NO NEUTRON STAR COMPANION TO THE LOWEST MASS SDSS WHITE DWARF

Journal Article · Sat Aug 01 04:00:00 EDT 2009 · Astrophysical Journal (Online)

DOI:https://doi.org/10.1088/0004-637X/700/2/L123; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21313794

Agueeros, Marcel A; Camilo, Fernando ^[1]; Heinke, Craig ^[2]; Kilic, Mukremin ^[3]; Anderson, Scott F; Silvestri, Nicole M ^[4]; Freire, Paulo ^[5]; Kleinman, Scot J ^[6]

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1. Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States)
2. Department of Physics, University of Alberta, Edmonton, AB T6G 2G7 (Canada)
3. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)
4. Department of Astronomy, University of Washington, Seattle, WA 98195 (United States)
5. Arecibo Observatory, Arecibo, PR 00612 (United States)
6. Gemini Observatory, Northern Operations Center, Hilo, HI 96720 (United States)

SDSS J091709.55+463821.8 (hereafter J0917+4638) is the lowest surface gravity white dwarf (WD) currently known, with log g = 5.55 {+-} 0.05 (M {approx} 0.17 M{sub sun}). Such low-mass white dwarfs (LMWDs) are believed to originate in binaries that evolve into WD/WD or WD/neutron star (NS) systems. An optical search for J0917+4638's companion showed that it must be a compact object with a mass {>=}0.28 M{sub sun}. Here we report on Green Bank Telescope 820 MHz and XMM-Newton X-ray observations of J0917+4638 intended to uncover a potential NS companion to the LMWD. No convincing pulsar signal is detected in our radio data. Our X-ray observation also failed to detect X-ray emission from J0917+4638's companion, while we would have detected any of the millisecond radio pulsars in 47 Tuc. We conclude that the companion is almost certainly another WD.

• OSTI ID: 21313794
• Journal Information: Astrophysical Journal (Online), Journal Name: Astrophysical Journal (Online) Journal Issue: 2 Vol. 700; ISSN 1538-4357
• Country of Publication: United States
• Language: English

Related Subjects

99 GENERAL AND MISCELLANEOUS
EMISSION
GRAVITATION
MASS
NEUTRON STARS
PULSARS
TELESCOPES
WHITE DWARF STARS
X RADIATION