Lord of LRDs: insights into a 'Little Red Dot' with a low-ionization spectrum at z = 0.1

Recent observations by the James Webb Space Telescope (JWST) have revealed a puzzling population of optically red and compact galaxies with peculiar ‘V’-shaped spectra at high redshift, known as ‘Little Red Dots’ (LRDs). Until now, most spectroscopically confirmed LRDs are found at and it has been speculated that LRDs are tracing the early stages of black hole evolution. We report an independent rediscovery of a broad-line active galactic nucleus (AGN), SDSS J102530.29+140207.3, at , which shows spectral features matching those of LRDs seen in the early Universe, including the V-shaped spectrum, broad Balmer lines (with widths of 1000–2000 ), and deep Balmer absorption. We present a new GTC observation of this LRD, which reveals an optical continuum similar to those of G-to-K giant stars including an unambiguous G-band absorption originating from the CH molecule. In addition, this local LRD shows a series of absorption lines potentially related to low-ionization ions or atoms but are deeper than what is observed in empirical stellar templates. We further identify a series of [Fe ii] emission lines indicative of low-ionization gas, which we find also present in a JWST-selected LRD at . We find small but statistically significant variability in the H of SDSS J102530.29+140207.3 consistent with previous findings. Finally, we report new observations with NuSTAR. We confirm the extreme X-ray weakness of this LRD, which might imply Compton-thick gas obscuration with . All evidence suggests SDSS J102530.29+140207.3 has a complex gaseous environment and the strong ionic, atomic, and molecular absorptions are hard to explain with typical stellar and AGN models.