(LRDs) 2 : The Low-ReDshift Little Red Dots Survey. II. DESI DR1 Sample

JWST has revealed a substantial population of “Little Red Dots” (LRDs) at z > 4, challenging conventional active galactic muclei (AGN) frameworks. However, the low-redshift regime remains largely unexplored. In the second paper of the (LRDs) 2 series, we present a systematic selection from DESI DR1 and identify 27 LRDs at z = 0.2–0.9, yielding a number density lower limit of 7.5 × 10 −10 cMpc −3 . We conducted near-IR spectroscopic follow-up observations for 21 of them, revealing their full spectral energy distribution (SED) shapes and emission lines. These low- z LRDs share the hallmark properties of their high- z counterparts: compact morphology, V-shaped UV-optical continua, broad Balmer emission with extreme decrements (median H α /H β ∼ 15), frequent Balmer absorption (70%), and blackbody-like optical-to-near-IR continua. All have low metallicity, occupy the same regions in the BPT diagram as high- z LRDs, and have softer ionizing spectra than typical AGNs. The consistency between low- z and high- z LRD properties indicates the same physical processes at work. The correlation between broad-line Balmer luminosity and L 5100 deviates from that of local type-1 AGNs, limiting the direct application of local BH mass calibrations. Ionized [O iii ] outflows are ubiquitous (78%). One LRD at z = 0.196, J1717+3807, shows robust long-term variability in the i and Wide-field Infrared Survey Explorer (WISE) bands. The optical-to-near-IR continua of LRDs reveal a wide range of temperatures ∼2000–4700 K (peak 0.6–1.4 μ m), with a subset showing cooler and larger envelopes than those at high z . Low- z LRDs serve not only as proximate laboratories for probing the nature of LRDs, but also trace the cosmic evolution of this population from the cosmic dawn to the present day.