Millimeter and Submillimeter Wavelength Continuum Observations of Massive Young Stellar Objects

McCutcheon, W. H.; Sato, Takehiko; Purton, C. R.; Matthews, H. E.; Dewdney, P. E.

doi:10.1086/117648

Cited by 34 publications

(41 citation statements)

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“…The region has several near IR and mid IR sources; the source of energy being close to IRS2. The size of this source at sub-mm wavelengths is ∼ 1 (McCutcheon et al 1995), consistent with the size for the best fit model. The mass of the envelope estimated by our model is not far from the estimate of Yamashita et al (1987), viz., 200M .…”

Section: Discussionsupporting

confidence: 81%

A new scheme of radiation transfer in HII regions including transient heating of grains

Ghosh

Verma

2000

J Astrophys Astron

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Abstract.A new scheme of radiation transfer for understanding infrared spectra of H II regions, has been developed. This scheme considers non-equilibrium processes (e.g. transient heating of the very small grains, VSG; and the polycyclic aromatic hydrocarbon, PAH) also, in addition to the equilibrium thermal emission from normal dust grains (BG). The spherically symmetric interstellar dust cloud is segmented into a large number of "onion skin" shells in order to implement the non-equilibrium processes. The scheme attempts to fit the observed SED originating from the dust component, by exploring the following parameters : (i) geometrical details of the dust cloud, (ii) PAH size and abundance, (iii) composition of normal grains (BG), (iv)

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Section: Discussionsupporting

confidence: 81%

A new scheme of radiation transfer in HII regions including transient heating of grains

Ghosh

Verma

2000

J Astrophys Astron

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“…Observations at mm and submm wavelengths have revealed two distinct clumps of dust continuum emission located several arcsecs northwest and southwest, respectively from the IRAS nominal position. This interpretation is supported by the two velocity components found in C 18 O spectra (McCutcheon et al 1995;Kelly & Mcdonald 1996). Kelly & McDonald (1996) suggest that the dust clumps probably contain the driving sources of the molecular outflows.…”

Section: A16 L379mentioning

confidence: 82%

Dense gas and the nature of the outflows

Sepúlveda

Anglada

Estalella

et al. 2011

A&A

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We present the results of the observations of the (J, K) = (1, 1) and the (J, K) = (2, 2) inversion transitions of the NH 3 molecule toward a large sample of 40 regions with molecular or optical outflows, using the 37 m radio telescope of the Haystack Observatory. We detected NH 3 emission in 27 of the observed regions, which we mapped in 25 of them. Additionally, we searched for the 6 16 −5 23 H 2 O maser line toward six regions, detecting H 2 O maser emission in two of them, HH265 and AFGL 5173. We estimate the physical parameters of the regions mapped in NH 3 and analyze for each particular region the distribution of high density gas and its relationship with the presence of young stellar objects. In particular, we identify the deflecting high-density clump of the HH270/110 jet. We were able to separate the NH 3 emission from the L1641-S3 region into two overlapping clouds, one with signs of strong perturbation, probably associated with the driving source of the CO outflow, and a second, unperturbed clump, which is probably not associated with star formation. We systematically found that the position of the best candidate for the exciting source of the molecular outflow in each region is very close to an NH 3 emission peak. From the global analysis of our data we find that in general the highest values of the line width are obtained for the regions with the highest values of mass and kinetic temperature. We also found a correlation between the nonthermal line width and the bolometric luminosity of the sources, and between the mass of the core and the bolometric luminosity. We confirm with a larger sample of regions the conclusion of Anglada et al. (1997) that the NH 3 line emission is more intense toward molecular outflow sources than toward sources with optical outflow, suggesting a possible evolutionary scheme in which young stellar objects associated with molecular outflows progressively lose their neighboring high-density gas, weakening both the NH 3 emission and the molecular outflow in the process, and making optical jets more easily detectable as the total amount of gas decreases.

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“…The associated radio continuum source, G25.65+1.05, has been observed at 3.6 cm (Kurtz et al 1994), at 6 cm (McCutcheon et al 1995) and at 3.5 cm (Walsh et al 1998). Its high emission measure (≥44 × 10 5 pc cm −6 ) and high electron density (≥15 × 10 3 cm −3 ) derived from the 6 cm observations show that this source is most probably an ultracompact H  region (see Sect.…”

Section: The Rafgl7009s Environmentmentioning

confidence: 89%

“…4.1). The resolved (diameter 3 ) 3.6 cm radio source McCutcheon et al 1995). A highly energetic molecular outflow is centred on G25.65+1.05 (Shepherd & Churchwell 1996).…”

Section: The Rafgl7009s Environmentmentioning

confidence: 99%

“…5 southwards of the radio source, and may be associated with the outflow (Lee et al 2001) or with a disk (de Buizer et al 2001). Flux measurements have been obtained at 350 µm (Hunter et al 2000), 450 µm, 800 µm and 1100 µm (McCutcheon et al 1995). The 10-1100 µm spectral energy distribution can be fitted by a two-component spherical distribution, a small warm component of diameter 5 (0.073 pc) with a temperature of 123 K and a cold component of diameter 20 (0.30 pc) and a temperature of 35 K (McCutcheon et al 1995; see also Hunter et al 2000).…”

Section: The Rafgl7009s Environmentmentioning

confidence: 99%

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Near-infrared imaging of RAFGL7009S

Zavagno¹,

Deharveng²,

Nadeau³

et al. 2002

A&A

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Abstract. RAFGL7009S is a deeply embedded massive young stellar objet (YSO) showing strong ice and saturated silicate absorption features in the mid infrared. It is associated with the ultracompact H  region G25.65+1.05, which may be excited by a B1V star. We have obtained JHK images of a 1 field centred on this YSO. In K we detect a non-resolved object coinciding with the radio continuum emission peak. Considering the high extinction towards this source (A V ≥ 100 mag), the observed K emission is more than 7 mag in excess of that expected for a B1V star. We suggest that this emission is mainly due to scattering of the central zone emission, as recently found for a sample of embedded massive YSOs associated with 3.1 µm H 2 O ice absorption (Ishii et al. 2002). We estimate the YSO's age to be 2×10 4 years. The outflow, the methanol maser emission and the strong ice absorption features suggest the presence of a dense medium very close to the star, possibly a disk.

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Millimeter and Submillimeter Wavelength Continuum Observations of Massive Young Stellar Objects

Cited by 34 publications

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A new scheme of radiation transfer in HII regions including transient heating of grains

A new scheme of radiation transfer in HII regions including transient heating of grains

Dense gas and the nature of the outflows

Near-infrared imaging of RAFGL7009S

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