TY - JOUR

T1 - Measuring the mass of the black widow PSR J1555-2908

AU - Kennedy, M. R.

AU - Breton, R. P.

AU - Clark, C. J.

AU - Mata Sánchez, D.

AU - Voisin, G.

AU - Dhillon, V. S.

AU - Halpern, J. P.

AU - Marsh, T. R.

AU - Nieder, L.

AU - Ray, P. S.

AU - Van Kerkwijk, M. H.

N1 - Funding Information: Based on observations collected at the European Southern Obser- vatory, Chile under ESO programme 0103.D-0878(A). Portions of this work performed at NRL were supported by NASA. The Pan-STARRS1 Surveys (PS1) and the PS1 public science archiv e hav e been made possible through contributions by the Institute for Astronomy, the University of Hawaii, the Pan-STARRS Project Office, the Max-Planck Society and its participating insti- tutes, the Max Planck Institute for Astronomy, Heidelberg and the Max Planck Institute for Extraterrestrial Physics, Garching, The Johns Hopkins Uni versity, Durham Uni versity, the Uni versity of Edinburgh, the Queen's University Belfast, the Harvard-Smithsonian Center for Astrophysics, the Las Cumbres Observatory Global Telescope Network Incorporated, the National Central University of Taiwan, the Space Telescope Science Institute, the National Aeronautics and Space Administration under Grant No. NNX08AR22G issued through the Planetary Science Division of the NASA Science Mission Directorate, the National Science Foundation Grant No. AST-1238877, the University of Maryland, Eotvos Lorand Univer- sity (ELTE), the Los Alamos National Laboratory, and the Gordon and Betty Moore Foundation. This work made use of ASTROPY (Astropy Collaboration 2013, 2018 ).

PY - 2022/5

Y1 - 2022/5

N2 - Accurate measurements of the masses of neutron stars are necessary to test binary evolution models, and to constrain the neutron star equation of state. In pulsar binaries with no measurable post-Keplerian parameters, this requires an accurate estimate of the binary system's inclination and the radial velocity of the companion star by other means than pulsar timing. In this paper, we present the results of a new method for measuring this radial velocity using the binary synthesis code ICARUS. This method relies on constructing a model spectrum of a tidally distorted, irradiated star as viewed for a given binary configuration. This method is applied to optical spectra of the newly discovered black widow PSR J1555-2908. By modeling the optical spectroscopy alongside optical photometry, we find that the radial velocity of the companion star is 397 +/- 4 km s(-1) (errors quoted at 95 per cent confidence interval), as well as a binary inclination of >75 degrees. Combined with gamma-ray pulsation timing information, this gives a neutron star mass of 1.67(-0.09)(+0.15) M-circle dot and a companion mass of 0.060(-0.003)(+0.005) M-circle dot, placing PSR J1555-2908 at the observed upper limit of what is considered a black widow system.

AB - Accurate measurements of the masses of neutron stars are necessary to test binary evolution models, and to constrain the neutron star equation of state. In pulsar binaries with no measurable post-Keplerian parameters, this requires an accurate estimate of the binary system's inclination and the radial velocity of the companion star by other means than pulsar timing. In this paper, we present the results of a new method for measuring this radial velocity using the binary synthesis code ICARUS. This method relies on constructing a model spectrum of a tidally distorted, irradiated star as viewed for a given binary configuration. This method is applied to optical spectra of the newly discovered black widow PSR J1555-2908. By modeling the optical spectroscopy alongside optical photometry, we find that the radial velocity of the companion star is 397 +/- 4 km s(-1) (errors quoted at 95 per cent confidence interval), as well as a binary inclination of >75 degrees. Combined with gamma-ray pulsation timing information, this gives a neutron star mass of 1.67(-0.09)(+0.15) M-circle dot and a companion mass of 0.060(-0.003)(+0.005) M-circle dot, placing PSR J1555-2908 at the observed upper limit of what is considered a black widow system.

KW - techniques: spectroscopic

KW - binaries: close

KW - stars: neutron

KW - pulsars: individual: PSR J1555-2908

UR - http://www.scopus.com/inward/record.url?scp=85128368964&partnerID=8YFLogxK

U2 - 10.1093/mnras/stac379

DO - 10.1093/mnras/stac379

M3 - Article

VL - 512

SP - 3001

EP - 3014

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

SN - 0035-8711

IS - 2

ER -