The BeppoSAX 2-10 keV Survey
| dc.creator | Giommi, P. | |
| dc.creator | Perri, M. | |
| dc.creator | Fiore, F. | |
| dc.date | 2000-06-23 | |
| dc.date.accessioned | 2026-07-07T01:54:06Z | |
| dc.date.available | 2026-07-07T01:54:06Z | |
| dc.description | We present the results of a 2-10 keV BeppoSAX survey based on 140 high galactic latitude MECS fields, 12 of which are deep exposures of ``blank'' parts of the sky. The limiting sensitivity is 5 10^-14 erg cm^-2 s^-1 where about 25% of the Cosmic X-ray Background (CXB) is resolved into discrete sources. The logN-logS function, built with a statistically complete sample of 177 sources, is steep and in good agreement with the counts derived from ASCA surveys. A CXB fluctuation analysis allowed us to probe the logN-logS down to about 1.5 10^-14 erg cm^-2 s^-1 where the contribution of discrete sources to the CXB grows to 40-50%. A hardness ratio analysis reveals the presence of a wide range of spectral shapes and that a fairly large fraction of sources appear to be heavily absorbed, some of which showing soft components. A comparison of the flux distribution of different subsamples confirms the existence of a spectral hardening with decreasing flux. This effect is probably due to an increasing percentage of absorbed sources at faint fluxes, rather than to a gradual flattening of the spectral slope. Nearly all the sources for which adequate ROSAT exposures exist, have been detected in the soft X-rays. This confirms that soft spectral components are present even in strongly absorbed objects, and that a large population of sources undetectable below a few keV does not exist. A Ve/Va test provides evidence for the presence of cosmological evolution of a magnitude similar to that found in soft X-ray extragalactic sources. Evolution is present both in normal and absorbed sources, with the latter population possibly evolving faster,although this effect could also be the result of complex selection effects. | |
| dc.description | 16 LaTeX pages, 6 PostScript figures. Accepted for publication in A&A | |
| dc.identifier | https://arxiv.org/abs/astro-ph/0006333 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/0006333 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/1218 | |
| dc.subject | Astrophysics | |
| dc.title | The BeppoSAX 2-10 keV Survey | |
| dc.type | text |