GMRT discovery of PSR J1544+4937, an eclipsing black-widow pulsar identified with a Fermi LAT source

B. Bhattacharyya (1) , J. Roy (1) , P. S. Ray (2) , Y. Gupta (1) , R. W. Romani (3) , S. M. Ransom (3) , E. C. Ferrara (4) , M. T. Wolff (2) , F. Camilo (5, 6) , Ismaël Cognard (7, 8) , A. K. Harding (9) , P. R. Den Hartog (3) , S. Johnston (10) , M. Keith (10) , M. Kerr (3) , P. F. Michelson (3) , P. M. Saz Parkinson (11) , D. L. Wood (2, 12) , K. S. Wood (2)

1 IUCAA - Inter-University Centre for Astronomy and Astrophysics [Pune]
2 NRL - Naval Research Laboratory
3 HEPL - Hansen Experimental Physics Lab [Stanford]
4 GSFC - NASA Goddard Space Flight Center
5 CAL - Columbia Astrophysics Laboratory
6 NAIC - Arecibo Observatory, National Astronomy and Ionosphere Center
7 USN - Unité Scientifique de la Station de Nançay
8 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace
9 GSFC Astrophysics Science Division
10 CSIRO Astronomy and Space Science
11 SCIPP - Santa Cruz Institute for Particle Physics
12 PRAXIS Inc.

Using the Giant Metrewave Radio Telescope (GMRT) we performed deep observations to search for radio pulsations in the directions of unidentified Fermi Large Area Telescope (LAT) gamma-ray sources. We report the discovery of an eclipsing black-widow millisecond pulsar, PSR J1544+4937, identified with the un-cataloged gamma-ray source Fermi J1544.2+4941. This 2.16 ms pulsar is in a 2.9 hours compact circular orbit with a very low-mass companion (Mc > 0.017 Msun). At 322 MHz this pulsar is found to be eclipsing for 13% of its orbit, whereas at 607 MHz the pulsar is detected throughout the low-frequency eclipse phase. Variations in the eclipse ingress phase are observed, indicating a clumpy and variable eclipsing medium. Moreover, additional short-duration absorption events are observed around the eclipse boundaries. Using the radio timing ephemeris we were able to detect gamma-ray pulsations from this pulsar, confirming it as the source powering the gamma-ray emission.

Mots clés: binaries: eclipsing; pulsars: general; pulsars: individual (PSR J1544+4937)

Domaines: Planète et Univers [physics]

B. Bhattacharyya, J. Roy, P. S. Ray, Y. Gupta, R. W. Romani, et al.. GMRT discovery of PSR J1544+4937, an eclipsing black-widow pulsar identified with a Fermi LAT source. The Astrophysical journal letters, 2013, 773 (1), 6 pp. ⟨10.1088/2041-8205/773/1/L12⟩. ⟨insu-01261369⟩