In previous paper we have shown that the soft X-ray spectra of two types of Seyfert 1 galaxies behave statistically differently with increasing intensity. In order to see how the spectrum of blazars changes, we made...In previous paper we have shown that the soft X-ray spectra of two types of Seyfert 1 galaxies behave statistically differently with increasing intensity. In order to see how the spectrum of blazars changes, we made plots of Hardness Ratio 1 versus Count Rates (HR1-Cts) for 18 blazars observed by ROSAT/PSPC. According to our criteria, ten showed a positive HR1-Cts correlation, two a negative correlation, and the remaining six, no clear correlation. Thus, most blazars of our sample show a hardening spectrum during overall flux increase, though some vary randomly. By investigating the photon index of these objects and different radiation theories, we argue that relative dominance between the synchrotron and inverse Compton emission in the soft X-ray band can well account for the differing spectral behaviours and that the different spectral variations might represent a sequence of synchrotron peaked frequency.展开更多
基金Supported by the National Natural Science Foundation of China under No.19973014the National Climbing program of Chinathe National 973 Project of China(NKBRSF G19990754)
文摘In previous paper we have shown that the soft X-ray spectra of two types of Seyfert 1 galaxies behave statistically differently with increasing intensity. In order to see how the spectrum of blazars changes, we made plots of Hardness Ratio 1 versus Count Rates (HR1-Cts) for 18 blazars observed by ROSAT/PSPC. According to our criteria, ten showed a positive HR1-Cts correlation, two a negative correlation, and the remaining six, no clear correlation. Thus, most blazars of our sample show a hardening spectrum during overall flux increase, though some vary randomly. By investigating the photon index of these objects and different radiation theories, we argue that relative dominance between the synchrotron and inverse Compton emission in the soft X-ray band can well account for the differing spectral behaviours and that the different spectral variations might represent a sequence of synchrotron peaked frequency.
