151. Formation of a Malin 1 analogue in IllustrisTNG by stimulated accretion
- Author
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Zhu, Qirong, Xu, Dandan, Gaspari, Massimo, Rodriguez-Gomez, Vicente, Nelson, Dylan, Vogelsberger, Mark, Torrey, Paul, Pillepich, Annalisa, Zjupa, Jolanta, Weinberger, Rainer, Marinacci, Federico, Pakmor, Rüdiger, Genel, Shy, Li, Yuexing, Springel, Volker, and Hernquist, Lars
- Subjects
Astrophysics - Astrophysics of Galaxies - Abstract
The galaxy Malin 1 contains the largest stellar disk known but the formation mechanism of this structure has been elusive. In this paper, we report a Malin 1 analogue in the 100 Mpc IllustrisTNG simulation and describe its formation history. At redshift zero, this massive galaxy, having a maximum circular velocity $V_{\rm max}$ of 430 ${\rm km\ s^{-1}}$, contains a 100 kpc gas/stellar disk with morphology similar to Malin 1. The simulated galaxy reproduces well many observed features of Malin 1's vast disk, including its stellar ages, metallicities, and gas rotation curve. We trace the extended disk back in time and find that a large fraction of the cold gas at redshift zero originated from the cooling of hot halo gas, triggered by the merger of a pair of intruding galaxies. Our finding provides a novel way to form large galaxy disks as extreme as Malin 1 within the current galaxy formation framework., Comment: 5 page, 5 figures; resubmitted to MNRAS Letters after first referee report; Comments welcome. Animations of gas/stars can be found here at https://youtu.be/Ibl4Cyybw2Q and https://youtu.be/3aIpCu6e9dQ, or downloaded at http://www.tng-project.org/movies/tng/TNG_Malin_1_gas.mpeg and http://www.tng-project.org/movies/tng/TNG_Malin_1_star.mpeg
- Published
- 2018
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