J/ApJ/742/125 Galaxies in X-ray groups. I. COSMOS memberships (George+, 2011) ================================================================================ Galaxies in X-ray groups. I. Robust membership assignment and the impact of group environments on quenching. George M.R., Leauthaud A., Bundy K., Finoguenov A., Tinker J., Lin Y.-T., Mei S., Kneib J.-P., Aussel H., Behroozi P.S., Busha M.T., Capak P., Coccato L., Covone G., Faure C., Fiorenza S.L., Ilbert O., Le Floc'h E., Koekemoer A.M., Tanaka M., Wechsler R.H., Wolk M. =2011ApJ...742..125G ================================================================================ ADC_Keywords: Galaxy catalogs; X-ray sources; Spectra, optical; Redshifts Keywords: catalogs ; galaxies: groups: general ; galaxies: star formation Abstract: Understanding the mechanisms that lead dense environments to host galaxies with redder colors, more spheroidal morphologies, and lower star formation rates than field populations remains an important problem. As most candidate processes ultimately depend on host halo mass, accurate characterizations of the local environment, ideally tied to halo mass estimates and spanning a range in halo mass and redshift, are needed. In this work, we present and test a rigorous, probabilistic method for assigning galaxies to groups based on precise photometric redshifts and X-ray-selected groups drawn from the COSMOS field. The groups have masses in the range 10^13^<~M_200c_/M_{sun}_<~10^14^ and span redshifts 0 in Simbad) (GROUP_ID) 5- 27 E23.18 deg RAdeg [149.4/151] X-ray right ascension (J2000) (RA) 29- 51 E23.18 deg DEdeg [1.5/3] X-ray declination (J2000) (DEC) 53- 67 E15.10 deg ePos [0.00014/0.009] Position uncertainty of X-ray source (XRAY_POS_ERR) 69- 83 E15.10 --- z [0.078/1] Group redshift (REDSHIFT) (1) 85- 99 E15.10 --- e_z [0.00013/0.014] z uncertainty (REDSHIFT_ERR) 101- 115 E15.10 [10-7W] logLx [41.3/44.1] Log of X-ray luminosity in the rest-frame 0.1-2.4keV band; in erg/s units (LX) 117- 131 E15.10 [10-7W] e_logLx [40.7/42.9] logLx uncertainty (LX_ERR) 133- 147 E15.10 --- LxScale [41.3/43.9] log of scaled X-ray luminosity (Lx/E(z)) (LX_SCALE) 149- 164 E16.10 [mW/m2] Fx [-15.5/-12.7] log of extrapolated 0.5-2kev flux within R500 in ergs/s/cm^2^ (XRAY_FLUX) 166- 181 E16.10 [mW/m2] e_Fx [-15.7/-14.3] Fx uncertainty (XRAY_FLUX_ERR) 183 I1 --- Mask [0/1] Mask flag (1=masked, 0=clean) (FLAG_MASK) 185 I1 --- Poor [0/1] Poor group flag (1=three or fewer members, 0=4+ members) (FLAG_POOR) 187 I1 --- Merger [0/4] Merger flag (N=number of overlapping groups) (FLAG_MERGER) 189 I1 --- Qual [0/1] Combined quality flag (1=good (129 occurrences) or 0=bad) (FLAG_INCLUDE) 191- 205 E15.10 [Msun] logM200c [12.8/14.4] log Mass M_200c_ (M200C) 207- 221 E15.10 Mpc R200c [0.36/1.1] Physical radius R_200c_ (R200C_MPC) 223- 237 E15.10 arcsec AR200c [53/347.1] Angular radius at group redshift (R200C_AS) 239- 253 E15.10 --- Conc200c [3.5/5.4] Concentration c_200c_ (C=R200/Rscale) 255- 257 I3 --- Nmm [0/219] Number of group members (P_MEM>0.5) (NMEM) 259- 273 E15.10 --- Pmm [0/166.418] Sum of P_MEM over all galaxies (NMEM_W) 275- 298 E24.18 deg RAMdeg [149.4/151]?=-999 Right ascension of Most Massive Group Galaxy within NFW scale radius (J2000) (RA_MMGGS) 300- 323 E24.18 deg DEMdeg [1.6/3]?=-999 Declination of Most Massive Group Galaxy within NFW scale radius (J2000) (DEC_MMGGS) 325- 330 I6 --- MMGGS [1050/200932]?=-1 ID number of Most Massive Group Galaxy within Navarro-Frenk-White (NFW) scale radius (MMGGS) (ID_MMGGS) 332- 347 E16.10 [Msun] logMM [9/12]?=-1 Log of stellar mass of MMGGS (SM_MMGGS) 349- 372 E24.18 deg RAZdeg [149.4/151]?=-999 RA_MMGGS using spectroscopic redshift (RA_MMGGS_ZBEST) 374- 397 E24.18 deg DEZdeg [1.6/3]?=-999 DEC_MMGGS using spectroscopic redshift (DEC_MMGGS_ZBEST) 399- 404 I6 --- IDzM [1050/200991]?=-1 ID_MMGGS using spectroscopic redshift (ID_MMGGS_ZBEST) 406- 431 A26 --- [GLB2011] COSMOS CL JHHMMSS.s+DDMMSS name (NAME) 433 I1 --- xFlag [1/3] X-ray quality flag (2) -------------------------------------------------------------------------------- Note (1): Group redshifts have been determined by searching for red sequence overdensities within 500kpc of the X-ray centers and are refined by using spectroscopic redshifts when available. We use groups with z<1 to ensure good optical identifications and small photoz uncertainties. Note (2): A quality flag is assigned to the reliability of the optical counterpart, with flags 1 and 2 indicating a secure association (165 groups), and higher flags indicating potential problems due to projections with other sources or bad photometry due to bright stars in the foreground. Code as follows: 1 = can use X-ray center, all good 2 = good ID, but cannot use X-ray center 3 = ID needs to be checked spectroscopically -------------------------------------------------------------------------------- Byte-by-byte Description of file: xgal.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 7 I7 --- ID [2/1443962] Galaxy ID number (<[GLB2011] Galaxy NNNNNNN> in Simbad) (GAL_ID) 9- 23 E15.10 mag F814mag [15/24.2] HST/ACS F814W SExtractor AB magnitude (Leauthaud+, 2007ApJS..172..219L) (MAG_AUTO) 25- 47 E23.18 deg RAdeg [149.4/150.8] Right ascension (J2000) (RA) 49- 71 E23.18 deg DEdeg [1.5/2.9] Declination (J2000) (DEC) 73- 87 E15.10 [Msun] logM [5.1/12.1] Log of stellar mass (SM) 89- 103 E15.10 [Msun] e_logM [4.7e-7/0.4] LogM uncertainty (EM_ERR) 105- 120 E16.10 --- zphot [0.001/4.7]?=-99 Photometric redshift from Ilbert+, 2009, J/ApJ/690/1236 122- 137 E16.10 --- e_zphot [0.0015/4.7]?=-99 Lower uncertainty on zphot (ZPHOT_ERRLO) 139- 154 E16.10 --- E_zphot [0.008/5]?=-99 Upper uncertainty on zphot (ZPHOT_ERRHI) 156 I1 --- MMGGS [0/1] Most Massive Group Galaxy within Navarro-Frenk-White (NFW) scale radius (Rs=R_200c_/c_200c_) 158- 172 E15.10 --- Pmm [0/1] Membership probability (P_MEM) 174- 176 I3 --- GID [11/345]?=-1 Group ID number of most likely group (GROUP_ID) 178 I1 --- f_GID [0/1] Group flag (1=good, 0=bad) (GROUP_FLAG) 180- 195 E16.10 pc Dist [0/1]?=-1 Projected distance to MMGGS of Group ID (R/R200) (DIST_MMGGS) 197 I1 --- MMGGz [0/1] MMGGS using GAL_ID's spectroscopic redshift (MMGGS_ZBEST) 199- 213 E15.10 --- PMMGGz [0/1] Membership probability using GAL_ID's spectroscopic redshift (P_MEM_ZBEST) 215- 217 I3 --- GIDz [11/345]?=-1 GROUP_ID using GAL_ID's spectroscopic redshift (GROUP_ID_ZBEST) 219 I1 --- f_GIDz [0/1] Group flag using GAL_ID's spectroscopic redshift (GROUP_FLAG_ZBEST) 221- 236 E16.10 --- Distz [0/1]?=-1 DIST_MMGGS using GAL_ID's spectroscopic redshift (R/R200) (DIST_MMGGS_ZBEST) 238- 253 E16.10 mag NUV-R [-0.85/6.4] NUV-R color index (MNUV_MR) -------------------------------------------------------------------------------- History: Downloaded from http://irsa.ipac.caltech.edu/data/COSMOS/tables/groups/ References: George et al. Paper II. 2012ApJ...757....2G George et al. Paper III. 2013ApJ...770..113G ================================================================================ (End) Emmanuelle Perret [CDS] 20-Jan-2021