Where did all the Little Red Dots go? The abundance of LRD analogues among objects with broad lines at $z < 0.35$

Lasse Seyberlich, Sarah E. I. Bosman

First listed 2026-08-07 | Last updated 2026-08-07

Abstract

Short digest

Seyberlich and Bosman search an unbiased SDSS parent catalogue of broad-Hα/Hβ galaxies and quasars at z<0.35 for local counterparts to JWST Little Red Dots, combining archival photometry and spectroscopy to identify v-shaped continua and modified-blackbody-like SEDs. Although 19% of broad-line objects have a v-shaped SED, only nine sources meet their local-LRD-analogue criterion, or 0.08% of the full broad-line sample; even among objects matched to typical LRD continuum and line luminosities, the corresponding fractions are just 5% and 0.37%. The recovery of the previously known "Egg" supports the selection, while J0302-0101 emerges as the strongest new candidate despite lying in a galaxy core; most remaining candidates admit alternative explanations. The result makes local analogues a very sparse population and reinforces the unusual combination of broad Balmer emission and LRD-like continuum structure seen at high redshift.

Key figures to inspect

• Figure 1. This is the selection foundation: the UV-versus-optical slope plane shows the colour cuts that define the v-shaped parent subset before the stricter analogue classification.
• Figure 3. The multi-panel diagnostic map places the final nine analogues alongside the local broad-line parent sample and high-redshift LRDs, showing how continuum, line, and Balmer-decrement properties compare across the populations.
• Figure 4. The assembled SDSS, broadband-photometric, and SPHEREx SEDs directly display the modified-blackbody-like continua of all nine selected analogues and locate their turnover relative to the Balmer limit.
• Figure 9. The imaging cutouts provide the key morphological context for the candidates, particularly the extent to which apparently LRD-like nuclei may be embedded in visible host galaxies rather than being compact isolated sources.