ATLASGAL – compact source catalogue: 330°  &lt; <i>ℓ</i> &lt;  21°

Contreras, Y.; Schüller, F.; Urquhart, J. S.; Csengeri, T.; Wyrowski, F.; Beuther, H.; Bontemps, Sylvain; Bronfman, L.; Henning, Thomas; Menten, K. M.; Schilke, P.; Walmsley, C. M.; Wienen, M.; Tackenberg, J.; Linz, H.

doi:10.1051/0004-6361/201220155

Cited by 238 publications

(343 citation statements)

References 40 publications

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“…8 the velocity integrated 12 CO map and spectra from selected positions, i.e. the strongest submm-continuum sources from ATLASGAL (Contreras et al 2013;Csengeri et al 2014) and two positions off-source but within the cloud. The continuum sources were also observed in the optically thin N 2 H + 1→0 line at 93.173 GHz with a velocity resolution of 0.2 km s −1 (Tackenberg et al 2014), and the centre velocities reported in their Table 3 are indicated as a dashed blue line in Fig.…”

Section: Collapse Signatures In Molecular Line Profilesmentioning

confidence: 99%

Understanding star formation in molecular clouds

Schneider

Csengeri

Klessen

et al. 2015

A&A

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We analyse column density and temperature maps derived from Herschel dust continuum observations of a sample of prominent, massive infrared dark clouds (IRDCs) i.e. G11.11-0.12, G18.82-0.28, G28.37+0.07, and G28.53-0.25. We disentangle the velocity structure of the clouds using 13 CO 1→0 and 12 CO 3→2 data, showing that these IRDCs are the densest regions in massive giant molecular clouds (GMCs) and not isolated features. The probability distribution function (PDF) of column densities for all clouds have a power-law distribution over all (high) column densities, regardless of the evolutionary stage of the cloud: G11.11-0.12, G18.82-0.28, and G28.37+0.07 contain (proto)-stars, while G28.53-0.25 shows no signs of star formation. This is in contrast to the purely log-normal PDFs reported for near and/or mid-IR extinction maps. We only find a log-normal distribution for lower column densities, if we perform PDFs of the column density maps of the whole GMC in which the IRDCs are embedded. By comparing the PDF slope and the radial column density profile of three of our clouds, we attribute the power law to the effect of large-scale gravitational collapse and to local free-fall collapse of pre-and protostellar cores for the highest column densities. A significant impact on the cloud properties from radiative feedback is unlikely because the clouds are mostly devoid of star formation. Independent from the PDF analysis, we find infall signatures in the spectral profiles of 12 CO for G28.37+0.07 and G11.11-0.12, supporting the scenario of gravitational collapse. Our results are in line with earlier interpretations that see massive IRDCs as the densest regions within GMCs, which may be the progenitors of massive stars or clusters. At least some of the IRDCs are probably the same features as ridges (high column density regions with N > 10 23 cm −2 over small areas), which were defined for nearby IR-bright GMCs. Because IRDCs are only confined to the densest (gravity dominated) cloud regions, the PDF constructed from this kind of a clipped image does not represent the (turbulence dominated) low column density regime of the cloud.

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Section: Collapse Signatures In Molecular Line Profilesmentioning

confidence: 99%

Understanding star formation in molecular clouds

Schneider

Csengeri

Klessen

et al. 2015

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“…Derived values are 776.0, 1047.2, 499.5, 213.3, and 69.3 Jy at 70, 160, 250, 350, and 500 μm, respectively. Figure 7 shows the spectral energy distribution (SED), which also includes the flux density at 870 μm obtained by Contreras et al (2013;14.63 ± 2.47 Jy), and the best fit (obtained using a graybody), which corresponds to T dust = 28 ± 1 K. Dust temperature for G341.217-0.237 from an SED is difficult to determine. As a result of the poor angular resolution of the Herschel images at 350 and 500 μm, fluxes estimated from these data include part of S 24, which can give a false impression of the dust temperature.…”

Section: Distribution Of the Interstellar Dustmentioning

confidence: 99%

“…Adopting T dust = 28 ± 1 K for G341.220-0.213, and a flux S 870 = 14.63 ± 2.47 Jy derived by Contreras et al (2013) for AGAL341.217-00.212, a dust mass M dust1 = 12.9 ± 6.3 M can be estimated for G341.220-0.213. Assuming the same dust temperature for G341.217-0.237and a flux S 870 = 25.55 ± 4.11 Jy (for AGAL341.216-00.236), we estimate M dust2 = 22.4 ± 11.0 M .…”

Section: Distribution Of the Interstellar Dustmentioning

confidence: 99%

Molecular gas and star formation toward the IR dust bubble S 24 and its environs

Cappa

Duronea

Firpo

et al. 2015

A&A

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Aims. We present a multiwavelength analysis of the infrared dust bubble S 24 and the extended IR sources G341.220-0.213 and G341.217-0.237 located in its environs. We aim to investigate the characteristics of the molecular gas and the interstellar dust linked to them and analyze the evolutionary state of the young stellar objects identified there and the relation of the bubble to S 24 and the IR sources. Methods. Using the APEX telescope, we mapped the molecular emission in the CO(2−1), 13 CO(2−1), C 18 O(2−1), and 13 CO(3−2) lines in a region of about 5 × 5 in size around the bubble. The cold dust distribution was analyzed using submillimeter continuum images from ATLASGAL and Herschel. Complementary IR and radio data at different wavelengths were used to complete the study of the interstellar medium in the region. Results. The molecular gas distribution shows that gas linked to the S 24 bubble and to G341.220-0.213 and G341.217-0.237 has velocities of between −48.0 km s −1 and −40.0 km s −1 , compatible with the kinematical distance of 3.7 kpc that is generally adopted for the region. The gas distribution reveals a shell-like molecular structure of ∼0.8 pc in radius bordering the S 24 bubble. A cold dust counterpart of the shell is detected in the LABOCA and Herschel-SPIRE images. The weak extended emission at 24 μm from warm dust and radio continuum emission projected inside the bubble indicates exciting sources and that the bubble is a compact Hii region. Part of the molecular gas bordering the S 24 Hii region coincides with the extended infrared dust cloud SDC341.194-0.221. A molecular and cold dust clump is present at the interface between the S 24 Hii region and G341.217-0.237, shaping the eastern border of the IR bubble. The arc-like molecular structure encircling the northern and eastern sections of the IR source G341.220-0.213 indicates that the source is interacting with the molecular gas. The analysis of the available IR point source catalogs reveals some young stellar object candidates linked to the IR-extended sources, thus confirming their nature as active star-forming regions. Gas and dust masses were estimated for the different features. The total gas mass in the region and the H 2 ambient density amount to 10 300 M and 5900 cm −3 , indicating that G341.220-0.213, G341.217-0.237, and the S 24 Hii region are evolving in a high-density medium. A triggering star formation scenario for the Hii region is investigated.

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“…Within the science demonstration field, there are 140 ATLAS-GAL clumps from the Compact Source Catalogue (CSC; Contreras et al 2013b;Urquhart et al 2014a). We have made use of the SEDIGISM data to estimate v lsr for all the clumps, which is essential to place them within their Galactic context, and to associate them with the molecular clouds extracted in Sect.…”

Section: Distribution Of Atlasgal Clumpsmentioning

confidence: 99%

SEDIGISM: Structure, excitation, and dynamics of the inner Galactic interstellar medium

Schüller

Csengeri

Urquhart

et al. 2017

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Context. The origin and life-cycle of molecular clouds are still poorly constrained, despite their importance for understanding the evolution of the interstellar medium. Many large-scale surveys of the Galactic plane have been conducted recently, allowing for rapid progress in this field. Nevertheless, a sub-arcminute resolution global view of the large-scale distribution of molecular gas, from the diffuse medium to dense clouds and clumps, and of their relationship to the spiral structure, is still missing. Aims. We have carried out a systematic, homogeneous, spectroscopic survey of the inner Galactic plane, in order to complement the many continuum Galactic surveys available with crucial distance and gas-kinematic information. Our aim is to combine this data set with recent infrared to sub-millimetre surveys at similar angular resolutions. Methods. The SEDIGISM survey covers 78 deg 2 of the inner Galaxy (−60CO. This isotopologue of CO is less abundant than 12 CO by factors up to 100. Therefore, its emission has low to moderate optical depths, and higher critical density, making it an ideal tracer of the cold, dense interstellar medium. The data have been observed with the SHFI single-pixel instrument at APEX. The observational setup covers the 13 CO(2 -1) and C 18 O(2 -1) lines, plus several transitions from other molecules. Results. The observations have been completed. Data reduction is in progress, and the final data products will be made available in the near future. Here we give a detailed description of the survey and the dedicated data reduction pipeline. To illustrate the scientific potential of this survey, preliminary results based on a science demonstration field covering −20 • ≤ ≤ -18.5 • are presented. Analysis of the 13 CO(2 -1) data in this field reveals compact clumps, diffuse clouds, and filamentary structures at a range of heliocentric distances. By combining our data with data in the (1-0) transition of CO isotopologues from the ThrUMMS survey, we are able to compute a 3D realization of the excitation temperature and optical depth in the interstellar medium. Ultimately, this survey will provide a detailed, global view of the inner Galactic interstellar medium at an unprecedented angular resolution of ∼30 .

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ATLASGAL – compact source catalogue: 330° < ℓ < 21°

Cited by 238 publications

References 40 publications

Understanding star formation in molecular clouds

Understanding star formation in molecular clouds

Molecular gas and star formation toward the IR dust bubble S 24 and its environs

SEDIGISM: Structure, excitation, and dynamics of the inner Galactic interstellar medium

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