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arXiv · 1509.01793

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

Yanli Qiu·JiFeng Liu·Jincheng Guo·Jing Wang
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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.

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Yanli Qiu, JiFeng Liu, Jincheng Guo, Jing Wang. 2015-09-06. Does the 62-day X-ray periodicity come from ULX M82 X-1?. https://doi.org/10.1088/2041-8205%2F809%2F2%2Fl28

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