J/ApJ/684/905 z>1 galaxy clusters from IRAC Shallow Survey (Eisenhardt+, 2008)
Clusters of galaxies in the first half of the universe from the IRAC Shallow
Survey.
Eisenhardt P.R.M., Brodwin M., Gonzalez A.H., Stanford S.A., Stern D.,
Barmby P., Brown M.J.I., Dawson K., Dey A., Doi M., Galametz A.,
Jannuzi B.T., Kochanek C.S., Meyers J., Morokuma T., Moustakas L.A.
<Astrophys. J., 684, 905-932 (2008)>
=2008ApJ...684..905E 2008ApJ...684..905E
ADC_Keywords: Redshifts ; Clusters, galaxy ; Spectroscopy ; Surveys ;
Photometry, infrared
Keywords: galaxies: clusters: general - surveys
Abstract:
We have identified 335 galaxy cluster and group candidates, 106 of
which are at z>1, using a 4.5um-selected sample of objects from a
7.25deg2 region in the Spitzer Infrared Array Camera (IRAC) Shallow
Survey. Clusters were identified as three-dimensional overdensities
using a wavelet algorithm, based on photometric redshift probability
distributions derived from IRAC and NOAO Deep Wide-Field Survey data.
We estimate only ∼10% of the detections are spurious. To date 12 of
the z>1 candidates have been confirmed spectroscopically, at redshifts
from 1.06 to 1.41. Velocity dispersions of ∼750km/s for two of these
argue for total cluster masses well above 1014M☉, as does the
mass estimated from the rest-frame near-infrared stellar luminosity.
Although not selected to contain a red sequence, some evidence for red
sequences is present in the spectroscopically confirmed clusters, and
brighter galaxies are systematically redder than the mean galaxy color
in clusters at all redshifts.
Description:
The IRAC Shallow Survey (Eisenhardt et al., 2004ApJS..154...48E 2004ApJS..154...48E)
covers ∼8.5deg2 and reaches an aperture-corrected 5σ depth of
∼19.1 and 18.3mag (Vega) at 3.6 and 4.5um in 3" diameter apertures.
This paper uses the NOAO Deep Wide-Field Survey (NDWFS) third data
release (DR3) images and SExtractor catalogs which can be obtained
through the NOAO data archive. Most of the high-redshift optical
spectroscopic confirmation of ISCS clusters has been obtained at Keck
Observatory, with DEIMOS and LRIS, and with FOCAS on Subaru, between
2005 June and 2007 May.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 77 12 z>1 ISCS clusters with spectroscopic confirmation
table3.dat 83 104 z>1 spectroscopic cluster members
--------------------------------------------------------------------------------
See also:
J/A+A/442/841 : High-redshift galaxy clusters (Olsen+, 2005)
http://www.noao.edu/noao/noaodeep : NOAO Deep images data archive home page
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq IRAC Shallow Survey catalog number (1)
5- 8 A4 --- --- [ISCS]
10- 21 A12 --- ISCS IAU cluster name JHHMM.m+DDMM
23- 24 I2 h RAh Hour of right ascension (J2000)
26- 27 I2 min RAm Minute of right ascension (J2000)
29- 33 F5.2 s RAs Second of right ascension (J2000)
35 A1 --- DE- Declinations sign (J2000)
36- 37 I2 deg DEd Degree of declination (J2000)
39- 40 I2 arcmin DEm Arcminute of declination (J2000)
42- 45 F4.1 arcsec DEs Arcsecond of declination (J2000)
47- 50 F4.2 --- zest Mean estimated photometric redshift (2)
52- 56 F5.3 --- Mean redshift of the spectroscopically
confirmed members
58- 59 I2 --- Np Number of photometric redshift members of the
cluster (3)
61- 62 I2 --- Np(bc) Reduced number (4)
64- 65 I2 --- Nsp Number of spectroscopically confirmed member
galaxies in each cluster
67- 70 F4.2 mag <I-3.6> Mean I-[3.6] color index for the photometric
redshift member galaxies
72- 73 I2 --- Ltot/L* Sum of luminosities for the photometric
redshift member galaxies (5)
75- 77 F3.1 --- Lbcg/L* Luminosities in [4.5] of the brightest
photometric redshift member galaxy relative
to L*.
--------------------------------------------------------------------------------
Note (1): The catalog numbers increase with decreasing detection significance.
These numbers extend beyond 335 for continuity with an earlier,
preliminary version of the catalog used to plan spectroscopic and
other follow-up observations. See section 5 for further details.
Note (2): A refined estimate (zest) of the mean cluster redshift was obtained
from the peak of the summed P(z) distribution for candidate cluster
members.
Note (3): Np defined as galaxies within 1Mpc of the cluster center and with
integrated P(z)≥0.3 in the range zest±0.06(1+zest). These
galaxies are used to calculate mean cluster colors in Section 7.2.
Note (4): Np(bc) reduces Np by the number of galaxies which satisfy criteria in
Note (3) for each cluster redshift over the entire field, scaled to
the 1Mpc radius area for each cluster redshift.
Note (5): Sum of luminosities in [4.5] relative to an L* value which evolves
according to the "red spike" model shown in Figure 1, corrected for
the average over the field.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- --- [ISCS]
6- 17 A12 --- ISCS Cluster name (JHHMM.m+DDMM)
18 A1 --- f_ISCS [cd] Flag on cluster (1)
20- 23 A4 --- --- [IRAC/ser ]
25- 40 A16 --- ID Cluster member identification
(IRAC/ser JHHMMSS.s+DDMMSS) (2)
41 A1 --- f_ID [b] Flag on "ser" ID (3)
43- 44 I2 h RAh Hour of right ascension (J2000)
46- 47 I2 min RAm Minute of right ascension (J2000)
49- 53 F5.2 s RAs Second of right ascension (J2000)
55 A1 --- DE- Declination sign (J2000)
56- 57 I2 deg DEd Degree of declination (J2000)
59- 60 I2 arcmin DEm Arcminute of declination (J2000)
62- 65 F4.1 arcsec DEs Arcsecond of declination (J2000)
67- 71 F5.2 mag [4.5] ? Spitzer/IRAC 4.5 µm band magnitude
(Vega scale; 0mag=179.5Jy)
73- 76 F4.2 --- zph ? Photometric redshift
78- 83 F6.4 --- zsp Spectroscopic redshift
--------------------------------------------------------------------------------
Note (1): Flags as follows:
c = Additional spectroscopic members for ISCS J1434.5+3427 published in
Brodwin et al. (2006ApJ...651..791B 2006ApJ...651..791B, <[BBA2006] IRAC JHHMMSS.s+DDMMSS>
in Simbad).
d = Additional spectroscopic members for ISCS J1438.1+3414 published in
Stanford et al. (2005ApJ...634L.129S 2005ApJ...634L.129S, <[SEB2005] IRAC JHHMMSS+DDMMSS> in
Simbad).
Note (2): Galaxies are <[EBG2008] IRAC JHHMMSS.s+DDMMSS> or
<[EBG2008] Ser JHHMMSS.s+DDMMSS> in Simbad.
Note (3): Serendipitous spectroscopic source not included in 5σ 4.5um
catalog.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 10-Dec-2010