NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-05-21 T00:11:45 PDT
Help | Comment | NED Home

For refcode 2014ApJS..212....9T:
Retrieve 45 NED objects in this reference.
Please click here for ADS abstract

NED Abstract

Copyright by American Astronomical Society. Reproduced by permission
2014ApJS..212....9T A Chandra-Swift View of Point Sources in Hickson Compact Groups: High AGN Fraction but a Dearth of Strong AGNs Tzanavaris, P.; Gallagher, S. C.; Hornschemeier, A. E.; Fedotov, K.; Eracleous, M.; Brandt, W. N.; Desjardins, T. D.; Charlton, J. C.; Gronwall, C. Abstract. We present Chandra X-ray point source catalogs for 9 Hickson Compact Groups (HCGs, 37 galaxies) at distances of 34-89 Mpc. We perform detailed X-ray point source detection and photometry and interpret the point source population by means of simulated hardness ratios. We thus estimate X-ray luminosities (L_X_) for all sources, most of which are too weak for reliable spectral fitting. For all sources, we provide catalogs with counts, count rates, power-law indices (Gamma), hardness ratios, and L_X_, in the full (0.5-8.0 keV), soft (0.5-2.0 keV), and hard (2.0-8.0 keV) bands. We use optical emission-line ratios from the literature to re-classify 24 galaxies as star-forming, accreting onto a supermassive black hole (AGNs), transition objects, or low-ionization nuclear emission regions. Two-thirds of our galaxies have nuclear X-ray sources with Swift/UVOT counterparts. Two nuclei have L_ X, 0.5-8.0 keV_ >10^42^ erg s^--1^, are strong multi-wavelength active galactic nuclei (AGNs), and follow the known {alpha}_OX_-nuL_nu__(nearUV)_ correlation for strong AGNs. Otherwise, most nuclei are X-ray faint, consistent with either a low-luminosity AGN or a nuclear X-ray binary population, and fall in the "non-AGN locus" in {alpha}_OX_-nuL_nu__(nearUV)_ space, which also hosts other normal galaxies. Our results suggest that HCG X-ray nuclei in high specific star formation rate spiral galaxies are likely dominated by star formation, while those with low specific star formation rates in earlier types likely harbor a weak AGN. The AGN fraction in HCG galaxies with M_R_ <= --20 and L_ X, 0.5-8.0 keV_ >=10^41^ erg s^--1^ is 0.08^{+0.35}_{-0.01}_, somewhat higher than the ~5% fraction in galaxy clusters. Key words: catalogs, galaxies: active, galaxies: nuclei, ultraviolet: galaxies, X-rays: galaxies
Retrieve 45 NED objects in this reference.
Please click here for ADS abstract

Back to NED Home