The Wolf-Rayet star population in the dwarf galaxy NGC 625

Abstract

ABRIGED: Quantifying the number, type and distribution of W-R stars is a key component in the context of galaxy evolution, since they put constraints on the age of the star formation bursts. Nearby galaxies (d<5 Mpc) are particularly relevant in this context since they fill the gap between studies in the Local Group, where individual stars can be resolved, and galaxies in the Local Volume and beyond. We intend to characterize the W-R star population in NGC625, a low-metallicity dwarf galaxy suffering a currently declining burst of star formation. Optical IFS data have been obtained with the VIMOS-IFU covering the starburst region. We estimate the number of W-R stars using a linear combination of 3 W-R templates: 1 early-type nitrogen (WN) star, 1 late-type WN star and 1 carbon-type (WC) star (or oxygen-type (WO) star). Fits using several ensembles of templates were tested. Results were confronted with: i) high spatial resolution HST photometry; ii) numbers of W-R stars in nearby galaxies; iii) model predictions. The W-R star population is spread over the main body of the galaxy, not necessarily coincident with the overall stellar distribution. Our best estimation for the number of W-R stars yields a total of 28 W-R stars in the galaxy, out of which 17 are early- type WN, 6 are late-type WN and 5 are WC stars. The width of the stellar features nicely correlates with the dominant W-R type found in each aperture. The distribution of the different types of WR in the galaxy is roughly compatible with the way star formation has propagated in the galaxy, according to previous findings using HST images. Fits using templates at the metallicity of the LMC yield more reasonable number of W-R than those using templates at the metallicity of the SMC. Given the metallicity of NGC 625, this suggests a non-linear relation between the metallicity and the luminosity of the W-R spectral features.

13 pages, 6 figures, accepted by A&A; Labels in the axes of some figures are not displayed properly after the compilation on arXiv. Another version with the proper figures can be found here: https://www.dropbox.com/s/u2bx2li5jogmfkp/manuscript_astroph.pdf?dl=0

References in corpus (14)

• The Supernova -- Gamma-Ray Burst Connection
• Physical Properties of Wolf-Rayet Stars
• The effect of massive binaries on stellar populations and supernova progenitors
• Galaxies with Wolf-Rayet signatures in the low-redshift Universe - A survey using the Sloan Digital Sky Survey
• The Galactic WC stars: Stellar parameters from spectral analyses indicate a new evolutionary sequence
• Spatial distribution of Galactic Wolf-Rayet stars and implications for the global population
• Statistical Analysis of Supernova Remnants in the Large Magellanic Cloud
• A Modern Search for Wolf-Rayet Stars in the Magellanic Clouds: First Results
• Deep Near-IR Surface Photometry of 57 Galaxies in the Local Sphere of Influence
• VLT-VIMOS integral field spectroscopy of luminous and ultraluminous infrared galaxies. I. The sample and first results
• A survey of the Wolf-Rayet population of the barred, spiral galaxy NGC 1313
• PyCosmic: a robust method to detect cosmics in CALIFA and other fiber-fed integral-field spectroscopy datasets
• A Modern Search for Wolf-Rayet Stars in the Magellanic Clouds. II. A Second Year of Discoveries
• On the optical counterpart of NGC300 X-1 and the global Wolf-Rayet content of NGC300

Cited by in corpus (6)

• Line Luminosities of Galactic and Magellanic Cloud Wolf-Rayet stars
• Metallicity calibrations based on auroral lines from PHANGS-MUSE data
• Binary Fraction Indicators in Resolved Stellar Populations and Supernova Type Ratios
• Wolf-Rayet stars in the Antennae unveiled by MUSE
• Gas, dust, and the CO-to-molecular gas conversion factor in low-metallicity starbursts
• UM462, a local green pea galaxy analogue under the MUSE magnifying glass