Séminaire IPAG

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Feedback from Supernova Remnants in Molecular Clouds: How Shocks May Trigger Star Formation

jeudi 11 décembre 2025 - 11h00

Giuliana Cosentino - IRAM
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Supernova remnants (SNRs) drive large-scale shocks that enhance the density of the surrounding Interstellar Medium (ISM) . They also inject vast amounts of energy and momentum that perturb and disperse the ISM. The interplay between these effects may be paramount in regulating star formation in molecular clouds. However, how molecular clouds physical and chemical properties are affected by SNR-driven shocks is not well constrained observationally. In this talk, I will present our work aimed to address this questions. I will present our study of the large scale shock triggered by the SNR W44 on the molecular cloud G034.77-00.55. I will show how the shock, probed by Silicon Monoxide (SiO) and observed with ALMA, enhances the density of the processed gas to values compatible with those required by massive star formation. As revealed by N2H+(1-0) ALMA observations, at the shock interface, the dense, post-shocked material is organised into core-like structures that have mass, density, size and viral state similar to those reported for cold cores in other star-forming regions. Furthermore, the post-shocked gas exhibits high levels of deuterium fractionation (up to 0.1) measured from N2H+ and N2D+ single-pointing observations, and comparable to those typically measured in starless and pre-stellar cores. I will also present our exploratory large single-dish observing program SHREC, aimed to observe the molecular shock tracers toward a sample of∼30 SNRs known to be interacting with molecular clouds. I will introduce the aim and technical aspects of SHREC and present the first results obtained toward the SNRs IC443. IC443 is a well known SNR, expanding into and interacting with a nearby toroidal molecular cloud. Toward the major site of interaction, known as clump G, we estimate the mass of the shocked gas to be 100 Msun. The shock driven by IC443 into this material enhances its density by a factor >10, to value consistent with those required to ignite massive star formation. Finally, we estimate that between 35-50% of the momentum injected by IC443 is transferred to the nearby molecular material. Our work therefore indicates that, at least locally, SNR-driven shocks may play a role in the regulating star formation in molecular cloud.

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