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Exploring the causal effect of cosmic filaments on dark matter haloes

Storck, Anatole ; Cadiou, Corentin LU orcid ; Agertz, Oscar LU and Galárraga-Espinosa, Daniela (2025) In Monthly Notices of the Royal Astronomical Society 539(1). p.487-500
Abstract

The way in which the large-scale cosmic environment affects galactic properties is not yet understood. Dark matter haloes, which embed galaxies, initially evolve following linear theory. Their subsequent evolution is driven by non-linear structure formation in the halo region and in its outer environment. In this work, we present the first study where we explicitly control the linear part of the evolution of the halo, thus revealing the role of non-linear effects on halo formation. We focus specifically on the effect of proximity to a large cosmological filament. We employ the splicing method to keep fixed the initial density, velocity, and potential fields where a halo will form while changing its outer environment, from an isolated... (More)

The way in which the large-scale cosmic environment affects galactic properties is not yet understood. Dark matter haloes, which embed galaxies, initially evolve following linear theory. Their subsequent evolution is driven by non-linear structure formation in the halo region and in its outer environment. In this work, we present the first study where we explicitly control the linear part of the evolution of the halo, thus revealing the role of non-linear effects on halo formation. We focus specifically on the effect of proximity to a large cosmological filament. We employ the splicing method to keep fixed the initial density, velocity, and potential fields where a halo will form while changing its outer environment, from an isolated state to one where the halo is near a large filament. In the regime of Milky Way-mass haloes, we find that mass and virial radius of such haloes are not affected by even drastic changes of environment, whereas halo spin and shape orientation with respect to a massive filament is largely impacted, with fluctuations of up to 80 per cent around the mean value. Our results suggest that halo orientation and shape cannot be predicted accurately from a local analysis in the initial conditions alone. This has direct consequences on the modelling of intrinsic alignment for cosmic shear surveys, like Euclid. Our results highlight that non-linear couplings to the large-scale environment may have an amplitude comparable to linear effects, and should thus be treated explicitly in analytical models of dark matter halo formation.

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author
; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
(cosmology:) dark matter, (cosmology:) large-scale structure of the Universe, galaxies: haloes
in
Monthly Notices of the Royal Astronomical Society
volume
539
issue
1
pages
14 pages
publisher
Oxford University Press
external identifiers
  • scopus:105002557370
ISSN
0035-8711
DOI
10.1093/mnras/staf523
language
English
LU publication?
yes
id
8b99a3f9-d841-4f90-a016-9d35f88be237
date added to LUP
2025-08-11 11:58:16
date last changed
2025-08-12 13:42:48
@article{8b99a3f9-d841-4f90-a016-9d35f88be237,
  abstract     = {{<p>The way in which the large-scale cosmic environment affects galactic properties is not yet understood. Dark matter haloes, which embed galaxies, initially evolve following linear theory. Their subsequent evolution is driven by non-linear structure formation in the halo region and in its outer environment. In this work, we present the first study where we explicitly control the linear part of the evolution of the halo, thus revealing the role of non-linear effects on halo formation. We focus specifically on the effect of proximity to a large cosmological filament. We employ the splicing method to keep fixed the initial density, velocity, and potential fields where a halo will form while changing its outer environment, from an isolated state to one where the halo is near a large filament. In the regime of Milky Way-mass haloes, we find that mass and virial radius of such haloes are not affected by even drastic changes of environment, whereas halo spin and shape orientation with respect to a massive filament is largely impacted, with fluctuations of up to 80 per cent around the mean value. Our results suggest that halo orientation and shape cannot be predicted accurately from a local analysis in the initial conditions alone. This has direct consequences on the modelling of intrinsic alignment for cosmic shear surveys, like Euclid. Our results highlight that non-linear couplings to the large-scale environment may have an amplitude comparable to linear effects, and should thus be treated explicitly in analytical models of dark matter halo formation.</p>}},
  author       = {{Storck, Anatole and Cadiou, Corentin and Agertz, Oscar and Galárraga-Espinosa, Daniela}},
  issn         = {{0035-8711}},
  keywords     = {{(cosmology:) dark matter; (cosmology:) large-scale structure of the Universe; galaxies: haloes}},
  language     = {{eng}},
  number       = {{1}},
  pages        = {{487--500}},
  publisher    = {{Oxford University Press}},
  series       = {{Monthly Notices of the Royal Astronomical Society}},
  title        = {{Exploring the causal effect of cosmic filaments on dark matter haloes}},
  url          = {{http://dx.doi.org/10.1093/mnras/staf523}},
  doi          = {{10.1093/mnras/staf523}},
  volume       = {{539}},
  year         = {{2025}},
}