Name: Amal Abdulrahman
Affiliation: Senior Research Fellow, Farook College (Autonomous), University of Calicut
Conference ID : ASI2022_143
Title : Two population synchrotron model: The case of X-ray knots of 3C 273.
Authors : Amal Abdulrahman1, Sunder Sahayanathan2,3 and P A Subha1 1Department of Physics, Farook College, University of Calicut, Kerala - 673632, India 2Astrophysical Sciences Division, Bhabha Atomic Research Centre, Mumbai - 400085, India 3$Homi Bhabha National Institute, Mumbai 400094, India
Abstract Type: Poster
Abstract Category : Extragalactic Astronomy
Abstract : The X-ray spectrum from the knots of kilo-parsec scale active galactic nuclei (AGN) jets suggests the high energy emission process to be different from the radio/optical counterpart. The synchrotron self compton interpretation of the X-ray emission was ruled out since it demands large deviation from the equipartition between the magnetic field and the electron energy densities. Hence the X-ray emission is interpreted as inverse Compton scattering of cosmic microwave photons since this is the dominant external photon field at kilo-parsec scale. However, this emission model predicts significant gamma ray emission from these knots which are not consistent with the upper limits attained through Fermi gamma-ray observations. Alternate model interpreting the X-ray emission from a different electron population has been put forth as a plausible explanation. However, the co-existence of such two independent relativistic electron distribution cannot be easily envisaged and in addition, involve too many free parameters. On the other hand, the radiative cooling timescale of the emitting electron is inversely proportional to its energy. The low energy electron cool slower than the high energy ones and thereby can diffuse over long distance. Hence, the low energy emission can originate even from extended regions. In this work, we incorporate this spatial diffusion of energetic electrons in the emission model resulting in a two population and use it to understand the radio--optical--X-ray emission from the knots of kilo-parsec scale AGN jets of 3C 273.