Near-infrared emission line diagnostics for AGN from the local Universe to z ∼ 3

Antonello Calabrò, Laura Pentericci, Anna Feltre, Pablo Arrabal Haro, Mario Radovich, Lise Marie Seillé, Ernesto Oliva, Emanuele Daddi, Ricardo Amorín, Micaela B. Bagley, Laura Bisigello, Véronique Buat, Marco Castellano, Nikko J. Cleri, Mark Dickinson, Vital Fernández, Steven L. Finkelstein, Mauro Giavalisco, Andrea Grazian, Nimish P. HathiMichaela Hirschmann, Stéphanie Juneau, Jeyhan S. Kartaltepe, Anton M. Koekemoer, Ray A. Lucas, Casey Papovich, Pablo G. Pérez-González, Nor Pirzkal, Paola Santini, Jonathan Trump, Alexander De La Vega, Stephen M. Wilkins, L. Y. Aaron Yung, Paolo Cassata, Raphael A.S. Gobat, Sara Mascia, Lorenzo Napolitano, Benedetta Vulcani

Producción científica: Contribución a una revistaArtículorevisión exhaustiva

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Optical rest-frame spectroscopic diagnostics are usually employed to distinguish between star formation and active galactic nucleus (AGN) powered emission. However, this method is biased against dusty sources, hampering a complete census of the AGN population across cosmic epochs. To mitigate this effect, it is crucial to observe at longer wavelengths in the rest-frame near-infrared (near-IR), which is less affected by dust attenuation and can thus provide a better description of the intrinsic properties of galaxies. AGN diagnostics in this regime have not been fully exploited so far, due to the scarcity of near-IR observations of both AGN and star-forming galaxies, especially at redshifts higher than 0.5. Using Cloudy photoionization models, we identified new AGN star formation diagnostics based on the ratio of bright near-IR emission lines, namely [SIII] 9530 Å, [CI] 9850 Å, [PII] 1:188 μ m, [FeII] 1:257 μ m, and [FeII] 1:64 μ m to Paschen lines (either Pa or Paß), providing simple, analytical classification criteria. We applied these diagnostics to a sample of 64 star-forming galaxies and AGN at 0 = z = 1, and 65 sources at 1 = z = 3 recently observed with JWST-NIRSpec in CEERS. We find that the classification inferred from the near-IR is broadly consistent with the optical one based on the BPT and the [SII]/Ha ratio. However, in the near-IR, we find ∼60% more AGN than in the optical (13 instead of eight), with five sources classified as "hidden" AGN, showing a larger AGN contribution at longer wavelengths, possibly due to the presence of optically thick dust. The diagnostics we present provide a promising tool to find and characterize AGN from z = 0 to z 3 with low- and medium-resolution near-IR spectrographs in future surveys.

Idioma originalInglés
Número de artículoA80
PublicaciónAstronomy and Astrophysics
EstadoPublicada - 1 nov. 2023


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