arXiv subjects

S. Campitiello

Publications and source records attributed to S. Campitiello.

2 recordsLinked to original sources

arXiv2019

A NuSTAR view of powerful gamma-ray loud blazars

We observed with the NuSTAR satellite 3 blazars at z>2, detected in gamma-rays by Fermi/LAT and in the soft X-rays, but not yet observed above 10 keV. The flux and slope of their X-ray continuum, together with Fermi/LAT data allows us to estimate their total electromagnetic output and peak frequency. For some of them we can study the source in different states, and investigate the main cause of the observed different spectral energy distribution. We then collected all blazars at redshift greater than 2 observed by NuSTAR, and confirm that these hard and luminous X-ray blazars are among the most powerful persistent sources in the Universe. We confirm the relation between the jet power and the disk luminosity, extending it at the high energy end.

astro-ph.HE↗

arXiv2017

How to constrain mass and spin of supermassive black holes through their disk emission

We investigate the global properties of the radiation emitted by the accretion disk around Kerr black holes. Using the Kerr blackbody (KERRBB) numerical model, we build an analytic approximation of the disk emission features focusing on the pattern of the produced radiation as a function of the black hole spin, mass, accretion rate and viewing angle. The assumption of having a geometrically thin disk limits our analysis to systems emitting below ~0.3 of the Eddington luminosity. We apply this analytical model to four blazars (whose jets are pointing at us) at high redshift that show clear signatures of disk emission. For them, we derive the black hole masses as a function of spin. If these jetted sources are powered by the black hole rotation, they must have high spin values, further constraining their masses.

astro-ph.HE↗