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Title: DISCOVERY OF MILLIHERTZ X-RAY OSCILLATIONS IN A TRANSIENT ULTRALUMINOUS X-RAY SOURCE IN M82

Journal Article · · Astrophysical Journal Letters
;  [1];  [2]
  1. Department of Engineering Physics and Center for Astrophysics, Tsinghua University, Beijing 100084 (China)
  2. Department of Physics and Astronomy, University of Iowa, Van Allen Hall, Iowa City, IA 52242 (United States)

We report on the discovery of X-ray quasi-periodic oscillations (QPOs) at frequencies of 3-4 mHz from a transient ultraluminous X-ray source X42.3+59 in M82. The QPOs are strong and broad and appear with weak or absent red noise, and are detected only in Chandra observations when the source is brighter than 10{sup 40} erg s{sup -1}. The QPO behavior is similar to the type A-I QPOs found in XTE J1550 - 564, which is a subclass of low-frequency QPOs with properties in between types A and B. Therefore, we identify the QPOs in X42.3+59 as of type A or B and rule out the possibility of type C. With this identification, the mass of the black hole in X42.3+59 can be inferred as in the range of 12,000-43,000 solar masses by scaling the QPO frequency to that of the type A/B QPOs in stellar mass black holes. Cool disk emission is detected in one Chandra observation, and the disk inner radius suggests a similar black hole mass range. Black holes of such a high mass are able to produce an energy output in a manner similar to X42.3+59 by accreting from the interstellar medium directly.

OSTI ID:
21301284
Journal Information:
Astrophysical Journal Letters, Vol. 710, Issue 2; Other Information: DOI: 10.1088/2041-8205/710/2/L137; Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
Country of Publication:
United States
Language:
English