COSMOS-Web: The Overabundance and Physical Nature of “Little Red Dots”—Implications for Early Galaxy and SMBH Assembly

Abstract JWST has revealed a population of compact and extremely red galaxies at z ≳ 4, which likely host active galactic nuclei (AGNs). We present a sample of 434 “little red dots” (LRDs), selected from the 0.54 deg 2 COSMOS-Web survey. We fit galaxy and AGN spectral energy distribution models to derive redshifts and physical properties; the sample spans z ∼ 5–9 after removing brown dwarf contaminants. As a thought experiment, we consider two extreme physical scenarios: either LRDs are all AGNs, and their continuum emission is dominated by the accretion disk, or they are all compact star-forming galaxies, and their continuum is dominated by stars. If LRDs are AGN-dominated, our sample exhibits bolometric…

• NS
  National Science Foundation

  Awards: 2009577, 1814034, AST-1814034, NAS 5-26555, AST-2009577
• NA
  National Aeronautics and Space Administration

  Awards: JWST-GO-01727, NAS 5-26555, 5-26555
• RC
  Research Corporation for Science Advancement
• UO
  University of Texas at Austin
• ST
  Space Telescope Science Institute

  Awards: HST-AR-15802, NAS 5-26555, 5-26555, 26555, JWST-GO-01727
• CO
  College of Natural Sciences, University of Texas at Austin