Far-infrared and CO observations of the W33 complex

Stier, M. T.; Jaffe, D. T.; Rengarajan, T. N.; Fazio, G. G.; Maxson, C. W.; McBreen, B.; Loughran, L.; Serio, S.; Sciortino, S.

doi:10.1086/162342

Cited by 30 publications

(22 citation statements)

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“…While the temperatures of both components are similar for all sources, the luminosity covers a wide range of values from 6 × 10 3 L in W33 A1 to 4.5 × 10 5 L in W33 Main. The total bolometric luminosity of the W33 complex is 5.5 × 10 5 L which is only slightly smaller than the revised value (8 × 10 5 L ) of Stier et al (1984). The spectral emissivity index quantifies the frequency-dependence of the emissivity in the Rayleigh-Jeans part of the spectrum (Dent et al 1998).…”

Section: Dust Temperatures and Cloud Massesmentioning

confidence: 77%

“…Revising the results of Stier et al (1984) for a distance of 2.4 kpc, the W33 complex has a total bolometric luminosity of ∼8 × 10 5 L . Haschick & Ho (1983) detected the radio continuum emission of a cluster of zero age main sequence stars with spectral types between O7.5 and B1.5 (revised for a distance of 2.4 kpc) in W33 Main.…”

Section: The W33 Complexmentioning

confidence: 91%

“…Another infrared source was observed in W33 A with deep absorption features at 3 and 10 μm (Dyck & Simon 1977;Capps et al 1978;de Wit et al 2010). Stier et al (1984) conducted far-infrared observations of W33 at 40-250 μm and detected four sources in the complex (W33 B, W33 B1, W33 Main, and W33 A). In the center of W33 Main, infrared emission peaks at 3.6−8 μm and at 70−500 μm are observed in the Spitzer/GLIMPSE and the Herschel/Hi-GAL maps (Figs.…”

Section: The W33 Complexmentioning

confidence: 99%

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Diversity of chemistry and excitation conditions in the high-mass star forming complex W33

Immer

Galván-Madrid

König

et al. 2014

A&A

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The object W33 is a giant molecular cloud that contains star forming regions at various evolutionary stages from quiescent clumps to developed H ii regions. Since its star forming regions are located at the same distance and the primary material of the birth clouds is probably similar, we conducted a comparative chemical study to trace the chemical footprint of the different phases of evolution. We observed six clumps in W33 with the Atacama Pathfinder Experiment (APEX) telescope at 280 GHz and the Submillimeter Array (SMA) at 230 GHz. We detected 27 transitions of 10 different molecules in the APEX data and 52 transitions of 16 different molecules in the SMA data. The chemistry on scales larger than ∼0.2 pc, which are traced by the APEX data, becomes more complex and diverse the more evolved the star forming region is. On smaller scales traced by the SMA data, the chemical complexity and diversity increase up to the hot core stage. In the H ii region phase, the SMA spectra resemble the spectra of the protostellar phase. Either these more complex molecules are destroyed or their emission is not compact enough to be detected with the SMA. Synthetic spectra modelling of the H 2 CO transitions, as detected with the APEX telescope, shows that both a warm and a cold component are needed to obtain a good fit to the emission for all sources except for W33 Main1. The temperatures and column densities of the two components increase during the evolution of the star forming regions. The integrated intensity ratios N 2 H + (3−2)/CS(6−5) and N 2 H + (3−2)/H 2 CO(4 2,2 -3 2,1 ) show clear trends as a function of evolutionary stage, luminosity, luminosity-to-mass ratio, and H 2 peak column density of the clumps and might be usable as chemical clocks.

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Section: Dust Temperatures and Cloud Massesmentioning

confidence: 77%

Section: The W33 Complexmentioning

confidence: 91%

Section: The W33 Complexmentioning

confidence: 99%

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Diversity of chemistry and excitation conditions in the high-mass star forming complex W33

Immer

Galván-Madrid

König

et al. 2014

A&A

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“…The total IR luminosity of G12.81-0.19 assuming a distance of 3.7 kpc is 1.4 × 10 6 L (Stier et al 1984). According to the results of Stier et al the minimum mass of the star associated with the radio core is 20 M .…”

Section: W33mentioning

confidence: 89%

SiO and CH₃CCH abundances and dust emission in high-mass star-forming cores

Miettinen

Harju

Haikala

et al. 2006

A&A

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Aims. We determine the fractional SiO abundance in high-mass star-forming cores, and investigate its dependence on physical conditions, to provide constraints on the chemistry models of the formation of SiO in the gas phase or via grain mantle evaporation. The work addresses also CH 3 CCH chemistry, as the kinetic temperature is determined using this molecule. Methods. We estimate the physical conditions of 15 high-mass star-forming cores and derive the fractional SiO and CH 3 CCH abundances using spectral line and dust continuum observations with the SEST. Results. The kinetic temperatures as derived from CH 3 CCH range from 25 to 39 K, the average being 33 K. The average gas density in the cores is 4.5 × 10 6 cm −3 . The SiO emission regions are extended and typically half of the integrated line emission comes from the velocity range traced out by CH 3 CCH emission. The upper limit of SiO abundance in this "quiescent" gas component is ∼10 −10 . The average CH 3 CCH abundance is about 7 × 10 −9 . It shows a shallow, positive correlation with the temperature, whereas SiO shows the opposite tendency. Conclusions. We suggest that the high CH 3 CCH abundance and its possible increase when the clouds become warmer is related to the intensified desorption of the chemical precursors of the molecule from grain surfaces. In contrast, the observed tendency of SiO does not support the idea that the evaporation of Si-containing species from the grain mantles would be important, and it contradicts models where neutral reactions with activation barriers dominate SiO production. A possible explanation for the decrease is that warmer cores represent more evolved stages of core evolution with fewer high-velocity shocks and thus less efficient SiO replenishment.

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“…W33−Met. W33 is a giant and well studied HII region (Goldsmith & Mao 1983;Stier et al 1984). The region contains H 2 O and OH masers and far-infrared sources.…”

Section: S235b (Ggd 5)mentioning

confidence: 99%

Survey of bipolar outflows and methanol masers in the C³²S ($2-1)$ and C³⁴S (2-1) lines in the Northern sky

Larionov

Вальтц

Winnberg

et al. 1999

Astron. Astrophys. Suppl. Ser.

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Abstract.A survey of 158 sources (bipolar outflows and methanol masers) was carried out in the CS(2 − 1) and C 34 S(2 − 1) lines to measure and compare densities in a large number of bipolar outflows and in Class I and Class II methanol masers, both associated with and unrelated to bipolar outflows. The statistical characteristics of the regions, forming Class I methanol masers differ from those both in the centres of bipolar outflows and in the regions forming Class II methanol masers. It is possible that physical conditions in bipolar outflows are closer to physical conditions of Class II methanol masers.

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Far-infrared and CO observations of the W33 complex

Cited by 30 publications

References 0 publications

Diversity of chemistry and excitation conditions in the high-mass star forming complex W33

Diversity of chemistry and excitation conditions in the high-mass star forming complex W33

SiO and CH₃CCH abundances and dust emission in high-mass star-forming cores

Survey of bipolar outflows and methanol masers in the C³²S ($2-1)$ and C³⁴S (2-1) lines in the Northern sky

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Far-infrared and CO observations of the W33 complex

Cited by 30 publications

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Diversity of chemistry and excitation conditions in the high-mass star forming complex W33

Diversity of chemistry and excitation conditions in the high-mass star forming complex W33

SiO and CH3CCH abundances and dust emission in high-mass star-forming cores

Survey of bipolar outflows and methanol masers in the C32S ($2-1)$ and C34S (2-1) lines in the Northern sky

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Product

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About

SiO and CH₃CCH abundances and dust emission in high-mass star-forming cores

Survey of bipolar outflows and methanol masers in the C³²S ($2-1)$ and C³⁴S (2-1) lines in the Northern sky