Observations of NH<sub>3</sub> in Southern Sources

Batchelor, R.; Gardner, F. F.; Knowles, S. H.; Mebold, U.

doi:10.1017/s1323358000015186

Cited by 6 publications

(5 citation statements)

References 11 publications

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“…In the absence of MALT90, we use the molecular line information from earlier single pointing observations. The molecular line velocity is −12.0 km/s for CO and −11.7 km/s for CS observations, towards G351.63-1.25 (Batchelor et al 1977;Whiteoak, Otrupcek & Rennie 1982). However, being single dish and single pointing observations, its is difficult to segregate the emission from A and B regions.…”

Section: Bipolar Nature Of G35163-125mentioning

confidence: 91%

“…Detection of C172α emission towards outer regions where there is weak or no radio continuum emission suggests that these originate within regions whose physical properties such as ne, Te and emission measure (EM) are different from that of the PIM surrounding the H II region (e.g., Kantharia, Anantharamaiah & Goss 1998). From the molecular line data, the velocity of molecular cloud is estimated as ∼ −12 km/s (Batchelor et al 1977;Gardner & Whiteoak 1978).…”

Section: G35163-125mentioning

confidence: 99%

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Gas kinematics in the H ii regions G351.69-1.15 and G351.63-1.25

Veena

Vig

Tej

et al. 2016

Mon. Not. R. Astron. Soc.

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We probe the structure and kinematics of two neighbouring H II regions identified as cometary and bipolar, using radio recombination lines (RRL). The H172α RRLs from these H II regions: G351.69-1.15 and G351.63-1.25, are mapped using GMRT, India. We also detect carbon RRLs C172α towards both these regions. The hydrogen RRLs display the effects of pressure and dynamical broadening in the line profiles, with the dynamical broadening (∼ 15 km/s) playing a major role in the observed profile of G351.69-1.15. We investigate the kinematics of molecular gas species towards this H II region from the MALT90 pilot survey. The molecular gas is mostly distributed towards the north and north-west of the cometary head. The molecular line profiles indicate signatures of turbulence and outflow in this region. The ionized gas at the cometary tail is blue shifted by ∼8 km/s with respect to the ambient molecular cloud, consistent with the earlier proposed champagne flow scenario. The relative velocity of ∼5 km/s between the northern and southern lobes of the bipolar H II region G351.63-1.25 is consistent with the premise that the bipolar morphology is a result of the expanding ionized lobes within a flat molecular cloud.

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Section: Bipolar Nature Of G35163-125mentioning

confidence: 91%

Section: G35163-125mentioning

confidence: 99%

Gas kinematics in the H ii regions G351.69-1.15 and G351.63-1.25

Veena

Vig

Tej

et al. 2016

Mon. Not. R. Astron. Soc.

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“…The associated molecular cloud was detected by Gillespie et al (1977) during their observations of southern Galactic H ii regions in the transition of CO. Similarly, interstellar molecules like OH (Caswell & Haynes 1975), H 2 O (Kaufmann et al 1977), NH 3 (Batchelor et al 1977), CS (Gardner & Whiteoak 1978) and H 2 CO (Gardner & Whiteoak 1984) were detected towards this region, indicating extremely dense molecular material. Several maser sources in the lines of H 2 O (Batchelor et al 1980; Braz & Scalise 1982; Braz et al 1989; Scalise, Rodriguez & Mendoza‐Torres 1989), OH (Caswell, Haynes & Goss 1980) and methanol (Macleod & Gaylard 1992; Schutte et al 1993; Caswell et al 1995; van der Walt, Gaylard & Macleod 1995; van der Walt et al 1996; Ellingsen et al 1996; Macleod et al 1998) have been detected towards this complex in independent surveys and observations towards selected IRAS sources.…”

Section: Introductionmentioning

confidence: 89%

Study of star formation in RCW 106 using far-infrared observations

Karnik

Ghosh

Rengarajan

et al. 2001

Monthly Notices of the Royal Astronomical Society

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High‐resolution far‐infrared observations of a large area of the star‐forming complex RCW 106 obtained using the TIFR 1‐m balloon‐borne telescope are presented. Intensity maps have been obtained simultaneously in two bands centred around 150 and 210 μm. Intensity maps have also been obtained in the four IRAS bands using HIRES‐processed IRAS data. From the 150‐ and 210‐μm maps, reliable maps of dust temperature and optical depth have been generated. The star formation in this complex has occurred in five linear sub‐clumps. Using the map at 210 μm, which has a spatial resolution superior to that of IRAS at 100 μm, 23 sources have been identified. The spectral energy distribution (SED) and luminosity of these sources have been determined using the associations with the IRAS maps. The luminosity distribution of these sources has been obtained. Assuming these embedded sources to be zero‐age main‐sequence stars and using the mass–luminosity relation for these, the power‐law slope of the initial mass function is found to be −1.73±0.5. This index for this very young complex is about the same as that for more evolved complexes and clusters. Radiation transfer calculations in spherically symmetric geometry have been undertaken to fit the SEDs of 13 sources with fluxes in both the TIFR and the IRAS bands. From this, the r−2 density distribution in the envelopes is ruled out. Finally, a correlation is seen between the luminosity of embedded sources and the computed dust masses of the envelopes.

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“…In addition to the IRAS maps at the mid and far-infrared wavebands, far-infrared (FIR) balloon-borne observations (1 ′ angular resolution) of the dust continuum at 150 and 210 µm (Karnik et al 2001) identified 23 emission peaks with dust temperatures between 20 and 40 K. Largescale CO(1-0) observations by Bronfman et al (1989) with an angular resolution of 9 ′ obtained a global view of the molecular gas distribution in this region. However most of the remaining spectroscopic observations toward this GMC are primarily pointed mode observations of the emissions of the lines of CO (Gillespie et al 1977;Brand et al 1984), CS (Gardner & Whiteoak 1978;Bronfman et al 1996), H 2 CO (Gardner & Whiteoak 1984), NH 3 (Batchelor et al 1977), H 2 O, OH and methanol masers (Braz & Epchtein 1983;Caswell 1997;Walsh, Hyland, Robinson, & Burton 1997) toward predetected H  regions and IRAS sources. These observations suggest ongoing high-mass star formation activity and enhanced density cores associated with most of the strong emission peaks.…”

Section: Introductionmentioning

confidence: 99%

The Giant Molecular Cloud associated with RCW 106

Mookerjea¹,

Krämer²,

Nielbock

et al. 2004

A&A

151

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Abstract.We have mapped the dust continuum emission from the molecular cloud covering a region of 28 pc × 94 pc associated with the well-known H  region RCW 106 at 1.2 mm using SIMBA on SEST. The observations, having an HPBW of 24 (0.4 pc), reveal 95 clumps, of which about 50% have MSX associations and only 20% have IRAS associations. Owing to their higher sensitivity to colder dust and higher angular resolution the present observations identify new emission features and also show that most of the IRAS sources in this region consist of multiple dust emission peaks. The detected millimeter sources (MMS) include on one end the exotic MMS5 (associated with IRAS 16183-4958, one of the brightest infrared sources in our Galaxy) and the bright (and presumably cold) source MMS54, with no IRAS or MSX associations on the other end. Around 10% of the sources are associated with signposts of high mass star formation activity. Assuming a uniform dust temperature of 20 K we estimate the total mass of the GMC associated with RCW 106 to be ∼10 5 M . The constituent millimeter clumps cover a range of masses and radii between 40 to 10 4 M and 0.3 to 1.9 pc. Densities of the clumps range between (0.5-6) ×10 4 cm −3 . We have decomposed the continuum emission into Gaussian and arbitrary shaped clumps using the two independent structure analysis tools gaussclumps and clumpfind respectively. The clump mass spectrum was found to have an index α of 1.6 ± 0.3, independent of the decomposition algorithm used. The index of the mass spectrum for the mass and length scales covered here are consistent with results derived from large scale CO observations.

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Observations of NH₃ in Southern Sources

Cited by 6 publications

References 11 publications

Gas kinematics in the H ii regions G351.69-1.15 and G351.63-1.25

Gas kinematics in the H ii regions G351.69-1.15 and G351.63-1.25

Study of star formation in RCW 106 using far-infrared observations

The Giant Molecular Cloud associated with RCW 106

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Observations of NH3 in Southern Sources

Cited by 6 publications

References 11 publications

Gas kinematics in the H ii regions G351.69-1.15 and G351.63-1.25

Gas kinematics in the H ii regions G351.69-1.15 and G351.63-1.25

Study of star formation in RCW 106 using far-infrared observations

The Giant Molecular Cloud associated with RCW 106

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Observations of NH₃ in Southern Sources