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arXiv · 2007.04624

Formation of compact galaxies in the Extreme-Horizon simulation

Solène Chabanier·Frédéric Bournaud·Yohan Dubois·Sandrine Codis·Damien Chapon·David Elbaz·Christophe Pichon·Olivier Bressand·Julien Devriendt·Raphael Gavazzi·Katarina Kraljic·Taysun Kimm·Clotilde Laigle·Jean-Baptiste Lekien·Garreth Martin·Nathalie Palanque-Delabrouille·Sébastien Peirani·Pierre-Franck Piserchia·Adrianne Slyz·Maxime Trebitsch·Christophe Yèche
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Abstract

We present the Extreme-Horizon (EH) cosmological simulation: EH models galaxy formation with stellar and AGN feedback and uses a very high resolution in the intergalactic and circumgalactic medium. The high resolution in low-density regions results in smaller-size massive galaxies at redshift $z=2$, in better agreement with observations compared to other simulations. This results from the improved modeling of cold gas flows accreting onto galaxies. Besides, the EH simulation forms a population of particularly compact galaxies with stellar masses of $10^{10-11}$\,M$_\sun$ that are reminiscent of observed ultracompact galaxies at $z\simeq2$. These objects form mainly through repeated major mergers of low-mass progenitors, independently of baryonic feedback mechanisms. This formation process can be missed in simulations using a too low resolution in low-density intergalactic regions.

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Solène Chabanier, Frédéric Bournaud, Yohan Dubois, Sandrine Codis, Damien Chapon, David Elbaz, Christophe Pichon, Olivier Bressand, Julien Devriendt, Raphael Gavazzi, Katarina Kraljic, Taysun Kimm, Clotilde Laigle, Jean-Baptiste Lekien, Garreth Martin, Nathalie Palanque-Delabrouille, Sébastien Peirani, Pierre-Franck Piserchia, Adrianne Slyz, Maxime Trebitsch, Christophe Yèche. 2020-07-09. Formation of compact galaxies in the Extreme-Horizon simulation. https://doi.org/10.1051/0004-6361%2F202038614

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