Detalles de publicación
PP 023080
Neutron star mass estimates from gamma-ray eclipses in spider millisecond pulsar binaries
(1) MPI for Gravitational physics, (2) Leibniz Universitat Hannover, (3) Jodrell Bank, (4) NRL, (5) MPI- for Radioastronomy, (6) NCRA, (7) Laboratoire Leprince-Ringuet, (8) SARAO, (9) Université d’Orléan, (10) CNRS, (11) Cornell University, (12) Hubble Fellowship Program Einstein Postdoctoral Fellow, (13) NRL, (14) University of Sheffield, (15) IAC, (16) University College Cork, (17) ULL, (18) University of Virginia, (19) NRAO, (20) Eureka Scientific, (21) Université de Bordeaux, (22) OzGrav, (23) Swinburne University of Technology, (24) New York University Abu Dhabi, (25) West Virginia University, (26) Observatoire de Paris
Reliable neutron star mass measurements are key to determining the equation-of-state of cold nuclear matter, but these are rare. "Black Widows" and "Redbacks" are compact binaries consisting of millisecond pulsars and semi-degenerate companion stars. Spectroscopy of the optically bright companions can determine their radial velocities, providing inclination-dependent pulsar mass estimates. While inclinations can be inferred from subtle features in optical light curves, such estimates may be systematically biased due to incomplete heating models and poorly-understood variability. Using data from the Fermi Large Area Telescope, we have searched for gamma-ray eclipses from 49 spider systems, discovering significant eclipses in 7 systems, including the prototypical black widow PSR B1957+20. Gamma-ray eclipses require direct occultation of the pulsar by the companion, and so the detection, or significant exclusion, of a gamma-ray eclipse strictly limits the binary inclination angle, providing new robust, model-independent pulsar mass constraints. For PSR B1957+20, the eclipse implies a much lighter pulsar (M_psr = 1.81 +- 0.07 Msun) than inferred from optical light curve modelling.

