Search for High-Ionization Nebular Emission (SHINE). I. A Systematically Selected [Ne V] Sample at z > 3 with JWST/NIRSpec PRISM

@misc{satyapal2026search,
  title = {{Search for High-Ionization Nebular Emission (SHINE). I. A Systematically Selected [Ne V] Sample at z > 3 with JWST/NIRSpec PRISM}},
  author = {Shobita Satyapal and Sara Doan and Daniel Schaerer and Rui Marques-Chaves and Anurag Sawarkar and William Matzko and Camilo Vazquez and C. Daoutis and D. Korber and I. Morel and Mengyuan Xia},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.27130},
  eprint = {2609.27130},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.27130},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - Search for High-Ionization Nebular Emission (SHINE). I. A Systematically Selected [Ne V] Sample at z > 3 with JWST/NIRSpec PRISM
AU  - Shobita Satyapal
AU  - Sara Doan
AU  - Daniel Schaerer
AU  - Rui Marques-Chaves
AU  - Anurag Sawarkar
AU  - William Matzko
AU  - Camilo Vazquez
AU  - C. Daoutis
AU  - D. Korber
AU  - I. Morel
AU  - Mengyuan Xia
PY  - 2026
DA  - 2026/09/22
PB  - arXiv
DO  - 10.48550/arxiv.2609.27130
UR  - https://arxiv.org/abs/2609.27130
AB  - We conduct the first systematic Search for High-Ionization Nebular Emission (SHINE) using [Ne V]λ3426 in JWST/NIRSpec PRISM spectroscopy at z>3. From more than 9,000 galaxies, we identify 25 [Ne V] emitters spanning z=3.059-$9.444$ and log_10(L_[Ne V]/erg s^−1)=40.70-$42.86$. Their [Ne V] luminosities overlap with those of local [Ne V]-selected active galactic nuclei (AGNs) and exceed those of local metal-poor [Ne V] emitters, although such low-luminosity systems would fall below our sensitivity. The population is diverse, spanning compact and extended morphologies and a broad range of continuum properties and stellar masses, including very low-mass hosts. It includes sources with broad Balmer emission as well as others whose higher-resolution spectra do not require a broad component. The [Ne V] emitters overlap only partly with conventional AGN diagnostics: most do not satisfy conservative high-redshift AGN criteria based on strong rest-optical narrow-line ratios, and only a minority have adopted broad-line classifications. [Ne V] upper limits for independently selected broad-line AGNs and little red dots are too shallow to establish a population-wide [Ne V] deficit. Six sources have secure Chandra counterparts, showing that X-ray weakness is not universal among luminous [Ne V] emitters. Strong [Ne V]/[Ne III] emission is associated with redder ultraviolet slopes and stronger Balmer breaks, but not with UV luminosity, possibly linking strong high-ionization emission to recent changes in star formation. The observed incidence of luminous [Ne V] emission shows no significant evolution over z>3, despite an increasing robust [Ne III] detection fraction. The high [Ne V] luminosities and hard line ratios favor black-hole accretion as the dominant power source, establishing [Ne V] emission as a complementary probe of early black-hole growth.
ER  -