FIRESTORM I: stellar feedback and gas kinematics in the evolved W40 hub-filament system

Le résumé fourni par la source

ABSTRACT The FIRESTORM project – Feedback-Induced Regions and Emission from Star-forming Tracers of ObseRvable Molecular Gas – has targeted four star-forming regions to quantify the impact of stellar feedback on star formation. In this paper, we present multiwavelength results for one of the targets, the nearby high-mass star-forming region W40. Using dense-gas tracers C$^{18}$O(1–0) and H$^{13}$CO$^+$(1–0), we identified six velocity-coherent filaments: five at $V_{\mathrm{LSR}}$$~\sim$ 7.5$\mathrm{\, km\, s^{-1}}$ and one at $V_{\mathrm{LSR}}$$\sim$ 5$\mathrm{\, km\, s^{-1}}$. Four of these converge towards an infrared-bright cluster hosting the most massive star of the region (IRS 1A South, O9.5V), forming a hub-filament system (HFS). Key physical parameters, including filament lengths, widths, masses, velocity dispersions, and line masses, are derived. Five dense clumps traced by N$_2$H$^+$(1–0) exhibit subsonic to transonic turbulence, contrasting with the supersonic motions of their parental filaments, indicating turbulence dissipation. A deficit of emission at $V_{\mathrm{LSR}}$$\sim$ 7 $\mathrm{\, km\, s^{-1}}$ in several molecular lines, along with a blueshifted absorption dip in the HCN(1–0) profile, suggests that emission from OB-heated gas is being absorbed by a cold foreground cloud. A bridge-like feature in position–velocity space connects the $V_{\mathrm{LSR}}$$\sim$ 5 and $\sim$7.5 $\mathrm{\, km\, s^{-1}}$ filaments, and spatially coinciding with dense condensations and radio continuum peaks. These findings suggest that a past interaction – likely a cloud–cloud collision – triggered the formation of HFS and ultimately the central massive cluster.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.