TY - JOUR
T1 - A New Record Census of Dwarf AGN and a Bimodal MBH − M⋆ Scaling Relation with DESI DR1
AU - DESI Collaboration
AU - Pucha, Ragadeepika
AU - Juneau, S.
AU - Mezcua, M.
AU - Dey, Arjun
AU - Mao, Y. -Y.
AU - Alexander, D. M.
AU - Circosta, C.
AU - Fawcett, V. A.
AU - Guo, Wei-Jian
AU - Moustakas, J.
AU - Panda, S.
AU - Siudek, M.
AU - Yu, Z.
AU - Aguilar, J.
AU - Ahlen, S.
AU - Bianchi, D.
AU - Brooks, D.
AU - Claybaugh, T.
AU - Dawson, K. S.
AU - Macorra, A. de la
AU - Doel, P.
AU - Ferraro, S.
AU - Font-Ribera, A.
AU - Forero-Romero, J. E.
AU - Gaztañaga, E.
AU - Gontcho, Satya Gontcho A
AU - Gutierrez, G.
AU - Hahn, C.
AU - Honscheid, K.
AU - Joyce, R.
AU - Kehoe, R.
AU - Kisner, T.
AU - Kremin, A.
AU - Landriau, M.
AU - Guillou, L. Le
AU - Manera, M.
AU - Meisner, A.
AU - Miquel, R.
AU - Nadathur, S.
AU - Percival, W. J.
AU - Prada, F.
AU - Pérez-Ràfols, I.
AU - Rossi, G.
AU - Sanchez, E.
AU - Schlegel, D.
AU - Schubnell, M.
AU - Silber, J.
AU - Sprayberry, D.
AU - Tarlé, G.
AU - Weaver, B. A.
N1 - 32 pages, 15 figures, Submitted to AAS Journals
PY - 2026/9/24
Y1 - 2026/9/24
N2 - Using the first spectroscopic data release from the Dark Energy Spectroscopic Instrument (DESI DR1), we search for AGN signatures in 1,678,787 low-redshift (0.001≤z≤0.45) line-emitting galaxies. Based on the [NII]-BPT emission-line ratio diagnostic, we identify AGN in 314,245/1,211,573 (25.9%) high-mass (log(M⋆/M⊙)>9.5) and 9648/467,214 (2.1%) dwarf (log(M⋆/M⊙)≤9.5) galaxies. Among these AGN, 17,949 are broad-line candidates (BL-AGN) with broad Hα emission, enabling black hole (BH) mass estimates using single-epoch virial methods. We find that the AGN fraction in line-emitting galaxies increases monotonically with stellar mass, rising from ∼1.4% at the low-mass end to ∼93.3% at the high-mass end. Using the large BL-AGN sample, we extend the MBH−M⋆ scaling relation down to log(M⋆/M⊙)≈7.8 and log(MBH/M⊙)≈4.4. In the context of high-redshift overmassive BHs, our results suggest that galaxies and their central BHs may follow two distinct evolutionary pathways across cosmic time. With this paper, we release the EmFit value-added catalog, containing emission-line flux and width measurements for ∼7.4 million galaxies, the largest catalog with emission-line decomposition into narrow, broad, and outflow components to date. This work significantly expands upon the early DESI results and provides a statistical sample for probing the galaxy−BH connection in the low-mass galaxy regime.
AB - Using the first spectroscopic data release from the Dark Energy Spectroscopic Instrument (DESI DR1), we search for AGN signatures in 1,678,787 low-redshift (0.001≤z≤0.45) line-emitting galaxies. Based on the [NII]-BPT emission-line ratio diagnostic, we identify AGN in 314,245/1,211,573 (25.9%) high-mass (log(M⋆/M⊙)>9.5) and 9648/467,214 (2.1%) dwarf (log(M⋆/M⊙)≤9.5) galaxies. Among these AGN, 17,949 are broad-line candidates (BL-AGN) with broad Hα emission, enabling black hole (BH) mass estimates using single-epoch virial methods. We find that the AGN fraction in line-emitting galaxies increases monotonically with stellar mass, rising from ∼1.4% at the low-mass end to ∼93.3% at the high-mass end. Using the large BL-AGN sample, we extend the MBH−M⋆ scaling relation down to log(M⋆/M⊙)≈7.8 and log(MBH/M⊙)≈4.4. In the context of high-redshift overmassive BHs, our results suggest that galaxies and their central BHs may follow two distinct evolutionary pathways across cosmic time. With this paper, we release the EmFit value-added catalog, containing emission-line flux and width measurements for ∼7.4 million galaxies, the largest catalog with emission-line decomposition into narrow, broad, and outflow components to date. This work significantly expands upon the early DESI results and provides a statistical sample for probing the galaxy−BH connection in the low-mass galaxy regime.
KW - astro-ph.GA
U2 - 10.3847/1538-4357/ae9859
DO - 10.3847/1538-4357/ae9859
M3 - Article
SN - 0004-637X
VL - 1009
JO - The Astrophysical Journal
JF - The Astrophysical Journal
IS - 2
M1 - 150
ER -