Bibcode
DOI
Méndez, David I.; Esteban, César; Balcells, Marc
Bibliographical reference
The Astronomical Journal, Volume 117, Issue 3, pp. 1229-1236.
Advertised on:
3
1999
Citations
10
Refereed citations
10
Description
We present narrowband (Hα and adjacent continuum) and broadband (B
and V) optical images of the dwarf Wolf-Rayet galaxy Zw 0855+06 and its
companion, together with high-resolution Hα spectroscopy of the
main galaxy. We find a bridge of ~14.7 kpc (~65") in length and stellar
nature connecting both galaxies, a feature that undoubtedly indicates
their mutual interaction. We infer from the narrow width of the bridge
that at least one of these two dwarf galaxies had a well-developed disk
before the interaction. The light of the main galaxy (M_B=-17.82) is
dominated by a young and massive ionizing population. There is ample
reason to believe that a gravitational interaction with the companion
caused the starburst. The companion (M_B=-15.84) does not show any
evidence of ionized gas, and its population has a B-V color that
suggests the presence of intermediate-age (~10^9 yr) stars. This case
highlights the concept that bursts in H II dwarf galaxies may be caused
by interactions with lower luminosity companions. We anticipate that
ruling out interactions as the origin of bursts in dwarf galaxies will
require deeper surveys than are currently available. We find a backward
outflow with a velocity of about 47 km s^-1 in the southeast part (~880
pc from the center) of the main galaxy, suggesting the presence of
dynamical effects on the interstellar gas arising from the mechanical
action of the massive stars or the interaction process.