11 research outputs found
HI in the Outskirts of Nearby Galaxies
Full text linkThe HI in disk galaxies frequently extends beyond the optical image, and can
trace the dark matter there. I briefly highlight the history of high spatial
resolution HI imaging, the contribution it made to the dark matter problem, and
the current tension between several dynamical methods to break the disk-halo
degeneracy. I then turn to the flaring problem, which could in principle probe
the shape of the dark halo. Instead, however, a lot of attention is now devoted
to understanding the role of gas accretion via galactic fountains. The current
cold dark matter theory has problems on galactic scales, such as
the core-cusp problem, which can be addressed with HI observations of dwarf
galaxies. For a similar range in rotation velocities, galaxies of type Sd have
thin disks, while those of type Im are much thicker. After a few comments on
modified Newtonian dynamics and on irregular galaxies, I close with statistics
on the HI extent of galaxies.Comment: 38 pages, 17 figures, invited review, book chapter in "Outskirts of
Galaxies", Eds. J. H. Knapen, J. C. Lee and A. Gil de Paz, Astrophysics and
Space Science Library, Springer, in pres
Observations of neutral hydrogen in IC 1613, NCG 6822 and M 82
No full textWetensch. publicatieFaculteit der Wiskunde en Natuurwetenschappe
Preliminary observations of 21-cm emission from M 33
No full textWetensch. publicatieFaculteit der Wiskunde en Natuurwetenschappe
Photo-electric light-curves in blue and yellow light of the eclipsing variable RR Trianguli Australis
No full textWetensch. publicatieFaculteit der Wiskunde en Natuurwetenschappe
Neutral hydrogen in extra-galactic systems
No full textWetensch. publicatieFaculteit der Wiskunde en Natuurwetenschappe
