Bibcode
Méndez, D. I.; Esteban, C.; Filipović , M. D.; Ehle, M.; Haberl, F.; Pietsch, W.; Haynes, R. F.
Bibliographical reference
Astronomy and Astrophysics, v.349, p.801-811 (1999)
Advertised on:
9
1999
Journal
Citations
33
Refereed citations
32
Description
We present results from multi-wavelength observations of the Wolf-Rayet
(WR) blue compact dwarf galaxy He 2-10. These observations include
Hα and optical red continuum imaging, high resolution Hα
spectroscopy, high resolution radio-continuum mapping at 4.80 and 8.64
GHz and ROSAT X-ray observations. The deep Hα images reveal that
the galaxy is surrounded by a complex kiloparsec-scale bipolar
superbubble centered on the most intense star forming knot.
High-resolution spectroscopy of this feature indicates that it has a
complex structure of possibly different kinematic components expanding
at velocities from <=50 km s(-1) up to 250 km s(-1) . These kinds of
outflows are likely to be produced by the mechanical action of stellar
winds and supernova (SN) explosions in the intense starbursts that the
galaxy hosts. This scenario is consistent with the finding of a steep
overall radio spectral index (alpha =-0.59) that confirms the presence
of a large number of supernova remnants ( ~ 3750) in the galaxy. The
study of radio spectral index throughout the galaxy shows that the
eastern parts have significantly steeper spectra. These radio regions
have no counterparts in our Hα or X-ray images. The X-ray emission
extends to a similar scale as the Hα emission. The extensions of
the X-ray distribution towards northeast and southwest appears to be
well spatially correlated with the position of the bipolar lobes
indicating the hot gas is confined inside the bubbles. The comparison
between the energetics of the outflows and the expected mechanical
energy released by the supernovae and stellar winds indicates that the
large-scale expanding structures can be powered by the massive star
population of the galaxy and, therefore, can be considered a galactic
wind. Estimates of the escape velocity of the galaxy indicate that part
of the large-scale outflows can escape the weak potential well of the
galaxy, reinforcing the possibility of a blowout in He 2-10.