Spectroscopic Study of the Variability of Three Northern Of+ Supergiants (2009)
De Becker, Michaël, Rauw, Grégor, Linder, N.
The transition from early Of stars to WN-type objects is poorly understood. O-type supergiants with emission lines (OIf+) are considered to be intermediate between these two classes. The scope of...
Perrier, C, Breysacher, J, Rauw, Grégor
Aims. We present a technique to determine the orbital and physical parameters of eclipsing eccentric Wolf-Rayet + O-star binaries, where one eclipse is produced by the absorption of the O-star light...
Rauw, Grégor, Naze, Yaël, Fernández Lajús, E, Lanotte, Audrey, Solivella, G R, Sana, H, ...
We present the results of a spectroscopic monitoring campaign devoted to three O-type stars in the Carina nebula. We derive the full SB2 orbital solution of the binary system Tr16-112, an exceptional...
Mahy, Laurent, Naze, Yaël, Rauw, Grégor, Gosset, Eric, De Becker, Michaël, Sana, H, ...
Aims. We present the results obtained from a long-term spectroscopic campaign to study the multiplicity of O-type stars in both the young open cluster NGC 2244 and the Mon OB2 association. Methods:...
Gosset, Eric, Sana, H, Linder, N, Rauw, Grégor
Already suspected to be variable, the O9Ib((f)) supergiant HD 152249 has been the subject of a dedicated follow-up spectroscopic run. We report here on the preliminary results. This star is...
Spectroscopic and photometric variability of O and Wolf-Rayet stars (2009)
Low-level line profile variability in the optical domain is a ubiquitous feature of O, Of and Wolf-Rayet type stars. This variability can arise from pulsations, from magnetic fields or wind...
Spectroscopic study of the O-type runaway supergiant HD 195592 (2009)
De Becker, Michaël, Linder, Natacha, Rauw, Grégor
The scope of this paper is to perform a detailed spectroscopic study of the northern O-type supergiant HD195592. We use a large sample of high quality spectra in order to investigate its...
Dust formation by the colliding wind WC5+O9 binary WR19 at periastron passage (2009)
Williams, P M, Rauw, Grégor, Van Der Hucht, K A
We present infrared photometry of the episodic dust-making Wolf-Rayet system WR19 (LS3), tracking its fading from a third observed dust formation episode in 2007 and strengthening the view that these...
De Becker, Michaël, Blomme, Ronny, Micela, Giusi, Pittard, Julian Mark, Rauw, Grégor, Romero, Gustavo E., ...
Second International Simbol-X Symposium
A multiwavelength investigation of the massive eclipsing binary Cyg OB2 #5 (2009)
Linder, Natacha, Rauw, Grégor, Manfroid, Jean, Damerdji, Yassine, De Becker, Michaël, Eenens, P, ...
Context. The properties of the early-type binary Cyg OB2 #5 have been debated for many years and spectroscopic and photometric investigations yielded conflicting results. Aims. We have attempted to...
The multiwavelength picture of star formation in the very young open cluster NGC6383 (2008)
Rauw, Grégor, De Becker, Michaël
We review the properties of the very young (˜ 2 Myr) open cluster NGC 6383. The cluster is dominated by the massive binary HD 159176 (O7 V + O7 V). The distance to NGC 6383 is consistently found to...
The first orbital solution for the massive colliding-wind binary HD 93162 (= WR 25) (2008)
Gamen, R, Gosset, Eric, Morrell, N I, Niemela, V S, Sana, H, Naze, Yaël, ...
Since the discovery, with EINSTEIN, of strong X-ray emission associated with HD 93162, this object was recurrently predicted by some authors to be a colliding-wind binary system. However,...
Colliding Wind Signatures in Early-Type Binaries (2008)
Observations of early-type binaries not only allow us to establish the fundamental properties of massive stars in a model-independent fashion, but furthermore provide important information on the...
Evidence for short-term variations in two O-type stars (2008)
De Becker, Michaël, Linder, Natacha, Rauw, Grégor
Only a few O-type stars are known to display short-term (a fraction of a day) variations. Intense spectroscopic monitoring of the ON8V star HD 13268 revealed low amplitude variations with periods of...
A binary signature in the non-thermal radio-emitter Cyg OB2 #9 (2008)
Naze, Yaël, De Becker, Michaël, Rauw, Grégor, Barbieri, Cesare
Aims. Non-thermal radio emission associated with massive stars is believed to arise from a wind-wind collision in a binary system. However, the evidence of binarity is still lacking in some cases,...
Hard X-ray emission from eta Carinae (2008)
Leyder, Jean-Christophe, Walter, R, Rauw, Grégor
Context: If relativistic particle acceleration takes place in colliding-wind binaries, hard X-rays and gamma-rays are expected through inverse Compton emission, but to date these have never been...
XMM-Newton X-ray study of early type stars in the Carina OB1 association (2008)
Antokhin, I.I., Rauw, Grégor, Vreux, Jean-Marie, Van Der Hucht, K.A., Brown, J.C.
Aims. X-ray properties of the stellar population in the Carina OB I association are examined with special emphasis on early-type stars. Their spectral characteristics provide some clues to...
The massive star binary fraction in young open clusters - I. NGC 6231 revisited (2008)
Sana, H, Gosset, Eric, Naze, Yaël, Rauw, Grégor, Linder, Natacha
We present the results of a long-term high-resolution spectroscopy campaign on the O-type stars in NGC 6231. We revise the spectral classification and multiplicity of these objects and we constrain...
X-ray spectroscopy of early-type stars: The present and the future (2008)
Rauw, Grégor, Naze, Yaël, Oskinova, L M
XMM-Newton and Chandra have boosted our knowledge about the X-ray emission of early-type stars (spectral types OB and Wolf-Rayet). However, there are still a number of open questions that need to be...
The massive binary HD 152218 revisited: A new colliding wind system in NGC 6231 (2008)
Sana, H, Naze, Yaël, O'Donnell, B, Rauw, Grégor, Gosset, Eric
We present the results of an optical and X-ray monitoring campaign on the short-period massive SB2 binary HD 152218. Combining our HiRes spectroscopic data with previous observations, we unveil the...
High-resolution X-ray spectroscopy of theta Carinae (2008)
Context. The peculiar hot star. Car in the open cluster IC2602 is a blue straggler as well as a single-line binary with a short period (2.2d). Aims. Its high-energy properties are not well known,...
Naze, Yaël, Rauw, Grégor, Manfroid, Jean
Context. Westerlund 2 is a young and massive, obscured stellar cluster of our Galaxy. It harbors the most massive star with well-determined parameters, WR20a (82 + 83 M-circle dot), a dozen very...
HD 148937: A multiwavelength study of the third galactic member of the Of?p class (2008)
Naze, Yaël, Walborn, Nolan R., Rauw, Grégor, Martins, Fabrice, Pollock, A. M. T., Bond, Howard E.
Three Galactic O-type stars belong to the rare class of Of? p objects: HD 108, HD 191612, and HD 148937. The first two stars show a wealth of phenomena, including strong X-ray emission, light...
Spectroscopic and photometric variability of the O9.5Vp star HD93521 (2008)
Rauw, Grégor, De Becker, Michaël, Van Winckel, Hans, Aerts, Conny, Eenens, Philippe, Lefever, Karolien, ...
Aims. The line profile variability and photometric variability of the O9.5Vp star HD93521 are examined in order to establish the properties of the non-radial pulsations in this star. Methods. Fourier...
High-resolution optical spectroscopy of Plaskett's star (2008)
Linder, Natacha, Rauw, Grégor, Martins, Fabrice, Sana, Hugues, De Becker, Michaël, Gosset, Eric
Context. Plaskett's star (HD 47 129) is a very massive O + O binary that belongs to the Mon OB2 association. Previous work suggests that this system displays the Struve-Sahade effect although the...
The investigation of particle acceleration in colliding-wind massive binaries with SIMBOL-X. (2008)
De Becker, Michaël, Rauw, Grégor, Pittard, J M, Blomme, R, Romero, G E, Sana, H, ...
An increasing number of early-type (O and Wolf-Rayet) colliding wind binaries (CWBs) is known to accelerate particles up to relativistic energies. In this context, non-thermal emission processes such...
Towards an understanding of the Of ? p star HD 191612: optical spectroscopy (2007)
Howarth, Ian D., Walborn, Nolan R., Lennon, Danny J., Puls, Joachim, Naze, Yaël, Annuk, K, ...
We present extensive optical spectroscopy of the early-type magnetic star HD 191612 (O6.5f ? pe-O8fp). The Balmer and He i lines show strongly variable emission which is highly reproducible on a...
The Struve-Sahade effect in the optical spectra of O-type binaries - I. Main-sequence systems (2007)
Linder, Natacha, Rauw, Grégor, Sana, H, De Becker, Michaël, Gosset, Eric
Aims. We present a spectroscopic analysis of four massive binary systems that are known or are good candidates to display the Struve-Sahade effect (defined as the apparent strengthening of the...
De Becker, Michaël, Rauw, Grégor, Pittard, JM, Sana, H, Stevens, IR, Romero, GE
Aims. We analyze INTEGRAL-ISGRI data in order to probe the hard X-ray emission ( above 20 keV) from point sources in the CygOB2 region and to investigate the putative non-thermal high-energy emission...
Université de Liège
An XMM-Newton view of the young open cluster NGC 6231-III. Optically faint X-ray sources (2007)
Sana, H, Rauw, Grégor, Sung, H, Gosset, Eric, Vreux, Jean-Marie
We discuss the properties of the X-ray sources with faint optical counterparts in the very young open cluster NGC 6231. From their positions in the Hertzsprung-Russell diagram, we find that the bulk...
Long-term Spectroscopic Variability of Two Oe Stars (2007)
Rauw, Grégor, Naze, Yaël, Marique, PX, De Becker, Michaël, Sana, Hugues, Vreux, Jean-Marie
HD 45314 and HD 60848 are poorly studied Oe-type stars. Spectroscopic monitoring over 5 years reveals strong variations in the strength of the emission lines and for HD 45314 in the V/R ratio of the...
Constraining the fundamental parameters of the O-type binary CPD-41 7733 (2007)
Sana, H, Rauw, Grégor, Gosset, Eric
Using a set of high-resolution spectra, we studied the physical and orbital properties of the O-type binary CPD -41 7733, located in the core of NGC 6231. We report the unambiguous detection of a...
Early-type stars in the core of the young open cluster Westerlund 2 (2007)
Rauw, Grégor, Manfroid, Jean, Gosset, Eric, Naze, Yaël, Sana, H, De Becker, Michaël, ...
Aims. The properties of the early-type stars in the core of the Westerlund 2 cluster are examined in order to establish a link between the cluster and the very massive Wolf-Rayet binary WR 20a as...
Naze, Yaël, Rauw, Grégor, Pollock, AMT, Walborn, NR, Howarth, ID
We present the analysis of phase-resolved X-ray and optical observations of the peculiar hot star HD 191612 (Of ? p). This star is known to display line-profile variations that are recurrent with a...
New Colliding-Wind Massive Binaries (2007)
De Becker, Michaël, Rauw, Grégor
We report on the recent discovery of two new massive binary systems: WR20a and CygOB2#8A. For both systems, we briefly present the orbital solutions and we discuss the strong phase-locked line...
NGC6231: X-ray Properties of the Early-Type Star Population (2007)
Sana, H, Naze, Yaël, Gosset, Eric, Rauw, Grégor, Sung, H, Vreux, J-M
Based on a deep XMM-Newton observation of the young open cluster NGC6231, we derive the main X-ray properties of its early-type star population. Among the 610 X-ray sources detected in the field, 42...
Van Der Hucht, K A, Raassen, A J J, Mewe, R, Antokhin, I I, Rauw, Grégor, Vreux, J-M, ...
We report the analysis of high- and medium-resolution X-ray spectra of the Wolf-Rayet (WR) objects WR25 (HD93162, WN6h+O4f) and WR11 (gamma[SUP]2[/SUP] Velorum, WC8+O7.5III, P =78.53 d), obtained...
The first orbital solution for the massive colliding-wind binary HD 93162 ( WR 25) (2006)
Gamen, R, Gosset, Eric, Morrell, N, Niemela, V, Sana, H, Naze, Yaël, ...
Context. Since the discovery, with the EINSTEIN satellite, of strong X-ray emission associated with HD 93162 (equivalent to WR 25), this object has been predicted to be a colliding-wind binary...
An XMM-Newton view of the young open cluster NGC 6231 - II. The OB star population (2006)
Sana, H, Rauw, Grégor, Naze, Yaël, Gosset, Eric, Vreux, Jean-Marie
In this second paper of the series, we pursue the analysis of the 180-ks XMM-Newton campaign towards the young open cluster NGC 6231 and we focus on its rich OB star population. We present a...
The atypical emission-line star Hen 3-209 (2006)
Naze, Yaël, Rauw, Grégor, Hutsemekers, Damien, Gosset, Eric, Manfroid, Jean, Royer, P
We analyse observations, spanning 15 yr, dedicated to the extreme emission-line object Hen 3-209. Our photometric data indicate that the luminosity of the star undergoes marked variations with a...
GCIRS 16SW: A massive eclipsing binary in the Galactic center (2006)
Martins, F, Trippe, S, Paumard, T, Ott, T, Genzel, R, Rauw, Grégor, ...
We report on the spectroscopic monitoring of GCIRS 16SW, an Ofpe/WN9 star and LBV candidate in the central parsec of the Galaxy. SINFONI observations show strong daily spectroscopic changes in the K...
De Becker, Michaël, Rauw, Grégor, Sana, H, Pollock, AMT, Pittard, JM, Blomme, Ronny, ...
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-ray...
On the nature of the hard X-ray source IGR J2018+4043 (2006)
Bykov, Andrei Mikhailovich, Krassilchtchikov, Alexandre Mikhailovich, Uvarov, Yuri Alexandrovich, Kennea, JA, Pavlov, GG, Dubner, GM, ...
We found a very likely counterpart to the recently discovered hard X-ray source IGR J2018 + 4043 in the multiwavelength observations of the source field. The source, originally discovered in the...
The OB binary HD 152219: a detached, double-lined, eclipsing system (2006)
Sana, H, Gosset, Eric, Rauw, Grégor
We present the results of an optical spectroscopic campaign on the massive binary HD 152219 located near the core of the NGC 6231 cluster. Though the primary to secondary optical brightness ratio is...
De Becker, Michaël, Rauw, Grégor, Manfroid, Jean, Eenens, Philippe
Aims.We address the issue of the multiplicity of the three brightest early-type stars of the young open cluster IC 1805, namely HD 15570, HD 15629 and HD 15558. Methods: .For the three stars, we...
The XMM-Newton view of Plaskett's star and its surroundings (2006)
Linder, Natacha, Rauw, Grégor, Pollock, AMT, Stevens, IR
XMM-Newton data of Plaskett's star (HD 47129) are used in order to analyse its X-ray spectrum and variability and hence to derive further constraints on the wind interaction in this early-type binary...
High Resolution X-ray Spectroscopy of Early-Type Stars (2006)
Rauw, Grégor, Pollock, AMT, Naze, Yaël
Although X-ray emission from massive, early-type stars has been known for almost thirty years, it is only with the advent of the high-resolution spectrographs aboard Chandra and XMM-Newton that a...
An XMM-Newton view of the young open cluster NGC 6231 - I. The catalogue (2006)
Sana, H, Gosset, Eric, Rauw, Grégor, Sung, H, Vreux, Jean-Marie
This paper is the first of a series dedicated to the X-ray properties of the young open cluster NGC 6231. Our data set relies on an XMM-Newton campaign of a nominal duration of 180 ks and reveals...
New light on the peculiar star HD108 (2006)
Naze, Yaël, Barbieri, C, Segafredo, A, Rauw, Grégor, De Becker, Michaël
HD 108 is a peculiar massive star of type Of?p, which present recurrent line profile variations. Archival data confirm the very long (50-60 yr) period of this star. Recent data show that the minimum...
Bykov, A.M., Krassilchtchikov, A.M., Uvarov, Y.A., Lebrun, F., Renaud, M., Terrier, R, ...
Aims. We report the detection of hard X-ray emission from the field of the star-forming region NGC 6334 with the International Gamma-Ray Astrophysics Laboratory INTEGRAL. Methods. The JEM-X monitor...
The Peculiar Of?p Stars HD 108 and HD 191612: The X-ray View (2006)
Naze, Yaël, Rauw, Grégor, Walborn, N R, Howarth, I D
Not Available
An Exceptional X-ray View of the Young Open Cluster NGC 6231: What XMM-Newton Has Taught Us (2006)
Sana, H, Gosset, Eric, Rauw, Grégor, Vreux, J-M
Considered as the core of the Sco OB1 association, the young open cluster NGC 6231 harbours a rich O-type star population. In 2001, the XMM-Newton satellite targeted the cluster for a nominal...
Leyder, Jean-Christophe, Rauw, Grégor
Recent studies suggested that there might be a correlation between unidentified gamma-ray sources from the third EGRET catalogue and OB associations. Moreover, when extrapolating the fluxes measured...
The peculiar Of?p stars HD 108 and HD 191612 (2005)
Naze, Yaël, Rauw, Grégor, Walborn, N R, Howarth, I D
The Of?p spectral category was introduced by Walborn in 1972 to describe peculiar stars which possess intense emission lines of C III 4647,4650,4651. Recently, two of them, HD 108 and HD 191612, were...
A survey for gamma-ray emission from OB associations with INTEGRAL: some preliminary results (2005)
Leyder, Jean-Christophe, Rauw, Grégor
Recent studies indicated that there might be a correlation between OB associations and unidentified gamma-ray sources from the 3EG catalogue. Moreover, when extrapolating the fluxes measured by EGRET...
Are WC9 Wolf-Rayet stars in colliding-wind binaries? (2005)
Williams, P M, Van Der Hucht, K A, Rauw, Grégor
We present results from a spectroscopic search for massive companions to dust-making Galactic WC9 stars as a step to testing the paradigm that dust formation in these systems requires colliding winds...
The XMM-Newton view of Plaskett's star and its surroundings (2005)
XMM data of Plaskett's star (HD 47129) are used in order to analyse its X-ray spectrum and variability and hence to derive further constraints on the wind interaction in this early-type binary (O6 I...
The young open cluster NGC 6231: five years of investigations (2005)
Sana, H, Rauw, Grégor, Gosset, Eric
In this contribution, we present an overview of the main results obtained by the Liège multiwavelength (in the X-ray and optical domains) campaign on the young open cluster NGC 6231. We probe the...
CPD-41° 7742: an unusual wind interaction (2005)
Sana, H, Gosset, Eric, Rauw, Grégor, Antokhina, E, Royer, P, Manfroid, Jean, ...
We summarize the results of a multiwavelength observing campaign on the massive eclipsing binary CPD-41° 7742, another remarkable object in the young open cluster NGC 6231. Our campaign relies on...
Gosset, Eric, Rauw, Grégor, Manfroid, Jean, Antokhina, E, Stevens, I R, Sana, H
We present preliminary results of an observational campaign aiming at the study of the binary system LSS3074. A new lightcurve clearly indicates that the system is in contact. Recent spectroscopy...
Evidence for phase-locked X-ray variations from the colliding-wind massive binary Cyg OB2 #8A (2005)
De Becker, Michaël, Rauw, Grégor
JENAM 2005, "Distant Worlds"
XMM-Newton observations of the Cyg OB2 association (2005)
Rauw, Grégor, De Becker, Michaël, Linder, Natacha
JENAM 2005, "Distant Worlds"
On the multiplicity of the non-thermal radio emitters 9 Sgr and HD 168112 (2005)
Rauw, Grégor, Sana, H, Gosset, Eric, De Becker, Michaël, Arias, J, Morrell, N, ...
JENAM 2005, "Distant Worlds"
The massive binary CPD-41 degrees 7742 - II. Optical light curve and X-ray observations (2005)
Sana, H, Antokhina, E, Royer, P, Manfroid, Jean, Gosset, Eric, Rauw, Grégor, ...
In the first paper of this series, we presented a detailed high-resolution spectroscopic study of CPD - 41 degrees 7742, deriving for the first time an orbital solution for both components of the...
De Becker, Michaël, Rauw, Grégor, Blomme, Ronny, Pittard, JM, Stevens, IR, Runacres, MC
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 +...
Non-thermal radio emission from O-type stars. I. HD168112 (2005)
Blomme, Ronny, Van Loo, S, De Becker, Michaël, Rauw, Grégor, Runacres, MC, Gunawan, DYAS, ...
We present a radio lightcurve of the O5.5 III(f(+)) star HD 168112, based on archive data from the Very Large Array (VLA) and the Australia Telescope Compact Array (ATCA). The fluxes show...
Naze, Yaël, Antokhin, II, Sana, H, Gosset, Eric, Rauw, Grégor
We present the analysis of an extensive set of high-resolution spectroscopic observations of HD 93161, a visual binary with a separation of 2 arcsec. HD 93161 A is a spectroscopic binary, with both...
Rauw, Grégor, Crowther, PA, De Becker, Michaël, Gosset, Eric, Naze, Yaël, Sana, H, ...
We analyse the optical spectrum of the very massive binary system WR20a (WN6ha + WN6ha). The most prominent emission lines, Halpha and He II lambda4686, display strong phase-locked profile...
De Becker, Michaël, Rauw, Grégor, Swings, Jean-Pierre
We present the results of an intensive spectroscopic campaign in the optical waveband revealing that Cyg OB2 # 8A is an O6+ O5.5 binary system with a period of about 21.9 days. Cyg OB2 # 8A is a...
Gosset, Eric, Naze, Yaël, Rauw, Grégor, Vreux, Jean-Marie, Sana, H.
We present the results of an XMM-Newton observation of the field of the Wolf-Rayet star WR 40. Despite a nominal exposure of 20 ks and the high sensitivity of the satellite, the star itself is not...
A spectroscopic investigation of the young open cluster IC1805 (2005)
De Becker, Michaël, Rauw, Grégor
JENAM 2005, "Distant Worlds"
A period and a prediction for the Of ? p spectrum alternator HD 191612 (2004)
Walborn, Nolan R., Howarth, Ian D., Rauw, Grégor, Lennon, Daniel J., Bond, Howard E., Negueruela, Ignacio, ...
The observational picture of the enigmatic O-type spectrum variable HD 191612 has been sharpened substantially. A symmetrical, low-amplitude light curve with a period near 540 days has recently been...
Line profile variability in the spectra of Oef stars - II. HD192281, HD14442 and HD14434 (2004)
De Becker, Michaël, Rauw, Grégor
We present the very first analysis of the spectroscopic variability of the three rapidly rotating Oef stars HD 192281 (O5(ef)), HD14442 (O5.5ef) and HD 14434 (O6.5( ef)). Radial velocities of the He...
Hard X-ray emission clumps in the gamma-Cygni supernova remnant: An INTEGRAL-ISGRI view (2004)
Bykov, AM, Krassilchtchikov, AM, Uvarov, YA, Bloemen, H, Chevalier, RA, Gustov, MY, ...
Spatially resolved images of the galactic supernova remnant G78.2+2.1 (gamma-Cygni) in hard X-ray energy bands from 25 keV to 120 keV are obtained with the IBIS-ISGRI imager aboard the International...
De Becker, Michaël, Rauw, Grégor, Manfroid, Jean
We present the results of a spectroscopic campaign revealing that the non-thermal radio emitter Cyg OB2 #8A is an O6+O5.5 binary system. We propose the very first orbital solution indicating a period...
Rauw, Grégor, De Becker, Michaël
We investigate the multiplicity of three O-type stars in the very young open cluster IC 1805. All our targets were previously considered as spectroscopic binaries, but no orbital solution was...
De Becker, Michaël, Rauw, Grégor, Blomme, Ronny, Waldron, Wayne, Sana, Hugues, Stevens, Ian, ...
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...
WR 20a: A massive cornerstone binary system comprising two extreme early-type stars (2004)
Rauw, Grégor, De Becker, Michaël, Naze, Yaël, Crowther, PA, Gosset, Eric, Sana, H, ...
We analyse spectroscopic observations of WR20a revealing that this star is a massive early-type binary system with a most probable orbital period of similar to3.675 days. Our spectra indicate that...
A phase-resolved XMM-Newton campaign on the colliding-wind binary HD 152248 (2004)
Sana, H, Stevens, IR, Gosset, Eric, Rauw, Grégor, Vreux, Jean-Marie
We report the first results of an XMM-Newton monitoring campaign of the open cluster NGC 6231 in the Sco OB 1 association. This first paper focuses on the massive colliding-wind binary HD 152248,...
XMM-Newton observations of the giant H II region N 11 in the LMC (2004)
Naze, Yaël, Antokhin, II, Rauw, Grégor, Chu, YH, Gosset, Eric, Vreux, Jean-Marie
Using the sensitive XMM-Newton observatory, we have observed the giant H II region N11 in the LMC for similar to30 ks. We have detected several large areas of soft diffuse X-ray emission along with...
HD 108: The mystery deepens with XMM-Newton observations (2004)
Naze, Yaël, Rauw, Grégor, Vreux, Jean-Marie, De Becker, Michaël
In 2001, using a large spectroscopic dataset from an extensive monitoring campaign, we discovered that the peculiar Of star HD 108 displayed extreme line variations. This strange behaviour could be...
An XMM-Newton observation of the massive binary HD 159176 (2004)
De Becker, Michaël, Rauw, Grégor, Pittard, JM, Antokhin, II, Stevens, IR, Gosset, Eric, ...
We report the analysis of an XMM-Newton observation of the close binary HD 159176 (O7 V + O7 V). The observed L-x/L-bol ratio reveals an X-ray luminosity exceeding by a factor similar to7 the...
Massive binaries and colliding winds (2004)
In this contribution, I review recent results from observational investigations of early-type binaries of spectral types O and Wolf-Rayet. These studies aim at an accurate determination of...
An XMM-Newton observation of the very young open cluster NGC 6383 (2003)
Rauw, Grégor, De Becker, Michaël, Gosset, Eric, Pittard, JM, Stevens, IR
We report the detection of a number of X-ray sources associated with the very young open cluster NGC6383. About two thirds of these objects are correlated with a rather faint optical source and all...
WR bubbles and HeII emission (2003)
Naze, Yaël, Rauw, Grégor, Manfroid, Jean, Chu, YH, Vreux, Jean-Marie
We present the very first high quality images of the He II lambda4686 emission in three high excitation nebulae of the Magellanic Clouds. A fourth high excitation nebula, situated around the WR star...
The massive binary CPD-41 degrees 7742 - I. High-resolution optical spectroscopy (2003)
Sana, H, Hensberge, H, Rauw, Grégor, Gosset, Eric
We present the results of a spectroscopic campaign on the early-type binary CPD-41degrees 7742. For the first time, we unambiguously detect the secondary's spectral signature and derive an accurate...
Raassen, AJJ, Van Der Hucht, KA, Mewe, R, Antokhin, I, Rauw, Grégor, Vreux, Jean-Marie, ...
We report the analysis of the first high-resolution X-ray spectra of the Wolf-Rayet (WR) object WR25 (HD 93162, WN6ha+O4f) obtained with the reflection Grating spectrometers (RGS) and the European...
VLT observations of the highly ionized nebula around Brey2 (2003)
Naze, Yaël, Rauw, Grégor, Manfroid, Jean, Chu, YH, Vreux, Jean-Marie
We present the first high resolution He II lambda4686 images of the high excitation nebula around the WR star Brey2 in the LMC. This nebula presents a striking morphology: a small arc-like feature...
Line profile variability in the spectra of Oef stars. I. BD + 60deg 2522 (2003)
Rauw, Grégor, De Becker, Michaël, Vreux, Jean-Marie
We report the analysis of a long term observing campaign designed to monitor the spectroscopic variability of the Oef star BD +60deg 2522. We find that the double-peaked He {II} lambda 4686 emission...
XMM-Newton high-resolution X-ray spectroscopy of the Wolf-Rayet object WR25 (WN6ha+O4f) (2003)
Raassen, AJJ, Van Der Hucht, KA, Mewe, R, Antokhin, I, Rauw, Grégor, Vreux, Jean-Marie, ...
We report the analysis of the X-ray spectrum of the Wolf-Rayet star WR 25, observed by RGS and EPIC-MOS on board XMM-Newton. Temperatures up to 40 MK have been determined. Strong absorption,...
Gosset, Eric, Rauw, Grégor, Vreux, Jean-Marie, Naze, Yaël, Antokhin, Igor I, Sana, Hugues
A Massive Star Odyssey: From Main Sequence to Supernova, IAU S212
Chapman, Jessica M, Stevens, Ian R, Rauw, Grégor, Leitherer, Claus
We present results of the Australia Telescope Compact Array (ATCA) radio continuum observations of massive stars in the Sco OB1 association. Most stars detected in the program show spectral indices...
Antokhin, I I, Rauw, Grégor, Vreux, J-M, Van Der Hucht, K A
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Albacete Colombo, J.F., Morrell, NI, Rauw, Grégor, Corcoran, MF, Niemela, VS, Sana, H
High-resolution optical spectroscopy of CPD -59degrees2636, one of the O-type stars in the open cluster Trumpler 16 in the Carina Nebula, reveals this object to be a multiple system displaying triple...
An XMM-Newton observation of the Lagoon Nebula and the very young open cluster NGC6530 (2002)
Rauw, Grégor, Naze, Yaël, Gosset, Eric, Stevens, IR, Blomme, Ronny, Corcoran, MF, ...
We report the results of an XMM-Newton observation of the Lagoon Nebula (M8). Our EPIC images of this region reveal a cluster of point sources, most of which have optical counterparts inside the very...
A multi-wavelength investigation of the non-thermal radio emitting O-star 9 Sgr (2002)
Rauw, Grégor, Blomme, R, Waldron, WL, Corcoran, MF, Pittard, JM, Pollock, AMT, ...
We report the results of a multi-wavelength investigation of the O4 V star 9 Sgr (= HD164794). Our data include observations in the X-ray domain with XMM-Newton, in the radio domain with the VLA as...
The evolved early-type binary HDE 228766 revisited (2002)
Rauw, Grégor, Crowther, PA, Eenens, PRJ, Manfroid, Jean, Vreux, Jean-Marie
We use an extensive set of spectroscopic observations to reinvestigate the properties of the massive binary HDE 228766. Conventional classification criteria suggest that HDE 228766 consists of an O7...
Phase-resolved X-ray and optical spectroscopy of the massive binary HD93403 (2002)
Rauw, Grégor, Vreux, Jean-Marie, Stevens, IR, Gosset, Eric, Sana, H, Jamar, Claude, ...
We report the first results of a campaign aimed at the study of early-type binaries with the XMM-Newton observatory. Phase-resolved EPIC spectroscopy of the eccentric binary HD93403 reveals a clear...
Line-Profile Variability in the Massive Binary System HD 149404 (2002)
Naze, Yaël, Carrier, Fabien, Rauw, Grégor
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Searching for Colliding-Wind Signatures in a Sample of O-Star Binaries (2002)
Rauw, Grégor, Sana, H, Vreux, J-M, Gosset, Eric, Stevens, I R
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Optical Spectroscopy of Colliding-Wind Systems to be Observed with XMM (2002)
Sana, H, Rauw, Grégor, Gosset, Eric, Vreux, J-M
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A first detailed study of the colliding wind WR+O binary WR 30a (2001)
Gosset, Eric, Royer, P, Rauw, Grégor, Manfroid, Jean, Vreux, J-M
We present a detailed, extensive investigation of the photometric and spectroscopic behaviour of WR 30a. This star is definitely a binary system with a period around 4.6d. We propose the value...
Rauw, Grégor, Sana, H, Antokhin, I I, Morrell, N I, Niemela, V S, Albacete Colombo, J F, ...
We discuss the orbital elements of the multiple system Tr 16-104 which is usually believed to be a member of the open cluster Trumpler 16 in the Carina complex. We show that Tr 16-104 could be a...
Optical spectroscopy of X-Mega targets - II. The massive double-lined O-type binary HD 93205 (2001)
Morrell, N I, Barbá, R H, Niemela, V S, Corti, M A, Albacete Colombo, J F, Rauw, Grégor, ...
A new high-quality set of orbital parameters for the O-type spectroscopic binary HD 93205 has been obtained combining échelle and coudé CCD observations. The radial velocity orbits derived from the...
What is the real nature of HD 108? (2001)
Naze, Yaël, Vreux, J-M, Rauw, Grégor
Since the beginning of the past century, the nature of HD 108 has been a subject of intense debate. One after another, astronomers explored its variability and attributed it either to binarity, or to...
HD 152248: Evidence for a colliding wind interaction (2001)
Sana, H, Rauw, Grégor, Gosset, Eric
We present the results of a four year spectroscopic campaign on the early-type binary system HD 152248. Our analysis yields a new classification as O7.5III(f) + O7III(f), in contradiction with...
The strange case of the massive binary HD 149404 (2001)
Rauw, Grégor, Naze, Yaël, Carrier, F, Burki, G, Gosset, Eric, Vreux, J-M
We report the analysis of an extensive set of high-resolution spectroscopic observations of the massive binary system HD 149404. We compare different techniques to measure the radial velocities of...
The spectral variability of HD 192639 and its implications for the star's wind structure (2001)
Rauw, Grégor, Morrison, N D, Vreux, J-M, Gosset, Eric, Mulliss, C L
We report the analysis of an extensive set of spectroscopic data of the O(f) supergiant HD 192639. A Fourier analysis of our time-series reveals a recurrent variability with a ``period'' of roughly...
Kahn, S M, Leutenegger, M A, Cottam, J, Rauw, Grégor, Vreux, J-M, ...
We present the first high resolution X-ray spectrum of the bright O4Ief supergiant star zeta Puppis, obtained with the Reflection Grating Spectrometer on-board XMM-Newton. The spectrum exhibits...
Correction of Systematic Errors in Differential Photometry (2001)
Manfroid, Jean, Royer, P, Rauw, Grégor, Gosset, Eric
A common cause of errors in CCD differential photometry is an improper calibration of the array. The importance of these errors is evaluated for different cameras with fields between 3 and 30...
Coordinated monitoring of the eccentric O-star binary Iota Orionis: the X-ray analysis (2000)
Pittard, Julian M, Stevens, Ian R, Corcoran, Michael F, Gayley, Ken G, Marchenko, Sergey V, Rauw, Grégor
We analyse two ASCA observations of the highly eccentric O9 III+B1 III binary Iota Orionis obtained at periastron and apastron. Based on the assumption of a strong colliding-wind shock between the...
Marchenko, Sergey V, Rauw, Grégor, Antokhina, Eleonora A, Antokhin, Igor I, Ballereau, Dominique, Chauville, Jacques, ...
With the objective of investigating the wind-wind collision phenomenon and supporting contemporaneous X-ray observations, we have organized a large-scale, coordinated optical monitoring campaign of...
Compact star clusters of the LMC H ii region N11 C (2000)
Heydari-Malayeri, Mohammad, Royer, Pierre, Rauw, Grégor, Walborn, Nolan R
Based on imaging and spectroscopy obtained at the ESO NTT telescope and using an efficient image analysis algorithm, we study the core of the LMC OB association LH 13, particularly the two compact...
A new orbital solution for the massive binary system HD 93403 (2000)
Rauw, Grégor, Sana, H, Gosset, Eric, Vreux, J-M, Jehin, Emmanuel, Parmentier, Geneviève
We present a spectroscopic analysis of the early-type massive binary system HD 93403. Using high resolution optical spectra, we clearly separate the primary and secondary components. For the first...
Rauw, Grégor, Stevens, I R, Pittard, J M, Corcoran, M F
We discuss an ASCA observation of the eccentric WC8+O7.5III binary gamma[SUP]2[/SUP]Velorum near apastron. The X-ray spectrum is compared with two previous observations obtained when the system was...
Rauw, Grégor, Vreux, J-M, Bohannan, B
We present an analysis of an extensive set of spectroscopic observations of the mysterious early-type binary BD +40 deg4220. A new orbital solution is derived from the radial velocities of the...
Narrow-band photometry of the eclipsing WN7+O binary WR 22 (1999)
Royer, P, Rauw, Grégor, Manfroid, Jean, Gosset, Eric, Vreux, Jean-Marie
In the present paper, we discuss photometric observations of the February 1996 eclipse of the very massive WR+O binary WR 22. Our data were obtained with a set of narrow-band filters, specially...
New observational results on the colliding wind WR+O binary WR 30a (1999)
Gosset, Eric, Royer, P, Rauw, Grégor, Manfroid, Jean, Vreux, Jean-Marie
On the perspectives of using XMM to study fundamental parameters of early-type stars (1999)
Rauw, Grégor, Van Der Hucht, KA, Mewe, R, Gudel, M, Vreux, Jean-Marie, Gosset, Eric, ...
Line profile variability in the spectrum of the O(f) supergiant HD 192639 (1998)
We report the results of a medium-resolution spectroscopic investigation of the O(f) supergiant HD 192639. Particular attention is paid to the He {ii}\ lambda 4686 line. This line displays strong...
The LMC transition star R 84 and the core of the LH 39 OB association. (1997)
Heydari-Malayeri, M, Courbin, F, Rauw, Grégor, Esslinger, O, Magain, Pierre
On the basis of sub-arcsecond imaging obtained at the ESO NTT with SUSI and the ESO ADONIS adaptive optics system at the 3.6m telescope, we resolve and study the core components of the LMC OB...
The puzzling Luminous Blue Variable-like object HD 5980 in the Small Magellanic Cloud. (1997)
Heydari-Malayeri, M, Rauw, Grégor, Esslinger, O, Beuzit, J-L
We have observed the exceptional SMC star HD 5980 during several runs from 1989 to 1995 at ESO La Silla. CASPEC at the 3.6m telescope and EMMI in echelle and long slit modes at NTT were used for...
The WN 11-like Spectrum of HD 5980 during the early Stages of the 1994 Eruption (1997)
Heydari-Malayeri, M, Rauw, Grégor, Esslinger, O
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Search for Interacting Winds in the WN7 + O Binary WR 22 (1996)
Rauw, Grégor, Vreux, Jean-Marie, Gosset, Eric
We present new spectroscopic observations of the He I Lambda5876 line in WR22 which were obtained around periastron. These data show strong line profile variability. We use recently determined...
WR22: the most massive Wolf-Rayet star ever weighed. (1996)
Rauw, Grégor, Vreux, J-M, Gosset, Eric, Hutsemekers, Damien, Magain, Pierre, Rochowicz, K
The results of an extensive spectroscopic campaign on the eclipsing binary WR22 are presented. A new radial velocity curve is deduced for the WN7 component, allowing us to improve the parameters of...
Existence of a short period (3.5-4 hours) in the photometric variability of WR66. (1996)
Rauw, Grégor, Gosset, Eric, Manfroid, Jean, Vreux, J-M, Claeskens, J-F
We report here on an independent detection of a short period (~4hours) in the photometric variations of WR66, thus confirming in broad terms the discovery by Antokhin et al.. In addition, we present...
Spectropolarimetry of WR66 (1996)
Lamy, H, Hutsemekers, Damien, Rauw, Grégor
We have carried out spectropolarimetric observations of the Wolf-Rayet star WR66 (WN8) with EFOSC1 mounted on the ESO 3.6m telescope of La Silla. The results indicate a polarization level of about 5...
Rauw, Grégor, Vreux, Jean-Marie, Gosset, Eric
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Line-profile variability and mass-transfer in the early type binary BD+40° 4220 (1996)
Vreux, Jean-Marie, Rauw, Grégor, Bohannan, B, Manfroid, Jean
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A new orbital solution for the WNL binary system WR12 (1996)
Rauw, Grégor, Vreux, J-M, Gosset, Eric, Manfroid, Jean, Niemela, V S
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WR22 as a core hydrogen-burning Wolf-Rayet star (1995)
Rauw, Grégor, Vreux, Jean-Marie, Gosset, Eric, Hutsemekers, Damien, Magain, Pierre
The analysis of an extensive sample of high resolution spectra of the Wolf-Rayet binary WR22 recently allowed us to determine a minimum mass of 72 M_solar for the WN7 star. With such a high mass,...
A seven year campaign on WR 22 (1995)
Rauw, Grégor, Vreux, J-M, Gosset, Eric, Hutsemekers, Damien, Magain, Pierre, Manfroid, Jean, ...
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A seven year campaign on WR 22 (1995)
Rauw, Grégor, Vreux, J-M, Gosset, Eric, Hutsemekers, Damien, Magain, Pierre, Manfroid, Jean, ...
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