PGC 38025: A Star-forming Lenticular Galaxy with an Off-nuclear Star-forming Core
Abstract
Lenticular galaxies (S0s) were considered mainly as passive evolved spirals due to environmental effects for a long time; however, most S0s in the field cannot fit into this common scenario. In this work, we study one special case, Sloan Digital Sky Survey J120237.07+642235.3 (PGC 38025), a star-forming field S0 galaxy with an off-nuclear blue core. We present optical integral field spectroscopic observation with the 3.5 meter telescope at Calar Alto Observatory, and high-resolution millimeter observation with the NOrthern Extended Millimeter Array. We estimated the star formation rate (SFR = 0.446 M⊙ yr-1) and gaseous metallicity (12 + log(O/H) = 8.42) for PGC 38025, which follows the star formation main sequence and stellar mass-metallicity relation. We found that the ionized gas and cold molecular gas in PGC 38025 show the same spatial distribution and kinematics, while rotating misaligned with stellar component. The off-nuclear blue core is locating at the same redshift as PGC 38025 and its optical spectrum suggest it is H II region. We suggest that the star formation in PGC 38025 is triggered by a gas-rich minor merger, and the off-nuclear blue core might be a local star formation happened during the accretion/merger process.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- July 2021
- DOI:
- arXiv:
- arXiv:2104.10909
- Bibcode:
- 2021ApJ...915....1C
- Keywords:
-
- Lenticular galaxies;
- Star formation;
- Early-type galaxies;
- Galaxies;
- Galaxy kinematics;
- 915;
- 1569;
- 429;
- 573;
- 602;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 16 pages, 13 figures, accepted for publication in ApJ