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 04:00:00 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, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 709; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

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