MOSEL Survey: Extremely weak outflows in EoR analogues at z=3-4 by Anshu Gupta et al. on Monday 28 November

This paper presents deep K-band spectroscopic observations of galaxies at

z=3-4 with composite photometric rest-frame Hb+[OIII] equivalent widths

EW_0>600A, comparable to the EW of galaxies observed during the epoch of

reionisation (EoR, z>6). The typical spectroscopic [OIII] EW_0 and stellar mass

of our targets is ~ 700A and log(M_star/M_sun)=8.98. By stacking the [OIII]

emission profiles, we find evidence of a weak broad component with

F_broad/F_narrow ~ 0.2 and velocity width sigma_{broad} ~ 170 km/s. The

strength and velocity width of the broad component does not change

significantly with stellar mass and [OIII] EW_0 of the stacked sample. Assuming

similar broad component profiles for [OIII] and Halpha emission, we estimate a

mass loading factor ~0.2, similar to low stellar mass galaxies at z>1 even if

the star formation rates of our sample is 10 times higher. We hypothesize that

either the multi-phase nature of supernovae driven outflows or the suppression

of winds in the extreme star-forming regime is responsible for the weak

signature of outflows in the EoR analogues.

arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.13763v1