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Title: THE SPECTRUM OF THE RECYCLED PSR J0437-4715 AND ITS WHITE DWARF COMPANION

Journal Article · · Astrophysical Journal
;  [1]; ;  [2];  [3];  [4]
  1. Department of Astronomy, University of Florida, FL 32611-2055 (United States)
  2. Department of Astronomy and Astrophysics, Pennsylvania State University, PA 16802 (United States)
  3. Helmholtz Centre Potsdam-GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam (Germany)
  4. Department of Astronomy, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada)

We present extensive spectral and photometric observations of the recycled pulsar/white dwarf binary containing PSR J0437-4715, which we analyzed together with archival X-ray and gamma-ray data, to obtain the complete mid-infrared to gamma-ray spectrum. We first fit each part of the spectrum separately, and then the whole multi-wavelength spectrum. We find that the optical-infrared part of the spectrum is well fit by a cool white dwarf atmosphere model with pure hydrogen composition. The model atmosphere (T{sub eff} = 3950 {+-} 150 K, log g = 6.98 {+-} 0.15, R{sub WD} = (1.9 {+-} 0.2) Multiplication-Sign 10{sup 9} cm) fits our spectral data remarkably well for the known mass and distance (M = 0.25 {+-} 0.02 M{sub Sun }, d = 156.3 {+-} 1.3 pc), yielding the white dwarf age ({tau}{sub WD} = 6.0 {+-} 0.5 Gyr). In the UV, we find a spectral shape consistent with thermal emission from the bulk of the neutron star surface, with surface temperature between 1.25 Multiplication-Sign 10{sup 5} and 3.5 Multiplication-Sign 10{sup 5} K. The temperature of the thermal spectrum suggests that some heating mechanism operates throughout the life of the neutron star. The temperature distribution on the neutron star surface is non-uniform. In the X-rays, we confirm the presence of a high-energy tail which is consistent with a continuation of the cutoff power-law component ({Gamma} = 1.56 {+-} 0.01, E{sub cut} = 1.1 {+-} 0.2 GeV) that is seen in gamma rays and perhaps even extends to the near-UV.

OSTI ID:
22011861
Journal Information:
Astrophysical Journal, Vol. 746, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
Country of Publication:
United States
Language:
English