Scientists have explored the implications for the plasma composition of astrophysical jets, outflows of ionized matter that are emitted as extended beams from celestial objects such as black holes, neutron stars and pulsars.
Despite years of research, it is not known what type of matter astrophysical jets are made of – whether they are made of bare electrons or protons or whether positively charged electrons called positrons are also present. Knowing the jet structure is important because it will allow pinpointing the exact physical process operating near black holes and neutron stars. In general, theoretical studies do not account for the structure of the jet and the relation between thermodynamic quantities such as mass density, energy density and pressure. This type of relation is called the equation of state of the jet matter.
Scientists at Aryabhatta Research Institute of Observational Sciences (ARIES), an autonomous institute of the Department of Science and Technology (DST), Government of India, used a relativistic equation of state, which was partially proposed by them in an earlier paper on the role of the structure of relativistic plasma in the actual evolution of the jet.
The research was led by Raj Kishor Joshi and Dr Indranil Chattopadhyay of ARIES and has been published in the Astrophysical Journal (ApJ). The authors upgraded a numerical simulation code developed earlier by Dr Chattopadhyay, using the said equation of state to study the dynamics of astrophysical jets composed of a mix of electrons, positrons (positively charged electrons) and protons.