---
DOAJ_listed: '1'
OA_place: publisher
OA_type: gold
PlanS_conform: '1'
_id: '21846'
abstract:
- lang: eng
  text: 'We compile a sample of 83 little red dots (LRDs) with JWST imaging and find
    that a substantial fraction (∼43%, rising to ≳80% for the most luminous LRDs)
    host one or more spatially offset, UV-bright companions at projected separations
    of 0.5 kpc ≲ d ≲ 5 kpc, with median 〈d〉 = 1.0 kpc. This fraction is even higher
    when smaller spatial scales are probed at high signal-to-noise ratio: the two
    most strongly lensed LRDs, A383-LRD1 and the newly discovered A68-LRD1, both have
    UV-bright companions at separations of only d ∼ 0.3 kpc, below the resolution
    limit of most unlensed JWST samples. We explore whether these ubiquitous red/blue
    configurations may be physically linked to the formation of LRDs, in analogy with
    the “synchronized pair” scenario originally proposed for direct-collapse black
    hole formation. In this picture, UV radiation from the companions, with typically
    modest stellar masses (M∗ ∼ 108−109 M⊙), suppresses molecular hydrogen cooling
    in nearby gas, allowing nearly isothermal collapse and the formation of extremely
    compact objects, such as massive black holes, supermassive stars, or quasi-stars.
    Using component-resolved photometry and spectral energy distribution modeling,
    we infer Lyman–Werner radiation fields of J21,LW ∼ 102.5–105 at the locations
    of the red components, comparable to those required in direct-collapse models,
    suggesting that the necessary photodissociation conditions are realized in many
    LRD systems. This framework provides a simple and self-consistent explanation
    for the extreme compactness and distinctive spectral properties of LRDs and links
    long-standing theoretical models for early compact object formation directly to
    a population now observed with JWST in the early Universe.'
acknowledgement: 'We thank Earl Bellinger, Fabio Pacucci, Andrea Ferrara, and Dale
  Kocevski for useful discussions. This work is based on observations made with the
  NASA/ESA/CSA James Webb Space Telescope. The data were obtained from the Mikulski
  Archive for Space Telescopes at the Space Telescope Science Institute, which is
  operated by the Association of Universities for Research in Astronomy, Inc., under
  NASA contract NAS 5-03127 for JWST. These imaging observations are associated with
  programs 1345, 1180, 1181, 1243, 6882, 2561, 1324, 4111, and 1895. The compiled
  dataset can be accessed at doi:10.17909/1m8f-9c47. The Cosmic Dawn Center (DAWN)
  is funded by the Danish National Research Foundation under grant DNRF140. J.M. and
  A.T. acknowledge funding by the European Union (ERC, AGENTS, 101076224). This work
  was performed in part at Aspen Center for Physics, which is supported by National
  Science Foundation grant PHY-2210452. This work used the following Python packages:
  Matplotlib (J. D. Hunter 2007), SciPy (P. Virtanen et al. 2020), NumPy (S. van der
  Walt et al. 2011), AstroPy (Astropy Collaboration et al. 2022), colossus (B. Diemer
  2018), and photutils (L. Bradley et al. 2025).'
article_number: L4
article_processing_charge: Yes
article_type: original
arxiv: 1
author:
- first_name: Josephine F.W.
  full_name: Baggen, Josephine F.W.
  last_name: Baggen
- first_name: Matthew T.
  full_name: Scoggins, Matthew T.
  last_name: Scoggins
- first_name: Pieter
  full_name: Van Dokkum, Pieter
  last_name: Van Dokkum
- first_name: Zoltán
  full_name: Haiman, Zoltán
  id: 7c006e8c-cc0d-11ee-8322-cb904ef76f36
  last_name: Haiman
  orcid: 0000-0003-3633-5403
- first_name: Alberto
  full_name: Torralba Torregrosa, Alberto
  id: 018f0249-0e87-11f0-b167-cbce08fbd541
  last_name: Torralba Torregrosa
  orcid: 0000-0001-5586-6950
- first_name: Jorryt J
  full_name: Matthee, Jorryt J
  id: 7439a258-f3c0-11ec-9501-9df22fe06720
  last_name: Matthee
  orcid: 0000-0003-2871-127X
citation:
  ama: 'Baggen JFW, Scoggins MT, Van Dokkum P, Haiman Z, Torralba Torregrosa A, Matthee
    JJ. Connecting the dots: UV-bright companions of Little Red Dots as Lyman–Werner
    sources enabling direct-collapse Black Hole formation. <i>The Astrophysical Journal
    Letters</i>. 2026;1002(1). doi:<a href="https://doi.org/10.3847/2041-8213/ae58a5">10.3847/2041-8213/ae58a5</a>'
  apa: 'Baggen, J. F. W., Scoggins, M. T., Van Dokkum, P., Haiman, Z., Torralba Torregrosa,
    A., &#38; Matthee, J. J. (2026). Connecting the dots: UV-bright companions of
    Little Red Dots as Lyman–Werner sources enabling direct-collapse Black Hole formation.
    <i>The Astrophysical Journal Letters</i>. IOP Publishing. <a href="https://doi.org/10.3847/2041-8213/ae58a5">https://doi.org/10.3847/2041-8213/ae58a5</a>'
  chicago: 'Baggen, Josephine F.W., Matthew T. Scoggins, Pieter Van Dokkum, Zoltán
    Haiman, Alberto Torralba Torregrosa, and Jorryt J Matthee. “Connecting the Dots:
    UV-Bright Companions of Little Red Dots as Lyman–Werner Sources Enabling Direct-Collapse
    Black Hole Formation.” <i>The Astrophysical Journal Letters</i>. IOP Publishing,
    2026. <a href="https://doi.org/10.3847/2041-8213/ae58a5">https://doi.org/10.3847/2041-8213/ae58a5</a>.'
  ieee: 'J. F. W. Baggen, M. T. Scoggins, P. Van Dokkum, Z. Haiman, A. Torralba Torregrosa,
    and J. J. Matthee, “Connecting the dots: UV-bright companions of Little Red Dots
    as Lyman–Werner sources enabling direct-collapse Black Hole formation,” <i>The
    Astrophysical Journal Letters</i>, vol. 1002, no. 1. IOP Publishing, 2026.'
  ista: 'Baggen JFW, Scoggins MT, Van Dokkum P, Haiman Z, Torralba Torregrosa A, Matthee
    JJ. 2026. Connecting the dots: UV-bright companions of Little Red Dots as Lyman–Werner
    sources enabling direct-collapse Black Hole formation. The Astrophysical Journal
    Letters. 1002(1), L4.'
  mla: 'Baggen, Josephine F. W., et al. “Connecting the Dots: UV-Bright Companions
    of Little Red Dots as Lyman–Werner Sources Enabling Direct-Collapse Black Hole
    Formation.” <i>The Astrophysical Journal Letters</i>, vol. 1002, no. 1, L4, IOP
    Publishing, 2026, doi:<a href="https://doi.org/10.3847/2041-8213/ae58a5">10.3847/2041-8213/ae58a5</a>.'
  short: J.F.W. Baggen, M.T. Scoggins, P. Van Dokkum, Z. Haiman, A. Torralba Torregrosa,
    J.J. Matthee, The Astrophysical Journal Letters 1002 (2026).
date_created: 2026-05-10T22:02:15Z
date_published: 2026-04-10T00:00:00Z
date_updated: 2026-05-11T06:48:33Z
day: '10'
ddc:
- '520'
department:
- _id: ZoHa
- _id: JoMa
doi: 10.3847/2041-8213/ae58a5
external_id:
  arxiv:
  - '2602.02702'
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has_accepted_license: '1'
intvolume: '      1002'
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language:
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month: '04'
oa: 1
oa_version: Published Version
project:
- _id: bd9b2118-d553-11ed-ba76-db24564edfea
  grant_number: '101076224'
  name: Young galaxies as tracers and agents of cosmic reionization
publication: The Astrophysical Journal Letters
publication_identifier:
  eissn:
  - 2041-8213
  issn:
  - 2041-8205
publication_status: published
publisher: IOP Publishing
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'Connecting the dots: UV-bright companions of Little Red Dots as Lyman–Werner
  sources enabling direct-collapse Black Hole formation'
tmp:
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type: journal_article
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volume: 1002
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