PGC 44685: A Dwarf Star-forming Lenticular Galaxy with a Wolf–Rayet Population

Lenticular galaxies (S0s) are formed mainly from the gas stripping of spirals in the cluster. But how S0s form and evolve in the field is still in need of being resolved. Based on spatially resolved observations from the optical Hispanic Astronomical Center in Andalusia 3.5 m telescope with the PPAK...

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Main Authors: Shiying Lu, Qiusheng Gu, Yulong Gao, Yong Shi, Luwenjia Zhou, Rubén García-Benito, Xiangdong Li, Jiantong Cui, Xin Li, Liuze Long, Zhengyi Chen
Format: Article
Language:English
Published: IOP Publishing 2024-01-01
Series:The Astrophysical Journal
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Online Access:https://doi.org/10.3847/1538-4357/ad8349
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author Shiying Lu
Qiusheng Gu
Yulong Gao
Yong Shi
Luwenjia Zhou
Rubén García-Benito
Xiangdong Li
Jiantong Cui
Xin Li
Liuze Long
Zhengyi Chen
author_facet Shiying Lu
Qiusheng Gu
Yulong Gao
Yong Shi
Luwenjia Zhou
Rubén García-Benito
Xiangdong Li
Jiantong Cui
Xin Li
Liuze Long
Zhengyi Chen
author_sort Shiying Lu
collection DOAJ
description Lenticular galaxies (S0s) are formed mainly from the gas stripping of spirals in the cluster. But how S0s form and evolve in the field is still in need of being resolved. Based on spatially resolved observations from the optical Hispanic Astronomical Center in Andalusia 3.5 m telescope with the PPAK Integral Field Spectroscopy instrument and Northern Extended Millimeter Array, we study a dwarf ( M _* < 10 ^9 M _⊙ ) S0, PGC 44685, with triple star-forming regions in the central region, namely, A, B, and C, respectively. In northwest region C, we clearly detect the spectral features of Wolf–Rayet (W-R) stars and quantify the W-R population by stacking spectra with high W-R significance. Most of the molecular gas is concentrated in region C(W-R), and there is diffuse gas around regions A and B. The W-R region possesses the strongest intensities of H α , CO(1–0), and 3 mm continuum, indicating its ongoing violent star formation (gas depletion timescale ≲25 Myr) with tentative hundreds (<500) km s ^−1 of stellar winds accompanied by the W-R phase. Most (∼96%) of the three star-forming regions show relatively low-metallicity distributions, suggesting possible (minor) accretions of metal-poor gas that trigger the subsequent complex star formation in a field S0 galaxy. We speculate that PGC 44685 will become quiescent in less than 30 Myr if there is no new molecular gas to provide raw materials for star formation. The existence of this dwarf star-forming S0 presents an example of star formation in the low-mass/metallicity S0 galaxy.
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spelling doaj-art-848e274fde9e4b37bf1a6c967ea8cb952024-11-19T06:16:14ZengIOP PublishingThe Astrophysical Journal1538-43572024-01-01976114010.3847/1538-4357/ad8349PGC 44685: A Dwarf Star-forming Lenticular Galaxy with a Wolf–Rayet PopulationShiying Lu0Qiusheng Gu1https://orcid.org/0000-0002-3890-3729Yulong Gao2https://orcid.org/0000-0002-5973-694XYong Shi3https://orcid.org/0000-0002-8614-6275Luwenjia Zhou4Rubén García-Benito5Xiangdong Li6https://orcid.org/0000-0002-0584-8145Jiantong Cui7Xin Li8Liuze Long9https://orcid.org/0009-0003-6303-7329Zhengyi Chen10https://orcid.org/0000-0003-1583-7404School of Astronomy and Space Science, Nanjing University , Nanjing, Jiangsu 210093, People's Republic of China ; qsgu@nju.edu.cn; Key Laboratory of Modern Astronomy and Astrophysics ( Nanjing University ), Ministry of Education, Nanjing 210093, People's Republic of ChinaSchool of Astronomy and Space Science, Nanjing University , Nanjing, Jiangsu 210093, People's Republic of China ; qsgu@nju.edu.cn; Key Laboratory of Modern Astronomy and Astrophysics ( Nanjing University ), Ministry of Education, Nanjing 210093, People's Republic of ChinaSchool of Astronomy and Space Science, Nanjing University , Nanjing, Jiangsu 210093, People's Republic of China ; qsgu@nju.edu.cn; Key Laboratory of Modern Astronomy and Astrophysics ( Nanjing University ), Ministry of Education, Nanjing 210093, People's Republic of ChinaSchool of Astronomy and Space Science, Nanjing University , Nanjing, Jiangsu 210093, People's Republic of China ; qsgu@nju.edu.cn; Key Laboratory of Modern Astronomy and Astrophysics ( Nanjing University ), Ministry of Education, Nanjing 210093, People's Republic of ChinaSchool of Astronomy and Space Science, Nanjing University , Nanjing, Jiangsu 210093, People's Republic of China ; qsgu@nju.edu.cn; Key Laboratory of Modern Astronomy and Astrophysics ( Nanjing University ), Ministry of Education, Nanjing 210093, People's Republic of ChinaInstituto de Astrofísica de Andalucía-CSIC , Glorieta de la Astronomía s.n., Granada, 18008, SpainSchool of Astronomy and Space Science, Nanjing University , Nanjing, Jiangsu 210093, People's Republic of China ; qsgu@nju.edu.cn; Key Laboratory of Modern Astronomy and Astrophysics ( Nanjing University ), Ministry of Education, Nanjing 210093, People's Republic of ChinaSchool of Astronomy and Space Science, Nanjing University , Nanjing, Jiangsu 210093, People's Republic of China ; qsgu@nju.edu.cn; Key Laboratory of Modern Astronomy and Astrophysics ( Nanjing University ), Ministry of Education, Nanjing 210093, People's Republic of ChinaSchool of Astronomy and Space Science, Nanjing University , Nanjing, Jiangsu 210093, People's Republic of China ; qsgu@nju.edu.cn; Key Laboratory of Modern Astronomy and Astrophysics ( Nanjing University ), Ministry of Education, Nanjing 210093, People's Republic of ChinaSchool of Astronomy and Space Science, Nanjing University , Nanjing, Jiangsu 210093, People's Republic of China ; qsgu@nju.edu.cn; Key Laboratory of Modern Astronomy and Astrophysics ( Nanjing University ), Ministry of Education, Nanjing 210093, People's Republic of ChinaSchool of Astronomy and Space Science, Nanjing University , Nanjing, Jiangsu 210093, People's Republic of China ; qsgu@nju.edu.cn; Key Laboratory of Modern Astronomy and Astrophysics ( Nanjing University ), Ministry of Education, Nanjing 210093, People's Republic of ChinaLenticular galaxies (S0s) are formed mainly from the gas stripping of spirals in the cluster. But how S0s form and evolve in the field is still in need of being resolved. Based on spatially resolved observations from the optical Hispanic Astronomical Center in Andalusia 3.5 m telescope with the PPAK Integral Field Spectroscopy instrument and Northern Extended Millimeter Array, we study a dwarf ( M _* < 10 ^9 M _⊙ ) S0, PGC 44685, with triple star-forming regions in the central region, namely, A, B, and C, respectively. In northwest region C, we clearly detect the spectral features of Wolf–Rayet (W-R) stars and quantify the W-R population by stacking spectra with high W-R significance. Most of the molecular gas is concentrated in region C(W-R), and there is diffuse gas around regions A and B. The W-R region possesses the strongest intensities of H α , CO(1–0), and 3 mm continuum, indicating its ongoing violent star formation (gas depletion timescale ≲25 Myr) with tentative hundreds (<500) km s ^−1 of stellar winds accompanied by the W-R phase. Most (∼96%) of the three star-forming regions show relatively low-metallicity distributions, suggesting possible (minor) accretions of metal-poor gas that trigger the subsequent complex star formation in a field S0 galaxy. We speculate that PGC 44685 will become quiescent in less than 30 Myr if there is no new molecular gas to provide raw materials for star formation. The existence of this dwarf star-forming S0 presents an example of star formation in the low-mass/metallicity S0 galaxy.https://doi.org/10.3847/1538-4357/ad8349Elliptical galaxiesLenticular galaxiesGalaxiesDwarf galaxiesStar formationGalaxy evolution
spellingShingle Shiying Lu
Qiusheng Gu
Yulong Gao
Yong Shi
Luwenjia Zhou
Rubén García-Benito
Xiangdong Li
Jiantong Cui
Xin Li
Liuze Long
Zhengyi Chen
PGC 44685: A Dwarf Star-forming Lenticular Galaxy with a Wolf–Rayet Population
The Astrophysical Journal
Elliptical galaxies
Lenticular galaxies
Galaxies
Dwarf galaxies
Star formation
Galaxy evolution
title PGC 44685: A Dwarf Star-forming Lenticular Galaxy with a Wolf–Rayet Population
title_full PGC 44685: A Dwarf Star-forming Lenticular Galaxy with a Wolf–Rayet Population
title_fullStr PGC 44685: A Dwarf Star-forming Lenticular Galaxy with a Wolf–Rayet Population
title_full_unstemmed PGC 44685: A Dwarf Star-forming Lenticular Galaxy with a Wolf–Rayet Population
title_short PGC 44685: A Dwarf Star-forming Lenticular Galaxy with a Wolf–Rayet Population
title_sort pgc 44685 a dwarf star forming lenticular galaxy with a wolf rayet population
topic Elliptical galaxies
Lenticular galaxies
Galaxies
Dwarf galaxies
Star formation
Galaxy evolution
url https://doi.org/10.3847/1538-4357/ad8349
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