Wolf-Rayet stars in M33 - I. Optical spectroscopy using CFHT-MOS

Abbott, Jay B.; Crowther, P. A.; Drissen, Laurent; Martin, Pierre; Boivin, Guillaume

doi:10.1111/j.1365-2966.2004.07663.x

Cited by 18 publications

(17 citation statements)

References 56 publications

(107 reference statements)

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“…Schild, Smith & Willis (1990) have studied the WC content of M33 revealing a correlation between line width (C iv λ5808 FWHM) and galactocentric distance ( r / R 25 ), supported by results of Canada–France–Hawaii Telescope (CFHT) spectroscopy in Abbott et al (2004). In Fig.…”

Section: The Wolf–rayet Population Of Ngc 7793mentioning

confidence: 79%

“…8, we re‐produce Fig. 6 from Abbott et al (2004) together with unpublished M33 William Herschel Telescope (WHT)/Wide‐field Fibre Optic Spectrograph (WYFFOS) data taken in 1998 August, plus our own NGC 7793 observations. Indeed, there is a deficit of broad‐lined WC4–6 stars at low galactocentric distances.…”

Section: The Wolf–rayet Population Of Ngc 7793mentioning

confidence: 99%

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A Very Large Telescope imaging and spectroscopic survey of the Wolf-Rayet population in NGC 7793★

Bibby

Crowther

2010

Monthly Notices of the Royal Astronomical Society

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We present a Very Large Telescope/Focal Reducer and Low Dispersion Spectrograph #1 (VLT/FORS1) imaging and spectroscopic survey of the Wolf-Rayet (WR) population in the Sculptor group spiral galaxy NGC 7793. We identify 74 emission-line candidates from archival narrow-band imaging, from which 39 were observed with the Multi Object Spectroscopy mode of FORS1. 85 per cent of these sources displayed WR features. Additional slits were used to observe H II regions, enabling an estimate of the metallicity gradient of NGC 7793 using strong line calibrations, from which a central oxygen content of log(O/H) + 12 = 8.6 was obtained, falling to 8.25 at R 25 . We have estimated WR populations using a calibration of line luminosities of Large Magellanic Cloud stars, revealing ∼27 WN and ∼25 WC stars from 29 sources spectroscopically observed. Photometric properties of the remaining candidates suggest an additional ∼27 WN and ∼8 WC stars. A comparison with the WR census of the LMC suggests that our imaging survey has identified ∼80 per cent of WN stars and ∼90 per cent for the WC subclass. Allowing for incompleteness, NGC 7793 hosts ∼105 WR stars for which N(WC)/N(WN) ∼ 0.5. From our spectroscopy of H II regions in NGC 7793, we revise the global Hα star formation rate of Kennicutt et al. upward by 50 per cent to 0.45 M yr −1 . This allows us to obtain N(WR)/N(O) ∼ 0.018, which is somewhat lower than that resulting from the WR census by Schild et al. of another Sculptor group spiral NGC 300, whose global physical properties are similar to NGC 7793. Finally, we also report the fortuitous detection of a bright (m V = 20.8 mag) background quasar Q2358-32 at z ∼ 2.02 resulting from C IV λ1548-51 redshifted to the λ4684 passband.

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Section: The Wolf–rayet Population Of Ngc 7793mentioning

confidence: 79%

Section: The Wolf–rayet Population Of Ngc 7793mentioning

confidence: 99%

A Very Large Telescope imaging and spectroscopic survey of the Wolf-Rayet population in NGC 7793★

Bibby

Crowther

2010

Monthly Notices of the Royal Astronomical Society

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“…In M33, the Neugent & Massey (2011) catalogue only contains one WNh star. However, Hamann, Gräfener & Liermann (2006) listed many WNh stars in the Milky Way, providing circumstantial evidence that they should also exist in larger numbers in M33; one star in the Neugent & Massey (2011) catalogue is labeled "H-rich" but not classified WNh; one of the classification sources (Abbott et al 2004) intentionally omitted the Smith, Shara & Moffat (1996) WNh criteria; and one WN7h star from another source (Drissen et al 2008) is simply reported as a WN7 in Neugent & Massey (2011). Therefore, in M33, WN and WNh stars seem to be mixed and cannot be reliably separated.…”

Section: Resultsmentioning

confidence: 99%

Core-collapse supernova progenitor constraints using the spatial distributions of massive stars in local galaxies

Kangas

Portinari

Mattila

et al. 2017

A&A

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We study the spatial correlations between the H α emission and different types of massive stars in two local galaxies, the Large Magellanic Cloud (LMC) and Messier 33. We compare these to correlations derived for core-collapse supernovae (CCSNe) in the literature to connect CCSNe of different types with the initial masses of their progenitors and to test the validity of progenitor mass estimates which use the pixel statistics method. We obtain samples of evolved massive stars in both galaxies from catalogues with good spatial coverage and/or completeness, and combine them with coordinates of main-sequence stars in the LMC from the SIMBAD database. We calculate the spatial correlation of stars of different classes and spectral types with H α emission. We also investigate the effects of distance, noise and positional errors on the pixel statistics method. A higher correlation with H α emission is found to correspond to a shorter stellar lifespan, and we conclude that the method can be used as an indicator of the ages, and therefore initial masses, of SN progenitors. We find that the spatial distributions of type II-P SNe and red supergiants of appropriate initial mass ( 9 M ) are consistent with each other. We also find the distributions of type Ic SNe and WN stars with initial masses 20 M consistent, while supergiants with initial masses around 15 M are a better match for type IIb and II-L SNe. The type Ib distribution corresponds to the same stellar types as type II-P, which suggests an origin in interacting binaries. On the other hand, we find that luminous blue variable stars show a much stronger correlation with H α emission than do type IIn SNe.

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“…At subSolar metallicities, the LMC and SMC have been well sampled (Breysacher et al 1999;Massey et al 2003), as has M 33 (Massey & Johnson 1998;Abbott et al 2004). In contrast, M 31 is the only Local Group member with super-Solar metallicity, but its unfavourable inclination and large spatial extent makes surveying the complete WR population very challenging.…”

Section: Introductionmentioning

confidence: 99%

A spectroscopic search for the non-nuclear Wolf-Rayet population of the metal-rich spiral galaxy M 83

Hadfield

Crowther

Schild

et al. 2005

A&A

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Abstract. We present a catalogue of non-nuclear regions containing Wolf-Rayet stars in the metal-rich spiral galaxy M 83 (NGC 5236). From a total of 283 candidate regions identified using He  λ4686 imaging with VLT-FORS2, Multi Object Spectroscopy of 198 regions was carried out, confirming 132 WR sources. From this sub-sample, an exceptional content of ∼1035 ± 300 WR stars is inferred, with N(WC)/N(WN) ∼ 1.2, continuing the trend to larger values at higher metallicity amongst Local Group galaxies, and greatly exceeding current evolutionary predictions at high metallicity. Late-type stars dominate the WC population of M 83, with N(WC8-9)/N(WC4-7) = 9 and WO subtypes absent, consistent with metallicity dependent WC winds. Equal numbers of late to early WN stars are observed, again in contrast to current evolutionary predictions. Several sources contain large numbers of WR stars. In particular, #74 (alias region 35 from de Vaucouleurs et al.) contains ∼230 WR stars, and is identified as a Super Star Cluster from inspection of archival HST/ACS images. Omitting this starburst cluster would result in revised statistics of N(WC)/N(WN) ∼ 1 and N(WC8-9)/N(WC4-7) ∼ 6 for the "quiescent" disk population. Including recent results for the nucleus and accounting for incompleteness in our spectroscopic sample, we suspect the total WR population of M 83 may exceed 3000 stars.

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Wolf-Rayet stars in M33 - I. Optical spectroscopy using CFHT-MOS

Cited by 18 publications

References 56 publications

A Very Large Telescope imaging and spectroscopic survey of the Wolf-Rayet population in NGC 7793★

A Very Large Telescope imaging and spectroscopic survey of the Wolf-Rayet population in NGC 7793★

Core-collapse supernova progenitor constraints using the spatial distributions of massive stars in local galaxies

A spectroscopic search for the non-nuclear Wolf-Rayet population of the metal-rich spiral galaxy M 83

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