The MUSE Hubble Ultra Deep Field survey XVI: the angular momentum of low-mass star-forming galaxies: a cautionary tale and insights from TNG50

Bouché, N.F.; Genel, S.; Pellissier, A.; Dubois, C.; Contini, T.; Epinat, B.; ... ; Vogelsberger, M. (2021)

Article / Letter to editor

We investigate the specific angular momentum (sAM) j((star)((star) proportional to M-star(alpha) with an index alpha varying from alpha = 0.3 to alpha = 0.5, from log M-star/M-circle dot = 8 to log M-star/M-circle dot = 10.5. The UDF sample supports a redshift evolution (j) over tilde (star proportional to) (1 + z)(a), with a = 0.27(-0.56)(+0.42) which is consistent with the (1 + z)(-0.5) expectation from a universe in expansion. The scatter of the sAM sequence is a strong function of the dynamical state with logj vertical bar(M star) proportional to 0.65(-0.08)(+0.06) x log(V-max/sigma), where sigma is the velocity dispersion at 2R(e). In TNG50, SFGs also form a (j) over tilde (star) - M-star (V/sigma) plane, but it correlates more with galaxy size than with morphological parameters. Our results suggest that SFGs might experience a dynamical transformation, and lose their sAM, before their morphological transformation to becoming passive via either merging or secular evolution.

• All authors: Bouché, N.F.; Genel, S.; Pellissier, A.; Dubois, C.; Contini, T.; Epinat, B.; Pillepich, A.; Krajnović, D.; Nelson, D.; Abril-Melgarejo, V.; Richard, J.; Boogaard, L.A.; Maseda, M.V.; Mercier, W.; Bacon, R.; Steinmetz, M.; Vogelsberger, M.
• Date: 2021-10-08
• Journal: Astronomy & Astrophysics
• Volume: 654
• DOI: doi:10.1051/0004-6361/202040225