2009/04/27 by Tetsuichi Kishishita, Takaaki Tanaka, Yasunobu Uchiyama +1 · 2 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Astrophysics and Star Formation Studies #astro-ph.HE
paper · pdf · doi:10.1088/0004-637x/697/1/l1
published as Astrophys.J.697:L1-L5,2009 · 5 pages, 2 figures, accepted in ApJ Letters
openalex publication_date 2009/04/27 · arxiv created 2009/06/19 · arxiv updated 2011/02/11 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
We report on long-term stability of X-ray modulation apparently synchronized with an orbital period of 3.9 days in the γ-ray binary LS 5039. Recent observations with the Suzaku satellite in the year 2007, which continuously covered more than one orbital period, have provided us with detailed characterization of X-ray flux and spectral shape as a function of orbital phase. Motivated by the results from Suzaku , we have re-analyzed the X-ray data obtained with ASCA , XMM-Newton , and Chandra between 1999 and 2005, to investigate long-term behavior of LS 5039 in the X-ray band. We found that the modulation curves in 1999–2007 are surprisingly stable. Even fine structures in the light curves such as spikes and dips are found to be quite similar from one orbit to another. The spectral characteristics observed in the past are consistent with those seen with Suzaku for some orbital phase segments. We suggest that magnetohydrodynamical collisions between the relativistic outflow from a compact object and the stellar wind from the O star explain the clock-like nonthermal X-ray emission over eight years through remarkably stable production of high-energy particles near the binary system.