Astron. Astrophys. 326, 915-918
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Effects of galaxy interaction on the Tully-Fisher
CO vs H I linewidths
Y. Tutui and Y. Sofue
Institute of Astronomy, University of Tokyo,
Mitaka, Tokyo 181, Japan
Received 1 July 1996 / Accepted 9 June 1997
We investigate effects of galaxy-galaxy interaction on the
The HI linewidth in interacting galaxies is significantly
broader than the CO linewidth,
and the HI to CO linewidth ratio
is proportional to the strength of interaction.
This provides different distances to galaxies measured
by the Tully-Fisher relation with the CO and HI linewidths.
Distances derived from the HI linewidths
are 62% larger than those derived from the CO linewidths
for strongly interacting galaxies,
and 25% larger
for weakly interacting galaxies.
We argue that the CO-line Tully-Fisher relation will be more reliable
to measure the distances of interacting galaxies as well as galaxies
in rich clusters.
Key words: distance scale - galaxies: distances and redshifts -
galaxies: interactions - galaxies: general - galaxies: ISM -
radio lines: galaxies
Send offprint requests to: Y. Tutui
© European Southern Observatory (ESO) 1997
Online publication: October 1, 1997
Last change: April 8, 1998