Interstellar Plunging Waves: ALMA Resolves the Physical Structure of Nonstationary MHD Shocks

Cosentino, GiulianaEuropean Southern Observatory Santiago,University College London (UCL) (författare)

Magnetohydrodynamic (MHD) shocks are violent events that inject large amounts of energy in the interstellar medium dramatically modifying its physical properties and chemical composition. Indirect evidence for the presence of such shocks has been reported from the especial chemistry detected toward a variety of astrophysical shocked environments. However, the internal physical structure of these shocks remains unresolved since their expected spatial scales are too small to be measured with current instrumentation. Here we report the first detection of a fully spatially resolved, MHD shock toward the infrared dark cloud (IRDC) G034.77-00.55. The shock, probed by silicon monoxide (SiO) and observed with the Atacama Large Millimeter/submillimeter Array (ALMA), is associated with the collision between the dense molecular gas of the cloud and a molecular gas flow pushed toward the IRDC by the nearby supernova remnant (SNR) W44. The interaction is occurring on subparsec spatial scales thanks to the enhanced magnetic field of the SNR, making the dissipation region of the MHD shock large enough to be resolved with ALMA. Our observations suggest that molecular flow-flow collisions can be triggered by stellar feedback, inducing shocked molecular gas densities compatible with those required for massive star formation.

Jimenez-Serra, IzaskunQueen Mary University of London (författare)
Caselli, PaolaMax Planck Gesellschaft zur Förderung der Wissenschaften e.V. (MPG),Max Planck Society for the Advancement of Science (MPG) (författare)
Henshaw, Jonathan D.Max Planck Gesellschaft zur Förderung der Wissenschaften e.V. (MPG),Max Planck Society for the Advancement of Science (MPG) (författare)
Barnes, Ashley T. (författare)
Tan, Jonathan,1973University of Virginia,Chalmers tekniska högskola,Chalmers University of Technology(Swepub:cth)tanj (författare)
Viti, SerenaUniversity College London (UCL) (författare)
Fontani, FrancescoOsservatorio Astrofisico di Arcetri,Arcetri Astrophysical Observatory (författare)
Wu, BenjaminNational Astronomical Observatory of Japan (författare)
European Southern Observatory SantiagoUniversity College London (UCL) (creator_code:org_t)

Ingår i:Astrophysical Journal Letters: American Astronomical Society881:22041-82132041-8205

Av författaren/redakt...: Cosentino, Giuli ...; Jimenez-Serra, I ...; Caselli, Paola; Henshaw, Jonatha ...; Barnes, Ashley T ...; Tan, Jonathan, 1 ...; visa fler...; Viti, Serena; Fontani, Frances ...; Wu, Benjamin; visa färre...

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