Massive star formation in Wolf-Rayet galaxies. III: Analysis of the O and WR populations

Abstract

(Abridged) We perform a comprehensive multiwavelength analysis of a sample of 20 starburst galaxies that show the presence of a substantial population of Wolf-Rayet (WR) stars. In this paper we present the analysis of the O and WR star populations. We study the spatial localization of the WR-rich clusters via the detection of the blue WR bump (broad He II 4686) and the red WR bump (broad C IV 5808). We perform a detailed fitting of the nebular and broad emission lines within these broad features and derive the numbers of WN, WC and O stars using (i) the standard assumption of constant WR luminosities and (ii) considering metallicity-dependent WR luminosities. We then compare our results with the predictions given by evolutionary synthesis models and with previous empirical results. Aperture effects and the exact positioning of the slit onto the WR-rich bursts play a fundamental role in their detection. As expected, the total number of WR stars increases with increasing metallicity, but objects with 12+log(O/H)<8.2 show a rather constant WR/(WR+O) ratio. The computed WCE/WNL ratios are different than those empirically found in nearby star-forming galaxies, indicating that the observed galaxies are experiencing a strong and very short burst. Considering metallicity-dependent WR luminosities, our data agree with a Salpeter-like IMF in all regimes. We consider that the contribution of the WCE stars is not negligible at low metallicities. Although available models reproduce fairly well the WR properties at high metallicities, new evolutionary synthesis models for young starbursts including all involved parameters (age, metallicity, star-formation history, IMF and WR stars properties such as metallicity-dependent WR luminosities, stellar rotation and the WR binnary channel) are absolutely needed to perform an appropriate comparison with the observational data.

Accepted in A&A, 19 pages, 13 figures. Final version to appear in A&A.

References in corpus (16)

• 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 localized chemical pollution in NGC 5253 revisited: Results from deep echelle spectrophotometry
• Implications of the metallicity dependence of Wolf-Rayet winds
• The WR population predicted by massive single star and by massive binary evolution
• The interplay between ionized gas and massive stars in the HII galaxy IIZw70: integral field spectroscopy with PMAS
• Massive star formation in Wolf-Rayet galaxies: II. Optical spectroscopy results
• A survey of the Wolf-Rayet population of the barred, spiral galaxy NGC 1313
• How extreme are the Wolf-Rayet clusters in NGC3125?
• Oxygen abundance variations in the system of the two blue compact dwarf galaxies SBS 0335-052E and SBS 0335-052W
• Integral Field Spectroscopy of Blue Compact Dwarf Galaxies
• Spectrophotometric investigations of Blue Compact Dwarf Galaxies: Markarian 35
• Wolf-Rayet Galaxies in the Sloan Digital Sky Survey: the metallicity dependence of the initial mass function
• On the optical counterpart of NGC300 X-1 and the global Wolf-Rayet content of NGC300
• The nature of the Wolf-Rayet galaxy Mrk 209 from photoionization models

Cited by in corpus (60)

• Strongly star forming galaxies in the local Universe with nebular He II 4686 emission
• Ultraviolet spectra of extreme nearby star-forming regions --- approaching a local reference sample for JWST
• Constraints on the production and escape of ionizing radiation from the emission-line spectra of metal-poor star-forming galaxies
• Massive star formation in Wolf-Rayet galaxies. IV: Colours, chemical composition analysis and metallicity-luminosity relations
• The star formation history and metal content of the "Green Peas". New detailed GTC-OSIRIS spectrophotometry of three galaxies
• A Spectroscopic Study of Type Ibc Supernova Host Galaxies from Untargeted Surveys
• Wolf-Rayet stars in the Small Magellanic Cloud: I. Analysis of the single WN stars
• PISCO: The Pmas/ppak Integral-field Supernova hosts COmpilation
• The intriguing HI gas in NGC 5253: an infall of a diffuse, low-metallicity HI cloud?
• Extremely metal-poor galaxies with HST/COS: laboratories for models of low-metallicity massive stars and high-redshift galaxies
• Lya escape from z~0.03 star-forming galaxies: the dominant role of outflows
• Massive star formation in Wolf-Rayet galaxies. V: Star formation rates, masses and the importance of galaxy interactions
• CHAOS VI: Direct Abundances in NGC 2403
• The evolution of superluminous supernova LSQ14mo and its interacting host galaxy system
• Ultraviolet Detection of the Binary Companion to the Type IIb SN 2001ig
• The Lyman break analogue Haro 11: spatially resolved chemodynamics with VLT FLAMES
• Uncovering Blue Diffuse Dwarf Galaxies
• Gemini GMOS spectroscopy of HeII nebulae in M33
• The Type Ib SN 1999dn: One Year of Photometric and Spectroscopic Monitoring
• Piecing together the puzzle of NGC 5253: abundances, kinematics and WR stars
• EMPRESS. II. Highly Fe-Enriched Metal-poor Galaxies with $\sim 1.0$ (Fe/O)${}_{\odot }$ and $0.02$ (O/H)${}_{\odot }$ : Possible Traces of Super Massive ($>300M_{\odot }$) Stars in Early Galaxies
• The ionized gas at the center of IC 10: A possible localized chemical pollution by Wolf-Rayet stars
• Interaction effects on galaxy pairs with Gemini/GMOS- II: Oxygen abundance gradients
• Physical Properties of II Zw 40's Super Star Cluster and Nebula: New Insights and Puzzles from UV Spectroscopy
• The NGC 5253 star cluster system. I. Standard modelling and infrared-excess sources
• EMPRESS. VII. Ionizing Spectrum Shapes of Extremely Metal-Poor Galaxies: Uncovering the Origins of Strong HeII and the Impact on Cosmic Reionization
• High resolution spectroscopy of the BCD galaxy Haro 15: II. Chemodynamics
• Line Luminosities of Galactic and Magellanic Cloud Wolf-Rayet stars
• Gemini GMOS--IFU spectroscopy of the compact HII galaxies Tol 0104-388 and Tol 2146-391: The dependence on the properties of the interstellar medium
• The interstellar medium and feedback in the progenitors of the compact passive galaxies at z~2
• Abundance determination of multiple star-forming regions in the HII galaxy SDSS J165712.75+321141.4
• High resolution spectroscopy of the BCD galaxy Haro 15:I. Internal kinematics
• Carbon Abundances in Starburst Galaxies of the Local Universe
• First survey of Wolf-Rayet star populations over the full extension of nearby galaxies observed with CALIFA
• Detection of He++ ion in the star-forming ring of the Cartwheel using MUSE data and ionizing mechanisms
• Optical studies of two stripped envelope supernovae SN 2015ap (Type Ib) and SN 2016P (Type Ic)
• Spatially-resolved chemodynamics of the starburst dwarf galaxy CGCG 007-025: Evidence for recent accretion of metal-poor gas
• Metallicity calibrations based on auroral lines from PHANGS-MUSE data
• Photometric and spectroscopic studies of star-forming regions within Wolf-Rayet galaxies
• MEGARA-IFU detection of extended HeII4686 nebular emission in the central region of NGC1569 and its ionization budget
• Implications of the kinematical structure of circumnuclear star-forming regions on their derived properties
• The Trace of the CNO Cycle in the Ring Nebula NGC6888
• The Wolf-Rayet star population in the dwarf galaxy NGC 625
• Wolf-Rayet stars in the Antennae unveiled by MUSE
• Halpha imaging survey of Wolf-Rayet galaxies: morphologies and star formation rates
• Ionizing stellar population in the disc of NGC 3310 - II. The Wolf-Rayet population
• Strong nebular HeII emission induced by He${}^{+}$ ionizing photons escaping through the clumpy winds of massive stars
• Observational properties of a Type Ib Supernova MASTER OT J120451.50+265946.6 in NGC 4080
• He II Emission from Wolf-Rayet Stars as a Tool for Measuring Dust Reddening
• UM462, a local green pea galaxy analogue under the MUSE magnifying glass
• Chemical Abundances of a Sample of Oxygen-dominated Galaxies
• Blue galaxies: modelling nebular He II emission in high redshift galaxies
• Low-metallicity massive single stars with rotation. III. Source of ionization and C-IV emission in I Zw 18
• Looking for nebular He II emission south of the multiple-massive star system, HD 5980
• Optical spectroscopy of star-forming regions in dwarf Wolf-Rayet galaxies
• A MUSE view of the multiple interacting system HCG 31
• GMRT H I mapping of mid-infrared bright Blue Compact Dwarf Galaxies W1016+3754 & W2326+0608
• A study of 1000 galaxies with unusually young and massive stars in the SDSS: a search for hidden black holes
• The heart of NGC 5253 as seen with MUSE-NFM: nitrogen enrichment through stellar chemical feedback at parsec scales
• SDSS-V LVM: Detectability of Wolf-Rayet stars and their He II ionizing flux in low-metallicity environments I. The weak-lined, early-type WN3 stars in the SMC