We present a comprehensive study of the soft X-ray properties of the BeppoSA X High-Energy Large Area Survey (HELLAS) sources. A large fraction (about 2/3) of the hard X ray selected sources is detected by ROSAT. The soft X-ray colors for many of these objects, along with the 0.5-2 keV flux upper limits for those undetected in the ROSAT band, do imply the presence of absorption. The comparison with the ROSAT Deep Survey sources indicates that a larger fraction of absorbed objects among the HELLAS sources is present, in agreement with their hard X-ray selection and the predictions of the X-ray background synthesis: models. Another striking result is the presence, of a soft (additional) X-ray component in a significant fraction of absorbed objects.
Vignali, C., Comastri, A., Fiore, F., LA FRANCA, F. (2001). The BeppoSAX High Energy Large Area Survey - IV. On the soft X-ray properties of the hard X-ray-selected HELLAS sources. ASTRONOMY & ASTROPHYSICS, 370(3), 900-908.
The BeppoSAX High Energy Large Area Survey - IV. On the soft X-ray properties of the hard X-ray-selected HELLAS sources
LA FRANCA, Fabio
2001-01-01
Abstract
We present a comprehensive study of the soft X-ray properties of the BeppoSA X High-Energy Large Area Survey (HELLAS) sources. A large fraction (about 2/3) of the hard X ray selected sources is detected by ROSAT. The soft X-ray colors for many of these objects, along with the 0.5-2 keV flux upper limits for those undetected in the ROSAT band, do imply the presence of absorption. The comparison with the ROSAT Deep Survey sources indicates that a larger fraction of absorbed objects among the HELLAS sources is present, in agreement with their hard X-ray selection and the predictions of the X-ray background synthesis: models. Another striking result is the presence, of a soft (additional) X-ray component in a significant fraction of absorbed objects.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
