A Quasar-anchored Protocluster at <i>z</i> = 6.6 in the ASPIRE Survey. I. Properties of [O <scp>iii</scp>] Emitters in a 10 Mpc Overdensity Structure
Abstract A SPectroscopic survey of bIased halos in the Reionization Era is a quasar legacy survey primarily using JWST to target a sample of 25 z > 6 quasars with NIRCam slitless spectroscopy and imaging. The first study in this series found evidence of a strong overdensity of galaxies around J0305−3150, a luminous quasar at z = 6.61, within a single NIRCam pointing obtained in JWST Cycle 1. Here we present the first results of a JWST Cycle 2 mosaic that covers 35 arcmin 2 with NIRCam imaging/wide-field slitless spectroscopy of the same field to investigate the spatial extent of the putative protocluster. The F356W grism data target [O iii ]+H β at 5.3 < z < 7 and reveal a population of 124 line emitters down to a flux limit of 1.2 × 10 −18 erg s −1 cm −2 . Fifty-three of these galaxies lie at 6.5 < z < 6.8 spanning 10 cMpc on the sky, corresponding to an overdensity within a 2500 cMpc 3 volume of 12.5 ± 2.6, anchored by the quasar. Comparing to the [O iii ] luminosity function from the Emission line galaxies and Intergalactic Gas in the Epoch of Reionization project, we find a dearth of faint [O iii ] emitters at log( L /erg s −1 ) < 42.3, which we suggest is consistent with either bursty star formation causing galaxies to scatter around the grism detection limit or modest suppression from quasar feedback. While we find a strong filamentary overdensity of [O iii ] emitters consistent with a protocluster, we suggest that we could be insensitive to a population of older, more massive Lyman break galaxies with weak nebular emission on scales >10 cMpc.
Authors
- Tiago Costa (ORCID: https://orcid.org/0000-0002-6748-2900)
- Alessandro Lupi (ORCID: https://orcid.org/0000-0001-6106-7821)
- Maria Pudoka (ORCID: https://orcid.org/0000-0003-4924-5941)
- F. Loiacono (ORCID: https://orcid.org/0000-0002-8858-6784)
- Fengwu Sun (ORCID: https://orcid.org/0000-0002-4622-6617)
- Joseph F. Hennawi (ORCID: https://orcid.org/0000-0002-7054-4332)
- Hyunsung D. Jun (ORCID: https://orcid.org/0000-0003-1470-5901)
- Xiaohui Fan (ORCID: https://orcid.org/0000-0003-3310-0131)
- Jinyi Yang (ORCID: https://orcid.org/0000-0001-5287-4242)
- Jaclyn B. Champagne (ORCID: https://orcid.org/0000-0002-6184-9097)
- Xiangyu Jin (ORCID: https://orcid.org/0000-0002-5768-738X)
- Siwei Zou (ORCID: https://orcid.org/0000-0002-3983-6484)
- Feige Wang (ORCID: https://orcid.org/0000-0002-7633-431X)
- Bram Venemans (ORCID: https://orcid.org/0000-0001-9024-8322)
- Chiara Mazzucchelli (ORCID: https://orcid.org/0000-0002-5941-5214)
- Wei Leong Tee (ORCID: https://orcid.org/0000-0003-0747-1780)
- Anna–Christina Eilers (ORCID: https://orcid.org/0000-0003-2895-6218)
- Eduardo Bañados (ORCID: https://orcid.org/0000-0002-2931-7824)
- Weizhe Liu (ORCID: https://orcid.org/0000-0003-3762-7344)
- Sofía Rojas-Ruiz (ORCID: https://orcid.org/0000-0003-2349-9310)
- Sarah E. I. Bosman (ORCID: https://orcid.org/0000-0001-8582-7012)
- Maxime Trebitsch (ORCID: https://orcid.org/0000-0002-6849-5375)
- Ryan Endsley (ORCID: https://orcid.org/0000-0003-4564-2771)
- Ming-Yang Zhuang (ORCID: https://orcid.org/0000-0001-5105-2837)
- Klaudia Protušová
- Mingyu Li (ORCID: https://orcid.org/0000-0001-6251-649X)
- Haowen Zhang (ORCID: https://orcid.org/0000-0002-4321-3538)
- Xiaojing Lin (ORCID: https://orcid.org/0000-0001-6052-4234)
Publication Details
- Journal
- The Astrophysical Journal
- Published
- 2025-03-04
- DOI
- https://doi.org/10.3847/1538-4357/adb1bd
- Citations
- 11
- Primary Topic
- Galaxies: Formation, Evolution, Phenomena
- Type
- article
- Field-Weighted Citation Impact
- 12.70
Funders
- Space Telescope Science Institute