GBT25B-279

Confirming Three Spider Binary Millisecond Pulsar Candidates

Abstract

Three Fermi Large Area Telescope gamma-ray sources (4FGL J0935.3+0901, 4FGL J1838.2+3223, 4FGL J2054.2+6904) have an identified optical and X-ray counterpart that exhibit properties remarkably similar to those of the sample of confirmed eclipsing redback millisecond pulsars (MSPs). They are all in binary systems with a 2.4, 4.0, and 7.5 hour orbital period, respectively. These redback candidates can be confirmed through a deep, recurring, search for radio pulsations at L-band, targeting orbital phases near superior conjunction of the companion, where the deleterious effects of radio eclipses are expected to be minimal. Given the striking similarities with genuine redback MSPs, there is a strong possibility that the three Fermi LAT sources also represent transition objects between LMXBs and radio MSPs, and can serve as additional laboratories for studying the poorly understood transition mechanism of MSPs from accretion to rotation powered. Detection of radio pulsations would confirm the nature of these systems, while increasing the sample of redback binaries and potential tMSPs in the field of the Galaxy. This effort would also advance our understanding of compact binary evolution and the Galactic pulsar population.

Investigators

Name	Institution
Karen Perez *	Columbia University
Slavko Bogdanov	Columbia University
Vishal Gajjar	California at Berkeley, University of
Steve Croft	California at Berkeley, University of
Matt Lebofsky	California at Berkeley, University of
David MacMahon	California at Berkeley, University of
Jules Halpern	Columbia University

* indicates the PI