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arXiv · 2303.12141

Optical Counterparts of Two Candidate Ultraluminous X-ray Sources in NGC 4536

H. Avdan·E. Sonbas·K. S. Dhuga·A. Vinokurov·E. Göğüş·S. Avdan·Y. N. Solovyeva·A. E. Kostenkov·E. S. Shablovinskaya·D. Goktas
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Abstract

Archival {\it XMM-Newton}, {\it Chandra} and {\it Hubble Space Telescope (HST)} data have been used to study the X-ray and optical properties of two candidate ultraluminous X-ray sources (ULXs) in NGC\,4536. In order to search for potential optical counterparts, relative astrometry between {\it Chandra} and {\it HST} was improved, and as a result, optical counterparts were detected for both X-ray sources. To complement our findings (based on the archival data), ground-based optical spectra of the counterparts were obtained with the 6m BTA Telescope located at the Special Astrophysical Observatory (SAO). The calculated redshift (z = 0.4391$\pm$0.0010) for one of the sources (X-3) indicates that the source is, in fact, a background active galactic nucleus (AGN). Two possible optical counterparts (s1 and s2) were found for X-2. Whether s1 is point-like or an extended source is unclear: If it is point-like and the emission is dominated by the donor its spectral type indicates O-B star. The second source (s2) is point-like and is consistent with the colors and absolute magnitudes of a red supergiant.

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H. Avdan, E. Sonbas, K. S. Dhuga, A. Vinokurov, E. Göğüş, S. Avdan, Y. N. Solovyeva, A. E. Kostenkov, E. S. Shablovinskaya, D. Goktas. 2023-03-21. Optical Counterparts of Two Candidate Ultraluminous X-ray Sources in NGC 4536. https://doi.org/10.1093/mnras%2Fstad879

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