The environs of the ultracompact HII region G45.45+0.06

Paron, S.; Cichowolski, Silvina; Ortega, M. E.

doi:10.1051/0004-6361/200912646

Cited by 12 publications

(14 citation statements)

References 36 publications

(56 reference statements)

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“…In previous studies toward several H II regions (e.g., Zavagno et al 2006;Deharveng et al 2008;Paron et al 2009Paron et al , 2011Pomarès et al 2009;Dirienzo et al 2012), an initial number density of ∼10 3 cm −3 was determined. Alexander et al (2013) Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Collect and collapse (CC) and radiatively driven implosion (RDI) mechanisms may trigger star formation on the borders of H II regions (Elmegreen 1998). Several pieces of observational evidence have been found supporting these star FITS data cubes for 12 CO, 13 CO, and C 18 O are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/559/A113 formation mechanisms (e.g., Zavagno et al 2007;Deharveng et al 2008;Paron et al 2009;Tibbs et al 2012). Therefore, a detailed study of the star-forming regions at various wavebands is necessary to trace the star formation scenario of H II region environments.…”

Section: Introductionmentioning

confidence: 99%

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Triggered massive and clustered star formation by combined H II regions G38.91-0.44 and G39.30-1.04

Xu¹,

Wang²,

Liu³

2013

A&A

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Aims. We investigate the triggered star formation occurring in the infrared dark clouds (IRDC) G38.95-0.47 between H II regions G38.91-0.44 and G39.30-1.04, and study the detailed morphology, distribution, and physical parameters of the molecular gas and dust in this region. Methods. We present the radio continuum, infrared, and CO molecular observations of IRDC G38.95-0.47 and its adjacent H II regions G38.91-0.44 (N74), G38.93-0.39 (N75), and G39.30-1.04. The Purple Mountain Observation (PMO) 13.7 m radio telescope was used to detect 12 CO J = 1−0, 13 CO J = 1−0 and C 18 O J = 1−0 lines. The carbon monoxide (CO) molecular observations can ensure the real association between the ionized gas and the neutral material observed nearby. To select young stellar objects (YSOs) associated this region, we used the GLIMPSE I catalog. Results. The 13 CO J = 1−0 emission presents two large cloud clumps. The clump consistent with IRDC G38.95-0.47 shows a triangle-like shape, and has a steep integrated-intensity gradient toward H II regions G38.91-0.44 and G39.30-1.04, suggesting that the two H II regions have expanded into the IRDC. Four submillmeter continuum sources have been detected in the IRDC G38.95-0.47. Only the G038.95-00.47-M1 source with a mass of 117 M has outflow and infall motions, indicating a newly forming massive star. We detected a new collimated outflow in the clump compressed by G38.93-0.39. The derived ages of the three H II regions are 6.1 × 10 5 yr, 2.5 × 10 5 yr, and 9.0 × 10 5 yr, respectively. In the IRDC G38.95-0.47, the significant enhancement of several Class I YSOs indicates the presence of some recently formed stars. Comparing the ages of these H II regions with YSOs (Class I sources and massive G038.95-00.47-M1 source), we suggest that YSOs may be triggered by G38.91-0.44 and G39.30-1.04 together, which supports the radiatively driven implosion model. It may be the first time that the triggered star formation has occurred in the IRDC compressed by two H II regions. The new detected outflow may be driven by a star cluster.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Triggered massive and clustered star formation by combined H II regions G38.91-0.44 and G39.30-1.04

Xu¹,

Wang²,

Liu³

2013

A&A

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“…Our main BLAST detections corresponding to G045.39−00.76 are associated with a bubble (Churchwell et al 2006), separate from the main clouds of the field, and we therefore omit these sources from the main analysis. A common distance of ∼ 7 kpc (1 • ∼ 0.1 kpc scale) is assumed in the present study (in contrast with those used by previous authors of ∼ 6 and ∼ 8 kpc; e.g., Simon et al 2001;Kraemer et al 2003;Paron et al 2009).…”

Section: Distance Estimationmentioning

confidence: 92%

“…A28 is close to the most active region in the cloud as observed in the MIR (G45.45+0.06 [G45.45]), although from its position and extended morphology the submm emission may also be tracing the compressed and extended molecular gas. G45.45 (also a MYSO candidate in the RMS Survey; e.g., Mottram et al 2010) has been observed to lie in the border of a larger and fainter H II region ∼ 3 ′ in size (G45L; Paron et al 2009). Although this structure is also traced by the BLAST images, it has not been included in our photometry/radio analysis.…”

Section: G4545mentioning

confidence: 99%

THE BLAST VIEW OF THE STAR-FORMING REGION IN AQUILA (ℓ = 45°,b= 0°)

Rivera-Ingraham

Bock

Chapin

et al. 2010

ApJ

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We have carried out the first general submillimeter analysis of the field towards GRSMC 45.46+0.05, a massive star forming region in Aquila. The deconvolved 6 deg 2 (3 • ×2 • ) maps provided by BLAST in 2005 at 250, 350, and 500 µm were used to perform a preliminary characterization of the clump population previously investigated in the infrared, radio, and molecular maps. Interferometric COR-NISH data at 4.8 GHz have also been used to characterize the Ultracompact H II regions (UCHiiRs) within the main clumps. By means of the BLAST maps we have produced an initial census of the submillimeter structures that will be observed by Herschel, several of which are known Infrared Dark Clouds (IRDCs). Our spectral energy distributions of the main clumps in the field, located at ∼ 7 kpc, reveal an active population with temperatures of T ∼ 35-40 K and masses of ∼ 10 3 M ⊙ for a dust emissivity index β = 1.5. The clump evolutionary stages range from evolved sources, with extended H II regions and prominent IR stellar population, to massive young stellar objects, prior to the formation of an UCHiiR. The CORNISH data have revealed the details of the stellar content and structure of the UCHiiRs. In most cases, the ionizing stars corresponding to the brightest radio detections are capable of accounting for the clump bolometric luminosity, in most cases powered by embedded OB stellar clusters.

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“…Taking the distance of ∼4 kpc to Sh2-104 (Deharveng et al 2003), the H II region radius is 4.4 pc. As a rough estimate, n 0 can be determined by distributing the total molecular mass over a sphere (e.g., Zavagno et al 2007;Paron et al 2009;Cichowolski et al 2009;Anderson et al 2015;Duronea et al 2015). The mass of the ring is ∼2.2×10 4 M .…”

Section: Star Formation Scenariomentioning

confidence: 99%

Two-dimensional Molecular Gas and Ongoing Star Formation around H ii Region Sh2-104

et al. 2017

ApJ

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We performed a multiwavelength study towards H II region Sh2-104. New maps of 12 CO J=1-0 and 13 CO J=1-0 were obtained from the Purple Mountain Observatory (PMO) 13.7 m radio telescope. Sh2-104 displays a double-ring structure. The outer ring with a radius of 4.4 pc is dominated by 12 µm, 500 µm, 12 CO J=1-0, and 13 CO J=1-0 emission, while the inner ring with a radius of 2.9 pc is dominated by 22 µm and 21 cm emission. We did not detect CO emission inside the outer ring. The north-east portion of the outer ring is blueshifted, while the south-west portion is redshifted. The present observations have provided evidence that the collected outer ring around Sh2-104 is a twodimensional structure. From the column density map constructed by the Hi-GAL survey data, we extract 21 clumps. About 90% of all the clumps will form low-mass stars. A power-law fit to the clumps yields M = 281M (r/pc) 1.31±0.08 . The selected YSOs are associated with the collected material on the edge of Sh2-104. The derived dynamical age of Sh2-104 is 1.6×10 6 yr. Compared the Sh2-104 dynamical age with the YSOs timescale and the fragmentation time of the molecular ring, we further confirm that collect-and-collapse process operates in this region, indicating a positive feedback from a massive star for surrounding gas.

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The environs of the ultracompact HII region G45.45+0.06

Cited by 12 publications

References 36 publications

Triggered massive and clustered star formation by combined H II regions G38.91-0.44 and G39.30-1.04

Triggered massive and clustered star formation by combined H II regions G38.91-0.44 and G39.30-1.04

THE BLAST VIEW OF THE STAR-FORMING REGION IN AQUILA (ℓ = 45°,b= 0°)

Two-dimensional Molecular Gas and Ongoing Star Formation around H ii Region Sh2-104

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