URCAD Presentation Sneak Peek: Aryana Arsham

Mon, 15 Apr 2013 11:47:50 -0400

The purpose of Aryana's research was to study the radiative deceleration of relativistic jets of plasma found in very distant, thus high cosmological redshift z quasars. The deceleration is due to Inverse Compton scattering of CMB photons off the jet relativistic electrons. In this case, and if the jets decelerate substantially, no significant X-ray emission due to inverse Compton scattering of the CMB is anticipated from the large scale jet. We casted a system of two coupled autonomous, non - linear ordinary differential equations (ODEs). We produced an analytic solution, under the approximations: (i) the energy density of the plasma in the jet is dominated by the relativistic electrons and that the contribution of the protons can be neglected and (ii) the electron energy distribution is monoenergetic. We showed that the first assumption is justified for those large scale jets that exhibit a hard synchrotron spectrum extending to the optical energies. We found substantial deceleration taking place for values of z greater than approximately 4, corresponding to 11.5 billion years ago, about 2.2 billion years after the Big Bang. We are dropping the second assumption by adopting more realistic electron energy distributions, producing numerical solutions, and assessing its astrophysical implications.

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