A CLASS I AND CLASS II CH<sub>3</sub>OH MASER SURVEY OF EGOs FROM THE GLIMPSE SURVEY

Cyganowski, C. J.; Brogan, C. L.; Hunter, T. R.; Churchwell, E.

doi:10.1088/0004-637x/702/2/1615

Cited by 244 publications

(558 citation statements)

References 103 publications

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“…In Figure 7, we present the flux ratio map of the Spitzer/IRAC 4.5 µm to 3.6 µm emission (in color scale) overlaid with the SMA 1.1 mm continuum emission (in contours) towards the W3(OH) complex. The observations and analyses suggested that the morphologies observed at 3.6 µm and 4.5 µm are similar to each other and to H 2 1-0 S(1) line, and thus the emissions of the 4.5 µm and 3.6 µm bands include bright H 2 lines (e. g., Cyganowski et al 2009;Takami et al 2010) compared to the other bands of the Spitzer/IRAC instrument. It is thought that a 4.5 µm to 3.6 µm flux ratio larger than 1.5 traces shocked gas (e. g., Takami et al 2010).…”

Section: Infall Motionsmentioning

confidence: 67%

SMA observations of the W3(OH) complex: Dynamical differentiation between W3(H₂O) and W3(OH)

Qin¹,

Schilke²,

Wu³

et al. 2015

Mon. Not. R. Astron. Soc.

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We present Submillimeter Array (SMA) observations of the HCN (3-2) and HCO + (3-2) molecular lines toward the W3(H 2 O) and W3(OH) star-forming complexes. Infall and outflow motions in the W3(H 2 O) have been characterized by observing HCN and HCO + transitions. High-velocity blue/red-shifted emission, tracing the outflow, show multiple knots, which might originate in episodic and precessing outflows. 'Blue-peaked' line profiles indicate that gas is infalling onto the W3(H 2 O) dust core. The measured large mass accretion rate, 2.3×10 −3 M ⊙ yr −1 , together with the small free-fall time scale, 5×10 3 yr, suggest W3(H 2 O) is in an early evolutionary stage of the process of formation of high-mass stars. For the W3(OH), a two-layer model fit to the HCN and HCO + spectral lines and Spizter/IRAC images support that the W3(OH) Hii region is expanding and interacting with the ambient gas, with the shocked neutral gas being expanding with an expansion timescale of 6.4×10 3 yr. The observations suggest different kinematical timescales and dynamical states for the W3(H 2 O) and W3(OH).

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Section: Infall Motionsmentioning

confidence: 67%

SMA observations of the W3(OH) complex: Dynamical differentiation between W3(H₂O) and W3(OH)

Qin¹,

Schilke²,

Wu³

et al. 2015

Mon. Not. R. Astron. Soc.

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“…These two YSOs are massive and in an early evolutionary stage (Watson et al 2008). Using high resolution 6.7 GHz methanol maser measurements, Cyganowski et al (2009) suggest that a rotating disk is associated with YSO#3. An ultracompact H ii region nearby YSO#3 is shown in Fig.…”

Section: Hi-gal Results On N49mentioning

confidence: 94%

“…The 70 μm emission is dominated by YSO#3. This is an extended green object and is associated with a methanol maser (Cyganowski et al 2008(Cyganowski et al , 2009), which implies a massive YSO with an age younger than 3.5 × 10 4 years (Breen et al 2010). However, no emission is seen in its direction at 20 cm on the MAGPIS image.…”

Section: The Spectral Energy Distribution Fittingmentioning

confidence: 94%

Star formation triggered by H II regions in our Galaxy

Zavagno¹,

Anderson²,

Russeil³

et al. 2010

A&A

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Context. It has been shown that by means of different physical mechanisms the expansion of H ii regions can trigger the formation of new stars of all masses. This process may be important to the formation of massive stars but has never been quantified in the Galaxy. Aims. We use Herschel-PACS and -SPIRE images from the Herschel infrared survey of the Galactic plane, Hi-GAL, to perform this study. Methods. We combine the Spitzer-GLIMPSE and -MIPSGAL, radio-continuum and submillimeter surveys such as ATLASGAL with Hi-GAL to study young stellar objects (YSOs) observed towards Galactic H ii regions. We select a representative H ii region, N49, located in the field centered on l = 30 • observed as part of the Hi-GAL science demonstration phase, to demonstrate the importance Hi-GAL will have to this field of research. Results. Hi-GAL PACS and SPIRE images reveal a new population of embedded young stars, coincident with bright ATLASGAL condensations. The Hi-GAL images also allow us, for the first time, to constrain the physical properties of the newly formed stars by means of fits to their spectral energy distribution. Massive young stellar objects are observed at the borders of the N49 region and represent second generation massive stars whose formation has been triggered by the expansion of the ionized region. Conclusions. The first Hi-GAL images obtained using PACS and SPIRE have demonstrated the capability to investigate star formation triggered by H ii regions. With radio, submillimeter, and shorter wavelength infrared data from other surveys, the Hi-GAL images reveal young massive star-forming clumps surrounding the perimeter of the N49 H ii generated bubble. Hi-GAL enables us to detect a population of young stars at different evolutionary stages, cold condensations only being detected in the SPIRE wavelength range. The far IR coverage of Hi-GAL strongly constrains the physical properties of the YSOs. The large and unbiased spatial coverage of this survey offers us a unique opportunity to lead, for the first time, a global study of star formation triggered by H ii regions in our Galaxy.

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“…As such, each pairing of these maser species, one for each of the three radio continuum sources in SDC335, is indicative of the position of a forming massive star. Class I CH 3 OH masers have been found to trace the larger scale molecular outflows of protostellar systems (Kurtz et al 2004;Cyganowski et al 2009). Two of the four class I CH 3 OH maser spots in SDC335 inhabit the blue outflow arm originating from MM1a.…”

Section: Results and Analysismentioning

confidence: 99%

Tightening the belt: Constraining the mass and evolution in SDC335

Avison

Peretto

Fuller

et al. 2015

A&A

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Aims. Recent ALMA observations identified one of the most massive star-forming cores yet observed in the Milky Way: SDC335-MM1, within the infrared dark cloud SDC335.579-0.292. Along with an accompanying core MM2, SDC335 appears to be in the early stages of its star formation process. We aim to constrain the properties of the stars forming within these two massive millimetre sources. Methods. Observations of SDC335 at 6, 8, 23 and 25 GHz were made with the Australia Telescope Compact Array. We report the results of these continuum measurements, which combined with archival data, allow us to build and analyse the spectral energy distributions (SEDs) of the compact sources in SDC335. Results. Three hyper-compact H regions within SDC335 are identified, two of which are within the MM1 core. For each HCH region, we fit a free-free emission curve to the data, providing the derivation of the sources' emission measure, ionising photon flux, and electron density. Using these physical properties we assign each HCH region a zero-age main sequence (ZAMS) spectral type, finding two protostars with characteristics of spectral type B1.5 and one with a lower limit of B1-B1.5. Ancillary data from infrared to mm wavelength are used to construct free-free component subtracted SEDs for the mm-cores, which allows us to calculate the bolometric luminosities and revise the previous gas mass estimates. Conclusions. The measured luminosities for the two mm-cores are lower than expected from accreting sources displaying characteristics of the ZAMS spectral type assigned to them. The protostars are still actively accreting, suggesting that a mechanism is limiting the accretion luminosity. We present the case for two different mechanisms capable of causing lower than expected accretion luminosity. Finally, using the ZAMS mass values as lower limit constraints, a final stellar population for SDC335 was synthesised finding SDC335 is likely to be in the process of forming a stellar cluster comparable to the Trapezium cluster and NGC 6334 I(N).

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A CLASS I AND CLASS II CH₃OH MASER SURVEY OF EGOs FROM THE GLIMPSE SURVEY

Cited by 244 publications

References 103 publications

SMA observations of the W3(OH) complex: Dynamical differentiation between W3(H₂O) and W3(OH)

SMA observations of the W3(OH) complex: Dynamical differentiation between W3(H₂O) and W3(OH)

Star formation triggered by H II regions in our Galaxy

Tightening the belt: Constraining the mass and evolution in SDC335

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A CLASS I AND CLASS II CH3OH MASER SURVEY OF EGOs FROM THE GLIMPSE SURVEY

Cited by 244 publications

References 103 publications

SMA observations of the W3(OH) complex: Dynamical differentiation between W3(H2O) and W3(OH)

SMA observations of the W3(OH) complex: Dynamical differentiation between W3(H2O) and W3(OH)

Star formation triggered by H II regions in our Galaxy

Tightening the belt: Constraining the mass and evolution in SDC335

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Resources

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A CLASS I AND CLASS II CH₃OH MASER SURVEY OF EGOs FROM THE GLIMPSE SURVEY

SMA observations of the W3(OH) complex: Dynamical differentiation between W3(H₂O) and W3(OH)

SMA observations of the W3(OH) complex: Dynamical differentiation between W3(H₂O) and W3(OH)