Nearby galaxies and the GINGA X-ray background
We present here the results of cross-correlating the X-ray background measured by Ginga in the 2–10 keV band with several catalogues of extragalactic objects. Positive signals with an amplitude of a few per cent have been found for some catalogues implying that some fraction of the X-ray background...
| Autores: | , , , , , , |
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| Formato: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 1995 |
| País: | España |
| Recursos: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/170065 |
| Acesso em linha: | http://hdl.handle.net/10261/170065 |
| Access Level: | acceso abierto |
| Palavra-chave: | Diffuse radiation Infrared: galaxies X-ray galaxies X-ray general Galaxies: general |
| Resumo: | We present here the results of cross-correlating the X-ray background measured by Ginga in the 2–10 keV band with several catalogues of extragalactic objects. Positive signals with an amplitude of a few per cent have been found for some catalogues implying that some fraction of the X-ray background is produced either by the class of catalogued sources or by other classes spatially related to them. Detailed X-ray background simulations have been used to assess the significance of the results and, for the first time, the full angular shape of the cross-correlation. The inferred X-ray volume emissivity in the local Universe, j0, has been estimated for two galaxy catalogues (UGC and IRAS) for which the cross-correlation is highly significant. We obtain j0 = (0.74 ± 0.07) for UGC and j0 = (1.15 ± 0.10) for IRAS, in units of 1039h erg s–1 Mpc–3. Extrapolating this result back to z ~ 1 –4 leads to the conclusion that ≲ 10–30 per cent of the X-ray background could be produced by a non-evolving population of galaxies. These values are shown to be consistent with upper limits on the Auto Correlation Function derived here. |
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