FIRESTORM I: stellar feedback and gas kinematics in the evolved W40 hub-filament system
Year: 2025
Type: article
Abstract: 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.
Authors: Ming-Kang Lim, Ram K Yadav, L K Dewangan, Kee-Tae Kim, A Zavagno, Jedsada Maklai, Nicola Schneider, Doris Arzoumanian, Arshia M Jacob, L E Pirogov, Jihye Hwang, D K Ojha, Gyuho Lee, Affan Adly Nazri, Saurabh Sharma
Institutions: National Astronomical Research Institute of Thailand, Physical Research Laboratory, Korea Astronomy and Space Science Institute, Korea University of Science and Technology, Centre National de la Recherche Scientifique, Institut Universitaire de France, Aix-Marseille Université, Laboratoire d’Astrophysique de Marseille, Chiang Mai University, University of Cologne, Kyushu University, Kyushu University Institute for Advanced Study, Institute of Applied Physics, Tata Institute of Fundamental Research, University of Malaya, Aryabhatta Research Institute of Observational Sciences
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,046
OpenAlex ID: W4417347286