ASPIRE

The Impact of Galaxies on the CGM Metal Enrichment at z>6

Discovering the signatures of the first objects (stars, black holes, and galaxies) is one of the major goals of JWST. Zou et al. (2024) characterized the multiphase circumgalactic medium (CGM) and galaxy properties at z = 6.0-6.5 in four quasar fields using ASPIRE and VLT/Xshooter data. The results found that the α elements to iron ([α/Fe]) ratio in the CGM gas at z>6 exhibits an enhancement. Their modeling of the galaxy’s chemical abundance favors a top-heavy stellar initial mass function, and the Pop III IMF can possibly explain the observed value in the CGM. We may be witnessing the contribution of the first generation Pop III stars to the CGM at the end of the reionization epoch.

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.