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EDGE-INFERNO : Simulating Every Observable Star in Faint Dwarf Galaxies and Their Consequences for Resolved-star Photometric Surveys

Andersson, Eric P. ; Rey, Martin P. LU ; Pontzen, Andrew ; Cadiou, Corentin LU orcid ; Agertz, Oscar LU ; Read, Justin I. and Martin, Nicolas F. (2025) In Astrophysical Journal 978(2).
Abstract

Interpretation of data from faint dwarf galaxies is made challenging by observations limited to only the brightest stars. We present a major improvement to tackle this challenge by undertaking zoomed cosmological simulations that resolve the evolution of all individual stars more massive than 0.5 M, thereby explicitly tracking all observable stars for the Hubble time. For the first time, we predict observable color-magnitude diagrams and the spatial distribution of ≈100,000 stars within four faint (M ≈ 105 M) dwarf galaxies directly from their cosmological initial conditions. In all cases, simulations predict complex light profiles with multiple components, implying that typical... (More)

Interpretation of data from faint dwarf galaxies is made challenging by observations limited to only the brightest stars. We present a major improvement to tackle this challenge by undertaking zoomed cosmological simulations that resolve the evolution of all individual stars more massive than 0.5 M, thereby explicitly tracking all observable stars for the Hubble time. For the first time, we predict observable color-magnitude diagrams and the spatial distribution of ≈100,000 stars within four faint (M ≈ 105 M) dwarf galaxies directly from their cosmological initial conditions. In all cases, simulations predict complex light profiles with multiple components, implying that typical observational measures of structural parameters can make the total V-band magnitudes appear up to 0.5 mag dimmer compared to estimates from simulations. Furthermore, when only small (⪅100) numbers of stars are observable, shot noise from realizations of the color-magnitude diagram introduces uncertainties comparable to the population scatter in, e.g., the total magnitude, half-light radius, and mean iron abundance measurements. Estimating these uncertainties with fully self-consistent mass growth, star formation, and chemical enrichment histories paves the way for more robust interpretation of dwarf galaxy data.

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author
; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Astrophysical Journal
volume
978
issue
2
article number
129
publisher
American Astronomical Society
external identifiers
  • scopus:85215849454
ISSN
0004-637X
DOI
10.3847/1538-4357/ad99d6
language
English
LU publication?
yes
id
a526579d-eccc-4b60-b4ee-91ef3375bf46
date added to LUP
2025-06-02 09:02:41
date last changed
2025-06-02 09:03:06
@article{a526579d-eccc-4b60-b4ee-91ef3375bf46,
  abstract     = {{<p>Interpretation of data from faint dwarf galaxies is made challenging by observations limited to only the brightest stars. We present a major improvement to tackle this challenge by undertaking zoomed cosmological simulations that resolve the evolution of all individual stars more massive than 0.5 M<sub>⊙</sub>, thereby explicitly tracking all observable stars for the Hubble time. For the first time, we predict observable color-magnitude diagrams and the spatial distribution of ≈100,000 stars within four faint (M<sub>⋆</sub> ≈ 10<sup>5</sup> M<sub>⊙</sub>) dwarf galaxies directly from their cosmological initial conditions. In all cases, simulations predict complex light profiles with multiple components, implying that typical observational measures of structural parameters can make the total V-band magnitudes appear up to 0.5 mag dimmer compared to estimates from simulations. Furthermore, when only small (⪅100) numbers of stars are observable, shot noise from realizations of the color-magnitude diagram introduces uncertainties comparable to the population scatter in, e.g., the total magnitude, half-light radius, and mean iron abundance measurements. Estimating these uncertainties with fully self-consistent mass growth, star formation, and chemical enrichment histories paves the way for more robust interpretation of dwarf galaxy data.</p>}},
  author       = {{Andersson, Eric P. and Rey, Martin P. and Pontzen, Andrew and Cadiou, Corentin and Agertz, Oscar and Read, Justin I. and Martin, Nicolas F.}},
  issn         = {{0004-637X}},
  language     = {{eng}},
  number       = {{2}},
  publisher    = {{American Astronomical Society}},
  series       = {{Astrophysical Journal}},
  title        = {{EDGE-INFERNO : Simulating Every Observable Star in Faint Dwarf Galaxies and Their Consequences for Resolved-star Photometric Surveys}},
  url          = {{http://dx.doi.org/10.3847/1538-4357/ad99d6}},
  doi          = {{10.3847/1538-4357/ad99d6}},
  volume       = {{978}},
  year         = {{2025}},
}