Searching for luminous absorbed sources in the WISE AGN catalogue

Abstract

Mid-IR colour selection techniques have proved to be very efficient in finding AGN. This is because the AGN heats the surrounding dust producing warm mid-IR colours. Using the WISE 3.6, 4.5 and 12 $\mu m$ colours, the largest sample of IR selected AGN has already been produced containing 1.4 million AGN over the whole sky. Here, we explore the X-ray properties of this AGN sample by cross-correlating it with the subsample of the 3XMM X-ray catalogue that has available X-ray spectra and at the same time optical spectroscopy from SDSS. Our goal is to find rare luminous obscured AGN. Our final sample contains 65 QSOs with $\log \nu {\mathrm{L}}_{\nu }\ge 46.2$\,erg\,s${}^{-1}$. This IR luminosity cut corresponds to $\log {\mathrm{L}}_{\mathrm{X}}\approx 45$\,erg\,s${}^{-1}$, at the median redshift of our sample ($z=2.3$), that lies at the bright end of the X-ray luminosity function at $z>2$. The X-ray spectroscopic analysis reveals seven obscured AGN having a column density ${\mathrm{N}}_{\mathrm{H}}>10^{22}\mathrm{c}{\mathrm{m}}^{-2}$. Six of them show evidence for broad [CIV] absorption lines and five are classified as BALQSOs. We fit the optical spectra of our X-ray absorbed sources to estimate the optical reddening. We find that none of these show any obscuration according to the optical continuum. These sources add to the growing evidence for populations of luminous QSOs with evidence for substantial absorption by outflowing ionised material, similar to those expected to be emerging from their absorbing cocoons in the framework of AGN/galaxy co-evolution.

arXiv comment10 pages, 5 figures, 3 Tables, MNRAS accepted

References in corpus (55)

• The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
• The Leiden/Argentine/Bonn (LAB) Survey of Galactic HI: Final data release of the combined LDS and IAR surveys with improved stray-radiation corrections
• The Spitzer Space Telescope Mission
• The Eleventh and Twelfth Data Releases of the Sloan Digital Sky Survey: Final Data from SDSS-III
• A Cosmological Framework for the Co-Evolution of Quasars, Supermassive Black Holes, and Elliptical Galaxies: I. Galaxy Mergers & Quasar Activity
• A Quantitative Comparison of SMC, LMC, and Milky Way UV to NIR Extinction Curves
• Cosmological Evolution of the Hard X-ray AGN Luminosity Function and the Origin of the Hard X-ray Background
• Mid-Infrared Selection of Active Galaxies
• The SDSS Quasar Survey: Quasar Luminosity Function from Data Release Three
• Mid-Infrared Selection of AGN with the Wide-Field Infrared Survey Explorer. I. Characterizing WISE-Selected AGN in COSMOS
• Obscured and unobscured active galactic nuclei in the Spitzer Space Telescope First Look Survey
• 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
• Identifying Luminous AGN in Deep Surveys: Revised IRAC Selection Criteria
• AGN Dusty Tori: I. Handling of Clumpy Media
• Mid-Infrared Selection of Active Galactic Nuclei with the Wide-Field Infrared Survey Explorer. II. Properties of WISE-Selected Active Galactic Nuclei in the NDWFS Boötes Field
• A Catalog of Broad Absorption Line Quasars from the Sloan Digital Sky Survey Third Data Release
• Dust in active nuclei. I. Evidence for "anomalous" properties
• Unusual Broad Absorption Line Quasars from the Sloan Digital Sky Survey
• The evolution of the hard X-ray luminosity function of AGN
• The XMM-Newton serendipitous survey. VII. The third XMM-Newton serendipitous source catalogue
• Using the Bright Ultra-Hard XMM-Newton Survey to define an IR selection of luminous AGN based on WISE colours
• The incidence of obscuration in active galactic nuclei
• On the Nature of Soft X-ray Weak Quasi-Stellar Objects
• Dust Reddening in SDSS Quasars
• The Chandra COSMOS Survey: III. Optical and Infrared Identification of X-ray Point Sources
• Infrared power-law galaxies in the Chandra Deep Field South: AGN and ULIRGs
• X-ray, Optical, and Infrared Imaging and Spectral Properties of the 1 Ms Chandra Deep Field North Sources
• Chasing highly obscured QSOs in the COSMOS field
• The WISSH Quasars Project I. Powerful ionised outflows in hyper-luminous quasars
• Spitzer Power-law AGN Candidates in the Chandra Deep Field-North
• Characterizing the Mid-IR Extragalactic Sky with WISE and SDSS
• X-shooter reveals powerful outflows in z~1.5 X-ray selected obscured quasi stellar objects
• The effect of radiation pressure on dusty absorbing gas around AGN
• Identification of 1.4 Million AGNs in the Mid-Infrared using WISE Data
• The X-Ray to Mid-Infrared Relation of AGN at High Luminosity
• Revisiting the relationship between 6 μm and 2-10 keV continuum luminosities of AGN
• Mid-infrared properties of X-ray sources in the Extended Groth Strip
• XMM and Chandra measurements of the AGN intrinsic absorption: dependence on luminosity and redshift
• The cosmological properties of AGN in the XMM-Newton Hard Bright Survey
• The X-ray luminosity function of Active Galactic Nuclei in the redshift interval z=3-5
• XMM-Newton observations of the Lockman Hole IV: spectra of the brightest AGN
• AGN are cooler than you think: the intrinsic far-IR emission from QSOs
• XMM-Newton observations of Extremely Red Objects and the link with luminous, X-ray obscured Quasars
• Mid-infrared Properties and Color Selection for X-ray Detected AGN in the MUSYC ECDF-S field
• The XMM-Newton bright serendipitous survey. Identification and optical spectral properties
• Searching for mid-IR obscured AGN in the CDF-N
• A survey of hard spectrum ROSAT sources 2: optical identification of hard sources
• XMM-NEWTON Observations of Red AGN
• On R-W1 as A Diagnostic to Discover Obscured Active Galactic Nuclei in Wide-Area X-ray Surveys
• The nature of X-ray absorbed QSOs
• Unobscured QSO2: A New Class of Objects?
• XMMFITCAT: The XMM-Newton spectral-fit database
• Orbit of the young very low-mass spectroscopic binary CHXR 74
• X-ray selected BALQSOs
• VLT/FORS2 observations of the optical counterpart of the isolated neutron star RBS 1774

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• Heavy X-ray obscuration in the most-luminous galaxies discovered by WISE
• An obscured AGN population hidden in the VIPERS galaxies: identification through spectral energy distribution decomposition
• The relation between AGN type and host galaxy properties
• Chandra reveals a luminous Compton-thick QSO powering a $Ly\alpha$ blob in a $z=4$ starbursting protocluster
• X-ray properties of dust-obscured galaxies with broad optical/UV emission lines
• Fast SMBH growth in the SPT2349--56 protocluster at $z=4.3$
• BAT AGN Spectroscopic Survey -- XIII. The nature of the most luminous obscured AGN in the low-redshift universe
• Identification of AGN in the XMM-Newton X-ray survey of the SMC
• Forward modeling the multiwavelength properties of Active Galactic Nuclei: application to X-ray and WISE mid-infrared samples
• The $XXL$ survey: XL. Obscuration properties of red AGN in $XXL-N$
• Obscuration properties of mid-IR selected AGN
• A search for X-ray absorbed sources in the 3XMM catalogue, using photometric redshifts and Bayesian spectral fits
• Harnessing the XMM-Newton data: X-ray spectral modelling of 4XMM-DR11 detections and 4XMM-DR11s sources