The JCMT Gould Belt Survey: Understanding the influence of outflows on Gould Belt clouds

Abstract

Using JCMT Gould Belt Survey data from CO J = 3 → 2 isotopologues, we present a meta-analysis of the outflows and energetics of star-forming regions in several Gould Belt clouds. The majority of the regions are strongly gravitationally bound. There is evidence that molecular outflows transport large quantities of momentum and energy. Outflow energies are at least 20 per cent of the total turbulent kinetic energies in all of the regions studied and greater than the turbulent energy in half of the regions. However, we find no evidence that outflows increase levels of turbulence, and there is no correlation between the outflow and turbulent energies. Even though outflows in some regions contribute significantly to maintaining turbulence levels against dissipation, this relies on outflows efficiently coupling to bulk motions. Other mechanisms (e.g. supernovae) must be the main drivers of turbulence in most if not all of these regions. vey (GBS; Ward-Thompson et al. 2007) data to give a first look at the momenta and energetics of high-velocity outflows and compare their influence on star-forming regions. This brings together previous work that used Heterodyne Array Receiver Programme (HARP; Buckle et al. 2009) to observe CO J = 3 → 2 transitions and to analyse the mass and energetics of ambient and outflowing gas in Perseus regions (Curtis et al. 2010; C10), Serpens Main (Graves et al. 2010; G10) and Ophiuchus L1688 (White et al. 2015; W15). METHODWe base our meta-analysis on GBS observations of the J = 3 → 2 transitions of 12 CO (345.7960 GHz), 13 CO (330.5880 GHz) and C 18 O (329.3306 GHz). Details of the data reduction process and calculations of the ambient gas and outflow properties are given in C10 (Perseus), G10 (Serpens Main) and W15 (Oph L1688). The GBS utilised the same emission lines in each region, which helps ensure the ambient gas and outflow properties are being traced consistently. However, the methods used to determine the mass and energetics differed slightly between the studies as we now describe. The regional mass and energetics were cal-arXiv:1512.04813v1 [astro-ph.SR] 15 Dec 2015

Effects of infall and outflow on massive star-forming regions

“…All these findings imply that the outflow action has some impact on the local environment and cloud itself, but the contribution from outflow does not mainly drive turbulence. This observation is consistent with several other studies that suggest that turbulence is mostly driven by large-scale mechanisms (Ossenkopf & Mac Low 2002;Brunt et al 2009;Padoan et al 2009;Arce et al 2010;Mottram & Brunt 2012;Plunkett et al 2015;Drabek-Maunder et al 2016).…”

“…They also reported that there is a better correlation between the outflow energy and turbulent energy, but the core turbulence is not driven by the local input from the outflows. However, Drabek-Maunder et al (2016) and Yang et al (2018) reported that there is not correlation between the turbulent and outflow energies. Urquhart et al (2018) found that the clump mass and evolutionary stage are uncorrelated.…”

Protostellar Outflows and Radiative Feedback From Massive Stars. Ii. Feedback, Star-Formation Efficiency, and Outflow Broadening

“…On these scales, outflows may also contribute to the replenishment of turbulence within the star-forming region (see review by Mac Low & Klessen 2004, and references therein). However the importance of this contribution is being questioned and observations seem to produce contradictory results (Arce 2011;Drabek-Maunder et al 2016).…”

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“…Kim, Ostriker, & Kim (2014) and Kim & Ostriker (2015) also find that star formation properties, scale heights, and velocity dispersions in galaxies can be explained by supernova feedback. Still, internal cloud feedback from pre-main sequence winds is probably not generating the observed cloud line-widths, even though there is enough energy and momentum in the winds to do this; self-gravity seems to be involved instead (Drabek-Maunder et al 2016). Li & Burkert (2017) and Li (2017) also note that self-gravitational energy generation dominates turbulent energy decay in local molecular clouds.…”