Related papers: WR 143: A Wolf-Rayet Binary
As part of a search for Wolf-Rayet (WR) stars in the Magellanic Clouds, we have discovered a new type of WR star in the Large Magellanic Cloud (LMC). These stars have both strong emission lines, as well as He ii and Balmer absorption lines…
We present results from the first attempts to derive various physical characteristics of the dusty Wolf-Rayet star WR 48a based on a multi-wavelength view of its observational properties. This is done on the basis of new optical and…
The microquasar Cygnus X-3 was observed several times with the Gemini North Infrared Spectrograph while the source was in the hard X-ray state. We describe the observed 1.0-2.4 $\mu$m spectra as arising from the stellar wind of the…
We report the first results from deep X-ray observations of the Wolf-Rayet binary system WR147 with the Chandra HETG. Analysis of the zeroth order data reveals that WR147 is a double X-ray source. The northern counterpart is likely…
Recent results for Galactic and Magellanic Cloud Wolf-Rayet stars are summarised based on line blanketed, clumped model atmospheres together with UV, optical and IR spectroscopy. The trend towards earlier WN and WC spectral types with…
The discovery of new Wolf-Rayet (WR) stars in our Galaxy via large-scale narrowband optical surveys has been severely limited by dust extinction. Recent improvements in infrared technology have made narrowband-broadband imaging surveys…
We provide line luminosities and spectroscopic templates of prominent optical emission lines of 133 Galactic Wolf-Rayet stars by exploiting Gaia DR3 parallaxes and optical spectrophotometry, and provide comparisons with 112 counterparts in…
We present spatially resolved near-infrared and mid-infrared (1-25 microns) imaging of the WL 20 triple system in the nearby (d=125 pc) rho Ophiuchi star-forming cloud core. We find WL 20 to be a new addition to the rare class of "infrared…
We analyse the impact that spatial resolution has on the inferred numbers and types of Wolf-Rayet (WR) and other massive stars in external galaxies. Continuum and line images of the nearby galaxy M33 are increasingly blurred to mimic…
WR 125 is considered as a Colliding Wind Wolf-rayet Binary (CWWB), from which the most recent infrared flux increase was reported between 1990 and 1993. We observed the object four times from November 2016 to May 2017 with Swift and…
Massive star evolutionary models generally predict the correct ratio of WC-type and WN-type Wolf-Rayet stars at low metallicities, but underestimate the ratio at higher (solar and above) metallicities. One possible explanation for this…
We present first results of a Chandra X-ray observation of the rare oxygen-type Wolf-Rayet star WR 142 (= Sand 5 = St 3) harbored in the young, heavily-obscured cluster Berkeley 87. Oxygen type WO stars are thought to be the most evolved of…
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 radio emission from several WR+OB systems. The…
NGC 1313 is a bulgeless nearby galaxy, classified as SB(s)d. Its proximity allows high spatial resolution observations. We performed the first detailed analysis of the emission-line properties in the nuclear region of NGC 1313, using an…
We report the discovery of two new Wolf-Rayet (WR) galaxies: Mrk~1039, and F08208$+$2816. Two broad WR bumps at 5808\AA~ and 4650\AA~ indicate the presence of WCE and WNL star population in all two sources. We also confirm the presenceof WR…
We report on the first multi-color precision light curve of the bright Wolf-Rayet binary $\gamma^2$ Velorum, obtained over six months with the nanosatellites in the BRITE- Constellation fleet. In parallel, we obtained 488 high-resolution…
We present the analysis of the stellar and interstellar medium (ISM) properties of MARTA-4327, a star-forming galaxy at z=2.224 observed by means of deep JWST/NIRSpec spectroscopy in both medium- and high-resolution gratings as part of the…
Aims. We have gathered optical spectra of 8 long-duration GRB host galaxies selected from the archival data of VLT/FORS2. We investigated whether or not Wolf-Rayet (WR) stars can be detected in these GRB host galaxies. We also tried to…
Wolf-Rayet (WR) stars are evolved massive stars, presumably on their way to becoming supernova. They are characterized by high luminosities and fast and dense stellar winds. We have detected signs of a radio continuum pinwheel associated…
A growing number of Galactic Wolf-Rayet (WR) stars, in particular WC and transitional WN/C (WNC) objects, have been reported at comparatively low luminosities. If confirmed, these low-luminosity WR stars provide stringent tests of…