Searching for hidden Wolf-Rayet stars in the Galactic Plane - 15 new Wolf-Rayet stars

Abstract

We report the discovery of fifteen previously unknown Wolf-Rayet (WR) stars found as part of an infrared broad-band study of candidate WR stars in the Galaxy. We have derived an empirically-based selection algorithm which has selected ~5000 WR candidate stars located within the Galactic Plane drawn from the GLIMPSE (mid-infrared) and 2MASS (near-infrared) catalogues. Spectroscopic follow-up of 184 of these reveals eleven WN and four WC-type WR stars. Early WC subtypes are absent from our sample and none show evidence for circumstellar dust emission. Of the candidates which are not WR stars, ~120 displayed hydrogen emission line features in their spectra. Spectral features suggest that the majority of these are in fact B supergiants/hypergiants, ~40 of these are identified Be/B[e] candidates. Here, we present the optical spectra for six of the newly-detected WR stars, and the near-infrared spectra for the remaining nine of our sample. With a WR yield rate of ~7% and a massive star detection rate of ~65%, initial results suggest that this method is one of the most successful means for locating evolved, massive stars in the Galaxy.

Accepted for publication in MNRAS. Figures degraded in quality, full version available by anonymous ftp (ftp:astro1.shef.ac.uk, /pub/lh/hadfield.ps.gz)

References in corpus (3)

• UBVJHK synthetic photometry of Galactic O stars
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Cited by in corpus (16)

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• Spitzer SAGE Infrared Photometry of Massive Stars in the Large Magellanic Cloud
• Spatial distribution of Galactic Wolf-Rayet stars and implications for the global population
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• A survey of the Wolf-Rayet population of the barred, spiral galaxy NGC 1313
• Two extremely luminous WN stars in the Galactic center with circumstellar emission from dust and gas
• Discovery of a young massive stellar cluster near HESS J1813-178
• Variable dust emission by WC type Wolf-Rayet stars observed in the NEOWISE-R survey
• Massive Stars in the W33 Giant Molecular Complex
• Two O2 If*/WN6 stars possibly ejected from the massive young Galactic cluster Westerlund 2
• Chasing the Identification of ASCA Galactic Objects (ChIcAGO) - An X-ray Survey of Unidentified Sources in the Galactic Plane I: Source Sample and Initial Results
• Influence of Wolf-Rayet stars on surrounding star-forming molecular clouds
• WR 120bb and WR 120bc: a pair of WN9h stars with possibly interacting circumstellar shells
• A deep near-infrared spectroscopic survey of the Scutum-Crux arm for Wolf-Rayet stars
• Applications of Machine-Learning Algorithms for Infrared Colour Selection of Galactic Wolf-Rayet Stars
• Discovery of two Galactic Wolf-Rayet stars in Circinus