A CHANDRA X-RAY OBSERVATION OF THE BINARY MILLISECOND PULSAR PSR J1023+0038

Journal Article · Thu Dec 01 04:00:00 EST 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/742/2/97· OSTI ID:22004619

Bogdanov, Slavko; Archibald, Anne M; Kaspi, Victoria M ^[1]; Hessels, Jason W. T. ^[2]; Lorimer, Duncan; McLaughlin, Maura A ^[3]; Ransom, Scott M ^[4]; Stairs, Ingrid H ^[5]

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1. Department of Physics, McGill University, 3600 University Street, Montreal, QC H3A 2T8 (Canada)
2. Netherlands Institute for Radio Astronomy (ASTRON), Postbus 2, 7990 AA Dwingeloo (Netherlands)
3. Department of Physics, West Virginia University, 210E Hodges Hall, Morgantown, WV 26506 (United States)
4. National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22901 (United States)
5. Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada)

We present a Chandra X-Ray Observatory ACIS-S variability, spectroscopy, and imaging study of the peculiar binary containing the millisecond pulsar J1023+0038. The X-ray emission from the system exhibits highly significant (12.5{sigma}) large-amplitude (factor of two to three) orbital variability over the five consecutive orbits covered by the observation, with a pronounced decline in the flux at all energies at superior conjunction. This can be naturally explained by a partial geometric occultation by the secondary star of an X-ray-emitting intrabinary shock, produced by the interaction of outflows from the two stars. The depth and duration of the eclipse imply that the intrabinary shock is localized near or at the surface of the companion star and close to the inner Lagrangian point. The energetics of the shock favor a magnetically dominated pulsar wind that is focused into the orbital plane, requiring close alignment of the pulsar spin and orbital angular momentum axes. The X-ray spectrum consists of a dominant non-thermal component and at least one thermal component, likely originating from the heated pulsar polar caps, although a portion of this emission may be from an optically thin 'corona'. We find no evidence for extended emission due to a pulsar wind nebula or bow shock down to a limiting luminosity of L{sub X} {approx}< 3.6 Multiplication-Sign 10{sup 29} erg s{sup -1} (0.3-8 keV), {approx}< 7 Multiplication-Sign 10{sup -6} of the pulsar spin-down luminosity, for a distance of 1.3 kpc and an assumed power-law spectrum with photon index {Gamma} = 1.5.

• OSTI ID: 22004619
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 742; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ECLIPSE
GALACTIC EVOLUTION
GEOMETRY
LAGRANGIAN FUNCTION
LUMINOSITY
NEBULAE
NEUTRONS
ORBITAL ANGULAR MOMENTUM
ORBITS
PHOTONS
PULSARS
SHOCK WAVES
SPECTROSCOPY
STAR EVOLUTION
STARS
X RADIATION
X-RAY SPECTRA