Initial conditions for massive star birth–Infrared dark clouds

Menten, K. M.; Pillai, T.; Wyrowski, F.

doi:10.1017/s1743921305004321

Cited by 30 publications

(13 citation statements)

References 29 publications

(57 reference statements)

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“…Alternatively, dense condensations in Infrared Dark Clouds (IRDCs, see Simon et al 2006, for a compilation) are promising hunting grounds for the initial stages of high-mass star formation (e.g., Rathborne et al 2006; see also the reviews by Menten et al 2005;Wyrowski 2008). IRDCs appear in absorption by dust even at mid-infrared wavelengths against the diffuse emission of the Galactic Plane and trace high column densities.…”

Section: Article Published By Edp Sciencesmentioning

confidence: 99%

ATLASGAL – The APEX telescope large area survey of the galaxy at 870 $\mathsf{\mu}$m

Schüller¹,

Menten²,

Contreras

et al. 2009

A&A

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Context. Thanks to its excellent 5100 m high site in Chajnantor, the Atacama Pathfinder Experiment (APEX) systematically explores the southern sky at submillimeter wavelengths, in both continuum and spectral line emission. Studying continuum emission from interstellar dust is essential to locating the highest density regions in the interstellar medium, and deriving their masses, column densities, density structures, and large-scale morphologies. In particular, the early stages of (massive) star formation remain poorly understood, mainly because only small samples of high-mass proto-stellar or young stellar objects have been studied in detail so far. Aims. Our goal is to produce a large-scale, systematic database of massive pre-and proto-stellar clumps in the Galaxy, to understand how and under what conditions star formation takes place. Only a systematic survey of the Galactic Plane can provide the statistical basis for unbiased studies. A well characterized sample of Galactic star-forming sites will deliver an evolutionary sequence and a mass function of high-mass, star-forming clumps. This systematic survey at submillimeter wavelengths also represents a preparatory work for Herschel and ALMA. Methods. The APEX telescope is ideally located to observe the inner Milky Way. The Large APEX Bolometer Camera (LABOCA) is a 295-element bolometer array observing at 870 μm, with a beam size of 19. 2. Taking advantage of its large field of view (11. 4) and excellent sensitivity, we started an unbiased survey of the entire Galactic Plane accessible to APEX, with a typical noise level of 50−70 mJy/beam: the APEX Telescope Large Area Survey of the Galaxy (ATLASGAL). Results. As a first step, we covered ∼95 deg 2 of the Galactic Plane. These data reveal ∼6000 compact sources brighter than 0.25 Jy, or 63 sources per square degree, as well as extended structures, many of them filamentary. About two thirds of the compact sources have no bright infrared counterpart, and some of them are likely to correspond to the precursors of (high-mass) proto-stars or protoclusters. Other compact sources harbor hot cores, compact H ii regions, or young embedded clusters, thus tracing more evolved stages after massive stars have formed. Assuming a typical distance of 5 kpc, most sources are clumps smaller than 1 pc with masses from a few 10 to a few 100 M . In this first introductory paper, we show preliminary results from these ongoing observations, and discuss the mid-and long-term perspectives of the survey.

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Section: Article Published By Edp Sciencesmentioning

confidence: 99%

ATLASGAL – The APEX telescope large area survey of the galaxy at 870 $\mathsf{\mu}$m

Schüller¹,

Menten²,

Contreras

et al. 2009

A&A

Self Cite

725

927

View full text Add to dashboard Cite

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“…Beuther et al 2002). Very recently, clumps within infrared dark clouds (IRDCs) were found to be promising candidates for even earlier stages in the formation of massive stars (see Menten et al 2005, and references therein), sometimes called pre-protocluster clumps.…”

Section: Introductionmentioning

confidence: 99%

Terahertz ammonia absorption as a probe of infall in high-mass star forming clumps

Wyrowski

Güsten

Menten

et al. 2012

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Cloud contraction and infall are the fundamental processes of star formation. While "blue-skewed" line profiles observed in highmass star forming regions are commonly taken as evidence of infall by an ever increasing number of studies, their interpretation offers many pitfalls. Detecting infall via redshifted absorption in front of continuum sources is a much more direct and reliable method but so far mostly restricted toward absorption in the centimeter toward strong HII regions. Here we present a novel approach by probing absorption of rotational ammonia transitions in front of the strong dust emission of massive star-forming regions. A carefully selected sample of three regions with different stages of evolution is selected to study infall through the evolution of massive star-forming clumps. Redshifted absorption is detected toward all three sources and infall rates between 3−10 × 10 −3 M yr −1 are derived.

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“…Following the nomenclature proposed by Bergin & Tafalla (2007), we will refer to these condensations as IR-dark clumps. IRDCs are considered potential cluster and high-mass SFRs (see Menten et al 2005, for a review), and are therefore excellent candidates for studying the initial conditions of massive star formation.…”

Section: Introductionmentioning

confidence: 99%

A comparative study of high-mass cluster forming clumps

López-Sepulcre

Cesaroni

Walmsley

2010

A&A

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Aims. We have searched for star formation activity (mainly infall and outflow signatures) in a sample of high-mass molecular clumps (M > 100 M ) in different evolutionary stages and with a wide range of surface densities, with the aim of looking for evolutionary trends and testing observationally recent theoretical models which predict the need for a minimum surface density to form high-mass stars. Methods. Our sample has been selected from single-dish 1.2 mm continuum surveys and is composed of 48 massive molecular clumps, of which 29 are IR-loud and 19 are IR-dark. Each of these has been mapped in the HCO + (1-0), HCN(1-0) and C 18 O(2-1) transitions with the IRAM-30 m telescope on Pico Veleta (Spain). We derive basic parameters (mass, momentum, kinetic energy) for the clumps and their associated outflows and examine the HCO + (1-0) line profiles for evidence of infall or expansion. Results. Molecular outflows have been detected in 75% of our targets from the presence of high-velocity wings in the HCO + (1-0) spectra. These are equally frequent and massive (between ∼1 and ∼100 M ) in IR-dark and IR-loud clumps, implying similar levels of star formation activity in both kinds of objects. A surface density threshold at Σ = 0.3 g cm −2 has been found above which the outflow detection rate increases significantly and the outflows are on average more massive. The infall detection rate in our sample is low, but significantly higher in the IR-dark sub-sample. Our clump mass estimates using the mm dust emission and C 18 O(2-1) are sensitive to the temperature, but assuming a value of 15 K for the IR-dark sub-sample, we find evidence that C 18 O is depleted by a factor ∼4.5. The HCO + (1-0) to HCN(1-0) integrated intensity ratios measured reveal a greater dispersion about the mean value in the IR-dark sub-sample than in the IR-loud by a factor of about 5. We find that a considerable number of IR-dark sources are self-absorbed in HCN(1-0) suggesting that radiative transport effects in the ground state transitions have an important influence on the integrated intensity ratio. Conclusions. Our results indicate that, in terms of outflow frequency and energetics, both IR-dark and IR-loud molecular clumps present equivalent signatures of star formation activity, and that the formation of high-mass stars requires sufficiently high clump surface densities. The higher infall detection rate measured for the IR-dark subsample suggests that these objects could be associated with the onset of star formation.

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Initial conditions for massive star birth–Infrared dark clouds

Cited by 30 publications

References 29 publications

ATLASGAL – The APEX telescope large area survey of the galaxy at 870 $\mathsf{\mu}$m

ATLASGAL – The APEX telescope large area survey of the galaxy at 870 $\mathsf{\mu}$m

Terahertz ammonia absorption as a probe of infall in high-mass star forming clumps

A comparative study of high-mass cluster forming clumps

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