Compact, AGN-hosting Dwarf Galaxies with "Little Red Dots"-like SEDs in the Local Universe

Lulu Bao, Chao-Wei Tsai, Jingwen Wu, Jialai Wang

First listed 2026-05-06 | Last updated 2026-05-06

Abstract

Local active galactic nuclei (AGNs) in dwarf galaxies are often considered as analogs for the earliest supermassive black holes, although their connections require more comprehensive examinations. Motivated by finding the local analogs of "Little Red Dots" (LRDs), the compact, red galaxies discovered by JWST at z > 5 characterized by "V-shaped" SEDs, we compile a sample of local AGN-hosting dwarf galaxies (ADGs) with comparable luminosities to statistically evaluate this connection. By applying K-means clustering to SED shapes and morphological sizes, we classified four groups which trace a sequence in physical properties, including metallicity, star formation rate, and dust emission, mainly driven by their distinct UV-optical slopes. Within these groups, we find that about half of the ADGs exhibit "V-shaped" SEDs and relatively compact morphologies. However, a direct comparison reveals fundamental physical differences: local "V-shaped", compact ADGs appear significantly more evolved than high-z LRDs, characterized by systematically larger effective radii and distinct ionization states. Our results suggest that local compact ADGs likely follow a different formation pathway from LRDs, highlighting the complexity of black hole-galaxy co-evolution across cosmic time.

Short digest

Bao et al. compile a large local comparison set of 1,204 AGN-hosting dwarf galaxies, matched in broad luminosity regime to JWST little red dots, and classify them with K-means using rest-UV/optical SED shape plus galaxy size. The four resulting groups trace a sequence in UV-optical slope, metallicity, star formation, and dust emission, with roughly half of the local dwarf AGN sample showing the same kind of "V-shaped" SEDs and relatively compact morphologies that define LRDs. But the central result is negative in the most interesting way: the local V-shaped, compact systems are still systematically larger and show different ionization states than z>5 LRDs, implying they are more evolved systems rather than straightforward nearby counterparts. That matters because it argues against a simple local-analog picture and points instead to different black-hole/galaxy growth pathways across cosmic time.

Key figures to inspect

• Figure 2 is the key comparison plot: inspect where the local ADGs fall in UV and optical continuum-slope space relative to the LRD density contours and the Kocevski et al. V-shaped selection window to see how much overlap is real versus superficial.
• Figure 3a should show the paper's main phenomenology most clearly: compare the stacked SEDs of the four K-means groups to the LRD template to identify which groups truly reproduce the V-shaped UV-to-optical behavior and how the UV slope appears to drive the sequence.
• Figure 3b is where the local-analog claim is tested morphologically: use the effective-radius distributions to see whether the V-shaped groups are genuinely compact and how their sizes still remain larger than the high-z LRD expectation.
• Figure 4 helps connect the SED classes to dustier mid-IR behavior: inspect whether the groups with redder optical continua also move to distinct WISE color space, clarifying how AGN-heated dust emission differs across the sequence.
• Figure 1 is worth checking for sample context before over-interpreting the analogy: the redshift distributions by selection channel show how heterogeneous the local ADG compilation is, including the systematically higher-redshift DESI broad-line subset.