Tentative detection of neutral gas in a Little Red Dot at $z=4.46$

Understand

JWST has revealed a population of broad-line active galactic nuclei at $z>4$ with remarkably red colors, so-called "Little Red Dots." Ubiquitous Balmer breaks suggest that they harbor old stellar populations in massive, compact host galaxies.

• We present ALMA observations of three LRDs at $z=3.10$, $4.46$, and $7.04$, targeting molecular and neutral gas via CO(7-6) and [CI](2-1), respectively.
• We do not detect CO in any target, placing conservative limits on the host molecular gas mass $\lesssim 1$-$5\times10^{10}$ M$_\odot$.
• We report the tentative ($4.9\sigma$) detection of the [CI](2-1) line in A2744-45924 ($z=4.46$), one of the brightest known LRDs.