How was the mushroom-shaped GW 123.4--1.5 formed in the Galactic disk?

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dc.creatorBaek, Chang Hyun
dc.creatorKudoh, Takahiro
dc.creatorTomisaka, Kohji
dc.date2008-01-21
dc.date2008-07-21
dc.date.accessioned2026-07-07T09:51:30Z
dc.date.available2026-07-07T09:51:30Z
dc.descriptionThe unusual mushroom-shaped HI cloud, GW 123.4--1.5, is hundreds of parsecs in size but does not show any correlations to HI shells or chimney structures. To investigate the origin and velocity structure of GW 123.4--1.5, we perform three-dimensional hydrodynamical simulations of the collision of a high-velocity cloud with the Galactic disk. We also perform a parameter study of the density, radius, and incident angle of the impact cloud. The numerical experiments indicate that we reproduce the mushroom-shaped structure which resembles GW 123.4--1.5 in shape, size, position-velocity across the cap of the mushroom, and the density ratio between the mushroom and surrounding gas. GW 123.4--1.5 is expected to be formed by the almost head-on collision of a HVC with velocity $\sim 100 \kms$ and mass $\sim 10^5 \Msun$ about $5 \times 10^7 \yr$ ago. A mushroom-shaped structure like GW 123.4--1.5 must be infrequent on the Galactic plane, because the head-on collision which explains the mushroom structure seems rare for observed HVCs. HVC-disk collision explains not only the origin of the mushroom-shaped structure but also the formation of a variety of structures like shells, loops, and vertical structures in our Galaxy.
dc.descriptionRevised the manuscript and added references, 23 pages with 9 figures
dc.identifierhttps://arxiv.org/abs/0801.3186
dc.identifierhttp://arxiv.org/abs/0801.3186
dc.identifierAstrophys.J. 682 (2008) 434-444
dc.identifierdoi:10.1086/589556
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/165269
dc.subjectAstrophysics
dc.titleHow was the mushroom-shaped GW 123.4--1.5 formed in the Galactic disk?
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