JWST Discovers an Overdensity around a Metal Absorption-selected Galaxy at z~5.5
Theoretical models suggest a strong correlation between the strengths of early metal absorbers and the local galaxy overdensity, however, direct observational evidence is still lacking. Wu et al. (2023) utilized JWST/NIRcam WFSS observations to search for metal-associated galaxies by detecting their rest-frame [OIII] + Hβ emission. Seven galaxies are confirmed to be associated with a MgII absorber (rest-frame equivalent width = 0.7 Å) at z=5.428. This result suggests that early metals may be generated and reside in an overdense environment.
A Candidate Protocluster around a z=6.6 Quasar
Wang et al. (2023) presents an overdensity of [OIII] emitters a factor of ~10 above the blank field around J0305-3150, a z=6.6 quasar known to be overdense in LBGs, LAEs, and [CII] emitters (Farina et al. 2017, Ota et al. 2018, Venemans et al. 2020, Champagne et al. 2023). A spectroscopically confirmed candidate protocluster now reveals itself with NIRCam WFSS, as well as several serendipitously-discovered overdensities at z~5.5.
Measuring Black Hole Masses with Hβ
Constraining SMBH masses at high redshift is difficult with single epoch measurements, demanding more accurate calibrations with multiple emission lines. Yang et al. (2023) presents the first accurate Hβ-based SMBH measurements for the ASPIRE sample, finding consistency with previous MgII-based masses. The sample shows a remarkable diversity in Fe II emission strength and [OIII] line profiles, hinting at further exciting results to come with the delivery of the full dataset.