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DOE OSTI · 2530487

Tripling the Census of Dwarf AGN Candidates Using DESI Early Data

Pucha, Ragadeepika (ORCID:0000000249403009)·Juneau, S. (ORCID:0000000200002394)·Dey, Arjun (ORCID:0000000249284003)·Siudek, M. (ORCID:0000000229492155)·Mezcua, M. (ORCID:000000034440259X)·Moustakas, J. (ORCID:0000000227334559)·BenZvi, S. (ORCID:0000000155374710)·Hainline, K. (ORCID:0000000345658239)·Hviding, R. (ORCID:0000000246849005)·Mao, Yao-Yuan (ORCID:0000000212000820)·Alexander, D. M. (ORCID:0000000258966313)·Alfarsy, R.·Circosta, C. (ORCID:0000000185229434)·Guo, Wei-Jian (ORCID:0000000194570589)·Manwadkar, V. (ORCID:0000000271130262)·Martini, P. (ORCID:0000000242794182)·Weaver, B. A.·Aguilar, J. (ORCID:000000030822452X)·Ahlen, S. (ORCID:0000000160987247)·Bianchi, D. (ORCID:0000000197120006)·Brooks, D.·Canning, R.·Claybaugh, T.·Dawson, K.·de la Macorra, A. (ORCID:0000000217691640)·Dey, Biprateep (ORCID:0000000256657912)·Doel, P.·Font-Ribera, A. (ORCID:0000000230337312)·Forero-Romero, J. E. (ORCID:0000000228903725)·Gaztañaga, E.·Gontcho A Gontcho, S. (ORCID:000000033142233X)·Gutierrez, G.·Honscheid, K.·Kehoe, R.·Koposov, S. E. (ORCID:000000032644135X)·Lambert, A.·Landriau, M. (ORCID:0000000318388528)·Le Guillou, L. (ORCID:0000000171788868)·Meisner, A. (ORCID:0000000211257384)·Miquel, R.·Prada, F. (ORCID:0000000171458674)·Rossi, G.·Sanchez, E. (ORCID:0000000296468198)·Schlegel, D.·Schubnell, M.·Seo, H. (ORCID:0000000265883508)·Sprayberry, D.·Tarlé, G. (ORCID:0000000317040781)·Zou, H. (ORCID:0000000266843997)
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Abstract

Using early data from the Dark Energy Spectroscopic Instrument (DESI) survey, we search for active galactic nuclei (AGN) signatures in 410,757 line-emitting galaxies. By employing the BPT emission-line ratio diagnostic diagram, we identify AGNs in 75,928/296,261 (≈25.6%) high-mass ($\mathrm{log}({M}_{\star }/{M}_{\odot })\,\gt$ 9.5) and 2444/114,496 (≈2.1%) dwarf ($\mathrm{log}({M}_{\star }/{M}_{\odot })\,\leqslant$ 9.5) galaxies. Of these AGN candidates, 4181 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 AGNs and doubles the number of intermediate-mass black hole (M BH ≤ 10 6 M ⊙ ) candidates, spanning a broad discovery space in stellar mass (7 $\lt \mathrm{log}({M}_{\star }/{M}_{\odot })\,\lt$ 12) and redshift (0.001 < 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 ${\rm{log}}({M}_{\star }/{M}_{\odot })\,\approx$ 8.5 and $\mathrm{log}({M}_{\mathrm{BH}}/{M}_{\odot })\,\approx$ 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.

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79 ASTRONOMY AND ASTROPHYSICSAGN host galaxiesdwarf galaxiesintermediate-mass black holes

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Pucha, Ragadeepika (ORCID:0000000249403009), Juneau, S. (ORCID:0000000200002394), Dey, Arjun (ORCID:0000000249284003), Siudek, M. (ORCID:0000000229492155), Mezcua, M. (ORCID:000000034440259X), Moustakas, J. (ORCID:0000000227334559), BenZvi, S. (ORCID:0000000155374710), Hainline, K. (ORCID:0000000345658239), Hviding, R. (ORCID:0000000246849005), Mao, Yao-Yuan (ORCID:0000000212000820), Alexander, D. M. (ORCID:0000000258966313), Alfarsy, R., Circosta, C. (ORCID:0000000185229434), Guo, Wei-Jian (ORCID:0000000194570589), Manwadkar, V. (ORCID:0000000271130262), Martini, P. (ORCID:0000000242794182), Weaver, B. A., Aguilar, J. (ORCID:000000030822452X), Ahlen, S. (ORCID:0000000160987247), Bianchi, D. (ORCID:0000000197120006), Brooks, D., Canning, R., Claybaugh, T., Dawson, K., de la Macorra, A. (ORCID:0000000217691640), Dey, Biprateep (ORCID:0000000256657912), Doel, P., Font-Ribera, A. (ORCID:0000000230337312), Forero-Romero, J. E. (ORCID:0000000228903725), Gaztañaga, E., Gontcho A Gontcho, S. (ORCID:000000033142233X), Gutierrez, G., Honscheid, K., Kehoe, R., Koposov, S. E. (ORCID:000000032644135X), Lambert, A., Landriau, M. (ORCID:0000000318388528), Le Guillou, L. (ORCID:0000000171788868), Meisner, A. (ORCID:0000000211257384), Miquel, R., Prada, F. (ORCID:0000000171458674), Rossi, G., Sanchez, E. (ORCID:0000000296468198), Schlegel, D., Schubnell, M., Seo, H. (ORCID:0000000265883508), Sprayberry, D., Tarlé, G. (ORCID:0000000317040781), Zou, H. (ORCID:0000000266843997). 2025-03-11. Tripling the Census of Dwarf AGN Candidates Using DESI Early Data. https://doi.org/10.3847/1538-4357%2Fadb1dd

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