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... Show moreWe 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. Show less
We present the first measurements of the Lyman-continuum photon production efficiency xi(ion.0) at z similar to 4-5 for galaxies fainter than 0.2 L* (-19 mag). xi(ion.0) quantifies the production... Show moreWe present the first measurements of the Lyman-continuum photon production efficiency xi(ion.0) at z similar to 4-5 for galaxies fainter than 0.2 L* (-19 mag). xi(ion.0) quantifies the production rate of ionizing photons with respect to the UV luminosity density assuming a fiducial escape fraction of zero. Extending previous measurements of xi(ion.0) to the faint population is important, as ultra-faint galaxies are expected to contribute the bulk of the ionizing emissivity. We probe xi(ion.0) to such faint magnitudes by taking advantage of 200-h depth Spitzer/IRAC observations from the GREATS program and approximate to 300 3 < z < 6 galaxies with spectroscopic redshifts from the MUSE GTO Deep + Wide programs. Stacked IRAC [3.6] [4.5] colors are derived and used to infer the H alpha rest-frame equivalent widths, which range from 403 angstrom to 2818 angstrom. The derived xi(ion.0) is log(10)(xi(ion.0)/Hz erg(-1)) = 25.36 0.08 over-20.5 < Muv <-17.5, similar to those derived for brighter galaxy samples at the same redshift and therefore suggesting that 6011 shows no strong dependence on M-UV. The xi(ion.0) values found in our sample imply that the Lyman-continuum escape fraction for M-UV approximate to-19 star-forming galaxies cannot exceed approximate to 8-20% in the reionization era. Show less
