JADES and BlackTHUNDER: rest-frame Balmer-line absorption and the local environment in a Little Red Dot at z = 5
Francesco D’Eugenio, Ignas Juodv{z}balis, Xihan Ji, Jan Scholtz, Roberto Maiolino, Stefano Carniani, Michele Perna, Giovanni Mazzolari, Hannah "Ubler, Santiago Arribas, Rachana Bhatawdekar, Andrew J. Bunker, Giovanni Cresci, Emma Curtis-Lake, Kevin Hainline, Kohei Inayoshi, Yuki Isobe, Benjamin D. Johnson, Gareth C. Jones, Tobias J. Looser, Erica J. Nelson, Eleonora Parlanti, D’avid Pusk’as, Pierluigi Rinaldi, Brant Robertson, Bruno Rodr’iguez Del Pino, Irene Shivaei, Fengwu Sun, Sandro Tacchella, Giacomo Venturi, Marta Volonteri, Christina C. Williams, Christopher N. A. Willmer, Chris Willott, Joris Witstok
arXiv:2506.14870v1 Announce Type: new
Abstract: We present a broad-line active galactic nucleus (AGN) at z = 5.077, observed with both NIRSpec/MSA and NIRSpec/IFU by the JADES and BlackTHUNDER surveys. The target exhibits all the hallmark features of a ‘Little Red Dot’ (LRD) AGN. The combination of spatially resolved and high-resolution spectroscopy offers deeper insight into its nature. The H$alpha$ line has multiple components, including two broad Gaussians, yielding a black-hole mass of $log(M_{rm BH}/M_odot) = 7.65$, while the narrow [O III]$lambda$5007 gives a galaxy dynamical mass of $log(M_{rm dyn}/M_odot) = 9.1$, suggesting a dynamically overmassive black hole relative to the host galaxy. The target has two satellites, and is immersed in a 7-kpc wide pool of ionized gas. A spatially detached outflow is also tentatively detected. H$alpha$ shows strong absorption with high equivalent width (EW), ruling out a stellar origin, and with velocity and velocity dispersion of v = -13 km s$^{-1}$ and $sigma$ = 120 km s$^{-1}$. There is tentative evidence (2.6 $sigma$) of temporal variability in the EW of the H$alpha$ absorber over two rest-frame months. If confirmed, this would suggest a highly dynamic environment. Notably, while the H$alpha$ absorber is clearly visible and even dominant in the high-resolution G395H observations, it is not detected in the medium-resolution G395M data of the same epoch. This implies that the current incidence rate of absorbers in LRDs – and especially of rest-frame absorbers – may be severely underestimated, because most LRDs rely on lower-resolution spectroscopy. In this context, the high incidence rate of rest-frame absorbers in LRDs may indicate a configuration that is either intrinsically stationary, such as a rotating disc, or that exhibits time-averaged stability, such as an oscillatory ‘breathing mode’ accretion of cyclic expansion and contraction of the gas around the SMBH.arXiv:2506.14870v1 Announce Type: new
Abstract: We present a broad-line active galactic nucleus (AGN) at z = 5.077, observed with both NIRSpec/MSA and NIRSpec/IFU by the JADES and BlackTHUNDER surveys. The target exhibits all the hallmark features of a ‘Little Red Dot’ (LRD) AGN. The combination of spatially resolved and high-resolution spectroscopy offers deeper insight into its nature. The H$alpha$ line has multiple components, including two broad Gaussians, yielding a black-hole mass of $log(M_{rm BH}/M_odot) = 7.65$, while the narrow [O III]$lambda$5007 gives a galaxy dynamical mass of $log(M_{rm dyn}/M_odot) = 9.1$, suggesting a dynamically overmassive black hole relative to the host galaxy. The target has two satellites, and is immersed in a 7-kpc wide pool of ionized gas. A spatially detached outflow is also tentatively detected. H$alpha$ shows strong absorption with high equivalent width (EW), ruling out a stellar origin, and with velocity and velocity dispersion of v = -13 km s$^{-1}$ and $sigma$ = 120 km s$^{-1}$. There is tentative evidence (2.6 $sigma$) of temporal variability in the EW of the H$alpha$ absorber over two rest-frame months. If confirmed, this would suggest a highly dynamic environment. Notably, while the H$alpha$ absorber is clearly visible and even dominant in the high-resolution G395H observations, it is not detected in the medium-resolution G395M data of the same epoch. This implies that the current incidence rate of absorbers in LRDs – and especially of rest-frame absorbers – may be severely underestimated, because most LRDs rely on lower-resolution spectroscopy. In this context, the high incidence rate of rest-frame absorbers in LRDs may indicate a configuration that is either intrinsically stationary, such as a rotating disc, or that exhibits time-averaged stability, such as an oscillatory ‘breathing mode’ accretion of cyclic expansion and contraction of the gas around the SMBH.