We present the analysis of the ensemble structure function of the soft X-ray variability on a sample of about 3000 quasars. Our data are based on the observations of the ROSAT and XMM-Newton satellites, cross-correlated with the Sloan Digital Sky Survey Quasar catalogue. We measure for the first time the structure function up to a rest-frame time interval as large as 20 years (the longest time interval investigated through this type of study). The results of our analysis show that the X-ray variability of quasars still increases at these long time lags. This will be discussed in relation to the physical size of the emitting region.
The Long Term X-Ray Variability Of Quasars / Middei, Riccardo; Vagnetti, F.; Bianchi, S.; La Franca, F.; Paolillo, Maurizio. - (2016). (Intervento presentato al convegno Active Galactic Nuclei 12: A Multi-Messenger Perspective (AGN12) tenutosi a Napoli nel 26-29 Settembre 2016).
The Long Term X-Ray Variability Of Quasars
PAOLILLO, MAURIZIO
2016
Abstract
We present the analysis of the ensemble structure function of the soft X-ray variability on a sample of about 3000 quasars. Our data are based on the observations of the ROSAT and XMM-Newton satellites, cross-correlated with the Sloan Digital Sky Survey Quasar catalogue. We measure for the first time the structure function up to a rest-frame time interval as large as 20 years (the longest time interval investigated through this type of study). The results of our analysis show that the X-ray variability of quasars still increases at these long time lags. This will be discussed in relation to the physical size of the emitting region.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
