SIMBAD references

JWST has revealed a population of broad-line active galactic nuclei at z > 4 with remarkably red colors, so-called “Little Red Dots” (LRDs). Ubiquitous Balmer breaks suggest that they harbor old stellar populations in massive, compact host galaxies. We present Atacama Large Millimeter/submillimeter Array observations of three LRDs at z = 3.10, 4.46, and 7.04, targeting molecular and neutral gas via CO(7-6) and [C I](2-1), respectively. We do not detect CO in any target, placing conservative limits on the host molecular gas mass of ≲(1-5) × 10¹⁰M_⊙. We report the tentative (∼3.5σ) detection of the [C I](2-1) line in A2744-45924 (z = 4.46), one of the brightest known LRDs. The [C I] line is narrow (FWHM ∼ 80 km s^–1), implying a dynamical mass ≲10¹⁰M_⊙, adopting conservative limits for the size of the galaxy. The dynamical mass limit is significantly lower than expected from the local M_BH-M_dyn relation, and is an order of magnitude below the stellar mass derived from spectral energy distribution fitting, potentially supporting a nonstellar origin of the Balmer break. These results, while tentative, paint a picture of LRDs that is markedly different than typical high-z quasars, which live in massive, gas-rich, and actively star-forming host galaxies.