---
DOAJ_listed: '1'
OA_place: publisher
OA_type: gold
_id: '23150'
abstract:
- lang: eng
text: "High-redshift supermassive black holes (SMBHs) have challenged our understanding
of black hole formation and growth. The ‘heavy-seed’ pathway eases the problem
with the progenitors of these SMBHs having birth masses up to∼105 M\x03. Here,
we investigate the possibility that a local dwarf galaxy, Leo I, harbours a heavy-seed
descendant. Using Monte Carlo merger trees to generate the merger histories of
1000 dark matter haloes similar to the Milky Way (MW), we search for Leo- like
satellite haloes and investigate the probability that the progenitors of these
satellites formed a heavy seed. We derive the likelihood of such ‘heavy-seed survivors’
(HSSs) across various formation and survival criteria as well as Leo-similarity
criteria. We find that the virial temperature for the onset of atomic cooling
and rapid gas infall that yields heavy seeds, Tact , has the largest impact on
HSS frequency. We find HSSs in a fraction 0.7 per cent, 18.1 per cent, and 96.5
per cent of MW-like haloes when Tact is set to 9000, 7000, and 5000 K, respectively.
For the canonical atomic-cooling threshold ( Tact \x02 8000 K), the HSS fraction
is\x03 1per cent , indicating that Leo I hosting a heavy-seed descendant is unlikely
under well-motivated physical assumptions. Higher HSS fractions occur only under
optimistic and currently unsubstantiated assumptions on Tact . Nevertheless, these
results motivate future work that clarifies the possibility of heavy-seed BH formation
in pristine haloes with nominal virial temperatures below 8000 K. This may motivate
Leo I as a target for disentangling heavy seeds from other SMBH formation mechanisms."
acknowledgement: We thank the anonymous reviewer for feedback that helped clarify
this manuscript. ZH acknowledges support from NSF grant AST-2006176. FP acknowledges
support from the Black Hole Initiative at Harvard University, which is funded by
grants from the John Templeton Foundation and the Gordon and Betty Moore Foundation.
Merger tree generation and analysis were performed with NSF’s ACCESS allocations
AST-120046 and AST-140041 on the Stampede3 resource. The freely available plotting
library matplotlib (J. D. Hunter 2007) was used to construct the plots in this paper.
article_number: stag1839
article_processing_charge: Yes
article_type: original
arxiv: 1
author:
- first_name: Matthew T.
full_name: Scoggins, Matthew T.
last_name: Scoggins
- first_name: Zoltán
full_name: Haiman, Zoltán
id: 7c006e8c-cc0d-11ee-8322-cb904ef76f36
last_name: Haiman
orcid: 0000-0003-3633-5403
- first_name: Fabio
full_name: Pacucci, Fabio
last_name: Pacucci
citation:
ama: 'Scoggins MT, Haiman Z, Pacucci F. Heavy black hole seed survivors in dwarf
galaxies: A case study of Leo I. Monthly Notices of the Royal Astronomical
Society. 2026;552(3). doi:10.1093/mnras/stag1839'
apa: 'Scoggins, M. T., Haiman, Z., & Pacucci, F. (2026). Heavy black hole seed
survivors in dwarf galaxies: A case study of Leo I. Monthly Notices of the
Royal Astronomical Society. Oxford University Press. https://doi.org/10.1093/mnras/stag1839'
chicago: 'Scoggins, Matthew T., Zoltán Haiman, and Fabio Pacucci. “Heavy Black Hole
Seed Survivors in Dwarf Galaxies: A Case Study of Leo I.” Monthly Notices of
the Royal Astronomical Society. Oxford University Press, 2026. https://doi.org/10.1093/mnras/stag1839.'
ieee: 'M. T. Scoggins, Z. Haiman, and F. Pacucci, “Heavy black hole seed survivors
in dwarf galaxies: A case study of Leo I,” Monthly Notices of the Royal Astronomical
Society, vol. 552, no. 3. Oxford University Press, 2026.'
ista: 'Scoggins MT, Haiman Z, Pacucci F. 2026. Heavy black hole seed survivors in
dwarf galaxies: A case study of Leo I. Monthly Notices of the Royal Astronomical
Society. 552(3), stag1839.'
mla: 'Scoggins, Matthew T., et al. “Heavy Black Hole Seed Survivors in Dwarf Galaxies:
A Case Study of Leo I.” Monthly Notices of the Royal Astronomical Society,
vol. 552, no. 3, stag1839, Oxford University Press, 2026, doi:10.1093/mnras/stag1839.'
short: M.T. Scoggins, Z. Haiman, F. Pacucci, Monthly Notices of the Royal Astronomical
Society 552 (2026).
das_tickbox: '1'
dataavailabilitystatement: The code used to analyse the merger trees and generate
figures for this manuscript is available at this GitHub repository. All other data
will be shared upon reasonable request to the corresponding author.
date_created: 2026-10-18T22:01:51Z
date_published: 2026-11-01T00:00:00Z
date_updated: 2026-10-19T07:05:55Z
day: '01'
ddc:
- '520'
department:
- _id: ZoHa
doi: 10.1093/mnras/stag1839
external_id:
arxiv:
- '2511.04736'
file:
- access_level: open_access
checksum: 99a35f1305b7f1ed3813bcd51ba16724
content_type: application/pdf
creator: dernst
date_created: 2026-10-19T07:05:43Z
date_updated: 2026-10-19T07:05:43Z
file_id: '23164'
file_name: 2026_MonthNoticesRAS_Scoggins.pdf
file_size: 1450204
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success: 1
file_date_updated: 2026-10-19T07:05:43Z
fulldoi: https://doi.org/10.1093/mnras/stag1839
has_accepted_license: '1'
intvolume: ' 552'
issue: '3'
language:
- iso: eng
month: '11'
oa: 1
oa_version: Published Version
publication: Monthly Notices of the Royal Astronomical Society
publication_identifier:
eissn:
- 1365-2966
issn:
- 0035-8711
publication_status: published
publisher: Oxford University Press
quality_controlled: '1'
researchdata_availability: yes
scopus_import: '1'
status: public
supplementarymaterial: no
title: 'Heavy black hole seed survivors in dwarf galaxies: A case study of Leo I'
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 552
year: '2026'
...