J/ApJS/222/13 Swift AGN and Cluster Survey (SWCL). II. SDSS (Griffin+, 2016)
The Swift AGN and Cluster Survey.
II. Cluster confirmation with SDSS data.
Griffin R.D., Dai X., Kochanek C.S., Bregman J.N.
<Astrophys. J. Suppl. Ser., 222, 13 (2016)>
=2016ApJS..222...13G 2016ApJS..222...13G (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Redshifts ; X-ray sources ; Surveys ;
Photometry, SDSS
Keywords: catalogs; galaxies: clusters: general; galaxies: groups: general;
large-scale structure of universe; surveys
Abstract:
We study 203 (of 442) Swift AGN and Cluster Survey extended X-ray
sources located in the SDSS DR8 footprint to search for galaxy
over-densities in three-dimensional space using SDSS galaxy
photometric redshifts and positions near the Swift cluster candidates.
We find 104 Swift clusters with a >3σ galaxy over-density. The
remaining targets are potentially located at higher redshifts and
require deeper optical follow-up observations for confirmation as
galaxy clusters. We present a series of cluster properties including
the redshift, brightest cluster galaxy (BCG) magnitude, BCG-to-X-ray
center offset, optical richness, and X-ray luminosity. We also detect
red sequences in ∼85% of the 104 confirmed clusters. The X-ray
luminosity and optical richness for the SDSS confirmed Swift clusters
are correlated and follow previously established relations. The
distribution of the separations between the X-ray centroids and the
most likely BCG is also consistent with expectation. We compare the
observed redshift distribution of the sample with a theoretical model,
and find that our sample is complete for z≲0.3 and is still 80%
complete up to z∼0.4, consistent with the SDSS survey depth. These
analysis results suggest that our Swift cluster selection algorithm
has yielded a statistically well-defined cluster sample for further
study of cluster evolution and cosmology. We also match our SDSS
confirmed Swift clusters to existing cluster catalogs, and find 42,
23, and 1 matches in optical, X-ray, and Sunyaev-Zel'dovich catalogs,
respectively, and so the majority of these clusters are new
detections.
Description:
We downloaded all swift/XRT "GRB" observations before 2013 Jul 27, and
reprocessed the data as described in Dai et al. (2015, Paper I,
J/ApJS/218/8). From this, we made images and corresponding exposure
maps in different energy ranges: total (0.2-10keV), soft (0.5-2keV),
and hard (2-10keV). SDSS DR8 provides the optical data for this study.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 95 104 The Swift AGN and Cluster Survey:
SDSS confirmations
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See also:
IX/43 : 1SXPS Swift X-ray telescope point source catalogue (Evans+ 2014)
VIII/91 : Planck Catalog of Compact Sources Release 1 (Planck, 2013)
J/ApJS/218/8 : Swift AGN and Cluster Survey (SACS). I. (Dai+, 2015)
J/A+A/576/A130 : Ultra-deep cat. of X-ray groups in ECDF-S (Finoguenov+, 2015)
J/ApJS/216/28 : SWXCS III. Cluster cat. from 2005-2012 Swift data (Liu+, 2015)
J/MNRAS/437/2607 : Low X-ray luminosity galaxy clusters (Nilo Castellon+, 2014)
J/A+A/551/A142 : 7 year Swift-XRT point source catalog (1SWXRT) (D'Elia+, 2013)
J/ApJ/763/127 : Galaxy clusters discovered in SPT survey (Reichardt+, 2013)
J/A+A/547/A57 : Swift X-ray Telescope Cluster Survey (Tundo+, 2012)
J/MNRAS/423/1024 : XCS-DR1 Cluster Catalogue (Mehrtens+, 2012)
J/ApJS/199/34 : Clusters of galaxies in SDSS-III (Wen+, 2012)
J/A+A/536/A8 : Planck early results. VIII. ESZ sample. (Planck+, 2011)
J/A+A/534/A109 : MCXC Meta-Catalogue X-ray galaxy Clusters (Piffaretti+, 2011)
J/A+A/528/A122 : SwiftFT catalog (Puccetti+, 2011)
J/ApJS/191/254 : GMBCG galaxy cluster catalog from SDSS DR7 (Hao+, 2010)
J/MNRAS/404/325 : Massive galaxy clusters lensing analyse (Richard+, 2010)
J/ApJ/713/970 : Low-resolution SED templates of AGNs & galaxies (Assef+, 2010)
J/ApJ/697/506 : Mid-infrared galaxy luminosity function from AGN (Dai+, 2009)
J/A+A/499/357 : REFLEX galaxies redshifts (Guzzo+, 2009)
J/ApJS/172/561 : The 400d cluster Survey (Burenin+, 2007)
J/ApJS/172/182 : XMM Clusters of galaxies in COSMOS field (Finoguenov+ 2007)
J/MNRAS/379/867 : BCG C4 cluster catalog (von der Linden+, 2007)
J/ApJ/660/239 : MaxBCG cat. of galaxy clusters from SDSS (Koester+, 2007)
J/ApJ/645/955 : ChaMP serendipitous galaxy cluster survey (Barkhouse+, 2006)
J/ApJS/157/1 : Red-Sequence Cluster Survey (Gladders+, 2005)
J/A+A/423/449 : RASS-SDSS Galaxy Clusters Survey. I. (Popesso+, 2004)
J/AJ/125/2064 : Northern Optical Cluster Survey. II. (Gal+, 2003)
J/ApJS/129/435 : NORAS galaxy cluster survey. I. (Bohringer+, 2000)
http://swift.gsfc.nasa.gov/ : Swift GRB mission home page
http://heasarc.gsfc.nasa.gov/W3Browse/all/mcxc.html : MCXC meta-catalog of
X-ray detected clusters of galaxies
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [SWCL]
6- 21 A16 --- SWCL Swift name (JHHMMSS.s+DDMMSS)
23- 27 F5.3 --- z2' [0.06/0.8]? 2' source region size confirmed
redshift (1)
29- 33 F5.3 --- z3' [0.04/0.8]? 3' source region size confirmed
redshift (1)
35- 39 F5.3 --- z [0.04/0.8] Confirmed SDSS over-density (1)
41- 45 F5.2 --- sig [3.1/35.7] Confirmed significance σ (1)
47- 51 F5.2 --- Nnet [2.3/54.4] Number of galaxies above the
background count (2)
53- 59 F7.2 --- Nopt [2.2/1157] Estimated optical richness (see
section 6.3)
61- 65 F5.2 mag rmag [12.5/22.3] Brightest cluster galaxy (BCG)
SDSS r-band apparent magnitude
67- 72 F6.2 mag rMag [-29/-19.8] Brightest cluster galaxy (BCG)
r-band absolute magnitude
74- 77 F4.2 Mpc offset [0/1.2] BCG-to-X-ray offset
79- 86 E8.3 10-7W LX X-ray bolometric luminosity in erg/s
88- 95 E8.3 Msun M500 Mass M500 (3)
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Note (1): If the source region size (2' or 3') confirmed a redshift, the value
is given. If not, then the non-detection is blank. Cases where neither
source region size confirmed a redshift are not included in this
table. Confirmed SDSS galaxy over-densities are listed as well as the
significance of the detection. Cases where the 2' and 3'
regions' redshifts differ are discussed in Section 4.
Note (2): NNet is the number of galaxies above the background count for the
detected redshift bin.
Note (3): M500 is a mass estimate similar to the virialized mass.
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History:
From electronic version of the journal
References:
Dai et al. Paper I. 2015ApJS..218....8D 2015ApJS..218....8D Cat. J/ApJS/218/8
(End) Emmanuelle Perret [CDS] 08-Feb-2016