Star Formation Rates and Ridge Structures in High-Mass Star-Forming Regions

Abstract

International audienceMolecular cloud complexes are structures of molecular gas with sizes up to 50-200 pc. The multi-wavelength data of Herschel allow us to construct column density maps. From these maps, we discover prominent filamentary structures (N H 2 > 1 0 23 _{H2} > 1{0}^{23} cm-2), which we call "ridges". We use the number of burgeoning YSOs detected in submm wavelengths with Herschel to measure the star formation activity in molecular cloud complexes and show a definite increase of star formation with the mass surface density as measured from Herschel column density images. The star formation rates (SFRs) measured for the molecular clouds W43 & G0035.39-00.33 are higher than the classical ones, such that we term these regions as "ministarbursts" - miniature models of starburst galaxies. The ridge structures show the strong, low-velocity, extended shock which may emerge from the swept-up gas caused by converging flows

Clusters of high-mass protostars: From extreme clouds to mini-bursts of star formation

“…Based on Herschel and kinematic studies (Schneider et al 2010;Hill et al 2011;Hennemann et al 2012;Nguyen Luong et al 2011a, we proposed that most ridges/hubs could have been formed by dynamical scenarios such as converging flows (see Figs. 3 Right).…”

“…On cloud and ridge spatial scales (1 − 10 pc), we measured the present-day instantaneous SFR of the W43-main cloud as well as the G035.39-00.33 and W43-MM1 ridges (Motte et al 2003;Nguyen Luong 2011a;Louvet et al 2014). These cloud structures are the preferential sites for the formation of high-mass star clusters in their host complex (see, e.g., Figs.…”

HOBYS and W43-HERO: Two more steps toward a Galaxy-wide understanding of high-mass star formation

“…Based on Herschel and kinematic studies (Schneider et al 2010;Hill et al 2011;Hennemann et al 2012;Nguyen Luong et al 2011a, we proposed that most ridges/hubs could have been formed by dynamical scenarios such as converging flows (see Fig. 3 Right).…”

“…For this reason, W43-main, G035.39-00.33, and W43-MM1 qualify as mini-starburst regions, i.e. "miniature and instantaneous models of starburst galaxies" (Motte et al 2003;Nguyen Luong 2011a;Louvet et al 2014).…”

Herschel-HOBYS study of the earliest phases of high-mass star formation in NGC 6357

“…As a result, a flux scaling was performed assuming that sources have a quasi-spherical radial density distribution following a ρ(r) ∼ r −2 law as it is observed for protostellar envelopes (e.g. Beuther et al 2002;Nguyen Luong et al 2011a). This flux scaling allows to reconcile Herschel fluxes with higher resolution observations and has been explained at length in for example Nguyen Luong et al (2011a) and Tigé et al (2017).…”