Nanohertz gravitational wave astronomy during SKA era: An InPTA perspective

Decades long monitoring of millisecond pulsars, which exhibit highly stable rotational periods, in pulsar timing array experiments is on the threshold discovering nanohertz stochastic gravitational wave background. This paper describes Indian Pulsar (InPTA) experiment, employs upgraded Giant Metrewave Radio Telescope (uGMRT) for an ensemble pulsars this purpose. We highlight InPTA's observation strategies and analysis methods, are relevant a future PTA experiment with more sensitive Square Kilometer Array (SKA) telescope. show that unique multi-sub-array multi-band wide-bandwidth frequency coverage InPTA provides Dispersion Measure estimates unprecedented precision e.g., ~ 2 x 10{-5} pc-cm{-3} PSR J1909-3744. Configuring SKA-low SKA-mid as two four sub-arrays respectively, it shown comparable achievable, using similar to those pursued by InPTA, larger sample 62 requiring about 26 7 hours per epoch telescopes respectively. also review ongoing efforts develop PTA-relevant general relativistic constructs will be required search waves from isolated super-massive black hole binary systems like blazar OJ 287. These should pursue persistent multi-messenger astronomy during forthcoming era SKA telescope, Thirty Meter Telescope, next-generation Event Horizon Telescope.