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arXiv · 2211.13763

MOSEL Survey: Extremely weak outflows in EoR analogues at z=3-4

Anshu Gupta·Kim-Vy Tran·Trevor Mendel·Anishya Harshan·Ben Forrest·R. L. Davies·Emily Wisnioski·Themiya Nanayakkara·Glenn G. Kacprzak·Lisa J. Kewley
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Abstract

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.

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Anshu Gupta, Kim-Vy Tran, Trevor Mendel, Anishya Harshan, Ben Forrest, R. L. Davies, Emily Wisnioski, Themiya Nanayakkara, Glenn G. Kacprzak, Lisa J. Kewley. 2022-11-24. MOSEL Survey: Extremely weak outflows in EoR analogues at z=3-4. https://doi.org/10.1093/mnras%2Fstac3548

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