TY - JOUR
T1 - Post-starburst tidal tails in the archetypical ultra luminous infrared galaxy Arp 220
AU - Taniguchi, Y.
AU - Matsubayashi, K.
AU - Kajisawa, M.
AU - Shioya, Y.
AU - Ohyama, Y.
AU - Nagao, T.
AU - Ideue, Y.
AU - Murayama, T.
AU - Koda, J.
PY - 2012/7/1
Y1 - 2012/7/1
N2 - We present our new deep optical imaging and long-slit spectroscopy for Arp 220, the archetypical ultra luminous infrared galaxy in the local universe. Our sensitive Hα imaging has newly revealed large-scale Hα absorption, i.e., post-starburst regions in this merger. One is found in the eastern superbubble and the other is in the two tidal tails that are clearly revealed in our deep optical imaging. The size of the Hα absorption region in the eastern bubble is 5kpc × 7.5kpc, and the observed Hα equivalent widths are 2 Å ± 0.2 Å. The sizes of the northern and southern Hα-absorption tidal tails are 5kpc × 10kpc and 6kpc × 20kpc, respectively. The observed Hα equivalent widths range from 4 Å to 7 Å. In order to explain the presence of the two post-starburst tails, we suggest a possible multiple-merger scenario for Arp 220 in which two post-starburst disk-like structures merged into one, causing the two tails. This favors Arp 220 as a multiple merging system composed of four or more galaxies arising from a compact group of galaxies. Taking our new results into account, we discuss a star formation history in the last 1Gyr in Arp 220.
AB - We present our new deep optical imaging and long-slit spectroscopy for Arp 220, the archetypical ultra luminous infrared galaxy in the local universe. Our sensitive Hα imaging has newly revealed large-scale Hα absorption, i.e., post-starburst regions in this merger. One is found in the eastern superbubble and the other is in the two tidal tails that are clearly revealed in our deep optical imaging. The size of the Hα absorption region in the eastern bubble is 5kpc × 7.5kpc, and the observed Hα equivalent widths are 2 Å ± 0.2 Å. The sizes of the northern and southern Hα-absorption tidal tails are 5kpc × 10kpc and 6kpc × 20kpc, respectively. The observed Hα equivalent widths range from 4 Å to 7 Å. In order to explain the presence of the two post-starburst tails, we suggest a possible multiple-merger scenario for Arp 220 in which two post-starburst disk-like structures merged into one, causing the two tails. This favors Arp 220 as a multiple merging system composed of four or more galaxies arising from a compact group of galaxies. Taking our new results into account, we discuss a star formation history in the last 1Gyr in Arp 220.
KW - Galaxies: individual (Arp 220)
KW - Galaxies: interactions
KW - Galaxies: starburst
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U2 - 10.1088/0004-637X/753/1/78
DO - 10.1088/0004-637X/753/1/78
M3 - Article
AN - SCOPUS:84862521455
SN - 0004-637X
VL - 753
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1
M1 - 78
ER -