Discovery of a Little Red Dot Candidate at <i>z</i>  ≳ 10 in COSMOS-web Based on MIRI-NIRCam Selection

Abstract JWST has revealed a new high-redshift population called little red dots (LRDs). Since LRDs may be in the early phase of black hole growth, identifying them in the early Universe is crucial for understanding the formation of the first supermassive black holes. However, no robust LRD candidates have been identified at z &gt; 10, because commonly used NIRCam photometry covers wavelengths up to ∼5 μ m and is insufficient to capture the characteristic V-shaped spectral energy distributions (SEDs) of LRDs. In this study, we present the first search for z ≳ 10 LRD candidates using both NIRCam and MIRI imaging from COSMOS-Web, which provides the largest joint NIRCam-MIRI coverage to date (0.20 deg 2 ). Taking advantage of MIRI/F770W to remove contaminants, we identify one robust candidate, CW-LRD-z10 at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>z</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">phot</mml:mi> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>10</mml:mn> <mml:mo>.</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>5</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.6</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.7</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> with <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">UV</mml:mi> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:mo>−</mml:mo> <mml:mn>19</mml:mn> <mml:mo>.</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>9</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.2</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.1</mml:mn> </mml:mrow> </mml:msubsup> <mml:mspace width="0.25em"/> <mml:mi mathvariant="normal">mag</mml:mi> </mml:math> . CW-LRD-z10 exhibits a compact morphology, a distinct V-shaped SED, and a nondetection in F115W, all consistent with being an LRD at z ∼ 10. Based on this discovery, we place the first constraint on the number density of LRDs at z ∼ 10 with M UV ∼ −20 of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>1</mml:mn> <mml:mo>.</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1.0</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>2.7</mml:mn> </mml:mrow> </mml:msubsup> <mml:mo>×</mml:mo> <mml:mn>1</mml:mn> <mml:msup> <mml:mrow> <mml:mn>0</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>6</mml:mn> </mml:mrow> </mml:msup> <mml:mspace width="0.25em"/> <mml:msup> <mml:mrow> <mml:mi mathvariant="normal">Mpc</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>3</mml:mn> </mml:mrow> </mml:msup> <mml:mspace width="0.25em"/> <mml:msup> <mml:mrow> <mml:mi mathvariant="normal">mag</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:math> , suggesting that the fraction of LRDs among the overall galaxy population increases with redshift, reaching ∼3% at z ∼ 10. Although deep spectroscopy is necessary to confirm the redshift and the nature of CW-LRD-z10, our results imply that LRDs may be a common population at z &gt; 10, playing a key role in the first supermassive black hole formation.

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Journal
The Astrophysical Journal
Published
2025-12-02
DOI
https://doi.org/10.3847/1538-4357/ae145f
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2
Primary Topic
Astrophysical Phenomena and Observations
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article
Field-Weighted Citation Impact
2.31

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article

Discovery of a Little Red Dot Candidate at z  ≳ 10 in COSMOS-web Based on MIRI-NIRCam Selection

Seiji Fujimoto, Eiichi Egami, Xuheng Ding, Zhaoxuan Liu et al.
2 citations
The Astrophysical Journal
Astrophysical Phenomena and Observations
2.31
article

Discovery of a Little Red Dot Candidate at z  ≳ 10 in COSMOS-web Based on MIRI-NIRCam Selection

Seiji Fujimoto, Eiichi Egami, Xuheng Ding, Zhaoxuan Liu, Ali Ahmad Khostovan, Ezequiel Treister, Zijian Li, Masafusa Onoue, D. B. Sanders, Darshan Kakkad, Santosh Harish, Marko Shuntov, Jan–Torge Schindler, Hollis B. Akins, G. Gozaliasl, Vasily Kokorev, J. D. Silverman, Jorge A. Zavala, Xiaohui Fan, Jinyi Yang, Jaclyn B. Champagne, S. Matsui, Yuichi Harikane, Kazuhiro Shimasaku, Anton M. Koekemoer, Bahram Mobasher, Qinyue Fei, Anthony J. Taylor, Siwei Zou, Feige Wang, Kohei Inayoshi, Hiroya Umeda, Caitlin M. Casey, Jianwei Lyu, G. Magdis, Koki Kakiichi, Weizhe Liu, Sarah E. I. Bosman, Zijian Zhang, Maximilien Franco, Steven L. Finkelstein, Erini Lambrides, Jason Rhodes, Makoto Ando, Dale D. Kocevski, Brant E. Robertson, Arianna S. Long, Manuel Aravena, Akio Inoue, Steven Gillman, Laura Sommovigo, Sune Toft, Rafael C. Arango-Toro, Jeyhan S. Kartaltepe, Andrew Battisti, Daizhong Liu, Ming-Yang Zhuang, Takumi S. Tanaka, Andreas L. Faisst, Kei Ito, Junya Arita, Mingyu Li, Zihao Li, Haowen Zhang, Hossein Hatamnia, S. Newman, Yuki Shibanuma
article en
2 citations

Abstract

Abstract JWST has revealed a new high-redshift population called little red dots (LRDs). Since LRDs may be in the early phase of black hole growth, identifying them in the early Universe is crucial for understanding the formation of the first supermassive black holes. However, no robust LRD candidates have been identified at z &gt; 10, because commonly used NIRCam photometry covers wavelengths up to ∼5 μ m and is insufficient to capture the characteristic V-shaped spectral energy distributions (SEDs) of LRDs. In this study, we present the first search for z ≳ 10 LRD candidates using both NIRCam and MIRI imaging from COSMOS-Web, which provides the largest joint NIRCam-MIRI coverage to date (0.20 deg 2 ). Taking advantage of MIRI/F770W to remove contaminants, we identify one robust candidate, CW-LRD-z10 at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>z</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">phot</mml:mi> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>10</mml:mn> <mml:mo>.</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>5</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.6</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.7</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> with <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">UV</mml:mi> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:mo>−</mml:mo> <mml:mn>19</mml:mn> <mml:mo>.</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>9</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.2</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.1</mml:mn> </mml:mrow> </mml:msubsup> <mml:mspace width="0.25em"/> <mml:mi mathvariant="normal">mag</mml:mi> </mml:math> . CW-LRD-z10 exhibits a compact morphology, a distinct V-shaped SED, and a nondetection in F115W, all consistent with being an LRD at z ∼ 10. Based on this discovery, we place the first constraint on the number density of LRDs at z ∼ 10 with M UV ∼ −20 of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>1</mml:mn> <mml:mo>.</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1.0</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>2.7</mml:mn> </mml:mrow> </mml:msubsup> <mml:mo>×</mml:mo> <mml:mn>1</mml:mn> <mml:msup> <mml:mrow> <mml:mn>0</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>6</mml:mn> </mml:mrow> </mml:msup> <mml:mspace width="0.25em"/> <mml:msup> <mml:mrow> <mml:mi mathvariant="normal">Mpc</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>3</mml:mn> </mml:mrow> </mml:msup> <mml:mspace width="0.25em"/> <mml:msup> <mml:mrow> <mml:mi mathvariant="normal">mag</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:math> , suggesting that the fraction of LRDs among the overall galaxy population increases with redshift, reaching ∼3% at z ∼ 10. Although deep spectroscopy is necessary to confirm the redshift and the nature of CW-LRD-z10, our results imply that LRDs may be a common population at z &gt; 10, playing a key role in the first supermassive black hole formation.

The Astrophysical JournalVol. 995(1)
University of California, Riverside (US), University of Geneva (CH), University of Hawaiʻi at Mānoa (US), Australian National University (AU), California Institute of Technology (US), University of Copenhagen (DK), Centre National de la Recherche Scientifique (FR), Space Telescope Science Institute (US), Goddard Space Flight Center (US), Jet Propulsion Laboratory (US), University of Helsinki (FI), University of Arizona (US), University of Hertfordshire (GB), University of Kentucky (US), Waseda University (JP), University of California, Santa Barbara (US), Rochester Institute of Technology (US), University of Illinois Urbana-Champaign (US), Universität Hamburg (DE), Kavli Institute for the Physics and Mathematics of the Universe (JP), University of Groningen (NL), University of California, Santa Cruz (US), University of Toronto (CA), University of Tarapacá (CL), Chinese Academy of Sciences (CN), University of Washington (US), Peking University (CN), Université Paris Cité (FR), Aix-Marseille Université (FR), Heidelberg University (DE), University of Massachusetts Amherst (US), Commissariat à l'Énergie Atomique et aux Énergies Alternatives (FR), Colby College (US), Université Paris-Saclay (FR), University of Michigan (US), Purple Mountain Observatory (CN), Wuhan University (CN), Astrophysique, Instrumentation et Modélisation (FR), ASTRO-3D (AU), Kavli Institute for Theoretical Sciences (CN), Max Planck Institute for Astronomy (DE), Millennium Nucleus of Ion Channel Associated Diseases (CL), Université Bourgogne Franche-Comté (FR), CEA Paris-Saclay (FR), Flatiron Health (United States) (US), ARC Centre of Excellence for All-sky Astrophysics (AU), Millenium Nucleus for Planet Formation (CL), National Astronomical Observatory of Japan (JP), National Astronomical Observatories (CN), University of Chinese Academy of Sciences (CN), Infrared Processing and Analysis Center (US), Flatiron Institute (US), Seattle University (US), University of Portsmouth (GB), University of Chile (CL), Heidelberg Institute for Theoretical Studies (DE), The University of Tokyo (JP), The University of Texas at Austin (US), Universidad Diego Portales (CL), Technical University of Denmark (DK), Tsinghua University (CN), Aalto University (FI)
National Science Foundation, National Aeronautics and Space Administration, Astronomical Society of Japan, Space Telescope Science Institute, European Commission, National Research Foundation, Deutsche Forschungsgemeinschaft, Ministry of Education, Culture, Sports, Science and Technology, Danmarks Grundforskningsfond, National Natural Science Foundation of China, Centre National d’Etudes Spatiales, Agencia Nacional de Investigación y Desarrollo, Japan Society for the Promotion of Science
Openalex Percentile: Top 9%
Astrophysical Phenomena and Observations
2.31
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