IAFE   05512
INSTITUTO DE ASTRONOMIA Y FISICA DEL ESPACIO
Unidad Ejecutora - UE
artículos
Título:
Galactic H I supershells: kinetic energies and possible origin
Autor/es:
CAIAFA, C. F.; SUAD, L. A.; ARNAL, E. M.; CICHOWOLSKI, S.
Revista:
ASTRONOMY AND ASTROPHYSICS
Editorial:
EDP SCIENCES S A
Referencias:
Lugar: Paris; Año: 2019 vol. 624
ISSN:
0004-6361
Resumen:
Context. The Milky Way, when viewed in the neutral hydrogen line emission, presents large structures called Galactic supershells(GSs). The origin of these structures is still a subject of debate. The most common scenario invoked is the combined action of strongwinds from massive stars and their subsequent explosion as supernova.Aims. The aim of this work is to determine the origin of 490 GSs that belong to the catalogue of H I supershell candidates in the outerpart of the Galaxy.Methods. To know the physical processes that took place to create these expanding structures, it is necessary to determine their kineticenergies. To obtain all the GS masses, we developed and used an automatic algorithm, which was tested on 95 GSs whose masses werealso estimated by hand.Results. The estimated kinetic energies of the GSs vary from 1 1047 to 3:4 1051 erg. Considering an efficiency of 20% for theconversion of mechanical stellar wind energy into the kinetic energy of the GSs, the estimated values of the GS energies could bereached by stellar OB associations. For the GSs located at high Galactic latitudes, the possible mechanism for their creation could beattributed to collision with high velocity clouds (HVC). We have also analysed the distribution of GSs in the Galaxy, showing that atlow Galactic latitudes, jbj < 2; most of the structures in the third Galactic quadrant seem to be projected onto the Perseus Arm. Thedetection of GSs at very high distances from the Galactic centre may be attributed to diffuse gas associated with the circumgalacticmedium of M31 and to intra-group gas in the Local Group filament.