New Hubble Space Telescope imaging of the counterparts to six ultraluminous X-ray sources |
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| Authors: | T P Roberts A J Levan M R Goad |
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| Institution: | Department of Physics, Durham University, South Road, Durham DH1 3LE;Department of Physics, University of Warwick, Coventry CV4 7AL;X-ray and Observational Astronomy Group, Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH |
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| Abstract: | We report the results of new Hubble Space Telescope imaging of the positions of six ultraluminous X-ray sources (ULXs). Using images in three Advanced Camera for Surveys (ACS) filters, we detect good candidate counterparts to four out of six ULXs, with one more possible detection, and observed magnitudes in the range m ∼ 22–26 in the F 606 W filter. The extinction-corrected colours and absolute magnitudes vary from source to source, even after correcting for additional extinction in the host galaxy, and only one counterpart is readily explained as an OB star. Nevertheless, these counterparts are decent candidates for future follow-up in pursuit of dynamical mass constraints on the likely black holes powering these sources. |
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| Keywords: | black hole physics X-rays: binaries X-rays: galaxies |
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