Astronomy and Astrophysics Seminars

Extending the existing timing model for pulsars in almost circular orbits

by Mr. Abhimanyu S. (DAA - TIFR, Mumbai)

Thursday, March 15, 2018 from to (Asia/Kolkata)
We explore the implications of modifying the existing timing model for binary pulsars having tiny orbital eccentricities (e ~ 0). This widely used timing model, namely ELL1 model (due to Norbert Wex), accounts only for the linear in time variation of Laplace-Lagrange parameters, required to describe such binaries. The neglected secular variations in these parameters can lead to measurable timing residuals while pursuing decade-long monitoring campaigns of pulsar binaries. Such campaigns are required to test general relativity and for detecting nano-Hertz gravitational waves with Pulsar Timing Arrays. Our investigations reveal that inclusion of secular variations in the Laplace-Lagrange parameters should allow us to constrain apsidal motion constants in certain class of Milli-Second pulsar binaries. In the second part of my talk, I briefly describe our recent effort to model non-adiabatic evolution of compact binaries with tiny orbital eccentricities and its implications for constructing gravitational wave templates