# NGDEEP Epoch 1: The Faint-End of the Luminosity Function at $z \sim$ 9-12 from Ultra-Deep JWST Imaging

**Authors:** Gene C. K. Leung, Micaela B. Bagley, Steven L. Finkelstein, Henry C. Ferguson, Anton M. Koekemoer, Pablo G. Perez-Gonzalez, Alexa Morales, Dale D. Kocevski, Guang Yang, Rachel S. Somerville, Stephen M. Wilkins, L. Y. Aaron Yung, Seiji Fujimoto, Rebecca L. Larson, Casey Papovich, Nor Pirzkal, Danielle A. Berg, Jennifer M. Lotz, Marco Castellano, Oscar A. Chavez Ortiz  
**arXiv:** [2306.06244](https://arxiv.org/abs/2306.06244)  
**Date:** 2023-06-09  
**Summary page:** https://www.summarizepaper.com/en/paper/2306.06244v1/

## Key points

- The NGDEEP Survey has produced a sample of very high-redshift galaxy candidates from the first epoch of JWST/NIRCam imaging.
- The NGDEEP NIRCam imaging in HUDF-Par2 reaches m=30.4 (5σ, point-source) in F277W, making it the deepest public JWST GO imaging dataset to date.
- A sample of 38 z≳9 galaxy candidates has been identified using robust photometric redshift selection criteria.
- These objects span a redshift range of z=8.5-15.8, and apparent magnitudes of mF277W = 27-30.5 AB mag, reaching ~1.5 mag deeper than previous public JWST imaging surveys.
- The rest-frame ultraviolet (UV) luminosity function at z~9 and 11 has been calculated, and a new measurement of the luminosity function faint-end slope at z~11 has been presented with no significant evolution in the faint-end slope and number density from z=9 to 11.
- Depth estimation procedures have been developed that provide accurate estimates of survey depth as a function of position on the sky for more precise measurements of source counts and clustering properties.
- This study provides important insights into the early universe and the formation of galaxies at high redshifts.
- The deep imaging data and robust sample of galaxy candidates will be valuable for future studies of the high-redshift universe.

## Summary

The Next Generation Extragalactic Exploratory Deep (NGDEEP) Survey has produced a robust sample of very high-redshift galaxy candidates from the first epoch of {\it JWST}/NIRCam imaging. The NGDEEP NIRCam imaging in the Hubble Ultra Deep Field Parallel Field 2 (HUDF-Par2) reaches $m=30.4$ (5$\sigma$, point-source) in F277W, making it the deepest public {\it JWST} GO imaging dataset to date. The data reduction process incorporates custom corrections for systematic effects to produce high-quality calibrated images. Using robust photometric redshift selection criteria, a sample of 38 $z \gtrsim 9$ galaxy candidates has been identified. These objects span a redshift range of $z=8.5-15.8$, and apparent magnitudes of $m_\mathrm{F277W} = 27-30.5$ AB mag, reaching $\sim 1.5$ mag deeper than previous public {\it JWST} imaging surveys. The rest-frame ultraviolet (UV) luminosity function at $z \sim$ 9 and 11 has been calculated, and a new measurement of the luminosity function faint-end slope at $z \sim 11$ has been presented with no significant evolution in the faint-end slope and number density from $z=9$ to 11. Comparing these results with theoretical predictions can help to constrain how stellar feedback impacts star formation at these early epochs. Furthermore, depth estimation procedures have been developed that provide accurate estimates of survey depth as a function of position on the sky for more precise measurements of source counts and clustering properties. Overall, this study provides important insights into the early universe and the formation of galaxies at high redshifts. The deep imaging data and robust sample of galaxy candidates will be valuable for future studies of the high-redshift universe.