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
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) 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 --- <zsp> 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, <[BBA2006] IRAC JHHMMSS.s+DDMMSS> in Simbad). d = Additional spectroscopic members for ISCS J1438.1+3414 published in Stanford et al. (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
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