Eighteen years of the life of the Be/X-ray binary XMMU J054134.7-682550
Abstract
We investigate the Be/X-ray binary XMMU J054134.7-682550 from 21 XMM-Newton observations and almost daily monitoring carried out by the ASM/RXTE and Swift/BAT satellites, in a total coverage of ∼ 18 years. Its X-ray light curve is marked by the occurrence of several minor and three large outbursts, without clear recurrence that could be the signature of the (yet unknown) orbital period. Two minor outbursts were partially observed by the XMM-Newton and, as for one large outburst also observed by that satellite, they are followed by significant changes in the hardness ratio. Both soft and hard tails in the 0.5-12 keV band were more pronounced during the outbursts while the spectral shape in the 2-4.5 keV energy band remains essentially the same. Spin up episodes of the X-ray pulsar were observed during outbursts. The excess in low energy is more likely due to the prominence of a black body component during the outbursts. The spectral evolution and timing properties are discussed on the basis of the formation of a transient accretion disk and the geometry of the system. Finally, we present an optical characterization of the system from spectroscopy obtained with the 4.1m SOAR telescope and the 3.6m ESO/NTT.
- Publication:
-
The X-ray Universe 2014
- Pub Date:
- July 2014
- Bibcode:
- 2014xru..confE.276L