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Near-infrared counterparts of ultraluminous X-ray sources

Heida, M. and Jonker, P. G. and Torres, M. A. P. and Kool, E. and Servillat, M. and Roberts, T. P. and Groot, P. J. and Walton, D. J. and Moon, D.-S. and Harrison, F. A. (2014) Near-infrared counterparts of ultraluminous X-ray sources. Monthly Notices of the Royal Astronomical Society, 442 (2). pp. 1054-1067. ISSN 0035-8711. doi:10.1093/mnras/stu928.

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In this paper, we present the results of the first systematic search for counterparts to nearby ultraluminous X-ray sources (ULXs) in the near-infrared (NIR). We observed 62 ULXs in 37 galaxies within 10 Mpc and discovered 17 candidate NIR counterparts. The detection of 17 out of 62 ULX candidates points to intrinsic differences between systems that show and those that do not show infrared emission. For six counterparts, we conclude from the absolute magnitudes and – in some cases – additional information such as morphology and previously reported photometric or spectroscopic observations, that they are likely background active galactic nuclei or ULXs residing in star clusters. 11 counterparts have absolute magnitudes consistent with them being single red supergiant stars. Alternatively, these systems may have larger accretion discs that emit more NIR light than the systems that we do not detect. Other scenarios such as emission from a surrounding nebula or from a compact radio jet are also possible, although for Holmberg II X-1 the NIR luminosity far exceeds the expected jet contribution. The 11 possible red supergiant counterparts are excellent candidates for spectroscopic follow-up observations. This may enable us to measure the mass function in these systems if they are indeed red supergiant donor stars where we can observe absorption lines.

Item Type:Article
Related URLs:
URLURL TypeDescription
Heida, M.0000-0002-1082-7496
Jonker, P. G.0000-0001-5679-0695
Servillat, M.0000-0001-5443-4128
Roberts, T. P.0000-0001-8252-6337
Groot, P. J.0000-0002-4488-726X
Walton, D. J.0000-0001-5819-3552
Moon, D.-S.0000-0003-4200-5064
Harrison, F. A.0000-0003-2992-8024
Additional Information:© 2014 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2014 May 6. Received 2014 April 15; in original form 2014 March 4. First published online June 10, 2014. EK thanks Mischa Schirmer for his help with the data-reduction software THELI. We thank the anonymous referee for their comments that helped improve the paper. TPR’s contribution to this paper was funded as part of STFC consolidated grant ST/K000861/1. Based on observations collected at the European Southern Observatory, Chile, programmes 089.D-0663(A) and 090.D-0417(A). The William Hershel Telescope is operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. Observations reported here were obtained at the MMT Observatory, a joint facility of the Smithsonian Institution and the University of Arizona.
Group:Space Radiation Laboratory
Funding AgencyGrant Number
Science and Technology Facilities Council (STFC)ST/K000861/1
Subject Keywords:stars: black holes; infrared: stars
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory2014-38
Issue or Number:2
Record Number:CaltechAUTHORS:20140829-093124434
Persistent URL:
Official Citation:M. Heida, P. G. Jonker, M. A. P. Torres, E. Kool, M. Servillat, T. P. Roberts, P. J. Groot, D. J. Walton, D.-S. Moon, and F. A. Harrison Near-infrared counterparts of ultraluminous X-ray sources MNRAS (August 1, 2014) Vol. 442 1054-1067 doi:10.1093/mnras/stu928 First published online June 10, 2014
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:49057
Deposited On:29 Aug 2014 16:44
Last Modified:10 Nov 2021 18:39

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