Astronomy and Astrophysics – Astrophysics
Scientific paper
2001-10-10
Astronomy and Astrophysics
Astrophysics
30 pages, including 6 figures and 3 tables. To appear in The Astronomical Journal, November issue
Scientific paper
10.1086/323547
We analyze the idea that nuclear activity, either AGN or star formation, can be triggered by interactions, studying the percentage of active, HII and quiescent galaxies with companions. Our sample was selected from the Palomar survey, and avoids selection biases faced by previous studies. The comparison between the local galaxy density distributions showed that in most cases there is no statistically significant difference among galaxies of different activity types. The comparison of the percentage of galaxies with nearby companions showed that there is a higher percentage of LINERs, transition, and absorption line galaxies with companions than Seyferts and HII galaxies. However, we find that when we consider only galaxies of similar morphological types (ellipticals or spirals), there is no difference in the percentage of galaxies with companions among different activity types, indicating that the former result was due to the morphology-density effect. Also, only small differences are found when we consider galaxies with similar Halpha luminosities. The comparison between HII galaxies of different Halpha luminosities shows that there is a significantly higher percentage of galaxies with companions among the higher luminosity HII galaxies, indicating that interactions increase the amount of circumnuclear star formation, in agreement with previous results. The fact that we find that galaxies of different activity types have the same percentage of companions, suggests that interactions between galaxies is not a necessary condition to trigger the nuclear activity in AGNs. We compare our results with previous ones and discuss their implications. (abridged)
No associations
LandOfFree
The Frequency of Active and Quiescent Galaxies with Companions: Implications for the Feeding of the Nucleus 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 The Frequency of Active and Quiescent Galaxies with Companions: Implications for the Feeding of the Nucleus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Frequency of Active and Quiescent Galaxies with Companions: Implications for the Feeding of the Nucleus will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-712174