Detection of CO(1−0) Emission at the Tips of the Tidal Tail in the Antennae Galaxies
The tip of the tidal tail, resulting from an encounter between galaxies, features gas concentrations and some star-forming regions, such as tidal dwarf galaxies (TDGs). This region provides a unique laboratory for examining the star formation process in a dynamical environment distinct from that of...
Saved in:
Published in | The Astrophysical journal Vol. 962; no. 1; pp. 4 - 11 |
---|---|
Main Authors | , , , , , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Philadelphia
The American Astronomical Society
01.02.2024
IOP Publishing |
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | The tip of the tidal tail, resulting from an encounter between galaxies, features gas concentrations and some star-forming regions, such as tidal dwarf galaxies (TDGs). This region provides a unique laboratory for examining the star formation process in a dynamical environment distinct from that of disk galaxies. Using the Nobeyama 45 m telescope, we conducted
12
CO(1−0) position-switching observations at the tips of the southern tidal tail in the Antennae galaxies. We detected CO emission not only from the two star-forming TDG candidates but also in regions with no significant star formation. Adopting a Galactic CO-to-H
2
conversion factor without helium correction, the H
2
gas surface density is ∼5–12
M
⊙
pc
−2
. In most regions, the molecular-to-atomic gas ratio is around unity (0.6–1.9), but we find a region with a high ratio with a 3
σ
lower limit of >7.2. The star formation efficiency (SFE) of molecular gas is notably low (<0.15 Gyr
−1
), indicating less active star formation than in both nearby disk galaxies (∼0.5–1.0 Gyr
−1
) and other TDGs previously observed. Including previous observations, the molecular gas SFEs vary widely among TDGs/tidal tails, from 10
−2
to 10 Gyr
−1
, demonstrating significant variations in star formation activity. Potential factors contributing to the low SFE in the Antennae tail tips include extensive tides and/or the young age of the tail. |
---|---|
Bibliography: | Galaxies and Cosmology AAS51171 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 14 |
ISSN: | 0004-637X 1538-4357 |
DOI: | 10.3847/1538-4357/ad1932 |