Multiwavelength observations of serendipitous Chandra X-ray sources in the field of A 2390

被引:27
作者
Crawford, CS
Gandhi, P
Fabian, AC
Wilman, RJ
Johnstone, RM
Barger, AJ
Cowie, LL
机构
[1] Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England
[2] Leiden Observ, NL-2300 RA Leiden, Netherlands
[3] Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA
[4] Univ Wisconsin, Dept Astron, Madison, WI 53706 USA
关键词
galaxies : active; diffuse radiation; infrared : galaxies; X-rays : galaxies;
D O I
10.1046/j.1365-8711.2002.05454.x
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We present optical spectra and near-infrared imaging of a sample of 31 serendipitous X-ray sources detected in the field of Chandra observations of the A 2390 cluster of galaxies. The sources have 0.5-7 keV fluxes of (0.6-8)x10(-14) erg cm(-2) s(-1) and lie around the break in the 2-10 keV source counts. They are therefore typical of sources dominating the X-ray Background in that band. 12 of the 15 targets for which we have optical spectra show emission lines at a range of line luminosities, and half of these show broad lines. These active galaxies and quasars have soft X-ray spectra. Including photometric redshifts and published spectra, we have redshifts for 17 of the sources, ranging from z similar to0.2 up to z similar to3, with a peak between z =1-2. 10 of our sources have hard X-ray spectra indicating a spectral slope flatter than that of a typical unabsorbed quasar. Two hard sources that are gravitationally lensed by the foreground cluster are obscured quasars, with intrinsic 2-10 keV luminosities of (0.2-3)x10(45) erg s(-1), and absorbing columns of N (H) >10(23) cm(-2). Both of these sources were detected in the mid-infrared by ISOCAM on the Infrared Space Observatory , which when combined with radiative transfer modelling leads to the prediction that the bulk of the reprocessed flux emerges at similar to100 mum.
引用
收藏
页码:809 / 824
页数:16
相关论文
共 37 条
  • [1] ATTEMPT TO DETERMINE CIRCUMSTELLAR REDDENING LAW
    ALLEN, DA
    [J]. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1976, 174 (02) : P29 - P33
  • [2] Chandra measurements of the distribution of mass in the luminous lensing cluster Abell 2390
    Allen, SW
    Ettori, S
    Fabian, AC
    [J]. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 2001, 324 (04) : 877 - 890
  • [3] Altieri B, 1999, ASTRON ASTROPHYS, V343, pL65
  • [4] Arnaud KA, 1996, ASTR SOC P, V101, P17
  • [5] The nature of the hard X-ray background sources: Optical, near-infrared, submillimeter, and radio properties
    Barger, AJ
    Cowie, LL
    Mushotzky, RF
    Richards, EA
    [J]. ASTRONOMICAL JOURNAL, 2001, 121 (02) : 662 - 682
  • [6] Bolzonella M, 2000, ASTRON ASTROPHYS, V363, P476
  • [7] BRANDL B, 2000, IN PRESS ASP C SER
  • [8] The Chandra deep survey of the Hubble Deep Field North area.: IV.: An ultradeep image of the DHF-N
    Brandt, WN
    Hornschemeier, AE
    Alexander, DM
    Garmire, GP
    Schneider, DP
    Broos, PS
    Townsley, LK
    Bautz, MW
    Feigelson, ED
    Griffiths, RE
    [J]. ASTRONOMICAL JOURNAL, 2001, 122 (01) : 1 - 20
  • [9] SPECTRAL EVOLUTION OF STELLAR POPULATIONS USING ISOCHRONE SYNTHESIS
    BRUZUAL, G
    CHARLOT, S
    [J]. ASTROPHYSICAL JOURNAL, 1993, 405 (02) : 538 - 553
  • [10] The dust content and opacity of actively star-forming galaxies
    Calzetti, D
    Armus, L
    Bohlin, RC
    Kinney, AL
    Koornneef, J
    Storchi-Bergmann, T
    [J]. ASTROPHYSICAL JOURNAL, 2000, 533 (02) : 682 - 695