Abstract Details

Name: Siddhartha Gupta
Affiliation: Research scholar, Joint Astronomy Programme, IISc and RRI
Conference ID: ASI2017_951
Title : Lack of thermal energy in superbubbles : hint of cosmic rays ?
Authors and Co-Authors : Siddhartha Gupta(1,2), Biman B. Nath(1), Prateek Sharma(2) (1) Raman Research Institute, Bangalore, India (2) Indian Institute of Science, Bangalore, India
Abstract Type : Oral
Abstract Category : Stars,ISM and the Galaxy
Abstract : The observed X-ray temperature and the thermal pressure of the hot (>10^5 K) gas behind the shock, driven by OB associations, are found to be less than that expected from the theory. With the help of hydrodynamical simulations, we show that the expected thermal pressure is ~0.8 \rho_{amb} v_{sh}^2$ independent of the radiative energy loss and the ambient density profile where v_{sh} is the shock velocity and \rho_{amb} is the ambient density. We suggest that the absence of the hard X-ray ( >1 keV) component and the shortfall of the thermal pressure both can be explained if a significant fraction (~0.5) of the thermal energy goes to the non-thermal particles such as cosmic rays.