A kinematic study of the irregular dwarf galaxy NGC 2366 using HI and Halpha observations

• Main Authors: van Eymeren, J, Marcelin, M, Koribalski, B, Dettmar, R. -J, Bomans, D. J, Gach, J. -L, Balard, P
• Format: Journal Article
• Language: English
• Published: 17-11-2008
• Subjects: Physics - Astrophysics of Galaxies; Physics - Cosmology and Nongalactic Astrophysics; Physics - Earth and Planetary Astrophysics; Physics - High Energy Astrophysical Phenomena; Physics - Instrumentation and Methods for Astrophysics; Physics - Solar and Stellar Astrophysics
• DOI: 10.48550/arxiv.0811.2724

Abridged. Context. The metal content of dwarf galaxies and the metal
enrichment of the intergalactic medium both suggest that mass loss from
galaxies is a significant factor for the chemical evolution history of
galaxies, in particular of dwarf galaxies. However, no clear evidence of a
blow-away in local dwarf galaxies has been found so far.
Aims. We therefore performed a detailed kinematic analysis of the neutral and
ionised gas in the nearby star-forming irregular dwarf galaxy NGC 2366 in order
to make predictions about the fate of the gas and to get a more complete
picture of this galaxy.
Methods. A deep Halpha image and Fabry-Perot interferometric data of NGC 2366
were obtained. They were complemented by HI synthesis data from the THINGS
survey. We searched for line-splitting both in Halpha and HI by performing a
Gaussian decomposition. To get an idea whether the expansion velocities are
high enough for a gas blow-away, we used the pseudo-isothermal halo model,
which gives us realistic values for the escape velocities of NGC 2366. The good
data quality also allowed us to discuss some peculiarities of the morphology
and the dynamics in NGC 2366.
Results. A large red-shifted outflow north west of the giant extragalactic
HII region with an expansion velocity of up to 50 km/s is found in Halpha, but
not in HI. Additionally, a blue-shifted component north of the giant
extragalactic HII region was detected both in Halpha and HI with an expansion
velocity of up to 30 km/s. A comparison with the escape velocities of NGC 2366
reveals that the gas does not have enough kinetic energy to leave the
gravitational potential.