The BoRG-JWST Survey: Program Overview and First Confirmations of Luminous Reionization-era Galaxies from Pure-parallel Observations
Abstract We present the BoRG-JWST survey, a combination of two JWST Cycle 1 programs aimed at obtaining NIRSpec spectroscopy of representative, UV-bright 7 < z < 10 galaxy candidates across 22 independent sight lines selected from Hubble/WFC3 pure-parallel observations. We confirm the high- z nature of 12 out of 21 observed primary targets through low-resolution prism observations, with the rest revealing themselves unsurprisingly to be z ∼ 1–3 interlopers, brown dwarfs, or yielding inconclusive results. From the Multi Shutter Array (MSA) observations, we confirm an additional nine filler sources at z > 5, highlighting the large abundance of high-redshift galaxies even in individual WFC3 pointings. The primary sample spans the absolute magnitude range −20.4 mag < M UV < −22.4 mag and harbors UV continuum slopes of β ≃ −2.5 to −2.0, representing some of the most luminous z > 7 sources currently known and comparable to the brightest NIRCam sources at z > 10. Prominent [O iii ]+H β lines are found across the full sample, while a stack of sources reveals a plethora of other rest-optical lines and additional rest-UV C III ] 1909 Å emission. Despite their luminosities, none of the low-resolution spectra display evidence for type 1 active galactic nucleus activity based on a search for broad-line emission. Lastly, we present a spectroscopic data release of 188 confirmed 0.5 ≲ z ≲ 5.0 sources from filler MSA observations, highlighting the legacy value of the survey and a representative benchmark for comparisons to deep field observations.
Authors
- Christian Soto (ORCID: https://orcid.org/0000-0001-7840-2972)
- Guido Roberts-Borsani (ORCID: https://orcid.org/0000-0002-4140-1367)
- Óscar A. Chávez Ortiz (ORCID: https://orcid.org/0000-0003-2332-5505)
- Nicha Leethochawalit (ORCID: https://orcid.org/0000-0003-4570-3159)
- Charlotte Mason (ORCID: https://orcid.org/0000-0002-3407-1785)
- Rebecca L. Larson (ORCID: https://orcid.org/0000-0003-2366-8858)
- Tommaso Treu (ORCID: https://orcid.org/0000-0002-8460-0390)
- Gene C. K. Leung (ORCID: https://orcid.org/0000-0002-9393-6507)
- Rachel S. Somerville (ORCID: https://orcid.org/0000-0002-6748-6821)
- Pablo Arrabal Haro (ORCID: https://orcid.org/0000-0002-7959-8783)
- Katherine Chworowsky (ORCID: https://orcid.org/0000-0003-4922-0613)
- Susan A. Kassin (ORCID: https://orcid.org/0000-0002-3838-8093)
- Takahiro Morishita (ORCID: https://orcid.org/0000-0002-8512-1404)
- L. Y. Aaron Yung (ORCID: https://orcid.org/0000-0003-3466-035X)
- Eduardo Bañados (ORCID: https://orcid.org/0000-0002-2931-7824)
- Sofía Rojas-Ruiz (ORCID: https://orcid.org/0000-0003-2349-9310)
- Steven L. Finkelstein (ORCID: https://orcid.org/0000-0001-8519-1130)
- M. Stiavelli (ORCID: https://orcid.org/0000-0001-9935-6047)
- Micaela B. Bagley (ORCID: https://orcid.org/0000-0002-9921-9218)
- Taylor A. Hutchison (ORCID: https://orcid.org/0000-0001-6251-4988)
- Michele Trenti (ORCID: https://orcid.org/0000-0001-9391-305X)
Institutions
- Damien Foundation (BD)
Publication Details
- Journal
- The Astrophysical Journal
- Published
- 2025-04-01
- DOI
- https://doi.org/10.3847/1538-4357/adba60
- Citations
- 8
- Primary Topic
- Galaxies: Formation, Evolution, Phenomena
- Type
- article
- Field-Weighted Citation Impact
- 9.24
Funders
- National Science Foundation
- National Aeronautics and Space Administration
- Villum Fonden
- Space Telescope Science Institute
- Flatiron Health
- National Research Foundation
- Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung
- Danmarks Grundforskningsfond