First broad band study of the mysterious source 1E 1743.1–2843
Istituto di Astrofisica Spaziale e Fisica Cosmica di Roma – INAF, via del Fosso del Cavaliere 100, 40133 Roma, Italy e-mail: email@example.com
2 Istituto di Astrofisica Spaziale e Fisica Cosmica di Milano – INAF, via E. Bassini 15, 20133 Milano, Italy
3 Dipartimento di Astronomia, Universitá degli Studi di Bologna, via Ranzani 1, 40127 Bologna, Italy
4 Centre d'Étude Spatiale des Rayonnements, CNRS/UPS, BP 4346, 31028 Toulouse Cedex 4, France
Accepted: 4 July 2006
Context.In the last years, the persistent source 1E 1743.1–2843 has been observed in the X-rays, but never above 20 keV. In previous works, it was stressed that a possible high energy emission could give further indications on the accreting object nature which remains still unknown.
Aims.We present here more than two years of 1E 1743.1–2843 monitoring with INTEGRAL/IBIS as well as public XMM-Newton and Chandra X-ray observations.
Methods.The temporal study in the 20–40 keV band shows a rather constant flux on few months time scale. Based on this result we have performed the broad-band spectral analysis using EPIC/IBIS non simultaneous data and ACIS-I/IBIS data collected during 2004.
Results.In ~2 Ms, we report a detection of 6σ in the energy range 35–70 keV. The first broad-band study (2–70 keV) shows a steep slope (~3) and a black body temperature of 1.7 keV.
Conclusions.Combining spectral parameters and discussion about the luminosity evaluations for different possible distances, our conclusions are in favour of a LMXB system with a neutron star at distance higher than the Galactic Centre, even though a firm conclusion can not be stated.
Key words: γ-rays: observations / X-rays: binaries / stars: individual: 1E 1743.1–2843 / radiation mechanisms: general
© ESO, 2006