J/ApJ/853/47 Brightest cluster galaxies bright in 22um (W4BCGs) (Runge+, 2018)
"Red" but not "dead": actively star-forming brightest cluster galaxies at low
redshifts.
Runge J., Yan H.
<Astrophys. J., 853, 47 (2018)>
=2018ApJ...853...47R 2018ApJ...853...47R
ADC_Keywords: Clusters, galaxy; Galaxies, photometry; Photometry, SDSS;
Photometry, infrared; Redshifts; Active gal. nuclei
Keywords: galaxies: clusters: general ; galaxies: evolution
Abstract:
Brightest cluster galaxies (BCGs) are believed to have assembled most
of their stars early in time and therefore should be passively
evolving at low redshifts and appear "red-and-dead." However, there
have been reports that a minority of low-redshift BCGs still have
ongoing star formation rates (SFRs) of a few to even ∼100M☉/yr.
Such BCGs are found in "cool-core" ("CC") clusters, and their star
formation is thought to be fueled by "cooling flow." To further
investigate the implications of low-redshift, star-forming BCGs, we
perform a systematic search using the 22µm data ("W4" band) from
the Wide-field Infrared Survey Explorer (WISE) on the GMBCG catalog,
which contains 55424 BCGs at 0.1≲z≲0.55 identified in the Sloan
Digital Sky Survey (SDSS). Our sample consists of 389 BCGs that are
bright in W4 ("W4BCGs"), most being brighter than 5mJy. While some
(≲20%) might host active galactic nuclei, most W4BCGs should owe
their strong mid-IR emissions to dust-enshrouded star formation. Their
median total IR luminosity (LIR) is 5x1011L☉
(SFR∼50M☉/yr), and 27% of the whole sample has
LIR>1012L☉ (SFR>100M☉/yr). Using 10 W4BCGs that have
Chandra X-ray data, we show that 7 of them are possibly in CC
clusters. However, in most cases (five out of seven) the mass
deposition rate cannot account for the observed SFR. This casts doubt
on the idea that cooling flows are the cause of the star formation in
non-quiescent BCGs.
Description:
The critical data sets used to select star-forming brightest cluster
galaxies (BCGs) are the SDSS-based GMBCG catalog (Hao+ 2010,
J/ApJS/191/254) and the WISE all-sky survey data. In particular, we
adopt the "un-blurred" version of the WISE data (also known as
"unWISE") from Lang (2014AJ....147..108L 2014AJ....147..108L) for this study. A small
number of such selected BCGs also have far-IR (FIR) data from Herschel
or X-ray data from Chandra, which we have used for further analysis.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table5.dat 265 389 Photometry and derived properties for brightest
cluster galaxies (BCGs) that are bright in WISE
22µm (W4) data (W4BCGs)
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See also:
VIII/76 : Leiden/Argentine/Bonn (LAB) Survey of Galactic HI (Kalberla+ 2005)
VIII/95 : Herschel Multi-tiered Extragalactic Survey (Oliver+, 2012)
II/311 : WISE All-Sky Data Release (Cutri+ 2012)
II/328 : AllWISE Data Release (Cutri+ 2013)
J/ApJS/191/254 : GMBCG galaxy cluster catalog from SDSS DR7 (Hao+, 2010)
J/A+A/533/A119 : GOODS-Herschel North and South catalogs (Elbaz+, 2011)
J/ApJ/772/26 : AGN with WISE. II. The NDWFS Bootes field (Assef+, 2013)
J/ApJ/785/104 : redMaPPer. I. Algorithm applied to SDSS DR8 (Rykoff+, 2014)
J/ApJS/210/22 : Herschel Stripe 82 survey (HerS) first catalog (Viero+, 2014)
J/MNRAS/444/L63 : SFRs of Brightest Cluster Galaxies (Fraser-McKelvie+, 2014)
J/ApJ/811/58 : FIR properties of SDSS 0.1<z<5 quasars (Ma+, 2015)
J/MNRAS/462/3146 : Herschel-ATLAS DR1 (Valiante+, 2016)
Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- --- [GMBCG J]
8- 25 A18 --- GMBCG GMBCG catalog identifier
(Hao+, 2010, J/ApJS/191/254)
27- 42 F16.12 deg RAdeg Right Ascension (J2000) (1)
44- 63 F20.16 deg DEdeg Declination (J2000) (1)
65- 68 F4.2 --- zphot [0.1/0.6] Photometric redshift (1)
70- 73 F4.2 --- e_zphot [0.01/0.2] Uncertainty in zphot (1)
75- 83 F9.7 --- zspec [0/0.5] Spectroscpic redshift (1)
85- 86 I2 --- Rich [8/76] Richness (1)
88- 92 F5.2 mag umag [16.4/27.4] SDSS u band AB magnitude
94- 97 F4.2 mag e_umag [0/3.5] Uncertainty in umag
99-103 F5.2 mag gmag [15.3/22.3] SDSS g band AB magnitude
105-108 F4.2 mag e_gmag [0/0.2] Uncertainty in gmag
110-114 F5.2 mag rmag [14.5/23.6] SDSS r band AB magnitude
116-119 F4.2 mag e_rmag [0/0.4] Uncertainty in rmag
121-125 F5.2 mag imag [14/22.8] SDSS i band AB magnitude
127-130 F4.2 mag e_imag [0/0.3] Uncertainty in imag
132-136 F5.2 mag zmag [13.9/21.1] SDSS z band AB magnitude
138-141 F4.2 mag e_zmag [0/0.3] Uncertainty in zmag
143-147 F5.2 mag W1mag [13.6/19.7] WISE 3.4um band AB magnitude
149-152 F4.2 mag e_W1mag [0/0.08] Uncertainty in W1mag
154-158 F5.2 mag W2mag [13.2/19] WISE 4.6um band AB magnitude
160-163 F4.2 mag e_W2mag [0/0.2] Uncertainty in W2mag
165-170 F6.2 mag W3mag [11.5/22]?=-99 WISE 12um band AB magnitude
172-177 F6.2 mag e_W3mag [0/25.1]?=-99 Uncertainty in W3mag
179-183 F5.2 mag W4mag [10.8/18] WISE 22um band AB magnitude
185-188 F4.2 mag e_W4mag [0/2.4] Uncertainty in W4mag
190-194 F5.2 [Lsun] logLIR [10.1/13.3] log IR luminosity
196-199 F4.2 [Lsun] E_logLIR [0.03/0.6] Upper uncertainty in logLIR
201-204 F4.2 [Lsun] e_logLIR [0.03/0.7] Lower uncertainty in logLIR
206-212 F7.2 Msun/yr SFR [1.3/1664.2] Star Formation Rate
214-219 F6.2 Msun/yr E_SFR [0.2/391] Upper uncertainty in SFR
221-228 F8.4 Msun/yr e_SFR [0.1/314] Lower uncertainty in SFR
230-234 F5.2 Gyr Age [0.04/12] Age
236-239 F4.2 Gyr E_Age [0.01/5.7]? Upper uncertainty in Age
241-244 F4.2 Gyr e_Age [0.01/5.2]? Lower uncertainty in Age
246-250 F5.2 [Msun] logM* [7.6/12.1] log stellar mass
252-255 F4.2 [Msun] E_logM* [0.03/0.5]? Upper uncertainty in logM*
257-260 F4.2 [Msun] e_logM* [0.03/0.6]? Lower uncertainty in logM*
262-265 A4 --- AGN AGN diagnostic (2)
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Note (1): From the GMBCG catalog (Hao+, 2010, J/ApJS/191/254).
Note (2): AGN diagnostic as follows:
BPT = BPT diagram method;
WISE = WISE color selection;
BOTH = AGN according to both BPT and WISE diagnostic;
NONE = Not AGN by either diagnostic
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 25-Sep-2018