Euclid Quick Data Release (Q1). The metallicity of the intracluster light

@misc{collaboration2026euclid,
  title = {{Euclid Quick Data Release (Q1). The metallicity of the intracluster light}},
  author = {Euclid Collaboration and J. B. Golden-Marx and N. A. Hatch and S. P. Bamford and H. Gao and T. Kolcu and M. Montes and H. J. Brown and Y. M. Bahé and H. Gully and G. Martin and M. Urbano and S. L. Ahad and C. Bellhouse and M. Bolzonella and J. Butler and Weiguang Cui and F. Durret and A. Ellien and A. H. Gonzalez and M. Kluge and L. Moscardini and F. R. Pearce and R. Ragusa and B. Altieri and S. Andreon and N. Auricchio and C. Baccigalupi and M. Baldi and S. Bardelli and P. Battaglia and A. Biviano and E. Branchini and M. Brescia and J. Brinchmann and S. Camera and G. Cañas-Herrera and V. Capobianco and C. Carbone and V. F. Cardone and J. Carretero and S. Casas 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 A. Costille and F. Courbin and H. M. Courtois and M. Cropper and J. -C. Cuillandre and A. Da Silva and H. Degaudenzi and G. De Lucia},
  howpublished = {arXiv},
  year = {2026},
  month = oct,
  doi = {10.48550/arxiv.2610.29686},
  eprint = {2610.29686},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2610.29686},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - Euclid Quick Data Release (Q1). The metallicity of the intracluster light
AU  - Euclid Collaboration
AU  - J. B. Golden-Marx
AU  - N. A. Hatch
AU  - S. P. Bamford
AU  - H. Gao
AU  - T. Kolcu
AU  - M. Montes
AU  - H. J. Brown
AU  - Y. M. Bahé
AU  - H. Gully
AU  - G. Martin
AU  - M. Urbano
AU  - S. L. Ahad
AU  - C. Bellhouse
AU  - M. Bolzonella
AU  - J. Butler
AU  - Weiguang Cui
AU  - F. Durret
AU  - A. Ellien
AU  - A. H. Gonzalez
AU  - M. Kluge
AU  - L. Moscardini
AU  - F. R. Pearce
AU  - R. Ragusa
AU  - B. Altieri
AU  - S. Andreon
AU  - N. Auricchio
AU  - C. Baccigalupi
AU  - M. Baldi
AU  - S. Bardelli
AU  - P. Battaglia
AU  - A. Biviano
AU  - E. Branchini
AU  - M. Brescia
AU  - J. Brinchmann
AU  - S. Camera
AU  - G. Cañas-Herrera
AU  - V. Capobianco
AU  - C. Carbone
AU  - V. F. Cardone
AU  - J. Carretero
AU  - S. Casas
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  - A. Costille
AU  - F. Courbin
AU  - H. M. Courtois
AU  - M. Cropper
AU  - J. -C. Cuillandre
AU  - A. Da Silva
AU  - H. Degaudenzi
AU  - G. De Lucia
PY  - 2026
DA  - 2026/10/21
PB  - arXiv
DO  - 10.48550/arxiv.2610.29686
UR  - https://arxiv.org/abs/2610.29686
AB  - Colour provides key information to constrain the stellar population of the intracluster light (ICL), the diffuse light within galaxy clusters. We derive radial colour profiles (Y_E−H_E, J_E−H_E, I_E−H_E) of the brightest central galaxy (BCG) and ICL for 168 galaxy clusters from the Dark Energy Survey redMaPPer catalogue within the redshift range 0.1 < z < 0.75 and halo mass M_200m > 10^14.05M_⊙/h, within the Euclid Quick Data Release (Q1). By stacking the light profiles measured using elliptical annuli on the BCG and ICL images, we reliably measure the ICL colour out to approximately 300 kpc, over which we find a colour gradient, with the ICL becoming bluer than the BCG out to approximately 150 kpc. Using stellar population synthesis (SPS) models, we find that near-infrared (NIR) colours are sensitive to metallicity, but not age. Thus, we measure a metallicity profile in the BCG and ICL that extends out to 300 kpc for a statistical sample for the first time. While the colours, and the detection of a colour and metallicity gradient, are robust, we note that our metallicity measurement is dependent upon our choice of both SPS model and colour. We find that the metallicity of the BCG is super-solar [log_10 (Z/Z_⊙) > 0.1], while the ICL is metal-poor [log_10(Z/Z_⊙)≈ −0.5], placing the first statistical constraint on the metallicity of the ICL out to large radii. These results support our current understanding of BCG and ICL formation: BCGs form predominantly through mergers with massive galaxies or the cores of satellite galaxies, while the ICL grows via the tidal stripping of lower-metallicity stars from the outskirts of massive satellite galaxies.
ER  -