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Title: DISCOVERY OF ECLIPSES FROM THE ACCRETING MILLISECOND X-RAY PULSAR SWIFT J1749.4-2807

Abstract

We report the discovery of X-ray eclipses in the recently discovered accreting millisecond X-ray pulsar SWIFT J1749.4-2807. This is the first detection of X-ray eclipses in a system of this type and should enable a precise neutron star mass measurement once the companion star is identified and studied. We present a combined pulse and eclipse timing solution that enables tight constraints on the orbital parameters and inclination and shows that the companion mass is in the range 0.6-0.8 M{sub sun} for a likely range of neutron star masses, and that it is larger than a main-sequence star of the same mass. We observed two individual eclipse egresses and a single ingress. Our timing model shows that the eclipse features are symmetric about the time of 90{sup 0} longitude from the ascending node, as expected. Our eclipse timing solution gives an eclipse duration (from the mid-points of ingress to egress) of 2172 {+-} 13 s. This represents 6.85% of the 8.82 hr orbital period. This system also presents a potential measurement of 'Shapiro' delay due to general relativity; through this technique alone, we set an upper limit to the companion mass of 2.2 M{sub sun}.

Authors:
 [1]
  1. Department of Astronomy, University of Maryland, College Park, MD 20742 (United States)
Publication Date:
OSTI Identifier:
21451037
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal Letters
Additional Journal Information:
Journal Volume: 717; Journal Issue: 2; Other Information: DOI: 10.1088/2041-8205/717/2/L149; Journal ID: ISSN 2041-8205
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ECLIPSE; GENERAL RELATIVITY THEORY; INCLINATION; MAIN SEQUENCE STARS; MASS; NEUTRON STARS; NEUTRONS; PULSARS; PULSES; SYMMETRY; BARYONS; COSMIC RADIO SOURCES; ELEMENTARY PARTICLES; FERMIONS; FIELD THEORIES; HADRONS; NUCLEONS; RELATIVITY THEORY; STARS

Citation Formats

Markwardt, C B, and Strohmayer, T. E., E-mail: Craig.Markwardt@nasa.go. DISCOVERY OF ECLIPSES FROM THE ACCRETING MILLISECOND X-RAY PULSAR SWIFT J1749.4-2807. United States: N. p., 2010. Web. doi:10.1088/2041-8205/717/2/L149.
Markwardt, C B, & Strohmayer, T. E., E-mail: Craig.Markwardt@nasa.go. DISCOVERY OF ECLIPSES FROM THE ACCRETING MILLISECOND X-RAY PULSAR SWIFT J1749.4-2807. United States. https://doi.org/10.1088/2041-8205/717/2/L149
Markwardt, C B, and Strohmayer, T. E., E-mail: Craig.Markwardt@nasa.go. 2010. "DISCOVERY OF ECLIPSES FROM THE ACCRETING MILLISECOND X-RAY PULSAR SWIFT J1749.4-2807". United States. https://doi.org/10.1088/2041-8205/717/2/L149.
@article{osti_21451037,
title = {DISCOVERY OF ECLIPSES FROM THE ACCRETING MILLISECOND X-RAY PULSAR SWIFT J1749.4-2807},
author = {Markwardt, C B and Strohmayer, T. E., E-mail: Craig.Markwardt@nasa.go},
abstractNote = {We report the discovery of X-ray eclipses in the recently discovered accreting millisecond X-ray pulsar SWIFT J1749.4-2807. This is the first detection of X-ray eclipses in a system of this type and should enable a precise neutron star mass measurement once the companion star is identified and studied. We present a combined pulse and eclipse timing solution that enables tight constraints on the orbital parameters and inclination and shows that the companion mass is in the range 0.6-0.8 M{sub sun} for a likely range of neutron star masses, and that it is larger than a main-sequence star of the same mass. We observed two individual eclipse egresses and a single ingress. Our timing model shows that the eclipse features are symmetric about the time of 90{sup 0} longitude from the ascending node, as expected. Our eclipse timing solution gives an eclipse duration (from the mid-points of ingress to egress) of 2172 {+-} 13 s. This represents 6.85% of the 8.82 hr orbital period. This system also presents a potential measurement of 'Shapiro' delay due to general relativity; through this technique alone, we set an upper limit to the companion mass of 2.2 M{sub sun}.},
doi = {10.1088/2041-8205/717/2/L149},
url = {https://www.osti.gov/biblio/21451037}, journal = {Astrophysical Journal Letters},
issn = {2041-8205},
number = 2,
volume = 717,
place = {United States},
year = {Sat Jul 10 00:00:00 EDT 2010},
month = {Sat Jul 10 00:00:00 EDT 2010}
}