From "The Cliff" to "Virgil": Mapping the Spectral Diversity of Little Red Dots with JWST/NIRSpec
Guillermo Barro, Pablo G. Perez-Gonzalez, Dale Kocevski, Jonathan R. Trump, Mark Dickinson, Pablo Arrabal Haro, Madisyn Brooks, Callum T. Donnan, James S. Dunlop, Steven L. Finkelstein, Maximilien Franco, Giovanni Gandolfi, Mauro Giavalisco, Norman A. Grogin, Michaela Hirschmann

TL;DR
This study uses JWST/NIRSpec data to analyze 'Little Red Dots', revealing their spectral diversity, AGN characteristics, and the relationship between their UV-optical properties and underlying physical components.
Contribution
It provides the first comprehensive spectral analysis of LRDs, linking their spectral features to black hole and host galaxy properties, and introduces a model explaining their diversity.
Findings
Redder LRDs have higher-luminosity, less obscured black holes.
Bluer LRDs show more host-dominated emission and dust reddening.
Spectral properties correlate with black hole luminosity and obscuration levels.
Abstract
One of JWST's most unexpected discoveries is the emergence of "Little Red Dots'' (LRDs): compact sources at with blue rest-frame UV continua, red optical slopes, and broad Balmer emission lines that challenge standard models and suggest a population of early, unusual active galactic nuclei (AGNs). Using a comprehensive photometric selection and public NIRSpec/PRISM spectroscopy across six JWST deep fields, we identify a large sample of 118 LRDs with high-S/N spectra, enabling a population-wide analysis of their UV-optical continuum and emission lines. We find clear correlations between rest-frame color ([0.3-0.9\,m]) and slopes: bluer LRDs have blue UV slopes () and red optical slopes, while redder LRDs exhibit redder UV slopes (). The continuum shape shows a similar trend: redder LRDs display…
Peer Reviews
No public reviews on file for this paper yet. If you reviewed it on a platform where reviews are public (OpenReview, ICLR, NeurIPS, ICML), you can paste yours below so the community can read it here.
Videos
No videos yet. Explain this paper in a talk, walkthrough, or lecture? Add one.
Taxonomy
TopicsGalaxies: Formation, Evolution, Phenomena · Astrophysical Phenomena and Observations · Astronomy and Astrophysical Research
