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Journal Articles Astronomy and Astrophysics - A&A Year : 2022

The molecular gas resolved by ALMA in the low-metallicity merging dwarf galaxy Haro 11

Yulong Gao
  • Function : Author
Qiusheng Gu
  • Function : Author
Yong Shi
  • Function : Author
Luwenjia Zhou
  • Function : Author
Min Bao
  • Function : Author
Xiaoling Yu
  • Function : Author
Zhiyu Zhang
  • Function : Author
Tao Wang
Matthew Hayes
Shiying Lu
  • Function : Author
Ke Xu
  • Function : Author


Context. The physical mechanisms driving starbursts and quenching in less massive (M* ≤ 1010 M⊙) galaxies are unclear. The merger is one of the inescapable processes referred to as both starburst and quenching in massive galaxies. However, the effects of the merger on star formation in dwarf galaxies and their evolution are still uncertain.Aims. We aim to explore how star formation in dwarf galaxies is both triggered and quenched by studying metal-poor gas-rich dwarf mergers based on multi-band observations at a spatial resolution of ∼460 pc.Methods. We use archival data of Atacama Large Millimetre Array (Band 3 and 8) and Very Large Telescope/Multi Unit Spectroscopic Explorer to map CO(J = 1–0), [CI](3P1–3P0), and Hα emission in one of the most extreme merging starburst dwarf galaxies, Haro 11.Results. We find the molecular gas is assembled around the central two star-forming regions (knots B and C). The molecular and ionized gas and stellar components show complex kinematics, indicating that the gas is probably at a combined stage of collision of clouds and feedback from star formation. The peak location and distribution of [CI](1–0) closely coincide with the CO(1–0) emission, meaning that it might trace the same molecular gas as CO in such a dwarf merger starburst galaxy. The enhancement of line ratios (∼0.5) of [CI]/CO around knot C is probably generated by the dissociation of CO molecules by cosmic rays and far-ultraviolet photons. Globally, Haro 11 and its star-forming regions share similar star formation efficiency (SFE) to the high-z starburst galaxies or the clumps in nearby ultraluminous infrared galaxies.Conclusions. Given the high SFE, the high specific star formation rate, small stellar mass, low metallicity, and deficient HI gas, Haro 11 could be an analog of a high-z dwarf starburst and the potential progenitor of the nearby less massive elliptical galaxies. The significantly smaller turbulent pressure and viral parameter is probably triggering the intense starbursts. We predict that Haro 11 will quench at M* ≤ 8.5  ×  109 M⊙.Key words: galaxies: ISM / galaxies: starburst / galaxies: individual: Haro 11 / galaxies: interactions
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Dates and versions

hal-03595478 , version 1 (18-03-2023)



Yulong Gao, Qiusheng Gu, Yong Shi, Luwenjia Zhou, Min Bao, et al.. The molecular gas resolved by ALMA in the low-metallicity merging dwarf galaxy Haro 11. Astronomy and Astrophysics - A&A, 2022, 661, pp.A136. ⟨10.1051/0004-6361/202142309⟩. ⟨hal-03595478⟩
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