• Y. GUPTA

      Articles written in Journal of Astrophysics and Astronomy

    • The Central Point Source in G76.9+1.0

      V. R. Marthi J. N. Chengalur Y. Gupta G. C. Dewangan D. Bhattacharya

      More Details Abstract Fulltext PDF

      We describe the serendipitous discovery of a very steep-spectrum radio point source in low-frequency Giant Metrewave Radio Telescope (GMRT) images of the supernova remnant (SNR) G76.9+1.0. The steep spectrum, as well as the location of the point source near the centre of this SNR confirm that this indeed is the pulsar J2022+3842. Archival Chandra X-ray data shows a point source coincident with the radio point source. However, no pulsed radio emission was detected despite deep searches at 610 MHz and 1160 MHz – which can be understood to be due to temporal broadening of the pulses. Weak pulsed emission has indeed been seen at 2 GHz with the Green Bank Telescope (GBT), establishing the fact that scattering is responsible for its non-detection at low radio frequencies. We underline the usefulness of low-frequency radio imaging as a good technique to prospect for pulsar candidates.

    • Precision pulsar timing with the ORT and the GMRT and its applications in pulsar astrophysics

      BHAL CHANDRA JOSHI PRAKASH ARUMUGASAMY MANJARI BAGCHI DEBADES BANDYOPADHYAY AVISHEK BASU NEELAM DHANDA BATRA SURYARAO BETHAPUDI ARPITA CHOUDHARY KISHALAY DE L. DEY A. GOPAKUMAR Y. GUPTA M. A. KRISHNAKUMAR YOGESH MAAN P. K. MANOHARAN ARUN NAIDU RANA NANDI DHRUV PATHAK MAYURESH SURNIS ABHIMANYU SUSOBHANAN

      More Details Abstract Fulltext PDF

      Radio pulsars show remarkable clock-like stability, which make them useful astronomy tools in experiments to test equation of state of neutron stars and detecting gravitational waves using pulsar timing techniques. A brief review of relevant astrophysical experiments is provided in this paper highlighting thecurrent state-of-the-art of these experiments. A program to monitor frequently glitching pulsars with Indian radio telescopes using high cadence observations is presented, with illustrations of glitches detected in this program, including the largest ever glitch in PSR B0531 $+$ 21. An Indian initiative to discover sub-$\mu$Hz gravitational waves, called Indian Pulsar Timing Array (InPTA), is also described briefly, where time-of-arrival uncertainties and post-fit residuals of the order of $\mu$s are already achievable, comparable to other international pulsar timing array experiments. While timing the glitches and their recoveries are likely to provide constraints on the structure of neutron stars, InPTA will provide upper limits on sub-$\mu$Hz gravitational waves apart from auxiliary pulsarscience. Future directions for these experiments are outlined.

  • Journal of Astrophysics and Astronomy | News

    • Continuous Article Publication

      Posted on January 27, 2016

      Since January 2016, the Journal of Astrophysics and Astronomy has moved to Continuous Article Publishing (CAP) mode. This means that each accepted article is being published immediately online with DOI and article citation ID with starting page number 1. Articles are also visible in Web of Science immediately. All these have helped shorten the publication time and have improved the visibility of the articles.

    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

      Click here for Editorial Note on CAP Mode

© 2017-2019 Indian Academy of Sciences, Bengaluru.