DISCOVERY OF THE OPTICAL/ULTRAVIOLET/GAMMA-RAY COUNTERPART TO THE ECLIPSING MILLISECOND PULSAR J1816+4510
- Physics Department, University of Wisconsin-Milwaukee, Milwaukee WI 53211 (United States)
- Center for Advanced Radio Astronomy and Department of Physics and Astronomy, University of Texas at Brownsville, Brownsville, TX 78520 (United States)
- National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22901 (United States)
- Eureka Scientific, Inc., 2452 Delmer Street, Suite 100, Oakland, CA 94602-3017 (United States)
- Department of Physics, McGill University, 3600 University Street, Montreal, QC H3A 2T8 (Canada)
- Department of Physics, West Virginia University, White Hall, 115 Willey Street, Morgantown, WV 26506 (United States)
The energetic, eclipsing millisecond pulsar J1816+4510 was recently discovered in a low-frequency radio survey with the Green Bank Telescope. With an orbital period of 8.7 hr and a minimum companion mass of 0.16 M{sub Sun }, it appears to belong to an increasingly important class of pulsars that are ablating their low-mass companions. We report the discovery of the {gamma}-ray counterpart to this pulsar and present a likely optical/ultraviolet counterpart as well. Using the radio ephemeris, we detect pulsations in the unclassified {gamma}-ray source 2FGL J1816.5+4511, implying an efficiency of {approx}25% in converting the pulsar's spin-down luminosity into {gamma}-rays and adding PSR J1816+4510 to the large number of millisecond pulsars detected by Fermi. The likely optical/UV counterpart was identified through position coincidence (<0.''1) and unusual colors. Assuming that it is the companion, with R = 18.27 {+-} 0.03 mag and effective temperature {approx}> 15,000 K, it would be among the brightest and hottest of low-mass pulsar companions and appears qualitatively different from other eclipsing pulsar systems. In particular, current data suggest that it is a factor of two larger than most white dwarfs of its mass but a factor of four smaller than its Roche lobe. We discuss possible reasons for its high temperature and odd size, and suggest that it recently underwent a violent episode of mass loss. Regardless of origin, its brightness and the relative unimportance of irradiation make it an ideal target for a mass, and hence a neutron star mass, determination.
- OSTI ID:
- 22039360
- Journal Information:
- Astrophysical Journal, Vol. 753, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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