Astronomy and Astrophysics – Astronomy
Scientific paper
Jun 1992
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1992aj....103.1841p&link_type=abstract
Astronomical Journal (ISSN 0004-6256), vol. 103, no. 6, June 1992, p. 1841-1858, 2115-2123. Research supported by NSERC.
Astronomy and Astrophysics
Astronomy
226
Galactic Structure, Interstellar Matter, Milky Way Galaxy, Star Formation, Very Large Array (Vla), Astronomical Photometry, Galactic Evolution, H Alpha Line, Interstellar Gas, Mass Distribution
Scientific paper
High-resolution H I and H-alpha imaging of the dwarf irregular galaxy HoII is presented. Low surface brightness H I emission is observed over an approximately 15-arcmin diameter region in HoII. The low-resolution velocity field shows a regular pattern with a symmetrical warping of the H I layer in the outer regions. The total H I mass derived from the integrated intensity is about 7 x 10 exp 8 solar masses. The rotation curve, measured out to 7.5 kpc, shows a rapid rise in the inner parts out to a radius of about 2.5 kpc, after which it stays at a fixed level to the last measured velocity point. The maximum rotation velocity is about 40 km/s. Large-scale empty structures are prominent in the VLA H I high-resolution maps. Observed expansion velocities range between 1 and 15 km/s which leads to kinematic ages of the structures ranging from 1.0 x 10 exp 7 to 1.5 x 10 exp 8 yr. There is a striking correlation between the H I shells and H-alpha emission. The emission measure, calculated from the H-alpha flux, suggests that the small holes are filled with ionized gas.
Brinks Elias
Puche Daniel
ROY Jean-Rene
Westpfahl David
No associations
LandOfFree
Holmberg II - A laboratory for studying the violent interstellar medium does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Holmberg II - A laboratory for studying the violent interstellar medium, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Holmberg II - A laboratory for studying the violent interstellar medium will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1199405