Local star formation triggered by supernova shocks in magnetized diffuse neutral clouds

Author(s)

Leao, M. R. M. ^[1] ; Dal Pino, E. M. de Gouveia ^[1] ; Falceta-Goncalves, D. ^{[2, 3]} ; Melioli, C. ^{[1, 4]} ; Geraissate, F. G. ^[1]

Affiliation

^[1] Univ Sao Paulo, IAG, BR-05508900 Sao Paulo - Brazil

^[2] Univ Cruzeiro Sul, Nucleo Astrofis Teor, BR-01506000 Sao Paulo - Brazil

^[3] Univ Wisconsin, Dept Astron, Madison, WI 53711 - USA

^[4] Univ Bologna, Dipartimento Astron, I-40126 Bologna - Italy

• Document type: Journal article
• Source: Monthly Notices of the Royal Astronomical Society; v. 394, n. 1, p. 157-173, Mar. 2009.
• Field of knowledge: Physical Sciences and Mathematics - Astronomy
• Web of Science Citations: 29

Abstract

In this work, considering the impact of a supernova remnant (SNR) with a neutral magnetized cloud we derived analytically a set of conditions that are favourable for driving gravitational instability in the cloud and thus star formation. Using these conditions, we have built diagrams of the SNR radius, RSNR, versus the initial cloud density, nc, that constrain a domain in the parameter space where star formation is allowed. This work is an extension to previous study performed without considering magnetic fields (Melioli et al. 2006, hereafter Paper I). The diagrams are also tested with fully three-dimensional MHD radiative cooling simulations involving a SNR and a self-gravitating cloud and we find that the numerical analysis is consistent with the results predicted by the diagrams. While the inclusion of a homogeneous magnetic field approximately perpendicular to the impact velocity of the SNR with an intensity ~1 uG within the cloud results only a small shrinking of the star formation zone in the diagram relative to that without magnetic field, a larger magnetic field (~10 uG) causes a significant shrinking, as expected. Though derived from simple analytical considerations these diagrams provide a useful tool for identifying sites where star formation could be triggered by the impact of a supernova blast wave. Applications of them to a few regions of our own Galaxy (e.g. the large CO shell in the direction of Cassiopeia, and the Edge Cloud 2 in the direction of the Scorpious constellation) have revealed that star formation in those sites could have been triggered by shock waves from SNRs for specific values of the initial neutral cloud density and the SNR radius. Finally, we have evaluated the effective star formation efficiency for this sort of interaction and found that it is generally smaller than the observed values in our own Galaxy (SFE ~ 0.01-0.3)... (AU)

• FAPESP's process: 06/50654-3 - Investigation of high energy and plasma astrophysics phenomena: theory, observation, and numerical simulations
• Grantee: Elisabete Maria de Gouveia Dal Pino
• Support Opportunities: Research Projects - Thematic Grants