Abstract Details
| Name: Arun Mangalam Affiliation: Indian Institute of Astrophysics Conference ID: ASI2015_750 Title : Relativistic Signatures in emission from inner regions of Black hole and neutron star systems Authors and Co-Authors : Prashanth Mohan (ARIES) Abstract Type : Poster Abstract Category : Extragalactic astronomy Abstract : We present a general relativistic model of motion of an emitting particle in motion in Schwarzschild geometry which include Doppler and gravitational shifts, aberration, light bending and time delay. This formalism has applications to two situations: (i) jet based variability in active galactic nuclei due to an orbiting blob in helical motion along a funnel or cone shaped magnetic surface anchored to the accretion disk close to the black hole and (ii) emission from a hot spot on an X-ray Pulsar. Both these effects have observable consequences on the light curves from these objects. In the case of AGN, the simulated LCs are used to study quasi-periodic oscillations (QPOs) and the power spectral density (PSD) shape. These results strongly justify the use of a realistic magnetic surface geometry and a GR framework to describe effects on emission from orbital features in the jet, especially for launch radii close to the horizon radius. A power law shaped PSD with a typical slope of -2 and QPOs with timescales in the range (1.37 - 130.7) days consistent with optical variability in Blazars, emerge from the simulations for black hole masses $M_\bullet= (0.5--5) 10^8 M_\odot$ and initial blob Lorentz factors jet $\simeq 2-10$. In second case of pulse profiles from X-ray pulsar, the mass and radius can be extracted from several constraints that can be placed using the pulse profiles. |