Date: 12/20/2023
Harvard ADS: To high redshift and low mass: exploring the emergence of quenched galaxies and their environments at 3 < z < 6 in the ultra-deep JADES MIRI F770W parallel
Paper abstract: We present the robust selection of quiescent (QG) and post-starburst (PSB) galaxies using ultra-deep NIRCam and MIRI imaging from the JWST Advanced Deep Extragalactic Survey (JADES). Key to this is MIRI 7.7\mum imaging which breaks the degeneracy between old stellar populations and dust attenuation at 3=8.5) sample over 8.8 arcmin^2. Evaluation of this selection with and without 7.7\,\mum shows that dense wavelength coverage with NIRCam (8-11 bands including 1-4 medium-bands) can compensate for lacking the J-band anchor, meaning that robust selection of high-redshift QGs is possible with NIRCam alone. Our sample is characterized by rapid quenching timescales (~100-600 Myr) with formation redshifts z_{\rm f}<~8.5 and includes a potential record-holding massive QG at z_{\rm phot}=5.33_{-0.17}^{+0.16} and two QGs with evidence for significant residual dust content (A_{\rm V}~1-2). In addition, we present a large sample of 12 log M_{*}/M_{\odot}=8.5-9.5 PSBs, demonstrating that UVJ selection can be extended to low mass. Analysis of the environment of our sample reveals that the group known as the Cosmic Rose contains a massive QG and a dust-obscured star-forming galaxy (a so-called Jekyll and Hyde pair) plus three additional QGs within ~20 kpc. Moreover, the Cosmic Rose is part of a larger overdensity at z~3.7 which contains 7/12 of our low-mass PSBs. Another 4 low-mass PSBs are members of an overdensity at z~3.4; this result strongly indicates low-mass PSBs are preferentially associated with overdense environments at z>3.
