Wolf-Rayet stars in M81 using GTC/OSIRIS: 7 new detections, analysis and classification of the full sample

Abstract

We report the detection of 7 new Wolf-Rayet (WR) star locations in M81 using the Multi-Object Spectrograph of the OSIRIS instrument at Gran Telescopio Canarias. These detections are the result of a follow-up of an earlier study using the same instrumental set-up that resulted in the detection of 14 WR locations. We analyse the entire sample of 21 spectra to classify them to one of the known WR sub-types using template spectra of WR stars in the Large Magellanic Cloud (LMC), with similar metallicity to M81. Taking into consideration the dispersion in the strengths of the bumps for a given WR sub-type, we found that 19 of the 21 locations correspond to individual stars, including all the 7 new detections, of sub-types: WNL, WNE, WCE and the transitional WN/C. None of the detections correspond to WCL or WO types. The positions of these stars in the red bump vs blue bump luminosity diagram agrees well with an evolutionary path according to the Conti scenario. Based on this, we propose this diagram as a straightforward tool for spectral classification of extragalactic WR sources. The detection of individual WR stars in M81, which is at a distance of 3.6 Mpc, opens up a new environment for testing the massive star evolutionary models.

arXiv comment15 pages, 7 figures, 6 tables; accepted to MNRAS

References in corpus (21)

• Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD
• Binary Population and Spectral Synthesis Version 2.1: construction, observational verification and new results
• PARSEC evolutionary tracks of massive stars up to $350M_{\odot }$ at metallicities 0.0001$\le Z\le$0.04
• Stellar evolution with rotation XI: Wolf-Rayet star populations at different metallicities
• New Models for Wolf-Rayet and O Star Populations in Young Starbursts
• Reduced Wolf-Rayet Line Luminosities at Low Metallicity
• Ultraviolet Through Far-Infrared Spatially Resolved Analysis of the Recent Star Formation in M81 (NGC3031)
• Spatial distribution of Galactic Wolf-Rayet stars and implications for the global population
• Quantitative Spectroscopy of Blue Supergiant Stars in the Disk of M81: Metallicity, Metallicity Gradient and Distance
• Radiation-Hydrodynamic Models of the evolving Circumstellar Medium around Massive Stars
• The Wolf-Rayet Content of M33
• A Morphological Diagnostic for Dynamical Evolution of Wolf-Rayet Bubbles
• Uncovering multiple Wolf-Rayet star-clusters and the ionized ISM in Mrk178: the closest metal-poor Wolf-Rayet HII galaxy
• The Wolf-Rayet Content of M31
• A survey of the Wolf-Rayet population of the barred, spiral galaxy NGC 1313
• How extreme are the Wolf-Rayet clusters in NGC3125?
• A large Wolf-Rayet population in NGC300 uncovered by VLT-FORS2
• Wolf-Rayet stars in M81: Detection and Characterization using GTC/OSIRIS spectra and HST/ACS images
• The oxygen abundance gradient in M81 and the robustness of abundance determinations in H II regions
• In pursuit of gamma-ray burst progenitors: the identification of a sub-population of rotating Wolf-Rayet stars
• Luminous and Variable Stars in NGC 2403 and M81

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