|Budget Amount *help
¥2,400,000 (Direct Cost : ¥2,400,000)
Fiscal Year 1991 : ¥300,000 (Direct Cost : ¥300,000)
Fiscal Year 1990 : ¥2,100,000 (Direct Cost : ¥2,100,000)
A galaxy collision hypothesis was examined as a plausible mechanism of active galactic nuclei, e. g., Seyfert galaxies and quasars. According to this senario, gas in colliding or target galaxies can accrete onto central black holes in galaxies, and so activate their nuclei.
We studied nuclear spectra of more than 40 ring galaxies which are believed to have formed through galaxy collisions. Sample galaxies were taken from the Arp-Madore's Catalogue of Peculiar Galaxies (1989). CCD data, taken with the Cassegrain spectrograph of the 1.5m telescope-at CTIO, were reduced with IRAF system on SUN work station, which was purchased with the present grant. Our preliminary results are given bellow.
1) Most of ring galaxies show strong emission lines.
2) They are mostly star burst type or LINER, and only three nuclei are found to be Seyfert 2 type.
3) Among the present sample, we found no new ring galaxies of Seyfert 1 type, and so cannot confirm the above conjecture for the case of ring galaxies.
4) By cross checking their optical positions with IRAS Point. Source Catalog, most of ring galaxies are found to be strong IRAS sources.
5) These results may imply that this type of galaxy collisions, i. e., a vertical penetration of a galaxy through a disk of a target galaxy, may not be efficient for nuclear feeding.
Further observations are scheduled in this year.