The authors derive the fourth-order galaxy-galaxy lensing 4PCF and aperture statistics, implement a numerical pipeline and FFT estimator, and detect the connected ⟨N³ M_ap⟩ signal at SNR ~9 in stage IV mock data over 2000 deg².
Euclid: Galaxy morphology and photometry from bulge-disc decomposition of Early Release Observations
5 Pith papers cite this work. Polarity classification is still indexing.
abstract
The background galaxies in Euclid ERO images of the Perseus cluster make up a remarkable sample in its combination of 0.57 deg$^2$ area, 25.3 and 23.2 AB mag depth, as well as 0.1" and 0.3" angular resolutions, in optical and near-IR bands, respectively. We perform a morphological analysis of 2445 and 12,786 galaxies with $I_E < 21$ and $I_E < 23$, respectively. We use single-S\'ersic profiles and the sums of a S\'ersic bulge and an exponential disc to model these galaxies with SourceXtractor++ and analyse their parameters in order to assess their consistencies and discrepancies. The fitted galaxies to $I_E < 21$ span the various Hubble types with ubiquitous bulge and disc components, and a bulge-to-total light ratio B/T taking all values from 0 to 1. The effective radius of the single-S\'ersic 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-S\'ersic profile is higher than the disc axis ratio, increasingly so with B/T. The model impacts the photometry with -0.08 to 0.01 mag median systematic $I_E$ offsets between single-S\'ersic and bulge+disc total magnitudes, and a 0.05 to 0.15 mag dispersion, from low to high B/T. We measure a median $0.3$ mag bulge-disc colour difference in rest-frame $M_g - M_i$ that originates from the disc-dominated galaxies, whereas bulge-dominated galaxies have similar median colours for their components. We also measure redder-inside disc colour gradients based on 5 to 10$\%$ systematic variations of disc effective radii between the optical and near-IR bands. This analysis demonstrates the usefulness and limitations of single-S\'ersic 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.
years
2026 5representative citing papers
EGIDE provides 149,215 edge-on galaxy candidates from DESI DR10 with homogeneous photometry, masses, and redshifts, ten times larger than EGIPS.
Joint 2nd- and 3rd-order cosmic shear analysis on KiDS-Legacy data produces Ω_m = 0.297^{+0.056}_{-0.040} and S_8 = 0.806^{+0.025}_{-0.023}, consistent with Planck and prior KiDS results while improving Ω_m precision.
End-to-end validation on Euclid-like mocks shows RecSym and RecIso reconstruction yield unbiased BAO measurements, improving figure of merit for Omega_m and H0 rs by factor of ~3 across 0.9<z<1.8.
Euclid collaboration develops and validates direct and spherical-harmonic estimators plus a random-split optimization for measuring the three-point galaxy correlation function at the scale of the full Euclid survey.
citing papers explorer
-
Fourth-order galaxy-galaxy-lensing: Theoretical framework and direct estimation
The authors derive the fourth-order galaxy-galaxy lensing 4PCF and aperture statistics, implement a numerical pipeline and FFT estimator, and detect the connected ⟨N³ M_ap⟩ signal at SNR ~9 in stage IV mock data over 2000 deg².
-
The Edge-on Galaxies in the DESI survey (EGIDE): sample building and photometry
EGIDE provides 149,215 edge-on galaxy candidates from DESI DR10 with homogeneous photometry, masses, and redshifts, ten times larger than EGIPS.
-
KiDS-Legacy: Joint analysis of second- and third-order cosmic shear
Joint 2nd- and 3rd-order cosmic shear analysis on KiDS-Legacy data produces Ω_m = 0.297^{+0.056}_{-0.040} and S_8 = 0.806^{+0.025}_{-0.023}, consistent with Planck and prior KiDS results while improving Ω_m precision.
-
\textit{Euclid} preparation. Baryon acoustic oscillations extraction techniques: comparison and optimisation
End-to-end validation on Euclid-like mocks shows RecSym and RecIso reconstruction yield unbiased BAO measurements, improving figure of merit for Omega_m and H0 rs by factor of ~3 across 0.9<z<1.8.
-
Euclid preparation. Three-dimensional galaxy clustering in configuration space: Three-point correlation function estimation
Euclid collaboration develops and validates direct and spherical-harmonic estimators plus a random-split optimization for measuring the three-point galaxy correlation function at the scale of the full Euclid survey.