Abhimanyu Susobhanan (NAOC, Beijing)

Abhimanyu Susobhanan Colloquium: The Indian Pulsar Timing Array 3.5-year Data Release

Online

Abstract

Pulsar Timing Arrays (PTAs) are astronomical experiments that aim to detect gravitational waves in the nanohertz frequency regime by observing an ensemble of millisecond pulsars (MSPs). The Indian Pulsar Timing Array (InPTA) experiment, operational since 2015, aims to use the unique strengths of the Giant Metrewave Radio Telescope to help detect nanohertz gravitational waves. The wide low-frequency coverage provided by the uGMRT enables very accurate characterization of radio frequency-dependent effects in the pulsar signal, such as interstellar dispersion and scattering, which are major sources of noise in PTA experiments. In this talk, I will provide an overview of the InPTA experiment and present recent results from the upcoming InPTA data release 1, which includes precise time-of-arrival and dispersion measure estimates for 14 MSPs spanning 3.5 years. This dataset forms the basis of our recent studies and findings, including the 2021 profile change event in PSR J1713+0747, the detection of solar coronal mass ejection from DM excess in timing measurements of PSR J2145-0750, the investigation of scatter broadening in the low-frequency profile of PSR J1643-1224, and the determination of dispersion measures and ToA residuals in multiple pulsars using the wideband timing technique.