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The optical counterpart of the ultra-luminous x-ray source NGC 5204 X-1

M. R. Goad·T. P. Roberts·C. Knigge·P. Lira
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Abstract

We use archival HST/WFPC2 V and I band images to show that the optical counterpart to the ultra-luminous x-ray source NGC 5204 X-1, reported by Roberts et al., is composed of two sources separated by 0.5''. We have also identified a third source as a possible counterpart, which lies 0.8'' from the nominal x-ray position. PSF fitting photometry yields V-band magnitudes of 20.3, 22.0 and 22.4 for the three sources. The V-I band colours are 0.6, 0.1, and -0.2, respectively (i.e. the fainter sources are bluer). We find that all V-I colours and luminosities are consistent with those expected for young stellar clusters (age <10 Myr).

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M. R. Goad, T. P. Roberts, C. Knigge, P. Lira. 2002-07-19. The optical counterpart of the ultra-luminous x-ray source NGC 5204 X-1. https://doi.org/10.1046/j.1365-8711.2002.05852.x

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