The Chandra Multi-Wavelength Project: Optical Spectroscopy and the Broadband Spectral Energy Distributions of X-ray Selected AGN

Abstract

From optical spectroscopy of X-ray sources observed as part of ChaMP, we present redshifts and classifications for a total of 1569 Chandra sources from our targeted spectroscopic follow up using the FLWO, SAAO, WIYN, CTIO, KPNO, Magellan, MMT and Gemini telescopes, and from archival SDSS spectroscopy. We classify the optical counterparts as 50% BLAGN, 16% NELG, 14% ALG, and 20% stars. We detect QSOs out to z~5.5 and galaxies out to z~3. We have compiled extensive photometry from X-ray to radio bands. Together with our spectroscopic information, this enables us to derive detailed SEDs for our extragalactic sources. We fit a variety of templates to determine bolometric luminosities, and to constrain AGN and starburst components where both are present. While ~58% of X-ray Seyferts require a starburst event to fit observed photometry only 26% of the X-ray QSO population appear to have some kind of star formation contribution. This is significantly lower than for the Seyferts, especially if we take into account torus contamination at z>1 where the majority of our X-ray QSOs lie. In addition, we observe a rapid drop of the percentage of starburst contribution as X-ray luminosity increases. This is consistent with the quenching of star formation by powerful QSOs, as predicted by the merger model, or with a time lag between the peak of star formation and QSO activity. We have tested the hypothesis that there should be a strong connection between X-ray obscuration and star-formation but we do not find any association between X-ray column density and star formation rate both in the general population or the star-forming X-ray Seyferts. Our large compilation also allows us to report here the identification of 81 XBONG, 78 z>3 X-ray sources and 8 Type-2 QSO candidates. Also we have identified the highest redshift (z=5.4135) X-ray selected QSO with optical spectroscopy.

17 pages, 16 figures, accepted for publication in ApJS. Full data table and README file can be found online at http://hea-www.harvard.edu/~pgreen/Papers.html

References in corpus (4)

• An Observational Determination of the Bolometric Quasar Luminosity Function
• Chandra Multiwavelength Project X-ray Point Source Number Counts and the Cosmic X-ray Background
• AEGIS: Demographics of X-ray and Optically Selected AGNs
• A Full Year's Chandra Exposure on SDSS Quasars from the Chandra Multiwavelength Project

Cited by in corpus (39)

• Cosmic X-ray Surveys of Distant Active Galaxies: The Demographics, Physics, and Ecology of Growing Supermassive Black Holes
• BAT AGN Spectroscopic Survey I: Spectral Measurements, Derived Quantities, and AGN Demographics
• Accreting SMBHs in the COSMOS field and the connection to their host galaxies
• The Chandra COSMOS Survey: III. Optical and Infrared Identification of X-ray Point Sources
• The SDSS-IV extended Baryon Oscillation Spectroscopic Survey: Quasar Target Selection
• Chandra X-ray and Hubble Space Telescope Imaging of Optically Selected kiloparsec-Scale Binary Active Galactic Nuclei I. Nature of the Nuclear Ionizing Sources
• Double-peaked narrow emission-line galaxies from Sloan Digital Sky Survey. I. Sample and basic properties
• GOODS-Herschel: Ultra-deep XMM-Newton observations reveal AGN/star-formation connection
• The Hard X-Ray Luminosity Function of High-Redshift ($3<z\lesssim 5$) Active Galactic Nuclei
• Spectral Energy Distributions of Type 1 AGN in the COSMOS Survey I - The XMM-COSMOS Sample
• On the formation of the first quasars
• Observational Signatures of High-Redshift Quasars and Local Relics of Black Hole Seeds
• X-ray Properties of Intermediate-mass Black Holes in Active Galaxies. III. Spectral Energy Distribution and Possible Evidence for Intrinsically X-ray-weak AGNs
• Finding Rare AGN: XMM-Newton and Chandra Observations of SDSS Stripe 82
• Chandra High resolution Observations of CID-42, a candidate recoiling SMBH
• Star Formation in Luminous Quasars at 2<z<3
• X-ray Bright Active Galactic Nuclei in Massive Galaxy Clusters II: The Fraction of Galaxies Hosting Active Nuclei
• Star formation in high-redshift quasars: excess [O II] emission in the radio-loud population
• Quasar Variability in the Mid-Infrared
• Herschel-ATLAS: Far-infrared properties of radio-loud and radio-quiet quasars
• Finding Rare AGN: X-ray Number Counts of Chandra Sources in Stripe 82
• The high-redshift (z>3) AGN population in the 4 Ms Chandra Deep Field South
• The Chandra COSMOS Legacy survey: the z>3 sample
• A tale of two feedbacks: star-formation in the host galaxies of radio-AGN
• The Largest X-ray Selected Sample of z>3 AGNs: C-COSMOS & ChaMP
• Star formation in luminous quasar host galaxies at z=1-2
• X-ray properties of BzK-selected galaxies in the deepest X-ray fields
• Quasar feedback in the early Universe: the case of SDSS J1148+5251
• Disentangling star formation and AGN activity in powerful infrared luminous radio galaxies at 1<z<4
• Empirical Links between XRB and AGN accretion using the complete z<0.4 spectroscopic CSC/SDSS Catalog
• Spatially Offset Active Galactic Nuclei. II: Triggering in Galaxy Mergers
• Observational evidence that positive and negative AGN feedback depends on galaxy mass and jet power
• Some Like It Hot: Linking Diffuse X-ray Luminosity, Baryonic Mass, and Star Formation Rate in Compact Groups of Galaxies
• Center for Astrophysics Optical Infrared Science Archive. I. FAST Spectrograph
• Search for anomalous features in gamma-ray blazar spectra corrected for the absorption on the extragalactic background light
• Ultra-diffuse galaxies in the Coma cluster: Probing their origin and AGN occupation fraction
• Where the active galaxies live: a panchromatic view of radio-AGN in the AKARI-NEP field
• Spectral Energy Distribution Modeling of Broad Emission Line Quasars: From X-ray to Radio Wavelengths
• Where's Swimmy?: Mining unique color features buried in galaxies by deep anomaly detection using Subaru Hyper Suprime-Cam data