Bibcode
Quilley, L.; de Lapparent, V.; Bolzonella, M.; Baes, M.; Damjanov, I.; Häußler, B.; Marleau, F. R.; Nersesian, A.; Saifollahi, T.; Scott, D.; Sorce, J. G.; Tortora, C.; Urbano, M.; Aghanim, N.; Altieri, B.; Amara, A.; Andreon, S.; Auricchio, N.; Baccigalupi, C.; Baldi, M.; Balestra, A.; Bardelli, S.; Basset, A.; Battaglia, P.; Biviano, A.; Bonchi, A.; Bonino, D.; Branchini, E.; Brescia, M.; Brinchmann, J.; Caillat, A.; Camera, S.; Capobianco, V.; Carbone, C.; Carretero, J.; Casas, S.; Castellano, M.; Castignani, G.; Cavuoti, S.; Cimatti, A.; Colodro-Conde, C.; Congedo, G.; Conselice, C. J.; Conversi, L.; Copin, Y.; Courbin, F.; Courtois, H. M.; Cropper, M.; Cuillandre, J.-C.; Da Silva, A.; Degaudenzi, H.; De Lucia, G.; Di Giorgio, A. M.; Dinis, J.; Dubath, F.; Duncan, C. A. J.; Dupac, X.; Dusini, S.; Ealet, A.; Farina, M.; Farrens, S.; Faustini, F.; Ferriol, S.; Fotopoulou, S.; Frailis, M.; Franceschi, E.; Fumana, M.; Galeotta, S.; George, K.; Gillis, B.; Giocoli, C.; Gómez-Alvarez, P.; Grazian, A.; Grupp, F.; Haugan, S. V. H.; Hoar, J.; Holmes, W.; Hormuth, F.; Hornstrup, A.; Hudelot, P.; Jahnke, K.; Jhabvala, M.; Keihänen, E.; Kermiche, S.; Kiessling, A.; Kilbinger, M.; Kubik, B.; Kuijken, K.; Kümmel, M.; Kunz, M.; Kurki-Suonio, H.; Laureijs, R.; Le Mignant, D.; Ligori, S.; Lilje, P. B.; Lindholm, V.; Lloro, I.; Mainetti, G.; Maino, D.; Maiorano, E. et al.
Bibliographical reference
Astronomy and Astrophysics
Advertised on:
6
2026
Journal
Citations
1
Refereed citations
0
Description
The background galaxies in Euclid Early Release Observation images of the Perseus cluster make up a remarkable sample for the combination of a 0.57 deg2 area, 25.3 and 23.2 AB mag depth, and angular resolutions in the optical and near-infrared bands of 0⋅''1 and 0⋅''3, respectively. As part of the effort towards characterising the history of the Hubble sequence, we performed a morphological analysis of 2445 and 12 786 galaxies with IE ≤ 21 and IE ≤ 23, respectively. We used single-Sérsic profiles and the sums of a Sérsic bulge and an exponential disc to model these galaxies with SourceXtractor++ and analysed their positional, structural, and flux parameters in order to assess their similarities and differences. The fitted galaxies to IE ≤ 21 span the various Hubble types with ubiquitous bulge and disc components and a bulge-to-total light ratio (B/T) that takes all values from 0 to 1. The effective radius of the single-Sérsic profile is an intermediate estimate of galaxy size (between the bulge and disc effective radii) depending on B/T. The axis ratio of the single-Sérsic profile is higher than the disc axis ratio, and this difference increases with B/T. The choice of model impacts the photometry with −0.08 to 0.01 mag median systematic IE offsets between single-Sérsic and bulge-disc total magnitudes and a 0.05─0.15 mag dispersion from low to high B/T. We measured a median 0.3 mag bulge-disc colour difference in rest-frame Mg − Mi that originates from the disc-dominated galaxies, whereas bulge-dominated galaxies have median colours similar to those of their components. Remarkably, we also measured redder inside disc colour gradients based on 5 to 10% systematic variations of disc effective radii between the optical and near-infrared bands. This analysis demonstrates the usefulness and limitations of single-Sérsic profile modelling and the power of bulge-disc decomposition for characterising the morphology of lenticulars and spirals in Euclid images. We make available the catalogues of best-fit parameters for the morphological and SED fits.