The UNCOVER Survey: A first-look HST+JWST catalog of 60,000 galaxies near Abell 2744 and beyond (2301.02671v2)

Abstract: In November 2022, the James Webb Space Telescope (JWST) returned deep near-infrared images of Abell 2744 -- a powerful lensing cluster capable of magnifying distant, incipient galaxies beyond it. Together with the existing Hubble Space Telescope (HST) imaging, this publicly available dataset opens a fundamentally new discovery space to understand the remaining mysteries of the formation and evolution of galaxies across cosmic time. In this work, we detect and measure some 60,000 objects across the 49 arcmin$^2$ JWST footprint down to a $5\,\sigma$ limiting magnitude of $\sim$30 mag in 0.32" apertures. Photometry is performed using circular apertures on images matched to the point spread function of the reddest NIRCam broad band, F444W, and cleaned of bright cluster galaxies and the related intra-cluster light. To give an impression of the photometric performance, we measure photometric redshifts and achieve a $\sigma_{\rm NMAD}\approx0.03$ based on known, but relatively small, spectroscopic samples. With this paper, we publicly release our HST and JWST PSF-matched photometric catalog with optimally assigned aperture sizes for easy use, along with single aperture catalogs, photometric redshifts, rest-frame colors, and individual magnification estimates. These catalogs will set the stage for efficient and deep spectroscopic follow-up of some of the first JWST-selected samples in Summer 2023.

• The paper presents a groundbreaking HST+JWST photometric catalog of ~60K galaxies, enabling detailed studies of galaxy formation through gravitational lensing.
• It employs advanced circular aperture photometry and accurate photometric redshift estimation (σ_NMAD ~0.03) to ensure precise measurements of faint galaxies.
• The survey provides a vital resource for future spectroscopic follow-ups and refined models of high-redshift galactic evolution in the Abell 2744 region.

Insights from "The UNCOVER Survey: A first-look HST+JWST catalog of 60,000 galaxies near Abell 2744 and beyond"

The paper presented in "The UNCOVER Survey" paper provides a comprehensive photometric catalog of around 60,000 galaxies situated in the region of the Abell 2744 cluster. This work leverages observations from both the Hubble Space Telescope (HST) and the James Webb Space Telescope (JWST), specifically employing the capabilities of the NIRCam and NIRISS instruments on JWST to capture deep field images with remarkable sensitivity in the near-infrared spectrum. The primary focus of this catalog is to facilitate a deeper understanding of galactic formation and evolution over cosmic timescales, taking advantage of the gravitational lensing effect of the Abell 2744 cluster to observe distant galaxies.

Primary Achievements and Methodology

The catalog is based on a dataset obtained from a synergy of instruments involving the HST and JWST, targeting the Abell 2744 cluster region. Gravitational lensing was used as a tool to magnify and paper distant galaxies, enabling the survey to detect galaxies otherwise too faint to be observed. The researchers have identified approximately 60,000 objects across a 49 square arcminute area, with a detection sensitivity reaching a limiting magnitude of ~30 AB in 0.32 arcsec apertures for a 5σ detection threshold.

To ensure the accuracy and reliability of the data, several methodological steps and innovations were implemented, including:

• Photometry from JWST images was handled using circular apertures, matched to the point spread function (PSF) of the NIRCam's F444W filter, minimizing light interference from the cluster's intra-cluster medium.
• The catalog underwent rigorous photometric redshift estimation, achieving a σ_NMAD ~0.03, further validated with available spectroscopic redshift data.
• A refined public release accompanies these efforts, offering a comprehensive set of parameters, including photometric redshifts, rest-frame colors, and individual magnification estimates.

Implications and Future Prospects

The findings from the UNCOVER Survey have profound implications for our understanding of the high-redshift universe. The ability to detect faint galaxies through gravitational lensing increases the available sample size of galaxies during the epoch of reionization. This, in turn, enables astronomers to construct more accurate models of galaxy formation and evolution.

Practically, this catalog provides a foundational resource for designing and optimizing spectroscopic follow-up studies to explore the evolutionary trajectories of these distant galaxies rigorously. The availability of derived photometric redshifts presents researchers with a vital tool for initially characterizing these galaxies' properties and assembling a coherent picture of the cosmic history.

Theoretically, this research underscores the importance of combined optical-IR capabilities of the HST and JWST, highlighting how multi-wavelength imaging can overcome challenges associated with observing the distant universe. The approach demonstrated in this survey serves as a template for future observational campaigns, especially in the context of the ever-increasing demand for high-angular resolution cosmic inventories.

Conclusion

In synthesizing the unprecedented capabilities of the JWST with the enduring strengths of the HST, the UNCOVER Survey paper stands as a milestone in the field of astrophysics. It not only enriches our galactic repository with tens of thousands of new entries but also opens new pathways for studying the early universe, magnifying our understanding of both the methodology and the cosmic entities under investigation. Future explorations could expand upon this work by integrating more diverse datasets, potentially from other forthcoming space telescopes, broadening the survey’s scope both in volume and in depth.