Optical Identification of the ASCA Large Sky Survey

Abstract

We present results of optical identification of the X-ray sources detected in the ASCA Large Sky Survey. Optical spectroscopic observations were done for 34 X-ray sources which were detected with the SIS in the 2-7 keV band above 3.5 sigma. The sources are identified with 30 AGNs, 2 clusters of galaxies, and 1 galactic star. Only 1 source is still unidentified. The flux limit of the sample corresponds to 1 x 10^{-13} erg s^{-1} cm^{-2} in the 2-10 keV band. Based on the sample, the paper discusses optical and X-ray spectral properties of the AGNs, contribution of the sources to the Cosmic X-ray Background, and redshift and luminosity distributions of the AGNs. An interesting result is that the redshift distribution of the AGNs suggests a deficiency of high-redshift (0.5 < z < 2) and luminous (Lx(2-10 keV) > 10^{44} erg s^{-1}) absorbed narrow-line AGNs (so called type 2 QSOs).

Accepted for publication in ApJ. 57 pages with 13 figures, 9 JPG plates, 5 additional PS tables. Original EPS plates (gzipped format ~1Mbyte/plate) and TeX tables are available from ftp://ftp.kusastro.kyoto-u.ac.jp/pub/akiyama/0001289/

References in corpus (13)

• The distribution of absorbing column densities among Seyfert 2 galaxies
• Hubble Space Telescope Images of a Sample of Twenty Nearby Luminous Quasars
• A Catalog of 200 Galaxy Clusters Serendipitously Detected in the ROSAT PSPC Pointed Observations
• Limits on Cosmological Models From Radio-Selected Gravitational Lenses
• Log N - Log S Relations and Spectral Properties of Sources from the ASCA Large Sky Survey --- their Implications for the Origin of the Cosmic X-ray Background (CXB)
• The contribution of faint AGN to the hard X-ray background
• The average X-ray/gamma-ray spectrum of radio-quiet Seyfert 1s
• ASCA observations of Deep ROSAT fields - II. The 2-10keV AGN luminosity function
• ASCA observations of deep ROSAT fields I. the nature of the X-ray source populations
• ASCA observations of Deep ROSAT fields - III. The Discovery of an Obscured Type 2 AGN at z=0.67
• Hard X-ray emission from extragalactic IRAS 12um sources: constraints on the unified AGN model and the synthesis of the X-ray background
• Optical Identification of the Hardest X-ray Source in the ASCA Large Sky Survey
• The hardest X-ray source in the ASCA Large Sky Survey: Discovery of a new type 2 Seyfert

Cited by in corpus (106)

• Cosmological Evolution of the Hard X-ray AGN Luminosity Function and the Origin of the Hard X-ray Background
• Toward the Standard Population Synthesis Model of the X-Ray Background: Evolution of X-Ray Luminosity and Absorption Functions of Active Galactic Nuclei Including Compton-Thick Populations
• The Cosmic Evolution of Hard X-ray Selected Active Galactic Nuclei
• Dust in active nuclei. I. Evidence for "anomalous" properties
• Absorption Properties and Evolution of Active Galactic Nuclei
• XMM-Newton observation of the Lockman Hole; I. The X-ray Data
• The resolved fraction of the Cosmic X-ray Background
• The evolution of the hard X-ray luminosity function of AGN
• Optical and Infrared Properties of the 2 Ms Chandra Deep Field-North X-ray Sources
• The Fall of AGN and the Rise of Star-Forming Galaxies: A Close Look at the Chandra Deep Field X-ray Number Counts
• Study of the X-Ray Background Spectrum and its Large-Scale Fluctuation with ASCA
• The Chandra Deep Survey of the Hubble Deep Field North Area. II. Results from the Caltech Faint Field Galaxy Redshift Survey Area
• Most Supermassive Black Holes must be Rapidly Rotating
• The Chandra COSMOS Survey: III. Optical and Infrared Identification of X-ray Point Sources
• The HELLAS2XMM survey: IV. Optical identifications and the evolution of the accretion luminosity in the Universe
• X-ray, Optical, and Infrared Imaging and Spectral Properties of the 1 Ms Chandra Deep Field North Sources
• AEGIS-X: The Chandra Deep Survey of the Extended Groth Strip
• Testing current synthesis models of the X-ray background
• The Chandra Deep Field North Survey. VI. The Nature of the Optically Faint X-ray Source Population
• Obscuring Material around Seyfert Nuclei with Starbursts
• The Redshift Evolution of the 2-8 keV X-ray Luminosity Function
• The Changing AGN Population
• The ROSAT Deep Survey: VI. X-ray sources and Optical identifications of the Ultra Deep Survey
• Compton Thick AGN: the dark side of the X-ray background
• The HELLAS2XMM survey: I. The X-ray data and the Log(N)-Log(S)
• The Chandra Deep Field North Survey. XII. The Link Between Faint X-ray and Radio Source Populations
• Detailed Shape and Evolutionary Behavior of the X-ray Luminosity Function of Active Galactic Nuclei
• XMM-Newton observations expose AGN in apparently normal galaxies
• The XMM-Newton wide-field survey in the COSMOS field. IV: X-ray spectral properties of Active Galactic Nuclei
• The HELLAS2XMM survey: VI. X-ray absorption in the 1dfAGN sample through a spectral analysis
• The Quasar Luminosity Function at Redshift 4 with Hyper Suprime-Cam Wide Survey
• The Chandra Multiwavelength Project: Optical Followup of Serendipitous Chandra Sources
• The BeppoSAX High Energy Large Area Survey HELLAS, III: testing synthesis models for the X-ray background
• Optical Identification of the ASCA Medium Sensitivity Survey in the Northern Sky: Nature of Hard X-ray-selected Luminous Active Galactic Nuclei
• The NuSTAR Extragalactic Surveys: Overview and Catalog from the COSMOS Field
• A Comparison of X-ray and Mid-Infrared Selection of Obscured AGN
• The Serendipitous Extragalactic X-Ray Source Identification (SEXSI) Program. III. Optical Spectroscopy
• The NuSTAR Serendipitous Survey: The 40 month Catalog and the Properties of the Distant High Energy X-ray Source Population
• The Chandra Deep Field North Survey. XI. X-ray emission from luminous infrared starburst galaxies
• The OPTX Project II: Hard X-ray Luminosity Functions of Active Galactic Nuclei for z<5
• The Chandra Deep Field North Survey. X. X-ray Emission from Very Red Objects
• The Hellas2XMM survey: III. Multiwavelength observations of hard X-ray selected sources in the PKS 0312-77 field
• The BeppoSAX High Energy Large Area Survey -V. The nature of the hard X-ray source populations and its evolution
• The Serendipitous Extragalactic X-Ray Source Identification (SEXSI) Program: I. Characteristics of the Hard X-Ray Sample
• Conversion of relic gravitational waves into photons in cosmological magnetic fields
• X-ray spectra of XMM-Newton serendipitous medium flux sources
• SPICES II. Optical and Near-Infrared Identifications of Faint X-Ray Sources from Deep Chandra Observations of Lynx
• Black hole mass and Eddington ratio distribution functions of X-ray selected broad-line AGNs at z~1.4 in the Subaru XMM-Newton Deep Field
• The Extended Chandra Deep Field-South Survey: X-ray Point-Source Catalog
• The BeppoSAX High Energy Large Area Survey HELLAS, II: Number counts and X-ray spectral properties
• The X-ray emission of Lyman break galaxies
• The deepest X-ray look at the Universe
• An XMM-Newton Study of the Hard X-ray Sky
• Herschel/HerMES: The X-ray - Infrared correlation for star-forming galaxies at z~1
• Tools for computing the AGN feedback: radio-loudness distribution and the kinetic luminosity function
• Obscured and unobscured AGN populations in a hard-X-ray selected sample of the XMDS survey
• The Chandra X-ray point source catalog in the DEEP2 Galaxy Redshift Survey fields
• The European Large Area ISO Survey V: a BeppoSAX hard X-ray survey of the S1 region
• Looking for obscured QSOs in the X-ray emitting ERO population
• A survey of hard spectrum ROSAT sources 2: optical identification of hard sources
• The Ly-edge paradox and the need for obscured QSOs
• The Calan-Yale Deep Extragalactic Research (CYDER) Survey: Optical Properties and Deep Spectroscopy of Serendipitous X-ray Sources
• Obscured AGN from the ELAIS Deep X-ray Survey
• The X-ray luminosity function of AGN at z~3
• XMM-Newton 13H Deep field - I. X-ray sources
• The X-ray background and the deep X-ray surveys
• The OPTX Project III: X-ray versus Optical Spectral Type for AGNs
• Exploring the spectral properties of faint hard X-ray sources with XMM-Newton
• Comoving Space Density and Obscured Fraction of High-Redshift Active Galactic Nuclei in the Subaru/{\it XMM-Newton} Deep Survey
• An Extragalactic Spectroscopic Survey of the SSA22 Field
• Unobscured QSO2: A New Class of Objects?
• The large-scale bias of the hard X-ray background
• A Hard Medium Survey with ASCA. IV: the Radio-Loud Type 2 QSO AXJ0843+294 2
• The contribution of Quasars to the Far Infrared Background
• Near-Infrared Colors of Hard X-ray Selected Active Galactic Nuclei
• The Phoenix Deep Survey: the radio properties of the hard X-ray selected sample
• The NuSTAR Extragalactic Survey of the James Webb Space Telescope North Ecliptic Pole Time-Domain Field
• The Serendipitous Extragalactic X-Ray Source Identification (SEXSI) Program: II. Optical Imaging
• Seyfert Galaxies and the Hard X-ray Background: Artificial Chandra Observations of z = 0.3 Active Galaxies
• A physical model for the hard X-ray background
• The BeppoSAX High Energy Large Area Survey. IV. On the soft X-ray properties of the hard X-ray-selected HELLAS sources
• The XMM-Newton spectrum of the high-z optically-obscured QSO RX J1343.4+0001: a classic radio quiet QSO
• Dust and gas obscuration in ELAIS Deep X-ray Survey reddened quasars
• The BeppoSAX High Energy Large Area Survey (HELLAS) - VI. The radio properties
• PEARLS: NuSTAR and XMM-Newton Extragalactic Survey of the JWST North Ecliptic Pole Time-Domain Field II
• Unconventional AGN in hard X-ray surveys
• An extreme EXO: a type 2 QSO at z=1.87
• The European Large Area ISO Survey VII: ROSAT observations of ELAIS sources
• XMM-Newton spectra of hard spectrum Rosat AGN: X-ray absorption and optical reddening
• ASCA observations of deep ROSAT fields V. The X-ray spectrum of hard X-ray selected QSOs
• XMM-Newton observations of an absorbed z=0.67 QSO: no dusty torus?
• Near-Infrared Properties of Faint X-rays Sources from NICMOS Imaging in the Chandra Deep Fields
• The obscured QSO 1SAX J1218.9+2958
• Chandra Observations and Optical Identification of Hard X-ray Sources Discovered with ASCA
• Theoretical Models of Multi-waveband QSO Luminosity Functions
• Soft X-ray properties of a high redshift sample of QSOs observed with ROSAT
• Host Galaxies of Hard X-ray Selected Type-2 Active Galactic Nuclei at Intermediate Redshifts
• The XMM-Newton/2dF survey VII. Is there any X-ray absorption in optically selected QSOs?
• Optical Identification of the ASCA Lynx Deep Survey: An Association of QSOs and a Supercluster at z=1.3?
• An Extremely Red Nucleus in an Absorbed QSO at z=0.65
• X-ray Identifications of FIRST Radio Sources in the xBootes Field
• The XMM-SSC survey of hard-spectrum XMM-Newton sources 1: optically bright sources
• On the XMM-Newton spectra of soft X-ray selected QSOs
• The Challenge to Large Optical Telescopes from X-ray Astronomy
• The XMM-Newton/2dF survey - V. the radio properties of the X-ray population
• High Energy Large Area Surveys: from BeppoSAX to Chandra and XMM-Newton