# The Physical Properties of S0 Galaxy PGC 26218: The Origin of Starburst and Star Formation

DOI:
10.3847/1538-4357/ab65f6
Publication date:
01/02/2020
Main author:
Ge, Xue
IAA authors:
García-Benito, Rubén
Authors:
Ge, Xue;Gu, Qiu-Sheng;García-Benito, Rubén;Xiao, Meng-Yuan;Li, Zong-Nan
Journal:
The Astrophysical Journal
Refereed:
Yes
Publication type:
Article
Volume:
889
Pages:
132
Abstract:
We present 2D-spectroscopic observations from the Centro Astronómico Hispano Alemán 3.5 m telescope and millimeter observations from the NOrthern Extended Millimeter Array of the nearby S0 galaxy PGC 26218, which shows central star formation activity and post-starburst features in the disk. We estimate the star formation rate (SFR = 0.28 ± 0.01 M<SUB>☉</SUB> yr<SUP>−1</SUP>) and molecular gas mass ( $\mathrm{log}{M}_{{{\rm{H}}}_{2}}=7.60\pm 0.15\ {M}_{\odot }$ ) of PGC 26218 based on the extinction-corrected Hα emission line and the CO─H<SUB>2</SUB> conversion factor (α<SUB>CO</SUB>) of the Milky Way, respectively. We find that PGC 26218 follows the star-forming main sequence (SFMS) and the Kennicutt─Schmidt law. Comparing the kinematics of CO(J = 1─0), stars, and Hα, we find that the rotational axis of CO(J = 1─0) is 45° different from that of Hα. In addition, the profile of the CO(J = 1─0) emission line shows asymmetry and has an inflow component of ̃46 km s<SUP>−1</SUP>. With the decomposition of the optical image, we confirm that PGC 26218 shows multiple nuclear structures. The projected offset between the most luminous optical center and the center of CO(J = 1─0) is 5'2 (̃0.6 kpc) and the latter overlaps with one of the optical cores. These results indicate that PGC 26218 may have experienced a gas-rich minor merger, extending its star formation and locating it in the SFMS.
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