J/ApJ/731/97 Variable AGNs in GOODS fields (Sarajedini+, 2011)
Variability and multiwavelength-detected active galactic nuclei in the GOODS fields. Sarajedini V.L., Koo D.C., Klesman A.J., Laird E.S., Perez Gonzalez P.G., Mozena M. <Astrophys. J., 731, 97 (2011)> =2011ApJ...731...97S
ADC_Keywords: Active gal. nuclei ; Photometry, HST ; Redshifts ; X-ray sources ; Infrared sources Keywords: galaxies: active - surveys Abstract: We identify 85 variable galaxies in the GOODS North and South fields using five epochs of Hubble Space Telescope Advance Camera for Survey V-band (F606W) images spanning 6 months. The variables are identified through significant flux changes in the galaxy's nucleus and represent ∼2% of the survey galaxies. With the aim of studying the active galaxy population in the GOODS fields, we compare the variability-selected sample with X-ray and mid-IR active galactic nucleus (AGN) candidates. Forty-nine percent of the variables are associated with X-ray sources identified in the 2Ms Chandra surveys. Twenty-four percent of X-ray sources likely to be AGNs are optical variables and this percentage increases with decreasing hardness ratio of the X-ray emission. Stacking of the non-X-ray-detected variables reveals marginally significant soft X-ray emission. Forty-eight percent of mid-IR power-law sources are optical variables, all but one of which is also X-ray detected. Thus, about half of the optical variables are associated with either X-ray or mid-IR power-law emission. The slope of the power-law fit through the Spitzer IRAC bands indicates that two-thirds of the variables have BLAGN-like spectral energy distributions. Among those galaxies spectroscopically identified as AGNs, we observe variability in 74% of broad-line AGNs and 15% of NLAGNs. The variables are found in galaxies extending to z∼3.6. Description: The GOODS fields consist of two regions of the sky, each ∼130arcmin2 in size and located at RA=3:32, DE=-27:48 and RA=12:37, DE=+62:15. These fields were imaged with HST's Advance Camera for Surveys Wide Field Camera (ACS WFC) in four passbands (F435W, F606W, F775W, and F850LP). We chose to perform our analysis using the F606W (V-band). The south field images were obtained between 2002 August 1 and 2003 February 5 with five epochs separated by ∼45 days for a total time baseline of 6 months. The north field images were obtained between 2002 November 21 and 2003 May 23 with the same time sampling as in the south. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 76 85 Variable nucleus galaxies in GOODS
See also: B/hst : HST Archived Exposures Catalog (STScI, 2007) II/261 : GOODS initial results (Giavalisco+, 2004) J/ApJS/193/13 : Spitzer/IRAC sources in the EGS I. SEDs (Barro+, 2011) J/ApJ/723/737 : Variability selected AGNs in GOODS (Villforth+,2010) J/ApJ/697/1369 : GOODS Ks-selected multiwavelength compilations (Bundy+, 2009) J/ApJ/675/234 : Mass functions for galaxies z<4 (Perez-Gonzalez+, 2008) J/ApJ/689/687 : GOODS-N spectroscopic survey (Barger+, 2008) J/ApJS/179/19 : CDFS survey: 2 Ms source catalogs (Luo+, 2008) J/A+A/478/83 : GOODS-South Field VLT/FORS2 redshifts. III. (Vanzella+, 2008) J/ApJ/653/1004 : Galaxies at 1.4≲z≲3.0 in GOODS-North Field (Reddy+, 2006) J/ApJ/640/603 : Catalog of AGNs in the GOODS fields (Treister+, 2006) J/A+A/437/883 : K20 survey: spectroscopic catalogue (Mignoli+, 2005) J/AJ/127/3121 : TKRS catalog of GOODS-North Field (Wirth+, 2004) J/ApJS/155/271 : CDF-S: Optical spectroscopy (Szokoly+, 2004) J/A+A/428/1043 : Redshifts from VIMOS VLT Deep Survey (Le Fevre+, 2004) J/AJ/127/3137 : Hawaii redshifts in the ACS-GOODS region (Cowie+, 2004) J/AJ/127/180 : The Hawaii Hubble Deep Field North (Capak+, 2004) J/A+A/392/395 : Ks-band magnitudes of the K20 sample (Cimatti+, 2002) J/AJ/121/2895 : HDF-N Caltech faint galaxy redshift survey. XIII. (Cohen 2001) J/ApJ/513/34 : HDF photometric redshifts catalog (Fernandez-Soto+, 1999) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 5 I5 --- Name GOODS identification number 7- 17 F11.7 deg RAdeg Right ascension in decimal degrees (J2000) 19- 29 F11.7 deg DEdeg Declination in decimal degrees (J2000) 31- 36 F6.3 mag Vmag Mean V2.5 magnitude (mean HST/ACS V magnitude within r=2.5 pixel aperture) 38- 42 F5.3 mag CI Concentration index (magnitude difference between the r=2.5pix photometry and the r=5pix) 44- 48 F5.3 mag err Standard deviation around the mean (1) 50- 55 F6.3 --- Signi Variability significance 57- 61 F5.3 --- z Redshift 63- 64 A2 --- n_z [ph/sp] (ph)otometric or (sp)ectroscopic redshift 66 I1 --- r_z ?=- Redshift reference (2) 68- 76 A9 --- X/IR X-ray (from Chandra 2Ms) and/or IR (from Spitzer/IRAC) AGN?
Note (1): Standard deviation values are calculated using r=2.5 pixel apertures for extended sources and r=5 pixel apertures for unresolved sources. Note (2): Reference as follows: 1 = Barger et al. 2008, Cat. J/ApJ/689/687; 2 = Wirth et al. 2004, Cat. J/AJ/127/3121; 3 = Reddy et al. 2006, Cat. J/ApJ/653/1004; 4 = Perez-Gonzalez et al. (2005ApJ...630...82P, 2008, Cat. J/ApJ/675/234); 5 = Popesso et al. 2009A&A...494..443P; 6 = Bundy et al. 2009, Cat. J/ApJ/697/1369.
History: From electronic version of the journal
(End) Emmanuelle Perret [CDS] 19-Oct-2012
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