Speaker
Description
JWST has unveiled an abundant population of compact broad-line emitters at $z\gtrsim4$, the Little Red Dots (LRDs), which might represent a previously unprobed supermassive black hole (SMBH) evolution channel predominant at high redshift. However, the LRDs have remained mostly elusive at lower redshift ($z\lesssim0.5$) where detailed studies are possible from ground-based observatories.
We searched for local Little Red Dots (LRDs) in the catalog of the Dark Energy Spectroscopic Instrument (DESI) based on emission line properties, as opposed to earlier approaches that searched for specific spectral energy distributions in photometry. We report the discovery of eight local LRDs at $z=0.2-0.45$, which show similar properties to the high-redshift LRDs in the rest-frame optical. The eight sources are characterized by broad Balmer lines and compact morphologies like their high-redshift counterparts, also showing Balmer absorption features and/or strong He I emission, but weak HeII or other high excitation lines. For 7 out of 8 sources, we retrieve light curves from time-domain surveys and find weak to none intrinsic variability ($0.0-0.1$ mag) over several years in the rest-frame. During our search, we find an AGN which shows analogous features to our sources and we discuss its properties in comparison to LRDs. Given the effective area covered by DESI DR1 ($\sim 9500$ deg$^2$), our sample roughly corresponds to a number density of $1.6\times10^{-9}$Mpc$^{-3}$ at $z<0.45$, confirming about 10,000 lower number densities than in the first billion years of cosmic time.