# Quasi-simultaneous XMM-Newton and VLA observation of the non-thermal radio emitter HD 168112 (O5.5III(f^+))

@article{Becker2004QuasisimultaneousXA,
title={Quasi-simultaneous XMM-Newton and VLA observation of the non-thermal radio emitter HD 168112 (O5.5III(f^+))},
author={M. D. Becker and G. Rauw and R. Blomme and W. Waldron and H. Sana and J. Pittard and P. Eenens and I. Stevens and M. Runacres and S. Loo and A. Pollock},
journal={Astronomy and Astrophysics},
year={2004},
volume={420},
pages={1061-1077}
}
We report the results of a multiwavelength study of the non-thermal radio emitter HD 168112 (O5.5III(f + )). The detailed analysis of two quasi-simultaneous XMM-Newton and VLA observations reveals strong variability of this star both in the X-ray and radio ranges. The X-ray observations separated by five months reveal a decrease of the X-ray flux of ∼30%. The radio emission on the other hand increases by a factor 5-7 between the two observations obtained roughly simultaneously with the XMM… Expand

#### Figures and Tables from this paper

XMM-Newton observations of the massive colliding wind binary and non-thermal radio emitter Cyg OB2#8A [O6If+O5.5III(f)]
We report on the results of four XMM‐Newton observations separated by about ten days from each other of Cyg OB2 #8A [O6If + O5.5III(f)]. This massive colliding wind binary is a very bright X-rayExpand
Non-thermal radio emission from O-type stars II. HD 167971
HD 167971 is a triple system consisting of a 3.3-day eclipsing binary (O5‐8 V + O5‐8 V) and an O8 supergiant. It is also a well known non-thermal radio emitter. We observed the radio emission of HDExpand
The X-ray under-luminosity of the O-type supergiants HD 16691 and HD 14947 revealed by XMM-Newton ✩
Abstract The members of the scarce category of Of+ supergiants present properties that are intermediate between regular O-stars and Wolf–Rayet (WR) stars. Significant similarities between theseExpand
Radio, X-ray, and γ-ray emission models of the colliding-wind binary WR 140
• Physics
• 2006
We use hydrodynamical models of the wind-collision region in the archetype colliding-wind system WR 140 to determine the spatial and spectral distributions of the radio, X-ray, and γ-ray emissionExpand
The non-thermal radio emitter HD 93250 resolved by long baseline interferometry
• Physics
• 2011
As the brightest O-type X-ray source in the Carina nebula, HD 93250 (O4 III(fc)) is X-ray overluminous for its spectral type and has an unusually hard X-ray spectrum. Two different scenarios haveExpand
Long-term XMM–Newton investigation of two particle-accelerating colliding-wind binaries in NGC 6604: HD 168112 and HD 167971
The long-term (over more than one decade) X-ray emission from two massive stellar systems known to be particle accelerators is investigated using XMM-Newton. Their X-ray properties are interpretedExpand
Hints about the multiplicity of WR 133 based on multiepoch radio observations
• Physics
• 2019
Several tens of massive binary systems display indirect, or even strong evidence for non-thermal radio emission, hence their particle accelerator status. These objects are referred to asExpand
Hot stars observed by XMM-Newton - I. The catalog and the properties of OB stars
Aims. Following the advent of increasingly sensitive X-ray observatories, deep observations of early-type stars became possible. However, the results for only a few objects or clusters have until nowExpand
An XMM-Newton observation of the multiple system HD 167971 (O5-8V + O5-8V + (O8I)) and the young open cluster NGC 6604
• Physics
• 2005
We discuss the results of two XMM-Newton observations of the open cluster NGC 6604 obtained in April and September 2002. We concentrate mainly on the multiple system HD 167971 (O5-8V + O5-8V +Expand
INTEGRAL-ISGRI observations of the Cygnus OB2 region : Searching for hard X-ray point sources in a region containing several non-thermal emitting massive stars
• Physics
• 2007
Aims. We analyze INTEGRAL-ISGRI data in order to probe the hard X-ray emission (above 20 keV) from point sources in the Cyg OB2 region and to investigate the putative non-thermal high-energy emissionExpand

#### References

SHOWING 1-10 OF 56 REFERENCES
A multi-wavelength investigation of the non-thermal radio emitting O-star 9 Sgr
We report the results of a multi-wavelength investigation of the O4 V star 9 Sgr (= HD 164794). Our data include observations in the X-ray domain withXMM-Newton, in the radio domain with the VLA asExpand
XMM-Newton high-resolution X-ray spectroscopy of the Wolf-Rayet object WR 25 in the Carina OB1 association
We report the analysis of the first high-resolution X-ray spectra of the Wolf-Rayet (WR) object WR 25 (HD 93162, WN6ha+O4f) obtained with the reflection grating spectrometers (rgs )a nd theeuropeanExpand
An XMM-Newton observation of the massive binary HD 159176
We report the analysis of an XMM-Newton observation of the close binary HD 159176 (O7 V + O7 V). The ob- served LX/Lbol ratio reveals an X-ray luminosity exceeding by a factor ∼7 the expected valueExpand
X-Ray and Radio Observations of the Cygnus OB2 Association
• Physics
• 1998
Several OB stars in the Cygnus OB2 association are among the strongest stellar X-ray and radio sources in the Galaxy. The radio emission is particularly unusual, displaying a high level ofExpand
An Eight-Year Study of the Radio Emission from the Wolf-Rayet Binary HD 193793 = WR 140
• Physics
• 1995
HD 193793=WR 140 is a W-R+O binary system with a 7.9 yr, highly elliptical ({ital e}=0.85) orbit. It shows variable, nonthermal radio emission over its orbital period that is explained as synchrotronExpand
Gamma-ray emission from Wolf-Rayet binaries
• Physics
• 2003
In the colliding wind region of early-type binaries, electrons can be accelerated up to relativistic energies displaying power-law spectra, as demonstrated by the detection of non-thermal radioExpand
Synchrotron radiation from the winds of O supergiants - Tb = 10 to the 7. 6th K at 60 stellar radii
• Physics
• 1990
Results are presented on VLBI measurements of the nonthermal radio components around two O supergiant stars: Cyg OB2 No. 9 and HD 167971. The measurements were used to characterize the brightnessExpand
Nonthermal X-ray emission from winds of OB supergiants
• Physics
• 1991
The mechanisms responsible for the hard X-ray emission of OB supergiants (OBSGs) are investigated theoretically, modifying the periodic-shock model of Lucy (1982). The physical processes discussedExpand
Non-thermal radio emission from single hot stars
• Physics
• 2003
We present a theoretical model for the non-thermal radio emission from single hot stars, in terms of synchrotron radiation from electrons accelerated in wind-embedded shocks. The model is describedExpand
High resolution X-ray spectroscopy of $\zeta$ Puppis with the XMM-Newton reflection grating spectrometer
We present the rst high resolution X-ray spectrum of the bright O4Ief supergiant star Puppis, obtained with the Reflection Grating Spectrometer on-board XMM-Newton. The spectrum exhibits brightExpand