Does the 62-day X-ray periodicity come from ULX M82 X-1?

Abstract

M82 X-1 is the brightest ultraluminous X-ray source in starburst galaxy M82 and is one of the best intermediate mass black hole candidates. Previous studies based on the Rossi X-ray Timing Explorer/Proportional Counter Array (RXTE/PCA) reported a regular X-ray flux modulation of M82 with a period of 62 days, and attributed this periodic modulation to M82 X-1. However, this modulation is not necessarily from M82 X-1 because RXTE/PCA has a very poor spatial resolution of ~1 degree. In this work, we analyzed 1000 days of monitoring data of M82 X-1 from the Swift/X-ray telescope (XRT), which has a much better spatial resolution than RXTE/PCA. The periodicity distribution map of M82 reveals that the 62-day periodicity is most likely not from M82 X-1, but from the summed contributions of several periodic X-ray sources 4 arcsec southeast of M82 X-1. However, Swift/XRT is not able to resolve those periodic sources and locate the precise origin of the periodicity of M82. Thus, more long-term observations with higher spatial resolution are required.

5 pages, 5 figures

References in corpus (9)

• An Ultraluminous X-ray Source Powered by An Accreting Neutron Star
• A mass of less than 15 solar masses for the black hole in an ultraluminous X-ray source
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• Pulse phase resolved analysis of the HMXB Cen X-3 over two binary orbits
• Confirmation of the 62 Day X-Ray Periodicity from M82
• The Ultraluminous X-ray Sources near the Center of M82
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Cited by in corpus (8)

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• A 78 Day X-ray Period Detected from NGC 5907 ULX1 by Swift
• A ~60-day super-orbital period originating from the ultraluminous X-ray pulsar in M82
• Swift monitoring of M51: A 38-day super-orbital period for the pulsar ULX7 and a new transient ULX
• SWIFT Detection of a 65-Day X-ray Period from the Ultraluminous Pulsar NGC 7793 P13
• A Possible 55-day X-ray Period of the Ultraluminous Accreting Pulsar M82 X-2
• Study of accretion flows around an ultraluminous X-ray source M82 X-1 using NuSTAR data
• Investigation of the timing and spectral properties of an Ultra-luminous X-ray pulsar NGC 7793 P13