The Case for Local Collapse in the W51 Star‐forming Region

Sollins, P. K.; Zhang, Qizhou; Ho, P. T. P.

doi:10.1086/382035

Cited by 32 publications

(35 citation statements)

References 22 publications

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“…This is not always the case however; in G5.89-0.39, the large scale outflow (Klaassen et al 2006) is in a different direction than the smaller scale outflows of Sollins et al (2004) and Hunter et al (2008) who also see multiple outflows in various directions (see Qiu et al 2011, for an alternate interpretation of NGC 7538). Figure 5 of López-Sepulcre et al (2009) shows outflow mass, momentum and energy as a function of bolometric luminosity for a large sample of outflows from massive star forming regions observed with the IRAM 30 m telescope.…”

Section: Discussionmentioning

confidence: 97%

High resolution CO observation of massive star forming regions

Klaassen

Wilson

Keto

et al. 2011

A&A

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Context. To further understand the processes involved in the formation of massive stars, we have undertaken a study of the gas dynamics surrounding three massive star forming regions. By observing the large scale structures at high resolution, we are able to determine properties such as driving source, and spatially resolve the bulk dynamical properties of the gas such as infall and outflow. Aims. With high resolution observations, we are able to determine which of the cores in a cluster forming massive stars is responsible for the large scale structures. Methods. We present CO observations of three massive star forming regions with known HII regions and show how the CO traces both infall and outflow. By combining data taken in two SMA configurations with JCMT observations, we are able to see large scale structures at high resolution. Results. We find large (0.26-0.40 pc), massive (2-3 M ) and energetic (13-17 × 10 44 erg) outflows emanating from the edges of two HII regions suggesting they are being powered by the protostar(s) within. We find infall signatures in two of our sources with mass infall rates of order 10 −4 M yr −1 . Conclusions. We suggest that star formation is ongoing in these sources despite the presence of HII regions. We further conclude that the source(s) within a single HII region are responsible for the observed large scale structures; that these large structures are not the net effect of multiple outflows from multiple HII regions and hot cores.

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Section: Discussionmentioning

confidence: 97%

High resolution CO observation of massive star forming regions

Klaassen

Wilson

Keto

et al. 2011

A&A

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“…It is surrounded by powerful masers and ultra-compact HII regions yet has no associated radio HII region itself. Evidence for infall is seen in this region (Sollins et al 2004). IRS2E emits most of its X-ray photons in a broad 6.5-keV line probably due to fluorescent iron.…”

Section: W51a and The Enigmatic Source Irs2ementioning

confidence: 87%

Parsec-scale X-ray flows in high-mass star-forming regions

Townsley¹,

Feigelson²,

Montmerle³

et al. 2005

Proc. IAU

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Abstract. The Chandra X-ray Observatory is providing remarkable new views of massive starforming regions, revealing all stages in the life cycle of high-mass stars and their effects on their surroundings. We present a Chandra tour of several high-mass star-forming regions, highlighting physical processes that characterize the life of a cluster of high-mass stars, from deeply-embedded cores too young to have established an HII region to superbubbles so large that they shape our views of galaxies. Along the way we see that X-ray observations reveal hundreds of stellar sources powering great HII region complexes, suffused by both hard and soft diffuse X-ray structures caused by fast O-star winds thermalized in wind-wind collisions or by termination shocks against the surrounding media. Finally, we examine the effects of the deaths of high-mass stars that remained close to their birthplaces, exploding as supernovae within the superbubbles that these clusters created. We present new X-ray results on W51 IRS2E and 30 Doradus and we introduce new data on Trumpler 14 in Carina and the W3 HII region complexes W3 Main and W3(OH).

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“…As a matter of fact, the presence of infall in massive star forming regions has been observationally established (see e.g. Keto et al 1988;Ho et al 1996;Sollins et al 2004) and theoretically predicted (Keto 2003) as a crucial phenomenon profoundly affecting the formation of early-type stars. In order to estimate the accretion rate, we use the same approach as in C99:…”

Section: Infall and Nature Of The Ysomentioning

confidence: 99%

A study of the Keplerian accretion disk and precessing outflow in the massive protostar IRAS 20126+4104

Cesaroni¹,

Neri

Olmi

et al. 2005

A&A

197

264

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Abstract. We report on interferometric observations at 3.2 and 1.3 mm of the massive young stellar object IRAS 20126+4104 obtained in the C 34 S and CH 3 OH lines and in the continuum emission. The C 34 S data confirm the existence of a Keplerian disk, as already suggested by various authors. However, the mass of the central object is ∼7 M , significantly less than previous estimates. We believe that such a discrepancy is due to the fact that the rotation curve is affected not only by the star but also by the mass in the innermost regions of the disk itself: this leads to an overestimate of the stellar mass when low-density tracers are used to study the velocity field over regions larger than a few seconds of arc (i.e. a few 0.01 pc). On the basis of the line profiles we speculate that accretion onto the star might be still occurring through the disk. This seems consistent with current models of high-mass star formation which predict an accretion luminosity equal to that of IRAS 20126+4104 for a 7 M protostar. The CH 3 OH lines trace both the disk and the bipolar outflow previously detected in other molecules such as HCO + , SiO, and H 2 . New H 2 images obtained at 2.2 µm confirm that the outflow axis is undergoing precession. We elaborate a simple model that suitably fits the data thus allowing derivation of a few basic parameters of the precession.

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The Case for Local Collapse in the W51 Star‐forming Region

Cited by 32 publications

References 22 publications

High resolution CO observation of massive star forming regions

High resolution CO observation of massive star forming regions

Parsec-scale X-ray flows in high-mass star-forming regions

A study of the Keplerian accretion disk and precessing outflow in the massive protostar IRAS 20126+4104

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