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ROSAT observation of GRS 1739-278

J. Greiner·K. Dennerl·P. Predehl
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Abstract

We have observed GRS 1739-278 with the ROSAT HRI on March 31, 1996. The improved X-ray position proves the identification with an earlier discovered variable radio source. We derive an extinction of A_V = 14+/-2 from the dust scattering halo, which implies a distance of d approx. 6-8.5 kpc. Thus, GRS 1739-278 radiates at least near the Eddington limit for a 1 M_sun compact object. The existence of the dust scattering halo necessitates a prolonged X-ray activity period prior to the ROSAT observation. Combined with the non-detection by Granat during an earlier galactic center observation, we speculate that the X-ray turn-on of GRS 1739-278 happened in Nov./Dec. 1995.

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J. Greiner, K. Dennerl, P. Predehl. 1996-08-28. ROSAT observation of GRS 1739-278. https://arxiv.org/abs/astro-ph/9608184

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