourcesFeb 18 2001We combine deep Subaru near-infrared images of the massive lensing clusters A2390 and A370 with Keck optical data to map the spectral energy distributions (SEDs) of Chandra X-ray sources lying behind the clusters. The three sources behind A2390 are found ... More
The Cosmic Evolution Survey (COSMOS): The morphological content and enviromental dependence of the galaxy color-magnitude relation at z~0.7Jan 17 2007We study the enviromental dependence and the morphological composition of the galaxy color-magnitude diagram at z~0.7, using a pilot sub-sample of ~2000 galaxies from the COSMOS surve, with I_AB<24, photometric redshift within 0.61<z<0.85 and galaxy morphologies ... More
The stellar content of the COSMOS field as derived from morphological and SED based gtar/galaxy SeparationDec 13 2006Dec 14 2006We report on the stellar content of the COSMOS two degree field, as derived from a rigorous star/galaxy separation approach developed for using stellar sources to define the point spread function variation map used in a study of weak galaxy lensing. The ... More
ISM Masses and Star Formation at z = 1 to 6 ALMA Observations of Dust Continuum in 180 Galaxies in COSMOSMay 08 2015Mar 01 2016ALMA Cycle 2 observations of the long wavelength dust emission in 180 star-forming (SF) galaxies are used to investigate the evolution of ISM masses at z = 1 to 6.4. The ISM masses exhibit strong increases from z = 0 to $\rm <z>$ = 1.15 and further to ... More
Discovery of the Most-Distant Double-Peaked Emitter at z=1.369Jan 19 2009We report the discovery of the most-distant double-peaked emitter, CXOECDFS J033115.0-275518, at z=1.369. A Keck/DEIMOS spectrum shows a clearly double-peaked broad Mg II $\lambda2799$ emission line, with FWHM 11000 km/s for the line complex. The line ... More
Automated selection and characterization of emission-line sources in ACS WFC grism dataMar 12 2007We present complimentary techniques to find emission-line targets and measure their properties in a semi-automated fashion from grism observations obtained with the Advanced Camera for Surveys aboard the Hubble Space Telescope. The first technique is ... More
The Quasar-LBG Two-point Angular Cross-correlation Function at z ~ 4 in the COSMOS FieldJul 19 2015Aug 20 2015In order to investigate the origin of quasars, we estimate the bias factor for low-luminosity quasars at high redshift for the first time. In this study, we use the two-point angular cross-correlation function (CCF) for both low-luminosity quasars at ... More
The DEIMOS 10k spectroscopic survey catalog of the COSMOS fieldMar 25 2018We present a catalog of 10718 objects in the COSMOS field observed through multi-slit spectroscopy with the Deep Imaging Multi-Object Spectrograph (DEIMOS) on the Keck II telescope in the wavelength range ~5500-9800A. The catalog contains 6617 objects ... More
Reconciling Mass Functions with the Star-Forming Main Sequence Via MergersMar 01 2017We combine star formation along the `main sequence', quiescence, and clustering and merging to produce an empirical model for the evolution of individual galaxies. Main sequence star formation alone would significantly steepen the stellar mass function ... More
A Tight Relation Between N/O Ratio and Galaxy Stellar Mass Can Explain the Evolution of Strong Emission Line Ratios with RedshiftMay 13 2016The offset of high redshift star-forming galaxies in the [OIII]/H$\beta$ versus [NII]/H$\alpha$ (O3N2) diagram in comparison with the local star-forming galaxy sequence is now well established. The physical origin of the shift is the subject of some debate, ... More
Far-Infrared Properties of Type 1 QuasarsMar 08 2013We use the Spitzer Space Telescope Enhanced Imaging Products (SEIP) and the Spitzer Archival Far-InfraRed Extragalactic Survey (SAFIRES) to study the spectral energy distributions of spectroscopically confirmed type 1 quasars selected from the Sloan Digital ... More
Rest-frame Optical Emission Lines in Far-Infrared Selected Galaxies at z<1.7 from the FMOS-COSMOS SurveyMay 13 2015May 15 2015We have used FMOS on Subaru to obtain near-infrared spectroscopy of 123 far-infrared selected galaxies in COSMOS and obtain the key rest-frame optical emission lines. This is the largest sample of infrared galaxies with near-infrared spectroscopy at these ... More
Metallicity and Age of the Stellar Stream Around the Disk Galaxy NGC 5907Jul 13 2016Stellar streams have become central to studies of the interaction histories of nearby galaxies. To characterize the most prominent parts of the stellar stream around the well-known nearby (d = 17 Mpc) edge-on disk galaxy NGC 5907, we have obtained and ... More
The Interstellar Medium In Galaxies Seen A Billion Years After The Big BangMar 26 2015Evolution in the measured rest frame ultraviolet spectral slope and ultraviolet to optical flux ratios indicate a rapid evolution in the dust obscuration of galaxies during the first 3 billion years of cosmic time (z>4). This evolution implies a change ... More
Identifying Luminous AGN in Deep Surveys: Revised IRAC Selection CriteriaJan 18 2012Spitzer IRAC selection is a powerful tool for identifying luminous AGN. For deep IRAC data, however, the AGN selection wedges currently in use are heavily contaminated by star-forming galaxies, especially at high redshift. Using the large samples of luminous ... More
COLDz: Karl G. Jansky Very Large Array discovery of a gas-rich galaxy in COSMOSDec 03 2014The broad spectral bandwidth at mm and cm-wavelengths provided by the recent upgrades to the Karl G. Jansky Very Large Array (VLA) has made it possible to conduct unbiased searches for molecular CO line emission at redshifts, z > 1.31. We present the ... More
The Spitzer Archival Far-InfraRed Extragalactic SurveyMar 30 2015We present the Spitzer Archival Far-InfraRed Extragalactic Survey (SAFIRES). This program produces refined mosaics and source lists for all far-infrared extragalactic data taken during the more than six years of the cryogenic operation of the Spitzer ... More
Environmental Effects on the Star Formation Activity in Galaxies at z=1.2 in the COSMOS FieldMay 25 2009May 27 2009We investigate the relation between the star-formation activity in galaxies and environment at z=1.2 in the COSMOS field, using the fraction of [OII] emitters and the local galaxy density. The fraction of [OII] emitters appears to be almost constant over ... More
Are Dusty Galaxies Blue? Insights on UV Attenuation from Dust-Selected GalaxiesOct 02 2014Galaxies' rest-frame ultraviolet (UV) properties are often used to directly infer the degree to which dust obscuration affects the measurement of star formation rates. While much recent work has focused on calibrating dust attenuation in galaxies selected ... More
Constraints on the faint end of the quasar luminosity function at z~5 in the COSMOS fieldJul 06 2012We present the result of our low-luminosity quasar survey in the redshift range of 4.5 < z < 5.5 in the COSMOS field. Using the COSMOS photometric catalog, we selected 15 quasar candidates with 22 < i' < 24 at z~5, that are ~ 3 mag fainter than the SDSS ... More
AGN Host Galaxy Morphologies in COSMOSSep 01 2008We use HST/ACS images and a photometric catalog of the COSMOS field to analyze morphologies of the host galaxies of approximately 400 AGN candidates at redshifts 0.3 < z < 1.0. We compare the AGN hosts with a sample of non-active galaxies drawn from the ... More
Star-forming galaxies versus low- and high-excitation radio AGN in the VLA-COSMOS 3GHz Large ProjectMar 18 2016We study the composition of the faint radio population selected from the VLA-COSMOS 3GHz Large Project, a radio continuum survey performed at 10 cm wavelength. The survey covers the full 2 square degree COSMOS field with mean $rms\sim2.3$ $\mu$Jy/beam, ... More
Newly-quenched galaxies as the cause for the apparent evolution in average size of the populationFeb 20 2013Jul 08 2013Abridged. We use COSMOS to study in a self-consistent way the change in the number densities of quenched early-type galaxies (Q-ETGs) of a given size over the interval 0.2 < z < 1.0 to study the claimed size evolution of these galaxies. At 10^10.5<Mgalaxy<10^11 ... More
Star formation rates in Lyman break galaxies: radio stacking of LBGs in the COSMOS field and the sub-$μ$Jy radio source populationAug 18 2008We present an analysis of the radio properties of large samples of Lyman Break Galaxies (LBGs) at $z \sim 3$, 4, and 5 from the COSMOS field. The median stacking analysis yields a statistical detection of the $z \sim 3$ LBGs (U-band drop-outs), with a ... More
An unusually brilliant transient in the galaxy Messier 85May 24 2007Historically, variable and transient sources have both surprised astronomers and provided new views of the heavens. Here we report the discovery of an optical transient in the outskirts of the lenticular galaxy Messier 85 in the Virgo Cluster. With a ... More
The SPLASH survey: Quiescent galaxies are more strongly clustered but are not necessarily located in high-density environmentsNov 12 2015Dec 28 2015We use the stellar-mass-selected catalog from the Spitzer Large Area Survey with Hyper-Suprime-Cam (SPLASH) in the COSMOS field to study the environments of galaxies via galaxy density and clustering analyses up to $z \sim 2.5$. The clustering strength ... More
Rest-UV Absorption Lines as Metallicity Estimator: the Metal Content of Star-Forming Galaxies at z~5Nov 30 2015We measure a relation between the depth of four prominent rest-UV absorption complexes and metallicity for local galaxies and verify it up to z~3. We then apply this relation to a sample of 224 galaxies at 3.5 < z < 6.0 (<z> = 4.8) in COSMOS, for which ... More
A Deep, Wide Field, Optical, and Near Infrared Catalog of a Large Area around the Hubble Deep Field NorthDec 29 2003We have conducted a deep multi-color imaging survey of 0.2 degrees^2 centered on the Hubble Deep Field North (HDF-N). We shall refer to this region as the Hawaii-HDF-N. Deep data were collected in U, B, V, R, I, and z' bands over the central 0.2 degrees^2 ... More
The Properties of Microjansky Radio Sources in the HDF-N, SSA13, and SSA22 FieldsNov 05 2002(abridged) We present multiwavelength observations for a large sample of microjansky radio sources detected in ultradeep 1.4GHz maps centered on the Hubble Deep Field-North (HDF-N) and the Hawaii Survey Fields SSA13 and SSA22. Our spectroscopic redshifts ... More
Ultra-deep catalog of X-ray groups in the Extended Chandra Deep Field SouthJan 14 2015Apr 17 2015Ultra-deep observations of ECDF-S with Chandra and XMM-Newton enable a search for extended X-ray emission down to an unprecedented flux of $2\times10^{-16}$ ergs s$^{-1}$ cm$^{-2}$. We present the search for the extended emission on spatial scales of ... More
Bars in early- and late-type disks in COSMOSJan 11 2010Jul 06 2010We investigate the (large-scale) bar fraction in a mass-complete sample of M > 10^10.5 Msun disk galaxies at 0.2 < z < 0.6 in the COSMOS field. The fraction of barred disks strongly depends on mass, disk morphology, and specific star formation rate (SSFR). ... More
Analytical solutions for the Bohr Hamiltonian with the Woods-Saxon potentialJun 24 2015Approximate analytical solutions in closed form are obtained for the 5-dimensional Bohr Hamiltonian with the Woods-Saxon potential, taking advantage of the Pekeris approximation and the exactly soluble one-dimensional extended Woods-Saxon potential with ... More
Obscured Active Galactic Nuclei triggered in compact star-forming galaxiesDec 07 2016We present a structural study of 182 obscured Active Galactic Nuclei (AGNs) at z<=1.5, selected in the COSMOS field from their extreme infrared to X-ray luminosity ratio and their negligible emission at optical wavelengths. We fit optical to far-infrared ... 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
The Cosmic Evolution Survey (COSMOS) -- OverviewDec 12 2006The Cosmic Evolution Survey (COSMOS) is designed to probe the correlated evolution of galaxies, star formation, active galactic nuclei (AGN) and dark matter (DM) with large-scale structure (LSS) over the redshift range z $> 0.5 $ to 6. The survey includes ... More
The Nature of Low-Density Star FormationMar 13 2019How do stars manage to form within low-density, HI-dominated gas? Such environments provide a laboratory for studying star formation with physical conditions distinct from starbursts and the metal-rich disks of spiral galaxies where most effort has been ... More
Galaxy Stellar Mass Assembly between 0.2<z<2 from the S-COSMOS surveyFeb 28 2009Dec 03 2009We follow the galaxy stellar mass assembly by morphological and spectral type in the COSMOS 2-deg^2 field. We derive the stellar mass functions and stellar mass densities from z=2 to z=0.2 using 196,000 galaxies selected at F(3.6 micron) > 1 microJy with ... More