A Statistical Investigation of the Connection between X-ray and Water Maser Emission in Galaxy Centers
Abstract
Previous studies reveal a potential intimate connection between maser emission and X-ray obscuring columns in galaxy centers, with higher obscuration for more pronounced water maser activity. The number statistics involved in these investigations remain small, however. Currently, there are 151 confirmed maser detections and over 3300 surveyed non-maser galaxies. A careful crossmatch with public data from five X-ray telescope survey catalogs (the 2XMMi-DR3 from the XMM-Newton telescope, the Chandra Source Catalog, the ROSAT All-Sky Survey bright and faint source catalogs, the Swift Burst Alert Telescope 70 month survey, and the Integral IBIS 7-year All-Sky Survey) reveals X-ray information for 103 detected maser galaxies and ~650 non-detections, offering a clear statistical advantage over previous work. We are thus able to conduct a statistical comparison of the X-ray properties of the largest sample of X-ray active galaxies surveyed for water vapor emission at 22 GHz. We find that the X-ray detection rate of masers is on average 3.5 times greater than that of non-masers, with the rates increasing in harder X-ray bands. The X-ray apparent brightness of maser and non-maser detections are similar at soft X-rays, but the maser galaxies are increasingly brighter than the non-masers in the harder bands. The X-ray luminosities calculated without correction for intrinsic absorption are lower for maser galaxies, which supports previous results showing generally higher neutral hydrogen column densities (NH) in these sources. We statistically test the potential evidence for greater obscuration in increasingly more luminous maser galaxies via monte carlo simulations of various NH distributions that are motivated by previous studies, and explore the possible physical connections that could govern them.
- Publication:
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American Astronomical Society Meeting Abstracts #223
- Pub Date:
- January 2014
- Bibcode:
- 2014AAS...22325109N