Little Red Dots: An Abundant Population of Faint Active Galactic Nuclei at z ∼ 5 Revealed by the EIGER and FRESCO JWST Surveys

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 H α emitters at z ≈ 4–6 using deep JWST/NIRCam imaging and wide field slitless spectroscopy from the EIGER and FRESCO surveys. We identify 20 H α 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 ∼10 7–8 M ⊙ . In the UV luminosity range M UV,AGN+host…

• NA
  National Aeronautics and Space Administration

  Awards: 5-03127, NAS 5-03127
• ST
  Space Telescope Science Institute

  Awards: 5-03127, NAS 5-03127
• HE
  HORIZON EUROPE European Research Council

  Award: 101076224