2011/05/04 by Liang Chen, J. M. Bai · 2 citations
Physics and Astronomy · #Astronomy #Astrophysics #Astrophysics and Cosmic Phenomena #Black hole (networking) #Blazar #Fermi Gamma-ray Space Telescope #Gamma ray #Neutrino Physics Research #Nuclear physics #Physics #Radio Astronomy Observations and Technology #Synchrotron #astro-ph.CO
paper · pdf · doi:10.1088/0004-637x/735/2/108
9 figures, accepted by ApJ
arxiv created 2011/05/04 · openalex publication_date 2011/06/22 · arxiv updated 2015/05/28 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
In this paper, we use the quasi-simultaneous spectra of Fermi bright blazars and Fermi -detected narrow-line Seyfert 1 (NLS1) to study the blazar sequence and inverse Compton models. (1) The synchrotron peak luminosities ( L s ) significantly correlate inversely with the synchrotron peak frequencies (ν s ), L s ∝ν −0.44 ± 0.11 s , which is consistent with the blazar sequence. In addition to the correlation, there are some blazars showing low ν s and low L s . To study the relation between these low-ν s –low- L s blazars and the blazar sequence, we present correlations of the parameter L s ν 1/4 s with the ratio of Compton to synchrotron peak frequencies ( r Cs ≡ ν C /ν s ) and with the ratio of Compton to synchrotron luminosities (CD ≡ L C / L s ). The results indicate that both correlations are significant with a Pearson's probability for a null correlation of p = 0.0218 and p = 0.0286, respectively. This does not support the idea that the low-ν s –low- L s blazars are sources with less beaming. Another possibility, as suggested by Ghisellini & Tavecchio, is that these blazars have relatively lower black hole masses. To test this, we collect the black hole masses of 30 blazars from archives and find that the black hole mass correlates with the parameter L s ν 0.44 s ( p = 0.0344). Therefore, the black hole masses of low-ν s –low- L s blazars are statistically small. The NLS1s are thought to have lower black hole masses. We find that the four NLS1s detected by Fermi have low ν s and low L s . This supports the above result. (2) The ratio r Cs correlates with CD significantly ( p = 0.00375). The external Compton model can naturally explain this correlation, while the synchrotron self-Compton model cannot. This agrees with the findings of many authors that the EC process dominates the gamma-ray emission of flat spectrum radio quasars.