High‐Resolution Far‐Infrared Observations and Models of the Star Formation Core of G34.3+0.2C

Campbell, M. F.; Harvey, P. M.; Lester, D. F.; Clark, David M.

doi:10.1086/379659

Cited by 10 publications

(8 citation statements)

References 55 publications

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“…It contains a group of UC H ii regions (G34.3+0.2 A, B, C; Campbell et al 2004) Six more masers associated with N67bis, N70, N71, N75, N79, and N91 were detected by Pandian et al (2007). This unbiased survey, carried out using the Arecibo radio telescope, is complete at the level of 0.27 Jy over the region l = 35.2 • to 53.7 • , |b| ≤ 0.41 • .…”

Section: Other Signposts Of Massive-star Formationmentioning

confidence: 99%

A gallery of bubbles

Deharveng

Schüller

Anderson

et al. 2010

A&A

359

584

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Context. This study deals with infrared bubbles, the H ii regions they enclose, and triggered massive-star formation on their borders.Aims. We attempt to determine the nature of the bubbles observed by Spitzer in the Galactic plane, mainly to establish if possible their association with massive stars. We take advantage of the very simple morphology of these objects to search for star formation triggered by H ii regions, and to estimate the importance of this mode of star formation.Methods. We consider a sample of 102 bubbles detected by Spitzer-GLIMPSE, and catalogued by Churchwell et al. (2006; hereafter CH06). We use mid-infrared and radio-continuum public data (respectively the Spitzer-GLIMPSE and -MIPSGAL surveys and the MAGPIS and VGPS surveys) to discuss their nature. We use the ATLASGAL survey at 870 μm to search for dense neutral material collected on their borders. The 870 μm data traces the distribution of cold dust, thus of the dense neutral material where stars may form. Results. We find that 86% of the bubbles contain ionized gas detected by means of its radio-continuum emission at 20-cm. Thus, most of the bubbles observed at 8.0 μm enclose H ii regions ionized by O-B2 stars. This finding differs from the earlier CH06 results (∼25% of the bubbles enclosing H ii regions). Ninety-eight percent of the bubbles exhibit 24 μm emission in their central regions. The ionized regions at the center of the 8.0 μm bubbles seem to be devoid of PAHs but contain hot dust. PAH emission at 8.0 μm is observed in the direction of the photodissociation regions surrounding the ionized gas. Among the 65 regions for which the angular resolution of the observations is high enough to resolve the spatial distribution of cold dust at 870 μm, we find that 40% are surrounded by cold dust, and that another 28% contain interacting condensations. The former are good candidates for the collect and collapse process, as they display an accumulation of dense material at their borders. The latter are good candidates for the compression of pre-existing condensations by the ionized gas. Thirteen bubbles exhibit associated ultracompact H ii regions in the direction of dust condensations adjacent to their ionization fronts. Another five show methanol masers in similar condensations. Conclusions. Our results suggest that more than a quarter of the bubbles may have triggered the formation of massive objects.Therefore, star formation triggered by H ii regions may be an important process, especially for massive-star formation.

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Section: Other Signposts Of Massive-star Formationmentioning

confidence: 99%

A gallery of bubbles

Deharveng

Schüller

Anderson

et al. 2010

A&A

359

584

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“…The cometary G34.26+0.15C is not only associated with a hot molecular core (Hunter et al 1998;Campbell et al 2004;Mookerjea et al 2007), but also has an infall motion (Liu et al 2013) indicating that UC H II complex G34.26+0.15 is an ongoing massive star formation region. Additionally, several infrared bubbles are located in region III.…”

Section: Star Formation Scenariomentioning

confidence: 99%

Gas Kinematics and Star Formation in the Filamentary Irdc G34.43+0.24

Zhang

et al. 2016

ApJ

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We performed a multiwavelength study toward the infrared dark cloud (IRDC) G34.43+0.24. New maps of 13 CO J = 1-0 and C 18 O J = 1-0 were obtained from the Purple Mountain Observatory (PMO) 13.7 m radio telescope. At 8 μm (Spitzer-IRAC), IRDC G34.43+0.24 appears to be a dark filament extended by 18′ along the north-south direction. Based on the association with the 870 μm and C 18 O J = 1-0 emission, we suggest that IRDC G34.43+0.24 should not be 18′ in length, but extend to 34′. IRDC G34.43+0.24 contains some massive protostars, UC H II regions, and infrared bubbles. The spatial extend of IRDC G34.43+0.24 is about 37 pc, assuming a distance of 3.7 kpc. IRDC G34.43+0.24 has a linear mass density of ∼1.6×103 M e pc −1 , which is roughly consistent with its critical mass to length ratio. The turbulent motion may help stabilize the filament against the radial collapse. Both infrared bubbles N61 and N62 show a ringlike structure at 8 μm. In particular, N61 has a double-shell structure that has expanded into IRDC G34.43+0.24. The outer shell is traced by 8 μm and 13 CO J = 1-0 emission, while the inner shell is traced by 24 μm and 20 cm emission. We suggest that the outer shell (9.9×10 5 years) is created by the expansion of H II region G34.172+0.175, while the inner shell (4.1∼6.3×10 5 years) may be produced by the energetic stellar wind of its central massive star. From the GLIMPSE I catalog, we selected some Class I sources with an age of ∼10 5 years. These Class I sources are clustered along the filamentary molecular cloud.

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“…This dust represents coagulated grains with ice mantles that would be expected to form from dust originally in the diffuse interstellar medium during the process of molecular cloud formation. It has been used to fit submm SEDs of high-mass protostellar cores (van der Tak et al 1999(van der Tak et al , 2000 and far-ir observations of the UC HII region G34.3+0.2 (Campbell et al 2004). However, when we examined its K(λ) behavior around 10 µm, we found that its silicate feature is shifted longward from 9.7 µm and broadened so that it does not appear to be compatible with our grism spectra.…”

Section: Overview Of a Simple Dust Continuum Modelmentioning

confidence: 99%

“…Deriving physical information from the continuum spectra is difficult because the actual geometry of the dust distribution is unknown, except that the sizes of the N band and 24.8 µm images limit the extent of the emitting structures. Experience with one-dimensional radiative transfer models of spectral energy distributions from UC HII regions (Campbell et al 1995(Campbell et al , 2000(Campbell et al , 2004, and inspection of the new spectra themselves suggest that there are ranges of temperatures in the emitting regions. However, the two-dimensional radiative transfer models of De Buizer et al (2005b) and Whitney et al (2003aWhitney et al ( ,b, 2004 show that orientation of flattened envelopes and outflow cavities dramatically affects the depth of the silicate absorption feature, as does emission and absorption by individual clumps in a clumpy dust cloud in the three-dimensional models of Indebetouw et al (2006).…”

Section: Introductionmentioning

confidence: 99%

Mid‐Infrared Photometry and Spectra of Three High‐Mass Protostellar Candidates at IRAS 18151−1208 and IRAS 20343+4129

Campbell

Sridharan

Beuther

et al. 2008

ApJ

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We present arcsecond-scale mid-ir photometry (in the 10.5 µm N band and at 24.8 µm), and low resolution spectra in the N band (R ≃ 100) of a candidate high mass protostellar object (HMPO) in IRAS 18151-1208 and of two HMPO candidates in IRAS 20343+4129, IRS 1 and IRS 3. In addition we present high resolution mid-ir spectra (R ≃ 80000) of the two HMPO candidates in IRAS 20343+4129. These data are fitted with simple models to estimate the masses of gas and dust associated with the mid-ir emitting clumps, the column densities of overlying absorbing dust and gas, the luminosities of the HMPO candidates, and the likely spectral type of the HMPO candidate for which [Ne II] 12.8 µm emission was detected (IRAS 20343+4129 IRS 3). We suggest that IRAS 18151-1208 is a pre-ultracompact HII region HMPO, IRAS 20343+4129 IRS 1 is an embedded young stellar object with the luminosity of a B3 star, and IRAS 20343+4129 IRS 3 is a B2 ZAMS star that has formed an ultracompact HII region and disrupted its natal envelope.

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High‐Resolution Far‐Infrared Observations and Models of the Star Formation Core of G34.3+0.2C

Cited by 10 publications

References 55 publications

A gallery of bubbles

A gallery of bubbles

Gas Kinematics and Star Formation in the Filamentary Irdc G34.43+0.24

Mid‐Infrared Photometry and Spectra of Three High‐Mass Protostellar Candidates at IRAS 18151−1208 and IRAS 20343+4129

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