Euclid: Early Release Observations -- The formation of peanutty dwarf galaxies in Perseus

@article{kapoor2026euclid,
  title = {{Euclid: Early Release Observations -- The formation of peanutty dwarf galaxies in Perseus}},
  author = {A.U Kapoor and R Smith and A.J Zuiderwijk and S de Rijcke and A van der Wel and M Baes and F.R Marleau and P.-A Duc and R.F Peletier and B Altieri and S Andreon and N Auricchio and C Baccigalupi and M Baldi and A Balestra and S Bardelli and P Battaglia and A Biviano and E Branchini and M Brescia and S Camera and V Capobianco and C Carbone and J Carretero and M Castellano and G Castignani and S Cavuoti and K.C Chambers and A Cimatti and C Colodro-Conde and G Congedo and C.J Conselice and L Conversi and Y Copin and F Courbin and H.M Courtois and M Cropper and H Degaudenzi and G de Lucia and H Dole and F Dubath and X Dupac and M Fabricius and M Farina and R Farinelli and S Ferriol and M Frailis and S Galeotta and K George and B Gillis and C Giocoli and J Gracia-Carpio and A Grazian and F Grupp and S.V.H Haugan and J Hoar and W Holmes and I.M Hook and F Hormuth and A Hornstrup},
  journal = {Astronomy \& Astrophysics - A\&A},
  year = {2026},
  month = sep,
  doi = {10.1051/0004-6361/202661021},
  eprint = {2605.21342},
  archivePrefix = {arXiv},
  url = {https://hal.science/hal-05659463v1},
  note = {CC BY 4.0},
}

TY  - JOUR
TI  - Euclid: Early Release Observations -- The formation of peanutty dwarf galaxies in Perseus
AU  - A.U Kapoor
AU  - R Smith
AU  - A.J Zuiderwijk
AU  - S de Rijcke
AU  - A van der Wel
AU  - M Baes
AU  - F.R Marleau
AU  - P.-A Duc
AU  - R.F Peletier
AU  - B Altieri
AU  - S Andreon
AU  - N Auricchio
AU  - C Baccigalupi
AU  - M Baldi
AU  - A Balestra
AU  - S Bardelli
AU  - P Battaglia
AU  - A Biviano
AU  - E Branchini
AU  - M Brescia
AU  - S Camera
AU  - V Capobianco
AU  - C Carbone
AU  - J Carretero
AU  - M Castellano
AU  - G Castignani
AU  - S Cavuoti
AU  - K.C Chambers
AU  - A Cimatti
AU  - C Colodro-Conde
AU  - G Congedo
AU  - C.J Conselice
AU  - L Conversi
AU  - Y Copin
AU  - F Courbin
AU  - H.M Courtois
AU  - M Cropper
AU  - H Degaudenzi
AU  - G de Lucia
AU  - H Dole
AU  - F Dubath
AU  - X Dupac
AU  - M Fabricius
AU  - M Farina
AU  - R Farinelli
AU  - S Ferriol
AU  - M Frailis
AU  - S Galeotta
AU  - K George
AU  - B Gillis
AU  - C Giocoli
AU  - J Gracia-Carpio
AU  - A Grazian
AU  - F Grupp
AU  - S.V.H Haugan
AU  - J Hoar
AU  - W Holmes
AU  - I.M Hook
AU  - F Hormuth
AU  - A Hornstrup
PY  - 2026
DA  - 2026/09/30
JO  - Astronomy & Astrophysics - A&A
DO  - 10.1051/0004-6361/202661021
UR  - https://hal.science/hal-05659463v1
AB  - Dwarf galaxies in dense cluster environments are susceptible to tidal interactions that can alter their morphology and kinematics. Boxy isophotes are well studied in massive galaxies but remain poorly understood in dwarfs. We aim to identify and characterise boxy/peanutty dwarf galaxies in the Perseus cluster and determine the origin of their isophotal shapes. Using Euclid Early Release Observations of the Perseus cluster, we present a cumulative light fraction method for robustly measuring the isophotal shape parameter c_4, particularly suited to low surface brightness regimes. From ~1100 cataloged dwarfs, we select a clean sample of ~190 early-type systems with reliable c_4 measurement. Observed trends are interpreted through comparison with mock Euclid observations of N-body simulations of tidally transformed dwarfs. We identify 13 dwarfs with significantly boxy isophotes (c_4 < −0.0175). These galaxies lack visible thin disks, lie on the cluster red sequence, and show no preferential spatial concentration within Perseus. We find a significant anticorrelation between c_4 and effective radius: larger galaxies exhibit more boxy isophotes. An analogous size-shape anticorrelation is recovered in the simulations, where inner regions are dominated by box orbits associated with a triaxial peanut structure and outer regions by short-axis tube orbits. The boxy dwarfs in Perseus are tidally transformed remnants of moderately rotating progenitors, with boxy isophotes tracing inner box-orbit-dominated peanut structures. The size-shape correlation arises from viewing geometry: face-on orientations reveal the rectangular profile of the elongated triaxial structure (large and boxy), while edge-on views yield rounder, compact morphologies. Our sample represents an orientation-selected subset of tidally transformed, peanutty dwarfs in the cluster.
SN  - 0004-6361
SN  - 1432-0746
ER  -