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Title: 1FGL J0523.5–2529: A NEW PROBABLE GAMMA-RAY PULSAR BINARY

Journal Article · · Astrophysical Journal Letters
;  [1];  [2];  [3];  [4];  [5];  [6]
  1. Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)
  2. Department of Physics, University of Adiyaman, 02040 Adiyaman (Turkey)
  3. Astro Space Center of the Lebedev Physical Institute, 117810 Moscow (Russian Federation)
  4. Department of Physics, Texas Tech University, Box 41051, Lubbock, TX 79409 (United States)
  5. Special Astrophysical Observatory, Russian Academy of Sciences, Karachaevo-Cherkesskaya Republic, Nizhnii Arkhyz 369167 (Russian Federation)
  6. Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)

We report optical photometric and Southern Astrophysical Research spectroscopic observations of an X-ray source found within the localization error of the Fermi Large Area Telescope unidentified γ-ray source 1FGL J0523.5–2529. The optical data show periodic flux modulation and radial velocity variations indicative of a binary with a 16.5 hr period. The data suggest a massive non-degenerate secondary (≳ 0.8 M {sub ☉}), and we argue the source is likely a pulsar binary. The radial velocities have good phase coverage and show evidence for a measurable eccentricity (e = 0.04). There is no clear sign of irradiation of the secondary in either photometry or spectroscopy. The spatial location out of the Galactic plane and γ-ray luminosity of the source are more consistent with classification as a recycled millisecond pulsar than as a young pulsar. Future radio timing observations can confirm the identity of the primary and further characterize this interesting system.

OSTI ID:
22365777
Journal Information:
Astrophysical Journal Letters, Vol. 788, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
Country of Publication:
United States
Language:
English