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J/ApJ/642/673       IR-selected obscured AGN candidates        (Polletta+, 2006)

Chandra and Spitzer unveil heavily obscured quasars in the Chandra/SWIRE survey. Polletta M.D.C., Wilkes B.J., Siana B., Lonsdale C.J., Kilgard R., Smith H.E., Kim D.-W., Owen F., Efstathiou A., Jarrett T., Stacey G., Franceschini A., Rowan-Robinson M., Babbedge T.S.R., Berta S., Fang F., Farrah D., Gonzalez-Solares E., Morrison G., Surace J.A., Shupe D.L. <Astrophys. J., 642, 673-693 (2006)> =2006ApJ...642..673P
ADC_Keywords: Surveys ; Active gal. nuclei ; QSOs ; Photometry, infrared Keywords: galaxies: active - infrared: galaxies - quasars: individual: SWIRE J104409.95+585224.8 - quasars: individual: SWIRE J104406.30+583954.1 - X-rays: galaxies Abstract: Using the large multiwavelength data set in the Chandra/SWIRE Survey (0.6deg2 in the Lockman Hole), we show evidence for the existence of highly obscured (Compton-thick) AGNs, estimate a lower limit to their surface density, and characterize their multiwavelength properties. Two independent selection methods based on the X-ray and infrared spectral properties are presented. The two selected samples contain (1) five X-ray sources with hard X-ray spectra and column densities ≳1024cm-2 and (2) 120 infrared sources with red and AGN-dominated infrared SEDs. We estimate a surface density of at least 25 Compton-thick AGNs deg2 detected in the infrared in the Chandra/SWIRE field, of which 40% show distinct AGN signatures in their optical/near-infrared SEDs, the remaining being dominated by the host galaxy emission. Only ∼33% of all Compton-thick AGNs are detected in the X-rays at our depth [F(0.3-8keV)>10-15ergs/cm2/s]. We report the discovery of two sources in our sample of Compton-thick AGNs, SWIRE J104409.95+585224.8 (z=2.54) and SWIRE J104406.30+583954.1 (z=2.43), which are the most luminous Compton-thick AGNs at high z currently known. The properties of these two sources are discussed in detail with an analysis of their spectra, SEDs, luminosities, and black hole masses. Description: Optical imaging in U, g', r', and i' was obtained with the Mosaic Camera at the Kitt Peak National Observatory (KPNO) Mayall 4m Telescope on 2002 February (g', r', and i') and 2004 January (U). Near-IR Ks imaging observations were carried out with the 200" Hale Telescope of the Palomar Observatory using the Wide Infrared Camera (WIRC) on 2004 March 29 under photometric conditions. Observations with the Infrared Array Camera (IRAC) were performed on 2003 December 5 and 2004 April 24-30, and observations with the Multiband Imaging Photometer (MIPS) were performed on 2003 December 9 and 2004 May 4-11. The Chandra observations were obtained on 2004 September 12-26. A deep, 1.4GHz radio map covering in the Chandra/SWIRE field was obtained at the Very Large Array (VLA) during multiple dates, 2001 December 15, 2002 January-March, and 2003 January 6 (F. Owen et al. 2006, in preparation). Spectroscopic observations were carried out using various facilities, with Hydra on the WIYN Observatory on 2004 February 11-15, with the Low Resolution Imaging Spectrometer (LRIS) on the Keck I telescope on 2004 February 24-25 and 2005 March 34, and with the Gemini Multi-Object Spectrograph (GMOS) on the Gemini Observatory on 2004 February 21-23. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table4.dat 105 120 Properties IR-selected obscured AGN candidates
See also: II/255 : SWIRE ELAIS N1 Source Catalogs (Surace+, 2004) J/A+A/472/805 : Radio-X-ray sources in the HDF(N) region. (Richards+, 2007) J/A+A/467/73 : 3σ hard sample of XMDS survey (Tajer+, 2007) Byte-by-byte Description of file: table4.dat
Bytes Format Units Label Explanations
1- 6 A6 --- --- [SWIRE_] 7- 25 A19 --- SWIRE Source name (JHHMMSS.ss+DDMMSS.s) 27- 35 F9.5 deg RAdeg Right Ascension in decimal degrees (J2000) (1) 37- 45 F9.6 deg DEdeg Declination in decimal degrees (J2000) (1) 47 A1 --- l_r'mag Upper 5σ limit flag on r'mag 48- 52 F5.2 mag r'mag The r' band Vega magnitude (2) 54- 56 I3 uJy F3.6 The 3.6 micron flux density (2) 58- 60 I3 uJy F4.5 The 4.5 micron flux density (2) 62 A1 --- l_F5.8 Upper 5σ limit flag on F5.8um 63- 66 I4 uJy F5.8 The 5.8 micron flux density (2) 68 A1 --- l_F8.0 Upper 5σ limit flag on F8.0um 69- 72 I4 uJy F8.0 The 8.0 micron flux density (2) 74 A1 --- l_F24 Upper 5σ limit flag on F24um 75- 78 I4 uJy F24 The 24 micron flux density (2) 80 A1 --- l_F20cm Upper 5σ limit flag on F20um 81- 85 I5 uJy F20cm ? The 20 cm flux density 87- 88 I2 uJy e_F20cm ? Uncertainty in F20um 90- 94 F5.3 --- zsp ? Spectroscopic redshift 96- 99 F4.2 --- zph Photometric redshift 101-103 A3 --- Cl Source classification (3) 105 A1 --- X [c] Indicates an X-ray detection
Note (1): Infrared coordinates. Note (2): Typical uncertainties to the IR fluxes are ∼10% of the measured fluxes and to the optical magnitudes are around 0.04mag. Note (3): Classes as follows: I = Class I sources are characterized by convex IR SED fitted by a "Torus" template. II = Class II sources show power-law like optical-IR SEDs, similar to Mrk 231 or slightly redder (AV<1). III = Class III sources have power-law like optical-IR SED fitted by a reddened QSO template (AV=0.6-1.0). IV = Class IV sources show signatures from both a starburst and an AGN component. V = Class V sources area characterized by very red optical SEDs and power-law like IR SEDs. VI = Class VI objects are detected only in three bands from 3.6 to 24um.
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 02-May-2008
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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