Discovery of a Be/X‐Ray Binary Consistent with the Position of GRO J2058+42

Wilson, C. A.; Weisskopf, Martin C.; Finger, Mark H.; Coe, M. J.; Greiner, J.; Reig, P.; Papamastorakis, I.

doi:10.1086/428381

Cited by 31 publications

(53 citation statements)

References 41 publications

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“…Additional reddening would increase the temperature. An infrared excess detected above the blackbody fit (in the H band) may be an instrumental effect or the signature of a circumstellar disk (Wilson et al 2005). …”

Section: Likely Nearir Candidatementioning

confidence: 99%

Pulsed thermal emission from the accreting pulsar XMMU J054134.7-682550

Manousakis

Walter

Audard

et al. 2009

A&A

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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 ≈ 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.

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Section: Likely Nearir Candidatementioning

confidence: 99%

Pulsed thermal emission from the accreting pulsar XMMU J054134.7-682550

Manousakis

Walter

Audard

et al. 2009

A&A

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“…This system has been in the X-ray quiescent phase since 2002. During the X-ray quiescence phase, the Be disk was present, since Hα was in emission as seen from their spectroscopic study (Wilson et al 2005). …”

Section: Introductionmentioning

confidence: 83%

“…Subsequent Chandra observations did not find a source within the GRO positional error-box, but just outside, named CXOU J205847.5+414637. Wilson et al (2005) obtained optical observations of CXOU J205847.5+414637. Its optical spectrum contained a strong Hα line in the double-peaked emission.…”

Section: Introductionmentioning

confidence: 99%

“…The coordinates of CXOU J205847.5+414637 were taken from Reig et al (2004a) and Wilson et al (2005). We present optical spectroscopic observations obtained in 2006.…”

Section: Introductionmentioning

confidence: 99%

“…6. Epoch-folded orbital phase of the Be/X-ray binary system CXOU J205847.5+414637 for RXTE/ASM and ROTSEIIId data (using the ephemeris T = MJD 50411.3 + 55.03N given by Wilson et al 2005).…”

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confidence: 99%

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Optical variabilities in the Be/X-ray binary system

Kızıloğlu¹,

Kiziloglu²,

Baykal³

et al. 2007

A&A

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Aims. We present an analysis of long-term optical monitoring observations and optical spectroscopic observations of the counterpart to CXOU J205847.5+414637 (high-mass X-ray binary system). We search for variability in the light curve of Be star. Methods. We used differential magnitudes in the time-series analysis. The variability search in the optical light curve was made by using different algorithms. We used MIDAS and its suitable packages to reduce and analyse the spectra. Results. We have performed a frequency search that gave us the value 2.404 d −1 . This value is attributed to the non-radial pulsation of the Be star. The Hα emission line profiles always show double-peaked emissions with a mean equivalent width of 2.31 ± 0.19 Å and a peak separation of 516 ± 45 km s −1 . This suggests that the Be star disk is still present. CXOU J205847.5+414637 is in an X-ray quiescent state.Key words. stars: emission-line, Be -stars: early-type -stars: oscillations -X-rays: binaries IntroductionThe Be/X-ray binaries consist of a Be star and a neutron star that has little influence on the Be star. Be stars are on or just off the main sequence and they have rapid rotational velocities. The majority of them are found to rotate at 0.7 of their break-up velocity (Porter & Rivinius 2003). The Hα emission line and infrared excess are the observational characteristics of Be stars. Their emission lines disappear and reappear. Be stars often display enhancement or fading of their brightness. It is thought that enhancements in brightness are associated with the mass-loss episodes and appear to be induced by non radial pulsations . The spectroscopic variabilities in some line profiles are interpreted as due to non radial pulsations Neiner et al. 2005). A Be star has a dense disk in its equatorial plane (Quirrenbach 1997;Waters 1986) that is fed from the material expelled from the fast-rotating Be star due to either radiatively driven wind or photospheric pulsations (Porter & Rivinius 2003). The favored disk model is the viscous disk model (Lee et al. 1991;Okazaki 2001). QuasiKeplerian disks are held by viscosity Okazaki 2001) and the angular momentum is transferred from the inner regions of the disk towards the outer region by the viscosity. This disk causes the X-ray outburst of NS either at the periastron passage (type I outburst) or alters the outer part of the disk (type II outburst) without showing any correlation with orbital parameters (Negueruela 2004). X-rays are produced as a result of the accretion of matter onto the NS. In a Be/X-ray system, there can be X-ray quiescence periods, although a Be disk is present ).The transient 198 s X-ray pulsar, GRO J2058+42 (CXOU J205847.5+414637), was discovered by the BATSE instrument on the Compton Gamma Ray Observatory during a giant outburst in September 1995 (Wilson et al. 1996). Wilson et al. (1998) propose that GRO J2058+42 was undergoing periastron and apastron outbursts on a 110-day orbit. They estimated its luminosity as 0.2-1 × 10 37 erg/s, and no optical counterpart...

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Cooling of Accretion-Heated Neutron Stars

2017

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We present a brief, observational review about the study of the cooling behaviour of accretion-heated neutron stars and the inferences about the neutron-star crust and core that have been obtained from these studies. Accretion of matter during outbursts can heat the crust out of thermal equilibrium with the core and after the accretion episodes are over, the crust will cool down until crust-core equilibrium is restored. We discuss the observed properties of the crust cooling sources and what has been learned about the physics of neutron-star crusts. We also briefly discuss those systems that have been observed long after their outbursts were over, i.e, during times when the crust and core are expected to be in thermal equilibrium. The surface temperature is then a direct probe for the core temperature. By comparing the expected temperatures based on estimates of the accretion history of the targets with the observed ones, the physics of neutron-star cores can be investigated. Finally, we discuss similar studies performed for strongly magnetized neutron stars in which the magnetic field might play an important role in the heating and cooling of the neutron stars.Comment: Has appeared in Journal of Astrophysics and Astronomy special issue on 'Physics of Neutron Stars and Related Objects', celebrating the 75th birth-year of G. Srinivasan. In case of missing sources and/or references in the tables, please contact the first author and they will be included in updated versions of this revie

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Discovery of a Be/X‐Ray Binary Consistent with the Position of GRO J2058+42

Cited by 31 publications

References 41 publications

Pulsed thermal emission from the accreting pulsar XMMU J054134.7-682550

Pulsed thermal emission from the accreting pulsar XMMU J054134.7-682550

Optical variabilities in the Be/X-ray binary system

Cooling of Accretion-Heated Neutron Stars

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