Tripling the Census of Dwarf AGN Candidates Using DESI Early Data

2024/10/31 by Ragadeepika Pucha, S. Juneau, Pucha, Ragadeepika +114 · 1 voice · 10 citations
Engineering · Physics and Astronomy · #Astronomical Observations and Instrumentation #Astronomy and Astrophysical Research #Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #Gamma-ray bursts and supernovae #astro-ph.GA

paper · pdf · doi:10.48550/arxiv.2411.00091

openalex publication_date 2024/10/31 · arxiv published 2024/10/31 · arxiv updated 2025/02/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/03

Abstract

Using early data from the Dark Energy Spectroscopic Instrument (DESI) survey, we search for AGN signatures in 410,757 line-emitting galaxies. By employing the BPT emission-line ratio diagnostic diagram, we identify AGN in 75,928/296,261 (≈25.6%) high-mass (log (M_⋆/\rm M_\odot) > 9.5) and 2,444/114,496 (≈2.1%) dwarf (log (M_⋆/\rm M_\odot) ≤ 9.5) galaxies. Of these AGN candidates, 4,181 sources exhibit a broad Hα component, allowing us to estimate their BH masses via virial techniques. This study more than triples the census of dwarf AGN and doubles the number of intermediate-mass black hole (IMBH; M_BH ≤ 10⁶~\rm M_\odot) candidates, spanning a broad discovery space in stellar mass (7 < log (M_⋆/M_\odot) < 12) and redshift (0.001 < \rm z < 0.45). The observed AGN fraction in dwarf galaxies (≈2.1%) is nearly four times higher than prior estimates, primarily due to DESI's smaller fiber size, which enables the detection of lower luminosity dwarf AGN candidates. We also extend the M_BH - M_⋆ scaling relation down to log (M_⋆/M_\odot) ≈ 8.5 and log (M_BH/\rm M_\odot) ≈ 4.4, with our results aligning well with previous low-redshift studies. The large statistical sample of dwarf AGN candidates from current and future DESI releases will be invaluable for enhancing our understanding of galaxy evolution at the low-mass end of the galaxy mass function.

Cited by

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• The Eddington Ratio Distribution of Narrow Line Active Galactic Nuclei
• Chandra and HST Observations of Radio-Selected (Wandering) Massive Black Hole Candidates in Dwarf Galaxies
• Identifying the host of compact binary mergers
• Detecting Intermediate-Mass Black Holes out to 20 Mpc with ELT/HARMONI: The Case of FCC 119
• Central Massive Black Holes Are Not Ubiquitous in Local Low-Mass Galaxies
• Feeding frenzy in the mighty black holes: what we could learn from them?
• Search for Faint Lone Double-Peaked Hα Lines as IMBH Signatures in the MUSE Deep Field
• A Jetted Wandering Massive Black Hole Candidate in a Dwarf Galaxy

Discussions

• Tripling the Census of Dwarf #AGN Candidates Using DESI Early Data: arxiv.org/abs/2411.00091 -> DESI Uncovers 300 New Intermediate-Mass Black Holes Plus 2500 New Active Black Holes in Dwarf Galaxies: [bsky, 0 points, 0 comments]

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