A New Record Census of Dwarf AGN and a Bimodal M_BH-M_⋆ Scaling Relation with DESI DR1

@misc{pucha2026record,
  title = {{A New Record Census of Dwarf AGN and a Bimodal $M_\rm BH$-$M_\star$ Scaling Relation with DESI DR1}},
  author = {Ragadeepika Pucha and S. Juneau and M. Mezcua and Arjun Dey and Y. -Y. Mao and D. M. Alexander and C. Circosta and V. A. Fawcett and Wei-Jian Guo and J. Moustakas and S. Panda and M. Siudek and Z. Yu and J. Aguilar and S. Ahlen and D. Bianchi and D. Brooks and T. Claybaugh and K. S. Dawson and A. de la Macorra and P. Doel and S. Ferraro and A. Font-Ribera and J. E. Forero-Romero and E. Gaztañaga and Satya Gontcho A Gontcho and G. Gutierrez and C. Hahn and K. Honscheid and R. Joyce and R. Kehoe and T. Kisner and A. Kremin and M. Landriau and L. Le Guillou and M. Manera and A. Meisner and R. Miquel and S. Nadathur and W. J. Percival and F. Prada and I. Pérez-Ràfols and G. Rossi and E. Sanchez and D. Schlegel and M. Schubnell and J. Silber and D. Sprayberry and G. Tarlé and B. A. Weaver and H. Zou},
  howpublished = {arXiv},
  year = {2026},
  month = oct,
  doi = {10.48550/arxiv.2606.02699},
  eprint = {2606.02699},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2606.02699},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - A New Record Census of Dwarf AGN and a Bimodal M_BH-M_⋆ Scaling Relation with DESI DR1
AU  - Ragadeepika Pucha
AU  - S. Juneau
AU  - M. Mezcua
AU  - Arjun Dey
AU  - Y. -Y. Mao
AU  - D. M. Alexander
AU  - C. Circosta
AU  - V. A. Fawcett
AU  - Wei-Jian Guo
AU  - J. Moustakas
AU  - S. Panda
AU  - M. Siudek
AU  - Z. Yu
AU  - J. Aguilar
AU  - S. Ahlen
AU  - D. Bianchi
AU  - D. Brooks
AU  - T. Claybaugh
AU  - K. S. Dawson
AU  - A. de la Macorra
AU  - P. Doel
AU  - S. Ferraro
AU  - A. Font-Ribera
AU  - J. E. Forero-Romero
AU  - E. Gaztañaga
AU  - Satya Gontcho A Gontcho
AU  - G. Gutierrez
AU  - C. Hahn
AU  - K. Honscheid
AU  - R. Joyce
AU  - R. Kehoe
AU  - T. Kisner
AU  - A. Kremin
AU  - M. Landriau
AU  - L. Le Guillou
AU  - M. Manera
AU  - A. Meisner
AU  - R. Miquel
AU  - S. Nadathur
AU  - W. J. Percival
AU  - F. Prada
AU  - I. Pérez-Ràfols
AU  - G. Rossi
AU  - E. Sanchez
AU  - D. Schlegel
AU  - M. Schubnell
AU  - J. Silber
AU  - D. Sprayberry
AU  - G. Tarlé
AU  - B. A. Weaver
AU  - H. Zou
PY  - 2026
DA  - 2026/10/02
PB  - arXiv
DO  - 10.48550/arxiv.2606.02699
UR  - https://arxiv.org/abs/2606.02699
AB  - Using the first spectroscopic data release from the Dark Energy Spectroscopic Instrument (DESI DR1), we conduct the largest systematic search for active galactic nuclei (AGN) signatures in ≈1.7 million low-redshift (0.001 ≤ z ≤ 0.45) line-emitting galaxies. Based on the [NII]/Hα versus [OIII]/Hβ 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. The AGN fraction in line-emitting galaxies increases monotonically with stellar mass, from ∼1.4% at the low-mass end to ∼93.3% at the high-mass end. Among these AGN, 17,949 exhibit broad Hα emission (BL-AGN), which we use to estimate their black hole (BH) masses via single-epoch virial methods. Leveraging this large BL-AGN sample, we extend the M_BH − M_⋆ scaling relation down to log (M_⋆/M_⊙) ≈ 7.8 and log (M_BH/M_⊙) ≈ 4.4. We find a bimodal distribution of galaxies in this space, characterized by two distinct empirical relations. The relation for galaxies with high stellar and BH masses, extrapolates to overlap with the high-redshift overmassive BH candidates. Our results suggest at least two broad evolutionary pathways for these overmassive BHs and their host galaxies 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.
ER  -