Little Red Dots: An abundant population of faint active galactic nuclei at z ∼ 5 revealed by the EIGER and FRESCO JWST surveys
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.
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Author
Matthee, Jorryt JISTA ;
Naidu, Rohan P.;
Brammer, Gabriel;
Chisholm, John;
Eilers, Anna-Christina;
Goulding, Andy;
Greene, Jenny;
Kashino, Daichi;
Labbe, Ivo;
Lilly, Simon J.;
Mackenzie, Ruari;
Oesch, Pascal A.
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All
Department
Abstract
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.
Publishing Year
Date Published
2024-03-07
Journal Title
The Astrophysical Journal
Acknowledgement
We thank the anonymous referee for constructive comments that helped improve the manuscript. This work is based on observations made with the NASA/ESA/CSA James Webb Space Telescope. The data were obtained from the Mikulski Archive for Space Telescopes at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127 for JWST. These observations are associated with program Nos. 1243 and 1895. The specific observations analyzed can be accessed via doi:10.17909/4xx0-zj76. Funded by the European Union (ERC, AGENTS, 101076224). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council. Neither the European Union nor the granting authority can be held responsible for them. R.P.N. acknowledges funding from JWST programs GO-1933 and GO-2279. Support for this work for R.P.N. was provided by NASA through the NASA Hubble Fellowship grant HST-HF2-51515.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555. Support for this work for G.I. was provided by NASA through grant JWST-GO-01895 awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. This work has received funding from the Swiss State Secretariat for Education, Research and Innovation (SERI) under contract No. MB22.00072, as well as from the Swiss National Science Foundation (SNSF) through project grant 200020_207349. The Cosmic Dawn Center (DAWN) is funded by the Danish National Research Foundation under grant No. 140.
Facility: JWST - James Webb Space Telescope, HST - Hubble Space Telescope satellite
Software: Python, matplotlib (Hunter 2007), numpy (Harris et al. 2020), scipy (Virtanen et al. 2020), Astropy (Astropy Collaboration et al. 2013, 2018), Imfit (Erwin 2015).
Volume
963
Issue
2
Article Number
129
ISSN
eISSN
IST-REx-ID
Cite this
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:10.3847/1538-4357/ad2345
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. American Astronomical Society. https://doi.org/10.3847/1538-4357/ad2345
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. American Astronomical Society, 2024. https://doi.org/10.3847/1538-4357/ad2345.
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. American Astronomical Society, 2024.
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, 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, American Astronomical Society, 2024, doi:10.3847/1538-4357/ad2345.
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