Abstract Details
| Name: Shilpa Sarkar Affiliation: Aryabhatta Research Institute of Observational Sciences, Nainital Conference ID: ASI2018_1182 Title : Two-temperature flows around compact objects Authors and Co-Authors : Dr. Indranil Chattopadhyay, Scientist-E, Aryabhatta Research Institute of Observational Sciences, Nainital Abstract Type : Contributed Talk Abstract Category : Stars,ISM and the Galaxy Abstract : Two-temperature solutions (due to weak Coulomb coupling between electrons and proton lets electron and proton to equilibriate in two different temperatures, hence the name 'two') of rotating flows around black holes is one of the topics in astrophysics which is least understood and worked upon. So we addressed this problem in greater details in the pure general relativistic regime. We found a very big problem while working in two-temperature models. That is two-temperature solutions face a problem of 'degeneracy'. We have three equations : continuity equation, momentum balance equation, and energy equation but 4 unknowns : radius ,velocity, electron temperature (T_e), proton temperature (T_p). So several solutions are possible for a given set of constants of motion (energy, angular momentum and accretion rate). We found a smart way of fixing this problem by using the integrated form of first law of thermodynamics. Given an arbitrary value of entropy it fixes T_e and T_p. And then we follow the law of nature to always prefer a higher entropy solution and choose that solution to be the physical one. Since we have been mainly interested on developing general solutions without using approximations we have neglected here the viscosity part. We have considered Coulomb coupling as the main source of energy transfer from protons to electrons and cooling of electrons through bremsstrahlung, synchrotron and inverse Comptonisation of the soft photons. According to our knowledge no general way of finding the solutions taking into account the degeneracy problem have not been reported so far. This is the first time we have attempted towards obtaining the general picture of the physical solutions in the two-temperature regime. |