1. Pulsed Thermal Emission from the Accreting Pulsar XMMU J054134.7−682550
- Author
-
Antonis Manousakis, Roland Walter, Marc Audard, Thierry Lanz, Jéro^me Rodriguez, and Phillippe Ferrando
- Subjects
Astrophysics::High Energy Astrophysical Phenomena ,Cyclotron ,X-ray binary ,FOS: Physical sciences ,Astrophysics::Cosmology and Extragalactic Astrophysics ,02 engineering and technology ,Astrophysics ,01 natural sciences ,Power law ,Spectral line ,law.invention ,Pulsar ,law ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Astrophysics::Solar and Stellar Astrophysics ,Black-body radiation ,Large Magellanic Cloud ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,Spin-½ ,High Energy Astrophysical Phenomena (astro-ph.HE) ,Physics ,010308 nuclear & particles physics ,Astronomy ,Astronomy and Astrophysics ,020206 networking & telecommunications ,Accretion (astrophysics) ,Magnetic field ,Pulse (physics) ,Neutron star ,Space and Planetary Science ,13. Climate action ,020201 artificial intelligence & image processing ,Astrophysics - High Energy Astrophysical Phenomena - Abstract
Aims. Soft X-ray excesses have been detected in several Be/X-ray binaries and interpreted as the signature of hard X-ray reprocessing in the inner accretion disk. The system XMMU J054134.7-682550, located in the LMC, featured a giant Type II outburst in August 2007. The geometry of this system can be understood by studying the response of the soft excess emission to the hard X-ray pulses. Methods. We have analyzed series of simultaneous observations obtained with XMM-Newton/EPIC-MOS and RXTE/PCA in order to derive spectral and temporal characteristics of the system, before, during and after the giant outburst. Spectral fits were performed and a timing analysis has been carried out. Spectral variability, spin period evolution and energy dependent pulse shapes are analysed. Results. The outburst (L_X = 3* 10^38 erg/s \approx L_EDD) spectrum could be modeled successfully using a cutoff powerlaw, a cold disk emission, a hot blackbody, and a cyclotron absorption line. The magnetic field and magnetospheric radius could be constrained. The thickness of the inner accretion disk is broadened to a width of 75 km. The hot blackbody component features sinusoidal modulations indicating that the bulk of the hard X-ray emission is emitted preferentially along the magnetic equator. The spin period of the pulsar decreased very significantly during the outburst. This is consistent with a variety of neutron star equations of state and indicates a very high accretion rate., 6 pages. Accepted for publication in A&A
- Published
- 2009