The 2007 outburst of the X-ray binary XTE J1856+053
Abstract
Aims: On 28 February 2007 a new outburst of the previously known transient source XTE J1856+053 was detected with RXTE/ASM. We present here the results of an XMM-Newton (0.5-10.0 keV) Target of Opportunity observation performed on 14 March 2007, aimed at constraining the mass of the compact object in this X-ray binary and determining its main properties.
Methods: The EPIC-pn camera was used in Timing mode and its spectrum fit together with the RGS data. IR observations with GROND at the 2.2 m telescope in La Silla provide further information on the system.
Results: The X-ray light curve shows that both the 1996 and the 2007 outbursts had two peaks. The X-ray spectrum is well fit with a thermal accretion disk model, with kT_in = 0.75(±0.01) keV and foreground absorption N{H} = 4.5(±0.1)×1022 cm-2. The low disk temperature favours a black-hole as accreting object, with an estimated mass in the range 1.3-4.2 M⊙. From the IR upper limits we argue that XTE J1856+053 is a low mass X-ray binary. We estimate the orbital period of the system to be between 3 and 12 h.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- October 2008
- DOI:
- 10.1051/0004-6361:200809875
- arXiv:
- arXiv:0810.1523
- Bibcode:
- 2008A&A...489.1239S
- Keywords:
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- X-rays: binaries;
- stars: binaries: close;
- X-rays: individuals: XTE J1856+053;
- Astrophysics
- E-Print:
- Astron.Astrophys.489:1239,2008