1 research outputs found
Paper 1: The JWST PEARLS View of the El Gordo Galaxy Cluster and of the Structure It Magnifies
The massive galaxy cluster El Gordo (z=0.87) imprints multitudes of
gravitationally lensed arcs onto James Webb Space Telescope (JWST)
Near-Infrared Camera (NIRCam) images. Eight bands of NIRCam imaging were
obtained in the ``Prime Extragalactic Areas for Reionization and Lensing
Science'' (``PEARLS'') program. PSF-matched photometry across Hubble Space
Telescope (HST) and NIRCam filters supplies new photometric redshifts. A new
light-traces-mass lens model based on 56 image multiplicities identifies the
two mass peaks and yields a mass estimate within 500 kpc of ~(7.0 +/- 0.30) x
10^14 Msun. A search for substructure in the 140 cluster members with
spectroscopic redshifts confirms the two main mass components. The southeastern
mass peak that contains the BCG is more tightly bound than the northwestern
one. The virial mass within 1.7 Mpc is (5.1 +/- 0.60) x 10^14 Msun, lower than
the lensing mass. A significant transverse velocity component could mean the
virial mass is underestimated. We contribute one new member to the previously
known z=4.32 galaxy group. Intrinsic (delensed) positions of the five secure
group members span a physical extent of ~60 kpc. Thirteen additional candidates
selected by spectroscopic/photometric constraints are small and faint with a
mean intrinsic luminosity ~2.2 mag fainter than L*. NIRCam imaging admits a
fairly wide range of brightnesses and morphologies for the group members,
suggesting a more diverse galaxy population in this galaxy overdensity.Comment: 24 pages, accepted by Ap