Little Red Dots: An abundant population of faint active galactic nuclei at z ∼ 5 revealed by the EIGER and FRESCO JWST surveys

article Little Red Dots: An abundant population of faint active galactic nuclei at z ∼ 5 revealed by the EIGER and FRESCO JWST surveys published yes Jorryt J Matthee author 7439a258-f3c0-11ec-9501-9df22fe067200000-0003-2871-127X Rohan P. Naidu author Gabriel Brammer author John Chisholm author Anna-Christina Eilers author Andy Goulding author Jenny Greene author Daichi Kashino author Ivo Labbe author Simon J. Lilly author Ruari Mackenzie author Pascal A. Oesch author Andrea Weibel author Stijn Wuyts author Mengyuan Xiao author Rongmon Bordoloi author Rychard Bouwens author Pieter van Dokkum author Garth Illingworth author Ivan Kramarenko author Michael V. Maseda author Charlotte Mason author Romain A. Meyer author Erica J. Nelson author Naveen A. Reddy author Irene Shivaei author Robert A. Simcoe author Minghao Yue author JoMa department Young galaxies as tracers and agents of cosmic reionization project Characterizing the prevalence and properties of faint active galactic nuclei (AGNs) in the early Universe is key for understanding the formation of supermassive black holes (SMBHs) and determining their role in cosmic reionization. We perform a spectroscopic search for broad Hα emitters at z ≈ 4–6 using deep JWST/NIRCam imaging and wide field slitless spectroscopy from the EIGER and FRESCO surveys. We identify 20 Hα lines at z = 4.2–5.5 that have broad components with line widths from ∼1200–3700 km s−1, contributing ∼30%–90% of the total line flux. We interpret these broad components as being powered by accretion onto SMBHs with implied masses ∼107–8M⊙. In the UV luminosity range MUV,AGN+host = −21 to −18, we measure number densities of ≈10−5 cMpc−3. This is an order of magnitude higher than expected from extrapolating quasar UV luminosity functions (LFs). Yet, such AGN are found in only <1% of star-forming galaxies at z ∼ 5. The number density discrepancy is much lower when compared to the broad Hα LF. The SMBH mass function agrees with large cosmological simulations. In two objects, we detect complex Hα profiles that we tentatively interpret as caused by absorption signatures from dense gas fueling SMBH growth and outflows. We may be witnessing early AGN feedback that will clear dust-free pathways through which more massive blue quasars are seen. We uncover a strong correlation between reddening and the fraction of total galaxy luminosity arising from faint AGN. This implies that early SMBH growth is highly obscured and that faint AGN are only minor contributors to cosmic reionization. https://research-explorer.ista.ac.at/download/15180/15184/2024_AstrophysicalJourn_Matthee.pdf application/pdfno IOP Publishing2024 eng Space and Planetary ScienceAstronomy and Astrophysics The Astrophysical Journal 0004-637X 1538-4357 00118470360000110.3847/1538-4357/ad2345 9632 https://ista.ac.at/en/news/baby-quasars-growing-supermassive-black-holes/ J.J. Matthee, R.P. Naidu, G. Brammer, J. Chisholm, A.-C. Eilers, A. Goulding, J. Greene, D. Kashino, I. Labbe, S.J. Lilly, R. Mackenzie, P.A. Oesch, A. Weibel, S. Wuyts, M. Xiao, R. Bordoloi, R. Bouwens, P. van Dokkum, G. Illingworth, I. Kramarenko, M.V. Maseda, C. Mason, R.A. Meyer, E.J. Nelson, N.A. Reddy, I. Shivaei, R.A. Simcoe, M. Yue, The Astrophysical Journal 963 (2024). J. J. Matthee et al., “Little Red Dots: An abundant population of faint active galactic nuclei at z ∼ 5 revealed by the EIGER and FRESCO JWST surveys,” The Astrophysical Journal, vol. 963, no. 2. IOP Publishing, 2024. Matthee, Jorryt J, Rohan P. Naidu, Gabriel Brammer, John Chisholm, Anna-Christina Eilers, Andy Goulding, Jenny Greene, et al. “Little Red Dots: An Abundant Population of Faint Active Galactic Nuclei at z ∼ 5 Revealed by the EIGER and FRESCO JWST Surveys.” The Astrophysical Journal. IOP Publishing, 2024. <a href="https://doi.org/10.3847/1538-4357/ad2345">https://doi.org/10.3847/1538-4357/ad2345</a>. Matthee JJ, Naidu RP, Brammer G, Chisholm J, Eilers A-C, Goulding A, Greene J, Kashino D, Labbe I, Lilly SJ, Mackenzie R, Oesch PA, Weibel A, Wuyts S, Xiao M, Bordoloi R, Bouwens R, van Dokkum P, Illingworth G, Kramarenko I, Maseda MV, Mason C, Meyer RA, Nelson EJ, Reddy NA, Shivaei I, Simcoe RA, Yue M. 2024. Little Red Dots: An abundant population of faint active galactic nuclei at z ∼ 5 revealed by the EIGER and FRESCO JWST surveys. The Astrophysical Journal. 963(2), 129. Matthee JJ, Naidu RP, Brammer G, et al. Little Red Dots: An abundant population of faint active galactic nuclei at z ∼ 5 revealed by the EIGER and FRESCO JWST surveys. The Astrophysical Journal. 2024;963(2). doi:<a href="https://doi.org/10.3847/1538-4357/ad2345">10.3847/1538-4357/ad2345</a> Matthee, Jorryt J., et al. “Little Red Dots: An Abundant Population of Faint Active Galactic Nuclei at z ∼ 5 Revealed by the EIGER and FRESCO JWST Surveys.” The Astrophysical Journal, vol. 963, no. 2, 129, IOP Publishing, 2024, doi:<a href="https://doi.org/10.3847/1538-4357/ad2345">10.3847/1538-4357/ad2345</a>. Matthee, J. J., Naidu, R. P., Brammer, G., Chisholm, J., Eilers, A.-C., Goulding, A., … Yue, M. (2024). Little Red Dots: An abundant population of faint active galactic nuclei at z ∼ 5 revealed by the EIGER and FRESCO JWST surveys. The Astrophysical Journal. IOP Publishing. <a href="https://doi.org/10.3847/1538-4357/ad2345">https://doi.org/10.3847/1538-4357/ad2345</a> 151802024-03-25T08:54:47Z2026-07-06T12:20:54Z