A RADIO SEARCH FOR PULSAR COMPANIONS TO SLOAN DIGITAL SKY SURVEY LOW-MASS WHITE DWARFS
- Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States)
- Department of Astronomy, University of Washington, Seattle, WA 98195 (United States)
- Gemini Observatory, Northern Operations Center, Hilo, HI 96720 (United States)
We have conducted a search for pulsar companions to 15 low-mass white dwarfs (LMWDs; M <0.4 M {sub sun}) at 820 MHz with the NRAO Green Bank Telescope (GBT). These LMWDs were spectroscopically identified in the Sloan Digital Sky Survey (SDSS), and do not show the photometric excess or spectroscopic signature associated with a companion in their discovery data. However, LMWDs are believed to evolve in binary systems and to have either a more massive white dwarf (WD) or a neutron star (NS) as a companion. Indeed, evolutionary models of low-mass X-ray binaries, the precursors of millisecond pulsars (MSPs), produce significant numbers of LMWDs, suggesting that the SDSS LMWDs may have NS companions. No convincing pulsar signal is detected in our data. This is consistent with the findings of van Leeuwen et al., who conducted a GBT search for radio pulsations at 340 MHz from unseen companions to eight SDSS WDs (five are still considered LMWDs; the three others are now classified as 'ordinary' WDs). We discuss the constraints our nondetections place on the probability P {sub MSP} that the companion to a given LMWD is a radio pulsar in the context of the luminosity and acceleration limits of our search; we find that P {sub MSP} < 10{sup +4} {sub -2}%.
- OSTI ID:
- 21300575
- Journal Information:
- Astrophysical Journal, Vol. 697, Issue 1; Other Information: DOI: 10.1088/0004-637X/697/1/283; Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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