Year: 2026
Type: article
Abstract: Recent JWST observations have revealed a population of red, compact, high-redshift objects called “Little Red Dots” (LRD), whose host components have remained largely unconstrained, possibly due to their extreme compactness. Current morphological studies have been limited by small samples, as well as by insufficient imaging depth, which may not allow reliable separation between point-like and extended components, leaving the existence and properties of extended components in LRD largely unconstrained. Here, we perform the image stacking analysis of 217 LRDs in four NIRCam bands, representing the largest and homogeneous sample observed from COSMOS-Web survey to date. Our results reveal an unambiguous detection of faint extended emission in the F444W band, with a typical size of ~200 parsecs and magnitude of ~27.7 AB at z~6.5. We perform four-band photometric SED fitting based on galaxy templates and derive a stellar mass of 8.91+-~0.1 logM_sun. Given this stellar mass, the host galaxy is compact, i.e., ~2.5 times smaller than star-forming populations at similar mass, and the typical black hole mass of LRDs is elevated by ~1.5 dex above the local MBH-M* relation. This work provides direct observational evidence for the existence of LRD host galaxies and offers crucial insights into the growth of the host galaxy and the co-evolution of galaxies and their black holes within the first billion years after the Big Bang.
Source: Nature Astronomy
Authors: Yiyang Zhang, Xuheng Ding, Lilan Yang, Erini Lambrides, Hollis Akins, Andrew J. Battisti, Caitlin M. Casey, Chang-hao Chen, Isa Cox, Andreas Faisst, Maximilien Franco, Aryana Haghjoo, Luis C. Ho, Kohei Inayoshi, Shuowen Jin, Mitchell Karmen, Anton M. Koekemoer, Jeyhan S. Kartaltepe, Kai Liao, Ghassem Gozaliasl, Masafusa Onoue, Vasily Kokorev, Namrata Roy, R. Michael Rich, John D. Silverman, Takumi S. Tanaka, Bei You, Hassen M. Yesuf, Jorge A. Zavala
Institutions: Wuhan University, Rochester Institute of Technology, Hunan Normal University, Goddard Space Flight Center, The University of Texas at Austin, Australian National University, The University of Western Australia, International Centre for Radio Astronomy Research, University of California, Santa Barbara, Peking University, California Institute of Technology, Infrared Processing and Analysis Center, Centre National de la Recherche Scientifique, Université Paris Cité, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Université Paris-Saclay, CEA Paris-Saclay, University of California, Riverside, DTU Space, Technical University of Denmark, Johns Hopkins University, Space Telescope Science Institute, University of Helsinki, Aalto University, Waseda University, Kavli Institute for the Physics and Mathematics of the Universe, The University of Tokyo Institutes for Advanced Study, Waseda Institute for Advanced Study, The University of Tokyo, Arizona State University, University of California, Los Angeles, Chinese Academy of Sciences, Shanghai Astronomical Observatory, University of Massachusetts Amherst
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: Reconstruction of the climatic changes from borehole temperature and tree rings in the Kamchatka Peninsula, G3489712154, G3963932188, Cosmic Dawn Center (DAWN), G434337789, G4485681926, G4673423103, G4863782507, G5270046055, G551232673, G579566091, Probing the origin of supermassive black holes with Subaru Telescope, JWST, and Euclid, G6342778491, コンテクストの構造―その型態と機能―, G6877934016, G7328853082
OpenAlex ID: W7204073812