A CHANDRA X-RAY OBSERVATORY STUDY OF PSR J1740-5340 AND CANDIDATE MILLISECOND PULSARS IN THE GLOBULAR CLUSTER NGC 6397

Journal Article · Wed Jan 20 00:00:00 EST 2010 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/709/1/241· OSTI ID:21392344

Bogdanov, Slavko ^[1]; Van den Berg, Maureen; Grindlay, Jonathan E ^[2]; Heinke, Craig O ^[3]; Cohn, Haldan N

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1. Department of Physics, McGill University, 3600 University Street, Montreal, PQ H3A 2T8 (Canada)
2. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
3. Department of Physics, University of Alberta, Edmonton, AB T6G 2G7 (Canada)

We present a deep Chandra X-ray Observatory study of the peculiar binary radio millisecond pulsar (MSP) PSR J1740-5340 and candidate millisecond pulsars in the globular cluster NGC 6397. The X-rays from PSR J1740-5340 appear to be non-thermal and exhibit variability at the binary period. These properties suggest the presence of a relativistic intrabinary shock formed due to interaction of a relativistic rotation-powered pulsar wind and outflow from the unusual 'red-straggler/sub-subgiant' companion. We find the X-ray source U18 to show similar X-ray and optical properties to those of PSR J1740-5340, making it a strong MSP candidate. It exhibits variability on timescales from hours to years, also consistent with an intrabinary shock origin of its X-ray emission. The unprecedented depth of the X-ray data allows us to conduct a complete census of MSPs in NGC 6397. Based on the properties of the present sample of X-ray-detected MSPs in the Galaxy, we find that NGC 6397 probably hosts no more than six MSPs.

• OSTI ID: 21392344
• Journal Information: Astrophysical Journal, Vol. 709, Issue 1; Other Information: DOI: 10.1088/0004-637X/709/1/241; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
EMISSION
GALAXIES
NEUTRON STARS
NEUTRONS
OPTICAL PROPERTIES
PULSARS
RELATIVISTIC RANGE
ROTATION
X RADIATION
BARYONS
COSMIC RADIO SOURCES
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
ENERGY RANGE
FERMIONS
HADRONS
IONIZING RADIATIONS
MOTION
NUCLEONS
PHYSICAL PROPERTIES
RADIATIONS
STARS