1995/02/27 by H. C. Pan, G. K. Skinner, R. Sunyaev +3 · 11 citations
Engineering · Physics and Astronomy · #Accretion (finance) #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Binary number #Black hole (networking) #Electron #Mechanics and Biomechanics Studies #Nuclear physics #Optics #Photon #Physics #Spectral line #astro-ph
paper · pdf · doi:10.1093/mnras/274.1.l15
published in Monthly Notices of the Royal Astronomical Society 274(1), L15-L18 (Oxford University Press) · 4 pages, compressed and uuencoded postscript file, to be published in MNRAS (Letters)
arxiv created 1995/02/27 · openalex publication_date 1995/05/01 · arxiv updated 2016/06/08 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We report the first detection of a hard power-law tail in the X-ray spectrum of the black hole candidate (BHC) binary X1755−338, which was observed in 1989 March-September during the TTM Galactic Centre Survey. In addition, an ultrasoft thermal component with a temperature of ∼ 1.1−1.4 keV was also detected. We demonstrate that the soft and hard X-ray components of X1755−338 vary independently, as in the spectra of the well-known BHCs LMC X-1, LMC X-3 and GX339−4 in their high (intensity) state. If the hard tail observed from X1755−338 is generated near the black hole by energetic electrons upscattering low-energy photons, the uncorrelated variations imply that the soft X-rays from the accretion disc may not be the main photon seeds needed for inverse Comptonization. The TTM observations strongly suggest that X1755−338 does indeed belong to the family of BHCs.