Stacking X-Ray Observations of “Little Red Dots”: Implications for Their Active Galactic Nucleus Properties

Abstract Recent James Webb Space Telescope observations have revealed a population of compact extragalactic objects at z ≳ 4 with red near-infrared colors, which have been dubbed as “Little Red Dots” (LRDs). The spectroscopically selected LRDs exhibit broad H α emission lines, which likely indicate that type I active galactic nuclei (AGNs) are harbored in the galaxies’ dust-reddened cores. However, other mechanisms, like strong outflowing winds, could also produce broad H α emission lines, and thus, the nature of LRDs is still under debate. We test the AGN hypothesis for LRDs by stacking the archival Chandra observations of 34 spectroscopically selected LRDs. We obtain tentative detections in the soft (0.5–2…

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  National Aeronautics and Space Administration

  Award: 80NSSC23K0557