A too-many dwarf satellite galaxies problem in the MATLAS low-to-moderate density fields

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Main Authors: Kanehisa, Kosuke Jamie, Pawlowski, Marcel S., Heesters, Nick, Müller, Oliver
Format: Preprint
Published: 2024
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author Kanehisa, Kosuke Jamie
Pawlowski, Marcel S.
Heesters, Nick
Müller, Oliver
author_facet Kanehisa, Kosuke Jamie
Pawlowski, Marcel S.
Heesters, Nick
Müller, Oliver
contents Dwarf galaxy abundances can serve as discernment tests for models of structure formation. Previous small-scale tensions between observations and dark matter-only cosmological simulations may have been resolved with the inclusion of baryonic processes; however, these successes have been largely concentrated on the Local Group dwarfs the feedback models were initially calibrated on. We investigate whether the $Λ$CDM model can reliably reproduce dwarf abundances in the MATLAS low-to-moderate density fields that are centred upon early-type host galaxies beyond the Local Volume. We carried out mock observations of MATLAS-like fields with the high-resolution hydrodynamic simulation IllustrisTNG-50. We used matching selection criteria and compared the properties of dwarfs contained within them with their MATLAS analogues. Although simulated MATLAS-like dwarfs demonstrate photometric properties that are consistent with the observed galaxy population and follow the same scaling relations, TNG50 underestimates the number of dwarf galaxies in isolated MATLAS fields at the 6 sigma level. This significance is maintained within crowded fields containing more than a single bright host. Our 55-62% estimate of the fraction of background galaxies is in agreement with estimates by MATLAS, but is wholly insufficient to alleviate this discrepancy in dwarf abundances. Any incompleteness in the observed fields further exacerbates this tension. We identified a "too-many-satellites" problem in $Λ$CDM, emphasising the need for the continued testing and refining of current models of galaxy formation in environments beyond the Local Group.
format Preprint
id arxiv_https___arxiv_org_abs_2405_05303
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle A too-many dwarf satellite galaxies problem in the MATLAS low-to-moderate density fields
Kanehisa, Kosuke Jamie
Pawlowski, Marcel S.
Heesters, Nick
Müller, Oliver
Astrophysics of Galaxies
Dwarf galaxy abundances can serve as discernment tests for models of structure formation. Previous small-scale tensions between observations and dark matter-only cosmological simulations may have been resolved with the inclusion of baryonic processes; however, these successes have been largely concentrated on the Local Group dwarfs the feedback models were initially calibrated on. We investigate whether the $Λ$CDM model can reliably reproduce dwarf abundances in the MATLAS low-to-moderate density fields that are centred upon early-type host galaxies beyond the Local Volume. We carried out mock observations of MATLAS-like fields with the high-resolution hydrodynamic simulation IllustrisTNG-50. We used matching selection criteria and compared the properties of dwarfs contained within them with their MATLAS analogues. Although simulated MATLAS-like dwarfs demonstrate photometric properties that are consistent with the observed galaxy population and follow the same scaling relations, TNG50 underestimates the number of dwarf galaxies in isolated MATLAS fields at the 6 sigma level. This significance is maintained within crowded fields containing more than a single bright host. Our 55-62% estimate of the fraction of background galaxies is in agreement with estimates by MATLAS, but is wholly insufficient to alleviate this discrepancy in dwarf abundances. Any incompleteness in the observed fields further exacerbates this tension. We identified a "too-many-satellites" problem in $Λ$CDM, emphasising the need for the continued testing and refining of current models of galaxy formation in environments beyond the Local Group.
title A too-many dwarf satellite galaxies problem in the MATLAS low-to-moderate density fields
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2405.05303