Modelling Hecto & Nano Hertz Gravitational Wave Sources

The International Pulsar Timing Array (IPTA) consortium is expected to inaugurate the era of nano-hertz (nHz) gravitational wave (GW) astronomy in the coming years.

This is prompted by the very recent detailed and independent investigations that reveal the presence of a common red noise process in IPTA  pulsars with spectral signature consistent with a GW background due to merging Supermassive Black Hole (SMBH) binaries. 

This influenced us to develop an approach to model GWB associated with SMBH binaries inspiraling along general relativistic eccentric orbits. I will describe salient features of our approach and outline ongoing efforts to deliver it for  IPTA  GW  analysis. Thereafter, I will briefly describe our ongoing efforts to model and search for GW burst with memory (BWM) events in the IPTA & LIGO-Virgo-KAGRA data sets. It turns out that such events naturally arise from the detailed modeling of hyperbolic passages of BH binaries using post-Newtonian approximation to General Relativity. I will also list my ongoing contributions to our Indian Pulsar Timing Array efforts that routinely employ  TIFR’s uGMRT.