Astronomy and Astrophysics – Astrophysics – Cosmology and Extragalactic Astrophysics
Scientific paper
2010-06-20
Astronomy and Astrophysics
Astrophysics
Cosmology and Extragalactic Astrophysics
36 pages, 16 figures. Accepted for publication in AJ: corrected typos and references
Scientific paper
In this second paper of two analyses, we present near-infrared (NIR) morphological and asymmetry studies performed in sample of 92 galaxies found in different density environments: galaxies in Compact Groups (HCGs), Isolated Pairs of Galaxies (KPGs), and Isolated Galaxies (KIGs). Both studies have proved useful for identifying the effect of interactions on galaxies. In the NIR, the properties of the galaxies in HCGs, KPGs, and KIGs are more similar than they are in the optical. This is because the NIR band traces the older stellar populations, which formed earlier and are more relaxed than the younger populations. However, we found asymmetries related to interactions in both KPG and HCG samples. In HCGs, the fraction of asymmetric galaxies is even higher than what we found in the optical. In the KPGs the interactions look like very recent events, while in the HCGs galaxies are more morphologically evolved and show properties suggesting they suffered more frequent interactions. The key difference seems to be the absence of star formation in the HCGs; while interactions produce intense star formation in the KPGs, we do not see this effect in the HCGs. This is consistent with the dry merger hypothesis (Coziol & Plauchu-Frayn 2007); the interaction between galaxies in compact groups, (CGs), is happening without the presence of gas. If the gas was spent in stellar formation (to build the bulge of the numerous early-type galaxies), then the HCGs possibly started interacting sometime before the KPGs. On the other hand, the dry interaction condition in CGs suggests that the galaxies are on merging orbits, and consequently such system cannot be that much older either. [abridge]
Coziol Roger
Plauchu-Frayn I.
No associations
LandOfFree
Comparative Study of Asymmetry Origin of Galaxies in Different Environments. II. Near-Infrared observations 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 Comparative Study of Asymmetry Origin of Galaxies in Different Environments. II. Near-Infrared observations, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Comparative Study of Asymmetry Origin of Galaxies in Different Environments. II. Near-Infrared observations will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-185940