Dynamic star formation in the massive DR21 filament

By N. Schneider, T. Csengeri, S. Bontemps, Fr'ed'erique Motte, R. Simon, P. Hennebelle, Christoph Federrath, R. K. I. CEA-Saclay, F. Bordeaux, France I.Physik. Institut Koeln and 5 more. 2010

238 citations recorded by the source corpus.

The formation of massive stars is a highly complex process in which it is not clear whether the star-forming gas is in global gravitational collapse or in an equilibrium state, supported by turbulence. By studying one of the most massive and dense star-forming regions in the Galaxy at a distance of less than 3 kpc, the filament containing the well-known sources DR21 and DR21(OH), we expect to find observational signatures that allow to discriminate between the two views. We use molecular line data from our 13CO 1-0, CS 2-1, and N2H+ 1-0 survey of the Cygnus X region obtained with the FCRAO and high-angular resolution observations of CO, CS, HCO+, N2H+, and H2CO, obtained with the IRAM 30m telescope. We observe a complex velocity field and velocity dispersion in the DR21 filament in which regions of highest column-density, i.e. dense cores, have a lower velocity dispersion than the surrounding gas and velocity gradients that are not (only) due to rotation. Infall signatures in optically thick line profiles of HCO+ and 12CO are observed along and across the whole DR21 filament. From modelling the observed spectra, we obtain a typical infall speed of 0.6 km/s and mass accretion rates of the order of a few 10^-3 Msun/yr for the two main clumps constituting the filament. These massive (4900 and 3300 Msun) clumps are both gravitationally contracting. All observed kinematic features in the DR21 filament can be explained if it is formed by the convergence of flows at large scales and is now in a state of global gravitational collapse. Whether this convergence of flows originated from self-gravity at larger scales or from other processes can not be settled with the present study. The observed velocity field and velocity dispersion are consistent with results from (magneto)-hydrodynamic simulations where the cores lie at the stagnation points of convergent turbulent flows.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/ddbd44901911b78c89907100f56a0dae6f12b0c9

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

Citations in the corpus

An ALMA study of the Orion Integral Filament: I. Evidence for narrow fibers in a massive cloud (2018, background): “Typically located at kpc distances, most of these massive filaments are found in hub-like associations (Myers 2009) forming dense ridges of gas (Galván-Madrid et al. 2010; Schneider et al. 2010; Henning et al. 2010; Hill et al. 2011; Hennemann et al. 2012; Peretto et al. 2013).”
ON THE STAR FORMATION EFFICIENCY OF TURBULENT MAGNETIZED CLOUDS (2012, background): “In particular, the massive DR21 filament in Cygnus X shows signs of infall (Schneider et al. 2010), which is likely the reason for Cygnus X exhibiting a slightly positive α on length scales representative of that filament (length ∼ 20 pc, width ∼ 5 pc) and subfilaments collapsing toward the main…”
The spine of the swan: a Herschel study of the DR21 ridge and filaments in Cygnus X (2012, methodology): “Notably, the “sub-filaments” of Schneider et al. (2010) labeled F1 and F3 are recovered, both being resolved into nearly parallel northern and southern components that join close to the ridge.”
WHAT DETERMINES THE DENSITY STRUCTURE OF MOLECULAR CLOUDS? A CASE STUDY OF ORION B WITH HERSCHEL (2013, background): “Solenoidal forcing arises from galactic rotation and magneto-rotational instabilities. global gravitational collapse of larger spatial areas like filaments and ridges (see, e.g., Schneider et al. (2010), Hill et al. (2011), Palmeirim et al. (2013) for observational examples).”
The ATLASGAL survey: a catalog of dust condensations in the Galactic plane (2013, result): “This is in good agreement with kinematic studies of high-mass star-forming sites, where flows of dense gas have been observed at similar relative velocities (e.g. Schneider et al. 2010; Csengeri et al. 2011a,b; Nguyen-Lu’o’ng et al. 2013).”
Global collapse of molecular clouds as a formation mechanism for the most massive stars (2013, methodology): “However, there are several sources now for which large-scale infall has been suggested to play a major role in building up the mass of star-forming cores (e.g. Peretto et al. 2006; Schneider et al. 2010; Barnes et al. 2010; GalvánMadrid et al. 2010; Liu et al. 2012).”
Cluster-formation in the Rosette molecular cloud at the junctions of filaments (2012, unknown): “This confirms the finding of Schneider et al. (2010a) where a mass flow through subfilaments, probably governed by magnetic fields, was observed for the DR21 filament.”
THE STAR FORMATION RATE OF TURBULENT MAGNETIZED CLOUDS: COMPARING THEORY, SIMULATIONS, AND OBSERVATIONS (2012, background): “In particular, the orientation of magnetic fields might tell us about its dynamical influence (Schneider et al. 2010; Li & Henning 2011; Peretto et al. 2012).”
ATLASGAL — towards a complete sample of massive star forming clumps ⋆ (2014, background): “Parsec-sized, globally collapsing clumps provide the flow of material that is funnelled into the centre of the protocluster and on to the competing protostars (e.g. Schneider et al. 2010).”
FILAMENTARY ACCRETION FLOWS IN THE EMBEDDED SERPENS SOUTH PROTOCLUSTER (2013, background): “…other starforming regions – for example, Bally et al (1987) find a gradient of ∼0.7 km s−1 pc−1 along several pc of the Orion integral shaped filament; Schneider et al (2010) find gradients of ∼0.8-2.3 km s−1 pc−1 along the DR21 filament, and Kirk et al (2010) find a general relationship in…”
HERSCHEL SURVEY OF GALACTIC OH+, H2O+, AND H3O+: PROBING THE MOLECULAR HYDROGEN FRACTION AND COSMIC-RAY IONIZATION RATE (2014, background): “Indeed, the strongest absorption at 9 km s−1 matches a foreground cloud observed in CO and HCO+ associated with the nearby source W75N (Schneider et al. 2010).”
Global hierarchical collapse in molecular clouds. Towards a comprehensive scenario (2019, background): “The central clumps (“hubs”) appear to accrete from the filaments, while in turn the filaments seem to accrete radially from their surroundings (Schneider et al. 2010; Kirk et al. 2013; Peretto et al. 2014; Lu et al. 2018; Williams et al. 2018; Shimajiri et al. 2019; Gong et al. 2018).”
Filaments and ridges in Vela C revealed by Herschel: from low-mass to high-mass star-forming sites (2011, methodology): “An alternate method was used by Könyves et al. (2010) and Schneider et al. (2010b) who used extinction maps to determine absolute calibration of their Herschel Aquila and Rosette column density maps.”