Bibcode
DOI
Sabalisck, N. S. P.; Rozas, M.; Beckman, J. E.; Knapen, J. H.
Bibliographical reference
Publications Astronomical Society of Australia, vol. 15, no. 1, p. 161-62
Advertised on:
4
1998
Citations
1
Refereed citations
1
Description
We have used the TAURUS Fabry-Perot mapping spectrometer on the WHT to
produce a complete kinematic map of the disc of M100 in H-alpha. Here we
show how the internal velocity dispersion of the principal emission
components of the brightest regions varies with their H-alpha
luminosity. The plot shows ample scatter, but an upper envelope in the
velocity dispersion is clearly linear (in the log-log plane) with a
slope of 2.6, a result which agrees precisely with an earlier graph by
Arsenault et al., who selected instead the regions of highest surface
brightness. We show that this result, which differs from the
conventional prediction from the virial theorem, is consistent with
virialisation if the HII regions are density bounded and thus offers
evidence in support of the density bounding hypothesis for the most
luminous regions in disc galaxies.