Galactic Starburst NGC 3603 from X‐Rays to Radio

Moffat, A. F. J.; Corcoran, M. F.; Stevens, I. R.; Skalkowski, G.; Марченко, С. В.; Mücke, A.; Ptak, Andrew; Koribalski, B. S.; Brenneman, Laura; Mushotzky, R. F.; Pittard, J. M.; Pollock, A. M. T.; Brandner, W.

doi:10.1086/340491

Cited by 108 publications

(125 citation statements)

References 29 publications

Supporting

Mentioning

108

Contrasting

Order By: Relevance

“…We estimated for this source an X-ray luminosity of 2 × 10 30 erg s −1 assuming a plasma temperature kT = 2.16 keV, as for all the other sources in our sample. This luminosity corresponds to L X /L bol ∼ (0.5−1) × 10 −8 , which is about one order of magnitude lower than typically observed for older massive stars (Sciortino et al 1990), although there is a large scatter (±1 dex) on the L X /L bol relation for massive stars (e.g., Moffat et al 2002). The assumed X-ray plasma temperature for S106 IRS 4 is however likely too high for an early type star.…”

Section: S106 Irsmentioning

confidence: 71%

Chandraobservations of the massive star-forming region S106

Giardino¹,

Favata²,

Micela

2004

A&A

View full text Add to dashboard Cite

Abstract. We present Chandra observations of the massive star-forming region S106, a prominent H  region in Cygnus, associated with an extended molecular cloud and a young cluster. The nebula is excited by a single young massive star located at the center of the molecular cloud and the embedded cluster. The prominence of the cluster in the Chandra observation presented here confirms its youth and allows some of its members to be studied in more detail. We detect X-ray emission from the young massive central source S106 IRS 4, the deeply embedded central object which drives the bipolar nebula with a mass loss rate approximately 1-2 orders of magnitude higher than main sequence stars of comparable luminosity. Still, on the basis of its wind momentum flux the X-ray luminosity of S106 IRS 4 is comparable to the values observed in more evolved (main sequence and giant) massive stars, suggesting that the same process which is responsible for the observed X-ray emission from older massive stars is already at work at these early stages.

show abstract

Section: S106 Irsmentioning

confidence: 71%

Chandraobservations of the massive star-forming region S106

Giardino¹,

Favata²,

Micela

2004

A&A

View full text Add to dashboard Cite

show abstract

“…Moffat et al (2002) reported X-ray luminosities of three WN6ha stars in NGC 3603 as observed with ACIS-I. For NGC 3603 stars A1, B and C, these authors obtain >10 34 , 2-3 × 10 33 and >4 × 10 34 erg s −1 respectively (the lower limits for stars A1 and C are due to pile-up in the Chandra data).…”

Section: X-ray Emission From Wr 20amentioning

confidence: 81%

“…For NGC 3603 stars A1, B and C, these authors obtain >10 34 , 2-3 × 10 33 and >4 × 10 34 erg s −1 respectively (the lower limits for stars A1 and C are due to pile-up in the Chandra data). Although it remains to be established what fraction of their X-ray fluxes arises from colliding wind interactions, we note that the two X-ray brightest Wolf-Rayet objects in NGC 3603 are either confirmed or suspected binary systems (see the discussion in Moffat et al 2002). Since the wind properties of the components of WR 20a are more typical of extreme Of stars than of classical Wolf-Rayet stars, we compare the observed X-ray luminosity of WR 20a also to the empirical L X -L bol relation for OB stars derived by Berghöfer et al (1997).…”

Section: X-ray Emission From Wr 20amentioning

confidence: 93%

The spectrum of the very massive binary system WR 20a (WN6ha + WN6ha): Fundamental parameters and wind interactions

Rauw¹,

Crowther

Becker³

et al. 2005

A&A

137

View full text Add to dashboard Cite

Abstract. We analyse the optical spectrum of the very massive binary system WR 20a (WN6ha + WN6ha). The most prominent emission lines, Hα and He  λ 4686, display strong phase-locked profile variability. From the variations of their equivalent widths and from a tomographic analysis, we find that part of the line emission probably arises in a wind interaction region between the stars. Our analysis of the optical spectrum of WR 20a indicates a reddening of A V 6.0 mag and a distance of ∼7.9 kpc, suggesting that the star actually belongs to the open cluster Westerlund 2. The location of the system at ∼1.1 pc from the cluster core could indicate that WR 20a was gently ejected from the core via dynamical interactions. Using a non-LTE model atmosphere code, we derive the fundamental parameters of each component: T eff = 43 000 ± 2000 K, log L bol /L 6.0,Ṁ = 8.5 × 10 −6 M yr −1 (assuming a clumped wind with a volume filling factor f = 0.1). Nitrogen is enhanced in the atmospheres of the components of WR 20a, while carbon is definitely depleted. Finally, the position of the binary components in the Hertzsprung-Russell diagram suggests that they are core hydrogen burning stars in a pre-LBV stage and their current atmospheric chemical composition probably results from rotational mixing that might be enhanced in a close binary compared to a single star of same age.

show abstract

“…Lang 2003;Moffat et al 2002;Setia Gunawan et al 2003). The stellar radio sources are blue, A&A 511, A58 (2010) Fig.…”

Section: Identification Of Radio Starsmentioning

confidence: 96%

Radio emission from the massive stars in the galactic super star cluster Westerlund 1

Dougherty

Clark

Negueruela

et al. 2010

A&A

View full text Add to dashboard Cite

Aims. Current mass-loss rate estimates imply that main sequence line-driven winds are not sufficient to strip away the H-rich envelope to yield Wolf-Rayet (WR) stars. The rich transitional population of the young massive cluster Westerlund 1 (Wd 1) provides an ideal laboratory to observe and constrain mass-loss processes throughout the transitional phase of stellar evolution. Methods. We present an analysis of deep radio continuum observations of Wd 1 obtained with the Australia Telescope Compact Array at four frequency bands that permit investigation of the intrinsic characteristics of the radio emission. Results. We detect 18 cluster members, a sample dominated by the cool hypergiants, with additional detections amongst the hotter OB supergiants and WR stars. The radio properties of the sample are diverse, with thermal, non-thermal and composite thermal/nonthermal sources present. Mass-loss rates determined for stars with partially optically thick stellar winds are ∼10 −5 M yr −1 across all spectral types, insufficient to enable the formation of WRs during a massive star lifetime, and the stars must undergo a period of greatly enhanced mass loss. The sgB[e] star W9, the brightest radio source in Wd 1, may provide an example, with a current mass-loss rate an order of magnitude higher than the other cluster members, and an extended nebula interpreted as a wind from an earlier epoch with a density ∼3× the current wind. Such an envelope structure in W9 is reminiscent of luminous blue variables, and one that shows evidence of two eras of high, possibly eruptive mass loss. Surprisingly, three of the OB supergiants are detected, implying unusually dense winds, though they are embedded in more extended emission regions that may influence the derived parameters. They also may have composite spectra, suggesting binarity, which can lead to a higher flux than expected from a stellar wind. Spatially resolved nebulae are associated with three of the four RSGs and three of the six YHGs in the cluster, which are due to quiescent mass loss rather than outbursts. The extended nebulae of W20 and W26 have a cometary morphology, implying significant interaction with either the intracluster medium or cluster wind. For some of the cool star winds, the ionizing source may be a companion star though the cluster radiation density is sufficiently high to provide the necessary ionizing radiation. Five WR stars are detected with composite spectra, interpreted as arising in colliding-wind binaries.

show abstract

Galactic Starburst NGC 3603 from X‐Rays to Radio

Abstract: 1Ddpartementde physique,

Cited by 108 publications

References 29 publications

Chandraobservations of the massive star-forming region S106

Chandraobservations of the massive star-forming region S106

The spectrum of the very massive binary system WR 20a (WN6ha + WN6ha): Fundamental parameters and wind interactions

Radio emission from the massive stars in the galactic super star cluster Westerlund 1

Contact Info

Product

Resources

About