Pulsar timing as probe of Stochastic Gravitational Wave background and internal structure of NS

Regular monitoring of radio pulsars, some of the most stable clocks in the universe, are capable of testing alternative theories of gravity, detection of a stochastic gravitational wave background and providing constraints on internal structure of neutron stars and their equation of state. I will first introduce the technique for such studies, called pulsar timing, with illustrations from recent observations using two major radio observatories in India, the ORT and the GMRT. Then, I will briefly describe high precision timing of an ensemble of millisecond pulsars, called Pulsar Timing Array (PTA). with a mention of our efforts with the ORT and the GMRT. A discussion on a type of rotational irregularities in neutron star, called pulsar glitch, will be presented. The role of entrainment of crustal superfluid in interpreting observational constraints will be highlighted. The implied higher fractional moment of inertia of decoupled superfluid puts constraints on proposed equation of states. I will also present results on a recently detected glitch-recovery with the ORT timing along with possibilities of future work in modeling such recovery data.