The VLA Galactic Plane Survey

Stil, J. M.; Taylor, A. R.; Dickey, John M.; Kavars, D. W.; Martín, P. G.; Rothwell, Timothy A.; Boothroyd, Arnold I.; Lockman, Felix J.; McClure-Griffiths, N. M.

doi:10.1086/505940

Cited by 386 publications

(452 citation statements)

References 14 publications

(19 reference statements)

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“…Here, we use the distance estimations by Roman-Duval et al (2009), who utilized Hi self absorption from the VGPS project (Stil et al 2006). It is possible to associate several entries of their extensive catalog with clouds we found in our dataset.…”

Section: Determination Of the Distance Of W43mentioning

confidence: 99%

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Large scale IRAM 30 m CO-observations in the giant molecular cloud complex W43

Carlhoff

Luong

Schilke

et al. 2013

A&A

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We aim to fully describe the distribution and location of dense molecular clouds in the giant molecular cloud complex W43. It was previously identified as one of the most massive star-forming regions in our Galaxy. To trace the moderately dense molecular clouds in the W43 region, we initiated W43-HERO, a large program using the IRAM 30 m telescope, which covers a wide dynamic range of scales from 0.3 to 140 pc. We obtained on-the-fly-maps in 13 CO (2-1) and C 18 O (2-1) with a high spectral resolution of 0.1 km s −1 and a spatial resolution of 12 . These maps cover an area of ∼1.5 square degrees and include the two main clouds of W43 and the lower density gas surrounding them. A comparison to Galactic models and previous distance calculations confirms the location of W43 near the tangential point of the Scutum arm at approximately 6 kpc from the Sun. The resulting intensity cubes of the observed region are separated into subcubes, which are centered on single clouds and then analyzed in detail. The optical depth, excitation temperature, and H 2 column density maps are derived out of the 13 CO and C 18 O data. These results are then compared to those derived from Herschel dust maps. The mass of a typical cloud is several 10 4 M while the total mass in the dense molecular gas (>10 2 cm −3 ) in W43 is found to be ∼1.9 × 10 6 M . Probability distribution functions obtained from column density maps derived from molecular line data and Herschel imaging show a log-normal distribution for low column densities and a power-law tail for high densities. A flatter slope for the molecular line data probability distribution function may imply that those selectively show the gravitationally collapsing gas.

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Section: Determination Of the Distance Of W43mentioning

confidence: 99%

“…In Sect. 3, we present the resulting line - (Stil et al 2006) integrated and PV-maps and a list of clouds that were separated using the Duchamp Sourcefinder software (Whiting 2012). We also show the velocity structure of the complex and determine its position in the Milky Way in Sect.…”

Section: Introductionmentioning

confidence: 99%

Large scale IRAM 30 m CO-observations in the giant molecular cloud complex W43

Carlhoff

Luong

Schilke

et al. 2013

A&A

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“…In addition we used HI data with an angular resolution of ∼1 extracted from the VLA Galactic Plane Survey (VGPS; Stil et al 2006) and radio continuum data extracted from the NRAO VLA Sky Survey (NVSS) with an angular resolution of ∼45 (Condon et al 1998). 3. Presentation of G35.673-00.847 (G35.6) Figure 1 shows two composite three-color images of G35.6.…”

Section: Datamentioning

confidence: 99%

The HII region G35.673-00.847: another case of triggered star formation?

Paron

Petriella

Ortega

2010

A&A

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Aims. As part of a systematic study that we are performing to increase the observational evidence of triggered star formation in the surroundings of HII regions, we analyze the ISM around the HII region G35.673-00.847, a poorly studied source. Methods. Using data from the large-scale surveys Two Micron All Sky Survey, Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE), MIPSGAL, Galactic Ring Survey (GRS), VLA Galactic Plane Survey (VGPS), and NRAO VLA Sky Survey (NVSS), we performed a multiwavelength study of G35.673-00.847 and its surroundings. Results. The mid-IR emission shows that G35.673-00.847 has an almost semi-ring like shape with a cut towards the galactic west. The radius of this semi-ring is about 1. 5 (∼1.6 pc, at the distance of ∼3.7 kpc). The distance was estimated from an HI absorption study and the analysis of the molecular gas. We find a molecular shell composed of several clumps distributed around the HII region, suggesting that its expansion is collecting the surrounding material. We identify several YSO candidates across the molecular shell. Finally, comparing the HII region dynamical age and the fragmentation time of the molecular shell, we discard the so-called collect and collapse as being the mechanism responsible for the YSO formation, suggesting that other processes such as radiative-driven implosion and/or small-scale Jeans gravitational instabilities operate.

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“…1) is in the same velocity range as the gas related to the UCHII complex where G45.45+0.06 is embedded, which may suggest that G45L is at the same distance as the UCHII complex. In order to prove this suggestion, using HI data extracted from the VLA Galactic Plane Survey (VGPS) (Stil et al 2006), we studied the absorption features towards two regions: the UCHII complex where G45.45+0.06 is embedded (Fig. 3-up) and the radio continuum structure enclosed by the north and middle PDR ( Fig.…”

Section: Distancementioning

confidence: 99%

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

Paron¹,

Cichowolski²,

Ortega³

2009

A&A

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Aims. G45.45+0.06 is an ultra-compact HII (UCHII) region that has been extensively studied. It is known that G45.45+0.06 is embedded in a complex of UCHII regions, but to date, the surrounding ISM on a larger spatial scale has not been analyzed. Methods. Using data from large-scale surveys, the Two Micron All Sky Survey, GLIMPSE, MIPSGAL, MAGPIS and GRS, we performed a multiwavelength study of a region of about 7 × 7 in the vicinity of G45.45+0.06. Results. We found that the UCHII complex lies on the border of a larger (diameter of ∼3 ) and fainter HII region, which is located at the same distance as G45.45+0.06, ∼8 kpc. In this work, this larger HII region is called G45L. A good morphological correlation is observed between the PDRs and the molecular gas mapped in the 13 CO J = 1−0 and CS J = 2−1 lines, suggesting that G45L may be collecting molecular material. From a near-and mid-IR photometric study, we found three sources, likely O-type stars, that are possibly responsible for the creation of G45L. Additionally, we found several YSO candidates lying preferentially in the molecular shell that surrounds G45L. Our results confirm that the region southeast of the UCHII complex where G45.45+0.06 is embedded and east of G45L is undergoing active star formation. We suggest that G45L has been expanding for about 2 × 10 6 yr and could have triggered the formation of the zero-age main sequence stars that ionize the UCHII region G45.45+0.06. However we cannot discard that both HII regions are coeval.

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The VLA Galactic Plane Survey

Cited by 386 publications

References 14 publications

Large scale IRAM 30 m CO-observations in the giant molecular cloud complex W43

Large scale IRAM 30 m CO-observations in the giant molecular cloud complex W43

The HII region G35.673-00.847: another case of triggered star formation?

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

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