J/MNRAS/380/1467 AGN in supercluster A901/2 (Gilmour+, 2007) ================================================================================ Environmental dependence of active galactic nuclei activity in the supercluster A901/2. Gilmour R., Gray M.E., Almaini O., Best P., Wolf C., Meisenheimer K., Papovich C., Bell E. =2007MNRAS.380.1467G ================================================================================ ADC_Keywords: Clusters, galaxy ; Active gal. nuclei ; X-ray sources Keywords: galaxies: active - galaxies: clusters: individual: A901/2 Abstract: We present XMM data for the supercluster A901/2, at z~0.17, which is combined with deep imaging and 17-band photometric redshifts (from the COMBO-17 survey), two degree field (2dF) spectra and Spitzer 24um data, to identify active galactic nuclei (AGN) in the supercluster. The 90ks XMM image contains 139 point sources, of which 11 are identified as supercluster AGN with LX(0.5-7.5keV)>1.7x10^41^erg/cm^2^/s. The host galaxies have M_R_<-20 and only two of eight sources with spectra could have been identified as AGN by the detected optical emission lines. Using a large sample of 795 supercluster galaxies, we define control samples of massive galaxies with no detected AGN. The local environments of the AGN and control samples differ at >~98 per cent significance. The AGN host galaxies lie predominantly in areas of moderate projected galaxy density and with more local blue galaxies than the control sample, with the exception of one very bright type I AGN very near the centre of a cluster. These environments are similar to, but not limited to, cluster outskirts and blue groups. Despite the large number of potential host galaxies, no AGN are found in regions with the highest galaxy density (excluding some cluster cores where emission from the intra-cluster medium obscures moderate luminosity AGN). AGN are also absent from the areas with lowest galaxy density. We conclude that the prevalence of cluster AGN is linked to their environment. Description: In this paper, a new, deep (90ks) XMM-Newton image of the supercluster, obtained in 2003, is presented. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table1.dat 113 155 X-ray sources and possible optical matches and 24um fluxes notes.dat 80 32 Individual notes -------------------------------------------------------------------------------- See also: B/xmm : XMM-Newton Observation Log (XMM-Newton SOC, 2007) II/253 : Chandra Deep Field South: multi-colour data (Wolf+, 2004) VII/250 : The 2dF Galaxy Redshift Survey (2dFGRS) (2dFGRS Team, 1998-2003) Byte-by-byte Description of file: table1.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 3 I3 --- [GGA2007] Sequential X-ray number 5- 6 I2 h RAh X-ray right ascension (J2000) 8- 9 I2 min RAm X-ray right ascension (J2000) 11- 14 F4.1 s RAs X-ray right ascension (J2000) 16 A1 --- DE- X-ray declination sign (J2000) 17- 18 I2 deg DEd X-ray declination sign (J2000) 20- 21 I2 arcmin DEm X-ray declination sign (J2000) 23- 26 F4.1 arcsec DEs X-ray declination sign (J2000) 28- 34 F7.5 deg e_Pos Error on X-ray position, as described in Sect. 3.3 36- 41 F6.2 10-3ct/s CR Counts per second in the 0.5-7.5keV-band (1) 43- 47 I5 --- OptID ? Optical id sequential number 49 I1 --- n_OptID [1]? Note on OptID (2) 51 I1 h RAo.h ? Optical right ascension (J2000) 53- 54 I2 min RAo.m ? Optical right ascension (J2000) 56- 60 F5.2 s RAo.s ? Optical right ascension (J2000) 62 A1 --- DEo.- Optical declination sign (J2000) 63- 64 I2 deg DEo.d ? Optical declination sign (J2000) 66- 67 I2 arcmin DEo.m ? Optical declination sign (J2000) 69- 73 F5.2 arcsec DEo.s ? Optical declination sign (J2000) 75- 79 F5.3 --- zphot ? Photometric redshift 80 A1 --- n_zphot [x] Note on zphot (2) 82- 86 F5.3 --- Rel ? Reliability, the probability that the X-ray-optical association is not random 87 A1 --- n_Rel [l] l for low 89- 93 F5.3 --- Prob ? Probability, the chance that this X-ray-optical association gives the true counterpart (3) 94 A1 --- n_Prob [l] l for low 96-100 F5.2 mJy F24um ? Flux at 24um, from Spitzer data. 102-105 F4.2 --- P(Sp) ? Probability from 24um data (4) 107-113 A7 --- Notes Notes, detailed in notes.dat file -------------------------------------------------------------------------------- Note (1): Given by the average of the WAVDETECT count rates from the three images. The count rates from the PN detector were scaled down by a factor of 3 (calculated from the brightest sources) to match those from the MOS detectors. Note (2): Notes as follows: 1 = This source was found by eye and added to the COMBO catalogue, with a R-band magnitude of 23.7 x = The source is too faint to have a reasonable COMBO redshift, or is a star Note (3): The chance that this X-ray-optical association gives the true counterpart, given all possible associations and the chance of no counterpart existing. In the case of sources with more than one reliable match, this is much lower than the individual reliabilities. Note (4): Probability from 24um data, given by the combined probability of the X-ray-24um match being unique, and the 24um-optical match. If no optical match is found, then this is purely the X-ray-24um probability. -------------------------------------------------------------------------------- Byte-by-byte Description of file: notes.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 4 A4 --- Note Note code 6- 80 A75 --- Text Text of the note -------------------------------------------------------------------------------- History: From electronic version of the journal ================================================================================ (End) Patricia Vannier [CDS] 21-Jan-2008