Bibcode
Vladilo, G.; Centurion, M.; de Boer, K. S.; King, D. L.; Lipman, K.; Stegert, J.; Unger, S. W.; Walton, N. A.
Bibliographical reference
Astronomy and Astrophysics (ISSN 0004-6361), vol. 280, no. 1, p. L11-L14
Advertised on:
12
1993
Citations
20
Refereed citations
20
Description
During the first few nights following its discovery, we observed the
interstellar Ca II and Na I lines towards supernova 1993J at high
spectral resolution (full width half maximum (FWHM) approximately 5-6
km/s) with the William Herschel Telescope at La Palma. We find a crowd
of absorption components in the radial-velocity range -135 km/s less
than or equal to vlsr less than or equal to +165 km/s. In
order to understand the origin of these features, we re-examined
previous surveys of local interstellar gas, high-velocity gas, and
intergalactic gas in the field. We also observed the line of sight of
the supernova at 21 cm with the 100-m Radiotelescope of Effelsberg. We
find that the components between +85 and +165 km/s originate in
intergalactic gas within the M81 group of galaxies, tidally pulled out
from one of the galaxies of the group. According to our analysis the gas
at Vlsr approximately equal to -135 and -119 km/s originates
within M81; its detection proves that the supernova is embedded in the
inner region of that galaxy. The remaining components are produced in
our Galaxy, including its halo.