Monday, March 7 2022
16:00 - 18:00

IMSc Webinar

Probing the structural and orbital properties of binary pulsars

Dhruv Pathak

IMSc (and IUCAA)

The timing analysis of radio pulsars gives many interesting results and is expected to contribute further in many areas of fundamental physics in the future. In this connection, it is important to understand the external factors affecting the values of the parameters estimated in the timing analysis. Among all these timing parameters, the measured values of the time-derivatives of the frequencies (both spin and orbital) are affected by the velocity, acceleration, jerk, etc., of the pulsar. These effects are known as ‘dynamical contributions’. In this thesis, we explore these dynamical effects in the first as well as the second time-derivatives of the frequency (both spin and orbital). We provide analytical expressions for all the dynamical terms contributing to the first and the second derivatives of the frequency in terms of the Galactic coordinates, the proper motion, the distance, the radial velocity, and the observed values of the frequency and its derivatives, without resorting to any numerical fitting. We introduce a package, ‘GalDynPsr’, that evaluates these different dynamical effects in the first derivative of the period (both spin and orbital), following the traditional as well as improved methods based on a well-known model of the Galactic potential. We then introduce another python package ‘GalDynPsrFreq’ that estimates the dynamical terms in the measured values of the first and the second time derivatives of the frequency (both spin and orbital). We also investigate how dynamics can affect values of the braking index and the second derivative of the orbital frequency.

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