papers

Publications (103)

astro-ph.CO2026

Euclid preparation. Galaxy power spectrum modelling in redshift space

Euclid Collaboration, B. Camacho Quevedo, M. Crocce +292

Accurate modelling of redshift-space distortions (RSD) is essential for maximizing the cosmological information extracted from large galaxy redshift surveys. In preparation for the…

astro-ph.GA2025

Euclid preparation. Spatially resolved stellar populations of local galaxies with Euclid: a proof of concept using synthetic images with the TNG50 simulation

Euclid Collaboration, Abdurro'uf, C. Tortora +286

The European Space Agency's Euclid mission will observe approximately 14,000 of the extragalactic sky and deliver high-quality imaging for many galaxies. The depth a…

astro-ph.CO2025

Euclid preparation. Cosmology Likelihood for Observables in Euclid (CLOE). 4: Validation and Performance

Euclid Collaboration, M. Martinelli, A. Pezzotta +334

The Euclid satellite will provide data on the clustering of galaxies and on the distortion of their measured shapes, which can be used to constrain and test the cosmological model.…

astro-ph.GA2025

Euclid preparation. Predicting star-forming galaxy scaling relations with the spectral stacking code SpectraPyle

Euclid Collaboration, S. Quai, L. Pozzetti +309

We introduce SpectraPyle, a versatile spectral stacking pipeline developed for the Euclid mission's NISP spectroscopic surveys, aimed at extracting faint emission lines and spectra…

astro-ph.HE2025

Euclid Quick Data Release (Q1). The active galaxies of Euclid

Euclid Collaboration, T. Matamoro Zatarain, S. Fotopoulou +355

We present a catalogue of candidate active galactic nuclei (AGN) in the Quick Release (Q1) fields. For each source we collect multi-wavelength photometry and spec…

astro-ph.CO2026

Euclid preparation. XCVIII. Cosmology Likelihood for Observables in Euclid (CLOE). 5: Extensions beyond the standard modelling of theoretical probes and systematic effects

Euclid Collaboration, L. W. K. Goh, A. Nouri-Zonoz +301

Euclid is expected to establish new state-of-the-art constraints on extensions beyond the standard LCDM cosmological model by measuring the positions and shapes of billions of gala…

astro-ph.CO2025

Beyond Stage IV: Quasar and Galaxy Clustering and the Fundamental Physics of the 2040s

M. Guidi, M. Moresco, H. K. Herrera-Alcantar +24

Stage IV galaxy surveys (DESI, 4MOST, MOONS, Euclid) are establishing precision constraints on cosmological parameters through baryon acoustic oscillations and redshift-space disto…

astro-ph.GA2025

Euclid Quick Data Release (Q1). Galaxy shapes and alignments in the cosmic web

Euclid Collaboration, C. Laigle, C. Gouin +341

Galaxy morphologies and shape orientations are expected to correlate with their large-scale environment, since they grow by accreting matter from the cosmic web and are subject to…

astro-ph.CO2026

Euclid preparation. Three-dimensional galaxy clustering in configuration space: Three-point correlation function estimation

Euclid Collaboration, A. Veropalumbo, M. Moresco +303

Higher-order correlation functions are firmly established as a fundamental tool for the statistical analysis of clustering in modern galaxy surveys. It was demonstrated that they g…

astro-ph.GA2025

Euclid Quick Data Release (Q1). Spectroscopic unveiling of highly ionised lines at z = 2.48-3.88

Euclid Collaboration, D. Vergani, S. Quai +316

This study explores a rare population of sources in a currently uncharted region of spectroscopic redshift space in the Euclid Quick Data Release (Q1), and is intended potentially…

astro-ph.GA2026

Euclid Quick Data Release (Q1): Euclid spectroscopy of quasars. 1. Identification and redshift determination of 3500 bright quasars

Euclid Collaboration, Y. Fu, R. Bouwens +354

The slitless spectroscopy mode of the NISP onboard Euclid has enabled efficient spectroscopy of objects within a large FoV. We present a large and homogeneous sample of bright quas…

astro-ph.CO2026

Euclid preparation. Impact of redshift distribution uncertainties on the joint analysis of photometric galaxy clustering and weak gravitational lensing

Euclid Collaboration, K. A. Bertmann, A. Porredon +290

One of the mission's key projects is the so-called 32pt analysis, that is, the combination of cosmic shear, photometric galaxy clustering, and galaxy-gala…

astro-ph.GA2025

Euclid preparation: TBD. Cosmic Dawn Survey: evolution of the galaxy stellar mass function across 0.2<z<6.5 measured over 10 square degrees

Euclid Collaboration, L. Zalesky, J. R. Weaver +304

The Cosmic Dawn Survey Pre-launch (PL) catalogues cover an effective 10.13 deg area with uniform deep Spitzer/IRAC data ( mag, 5), the largest area covered to th…

astro-ph.IM2025

Euclid Structural-Thermal-Optical Performance

Euclid Collaboration, A. Anselmi, R. Laureijs +290

The Euclid system performance is defined in terms of image quality metrics tuned to the weak gravitational lensing (WL) cosmological probe. WL induces stringent requirements on the…

astro-ph.CO2026

Euclid preparation. XCII. Controlling angular systematics in the Euclid spectroscopic galaxy sample

Euclid Collaboration, P. Monaco, M. Y. Elkhashab +298

We present the strategy used to identify and mitigate potential sources of angular systematics in the \textit{Euclid} spectroscopic galaxy survey, and we quantify their impact on g…

astro-ph.CO2026

Euclid preparation. XCVI. Cosmology Likelihood for Observables in Euclid (CLOE). 3. Inference and Forecasts

Euclid Collaboration, G. Cañas-Herrera, L. W. K. Goh +337

The Euclid mission aims to measure the positions, shapes, and redshifts of over a billion galaxies to provide unprecedented constraints on the nature of dark matter and dark energy…

astro-ph.CO2026

Euclid preparation. LXXXIX. Accurate and precise data-driven angular power spectrum covariances

Euclid Collaboration, K. Naidoo, J. Ruiz-Zapatero +280

We develop techniques for generating accurate and precise internal covariances for measurements of clustering and weak-lensing angular power spectra. These methods have been design…

astro-ph.CO2025

Euclid Quick Data Release (Q1). The first catalogue of strong-lensing galaxy clusters

Euclid Collaboration, P. Bergamini, M. Meneghetti +375

We present the first catalogue of strong lensing galaxy clusters identified in the Euclid Quick Release 1 observations (covering ). This catalogue is the resu…

astro-ph.IM2025

Euclid VI. NISP-P optical ghosts

Euclid Collaboration, K. Paterson, M. Schirmer +309

The Near-Infrared Spectrometer and Photometer (NISP) onboard Euclid includes several optical elements in its path, which introduce artefacts into the data from non-nominal light pa…

astro-ph.CO2025

Euclid preparation. XLI. Galaxy power spectrum modelling in real space

Euclid Collaboration, A. Pezzotta, C. Moretti +246

We investigate the accuracy of the perturbative galaxy bias expansion in view of the forthcoming analysis of the Euclid spectroscopic galaxy samples. We compare the performance of…

astro-ph.CO2025

Euclid preparation. BAO analysis of photometric galaxy clustering in configuration space

Euclid Collaboration, V. Duret, S. Escoffier +286

With about 1.5 billion galaxies expected to be observed, the very large number of objects in the Euclid photometric survey will allow for precise studies of galaxy clustering from…

astro-ph.CO2024

Euclid. I. Overview of the Euclid mission

Euclid Collaboration, Y. Mellier, Abdurro'uf +1134

The current standard model of cosmology successfully describes a variety of measurements, but the nature of its main ingredients, dark matter and dark energy, remains unknown. Eucl…

astro-ph.CO2025

Euclid preparation: Expected constraints on initial conditions

Euclid Collaboration, F. Finelli, Y. Akrami +307

The Euclid mission of the European Space Agency will deliver galaxy and cosmic shear surveys, which will be used to constrain initial conditions and statistics of primordial fluctu…

astro-ph.GA2025

Euclid Quick Data Release (Q1). A first view of the star-forming main sequence in the Euclid Deep Fields

Euclid Collaboration, A. Enia, L. Pozzetti +348

The star-forming main sequence (SFMS) is a tight relation observed between stellar masses and star formation rates (SFR) in a population of galaxies. This relation is observed at d…

astro-ph.IM2025

Euclid preparation. Overview of Euclid infrared detector performance from ground tests

Euclid Collaboration, B. Kubik, R. Barbier +341

The paper describes the objectives, design and findings of the pre-launch ground characterisation campaigns of the Euclid infrared detectors. The pixel properties, including baseli…

astro-ph.CO2026

Euclid preparation. Galaxy 2-point correlation function modelling in redshift space

Euclid Collaboration, M. Kärcher, M. -A. Breton +309

The Euclid satellite will measure spectroscopic redshifts for tens of millions of emission-line galaxies. In the context of Stage-IV surveys, the 3-dimensional clustering of galaxi…

astro-ph.GA2025

Euclid Quick Data Release (Q1). The Strong Lensing Discovery Engine D -- Double-source-plane lens candidates

Euclid Collaboration, T. Li, T. E. Collett +335

Strong gravitational lensing systems with multiple source planes are powerful tools for probing the density profiles and dark matter substructure of the galaxies. The ratio of Eins…

astro-ph.CO2026

Euclid. Populating a dark universe with galaxies using SciPIC

Euclid Collaboration, E. J. Gonzalez, J. Carretero +305

High-fidelity galaxy mocks are crucial for validating analysis pipelines and for cosmological inference. In this context, the Science Pipeline at PIC (SciPIC) is a pipeline specifi…

astro-ph.CO2026

Euclid preparation. Galaxy power spectrum and bispectrum modelling

Euclid Collaboration, K. Pardede, A. Eggemeier +306

Higher-order correlation functions of the large-scale galaxy distribution offer access to information beyond that contained in standard 2-point statistics such as the power spectru…

astro-ph.CO2026

Euclid Quick Data Release (Q1). Searching for giant gravitational arcs in galaxy clusters with mask region-based convolutional neural networks

Euclid Collaboration, L. Bazzanini, G. Angora +306

Strong gravitational lensing (SL) by galaxy clusters is a powerful probe of their inner mass distribution and a key test bed for cosmological models. However, the detection of SL e…

astro-ph.CO2025

Euclid Quick Data Release (Q1). Combined Euclid and Spitzer galaxy density catalogues at 1.3 and detection of significant Euclid passive galaxy overdensities in Spitzer overdense regions

Euclid Collaboration, N. Mai, S. Mei +308

Euclid will detect tens of thousands of clusters and protoclusters at >1.3. With a total coverage of 63.1deg, the Euclid Quick Data Release 1 (Q1) is large enough to detect…

astro-ph.IM2025

Euclid preparation: The NISP spectroscopy channel, on ground performance and calibration

Euclid Collaboration, W. Gillard, T. Maciaszek +356

ESA's Euclid cosmology mission relies on the very sensitive and accurately calibrated spectroscopy channel of the Near-Infrared Spectrometer and Photometer (NISP). With three opera…

astro-ph.CO2026

\textit{Euclid} preparation. Baryon acoustic oscillations extraction techniques: comparison and optimisation

Euclid Collaboration, E. Sarpa, A. Veropalumbo +296

We present the first end-to-end validation of the Euclid baryon acoustic oscillation (BAO) analysis pipeline, encompassing density-field reconstruction, two-point correlation funct…

astro-ph.GA2026

Euclid Quick Data Release (Q1): The impact of AGN emission on SED-derived physical properties

Euclid Collaboration, B. Laloux, A. Bongiorno +309

The Euclid Quick Data Release (Q1) is a powerful dataset to study active galactic nuclei (AGN) and their host galaxies. Deriving their physical properties through multi-component s…

astro-ph.CO2026

Euclid Quick Data Release (Q1). The role of cosmic connectivity in shaping galaxy clusters

Euclid Collaboration, C. Gouin, C. Laigle +337

The matter distribution around galaxy clusters is distributed over several filaments, reflecting their positions as nodes in the large-scale cosmic web. The number of filaments con…

astro-ph.GA2026

Euclid Quick Data Release (Q1). The Strong Lensing Discovery Engine F -- Bright and low-redshift strong lenses

Euclid Collaboration, L. R. Ecker, M. Fabricius +346

We present 72 additional galaxy-galaxy strong lenses that complement the sample discovered in the Euclid Quick Release 1 data (63.1 deg^2) of the Strong Lens Discovery Engine (SLDE…

astro-ph.GA2025

Euclid Quick Data Release (Q1). Active galactic nuclei identification using diffusion-based inpainting of Euclid VIS images

Euclid Collaboration, G. Stevens, S. Fotopoulou +271

Light emission from galaxies exhibit diverse brightness profiles, influenced by factors such as galaxy type, structural features and interactions with other galaxies. Elliptical ga…

astro-ph.CO2025

Euclid preparation. Constraining parameterised models of modifications of gravity with the spectroscopic and photometric primary probes

Euclid Collaboration, I. S. Albuquerque, N. Frusciante +285

The Euclid mission has the potential to understand the fundamental physical nature of late-time cosmic acceleration and, as such, of deviations from the standard cosmological model…

astro-ph.CO2026

Euclid Quick Data Release (Q1). LEMON -- Lens Modelling with Neural networks. Automated and fast modelling of Euclid gravitational lenses with a singular isothermal ellipsoid mass profile

Euclid Collaboration, V. Busillo, C. Tortora +312

The Euclid mission aims to survey around 14000 deg^{2} of extragalactic sky, providing around 10^{5} gravitational lens images. Modelling of gravitational lenses is fundamental to…

astro-ph.GA2025

Euclid Quick Data Release (Q1): Hunting for luminous z > 6 galaxies in the Euclid Deep Fields -- forecasts and first bright detections

Euclid Collaboration, N. Allen, P. A. Oesch +309

The evolution of the rest-frame ultraviolet luminosity function (UV LF) is a powerful probe of early star formation and stellar mass build-up. At z > 6, its bright end (MUV < -21)…

astro-ph.CO2025

Euclid preparation. Full-shape modelling of 2-point and 3-point correlation functions in real space

Euclid Collaboration, M. Guidi, A. Veropalumbo +308

We investigate the accuracy and range of validity of the perturbative model for the 2-point (2PCF) and 3-point (3PCF) correlation functions in real space in view of the forthcoming…

astro-ph.GA2026

Euclid preparation. Probing galaxy evolution within cosmic voids in Euclid-like simulations

Euclid Collaboration, G. Papini, O. Cucciati +294

The evolution of galaxies is profoundly influenced by the environment in which they reside. Cosmic voids serve as pristine laboratories for studying galaxy evolution in the relativ…

astro-ph.CO2026

Euclid preparation. Decomposing components of the extragalactic background light using multi-band intensity mapping cross-correlations

Euclid Collaboration, Y. Cao, A. R. Cooray +269

The extragalactic background light (EBL) fluctuations in the optical/near-IR encode the cumulative integrated galaxy light (IGL), diffuse intra-halo light (IHL), and high- sourc…

astro-ph.GA2026

Euclid Quick Data Release (Q1): The geometry of dark matter halos from extragalactic streams

Euclid Collaboration, N. Starkman, J. Nibauer +295

Wide-field surveys like Euclid mark a new era of extragalactic stellar stream studies. With a large number of streams, it is now possible to constrain the dark matter halos of gala…

astro-ph.CO2026

Euclid Quick Data Release (Q1). The first Euclid view of Planck galaxy protocluster candidates at cosmic noon

Euclid Collaboration, T. Dusserre, H. Dole +339

[ABRIGED ABSTRACT] A large catalogue of candidate galaxy protoclusters with high star-formation rates was produced by the Planck collaboration. We search, in the first data release…

astro-ph.GA2025

Euclid Quick Data Release (Q1): The Strong Lensing Discovery Engine A -- System overview and lens catalogue

Euclid Collaboration, M. Walmsley, P. Holloway +372

We present a catalogue of 497 galaxy-galaxy strong lenses in the Euclid Quick Release 1 data (63 deg). In the initial 0.45\% of Euclid's surveys, we double the total number of…

astro-ph.GA2025

Euclid Quick Data Release (Q1) First study of red quasars selection

Euclid Collaboration, F. Tarsitano, S. Fotopoulou +322

Red quasars constitute an important but elusive phase in the evolution of supermassive black holes, where dust obscuration can significantly alter their observed properties. They h…

astro-ph.CO2026

Euclid preparation. Cosmology Likelihood for Observables in Euclid (CLOE). 2. Code implementation

Euclid Collaboration, S. Joudaki, V. Pettorino +345

We provide a description of the code implementation and structure of Cosmology Likelihood for Observables in Euclid (CLOE), developed by members of the Euclid Consortium. CLOE is a…

astro-ph.GA2025

Euclid Quick Data Release (Q1): Identification of massive galaxy candidates at the end of the Epoch of Reionisation

Euclid Collaboration, R. Navarro-Carrera, K. I. Caputi +295

Probing the presence and properties of massive galaxies at high redshift is one of the most critical tests for galaxy formation models. In this work, we search for galaxies with st…

astro-ph.GA2025

Euclid Quick Data Release (Q1). First Euclid statistical study of galaxy mergers and their connection to active galactic nuclei

Euclid Collaboration, A. La Marca, L. Wang +334

Galaxy major mergers are a key pathway to trigger AGN. We present the first detection of major mergers in the Euclid Deep Fields and analyse their connection with AGN. We construct…

astro-ph.GA2025

Euclid Quick Data Release (Q1) Exploring galaxy properties with a multi-modal foundation model

Euclid Collaboration, M. Siudek, M. Huertas-Company +321

Modern astronomical surveys, such as the Euclid mission, produce high-dimensional, multi-modal data sets that include imaging and spectroscopic information for millions of galaxies…

astro-ph.GA2025

Euclid preparation LXX. Forecasting detection limits for intracluster light in the Euclid Wide Survey

Euclid Collaboration, C. Bellhouse, J. B. Golden-Marx +292

The intracluster light (ICL) permeating galaxy clusters is a tracer of the cluster's assembly history, and potentially a tracer of their dark matter structure. In this work we expl…

astro-ph.GA2025

Euclid Quick Data Release (Q1). The Strong Lensing Discovery Engine C: Finding lenses with machine learning

Euclid Collaboration, N. E. P. Lines, T. E. Collett +350

Strong gravitational lensing has the potential to provide a powerful probe of astrophysics and cosmology, but fewer than 1000 strong lenses have been confirmed so far. With a 0.16'…

astro-ph.CO2026

Euclid preparation. CIV. Impact of galaxy intrinsic alignment modelling choices on Euclid 3x2pt cosmology

Euclid Collaboration, D. Navarro-Gironés, I. Tutusaus +274

The Euclid galaxy survey will provide unprecedented constraints on cosmology, but achieving unbiased results will require an optimal characterisation and mitigation of systematic e…

astro-ph.GA2025

Euclid Quick Data Release (Q1): First visual morphology catalogue

Euclid Collaboration, M. Walmsley, M. Huertas-Company +352

We present a detailed visual morphology catalogue for Euclid's Quick Release 1 (Q1). Our catalogue includes galaxy features such as bars, spiral arms, and ongoing mergers, for the…

astro-ph.IM2026

Euclid Quick Data Release (Q1). AstroVink: A vision transformer approach to find strong gravitational lens systems

Euclid Collaboration, S. H. Vincken, K. Rojas +302

We present AstroVink, a vision transformer classifier designed for automated identification of strong lens candidates in Euclid imaging. We build upon the DINOv2 encoder, fine tune…

astro-ph.GA2025

Euclid Quick Data Release (Q1) The Strong Lensing Discovery Engine B -- Early strong lens candidates from visual inspection of high velocity dispersion galaxies

Euclid Collaboration, K. Rojas, T. E. Collett +336

We present a search for strong gravitational lenses in Euclid imaging with high stellar velocity dispersion ( km/s) reported by SDSS and DESI. We performed expert visua…

astro-ph.CO2026

Euclid preparation. Simulated galaxy catalogues for non-standard cosmological models

Euclid Collaboration, M. -A. Breton, P. Fosalba +289

Stage-IV galaxy surveys will provide the opportunity to test cosmological models and the underlying theory of gravity with unparalleled precision. In this context, it is crucial fo…

astro-ph.CO2026

Euclid Quick Data Release (Q1) -- Characteristics and limitations of the spectroscopic measurements

Euclid Collaboration, V. Le Brun, M. Bethermin +344

The SPE processing function (PF) of the \Euclid pipeline is dedicated to the automatic analysis of one-dimensional spectra to determine redshifts, line fluxes, and spectral classif…

astro-ph.GA2025

Euclid Quick Data Release (Q1) -- Data release overview

Euclid Collaboration, H. Aussel, I. Tereno +407

The first Euclid Quick Data Release, Q1, comprises 63.1 sq deg of the Euclid Deep Fields (EDFs) to nominal wide-survey depth. It encompasses visible and near-infrared space-based i…

astro-ph.GA2025

Euclid preparation LXXIX. Using mock low surface brightness dwarf galaxies to probe Euclid Wide Survey detection capabilities

Euclid Collaboration, M. Urbano, P. -A. Duc +313

Local Universe dwarf galaxies can serve as both cosmological and mass assembly probes. Deep surveys have enabled the study of these objects down to the low surface brightness (LSB)…

astro-ph.CO2026

Euclid preparation. First investigation of the impact of cross-contamination on spectroscopic redshift measurements with pixel-level simulations

Euclid Collaboration, F. Passalacqua, S. Anselmi +299

We present a study on simulated data focused on understanding the performance of the spectroscopic redshift measurements with the Near-Infrared Spectrometer and Photometer (NISP) i…

astro-ph.IM2026

Euclid. Properties and performance of the NISP signal estimator

Euclid Collaboration, F. Cogato, B. Kubik +292

The Euclid spacecraft, located at the second Lagrangian point of the Sun-Earth system, hosts the Near-Infrared Spectrometer and Photometer (NISP) instrument. NISP is equipped with…

astro-ph.CO2026

Euclid preparation. Calibrated intrinsic galaxy alignments in the Euclid Flagship simulation

Euclid Collaboration, K. Hoffmann, R. Paviot +298

Intrinsic alignments of galaxies are potentially a major contaminant of cosmological analyses of weak gravitational lensing. We construct a semi-analytic model of galaxy ellipticit…

astro-ph.GA2025

Euclid Quick Data Release (Q1). An investigation of optically faint, red objects in the Euclid Deep Fields

Euclid Collaboration, G. Girardi, G. Rodighiero +326

Our understanding of cosmic star-formation at used to largely rely on rest-frame UV observations. However, these observations overlook dusty and massive sources, resulting in…

astro-ph.CO2025

Euclid Quick Data Release (Q1). NIR processing and data products

Euclid Collaboration, G. Polenta, M. Frailis +367

This paper describes the near-infrared processing function (NIR PF) that processes near-infrared images from the Near-Infrared Spectrometer and Photometer (NISP) instrument onboard…

astro-ph.GA2025

Euclid Quick Data Release (Q1). Extending the quest for little red dots to z<4

Euclid Collaboration, L. Bisigello, G. Rodighiero +348

Recent James Webb Space Telescope (JWST) observations have revealed a population of sources with a compact morphology and a characteristic `v-shaped' continuum, namely blue at rest…

astro-ph.GA2025

Euclid Quick Data Release (Q1). First Euclid statistical study of the active galactic nuclei contribution fraction

Euclid Collaboration, B. Margalef-Bentabol, L. Wang +331

Active galactic nuclei (AGN) play a key role in galaxy evolution but are challenging to identify due to their varied observational signatures. Furthermore, understanding their impa…

astro-ph.CO2026

Euclid: Galaxy SED reconstruction in the PHZ processing function: impact on the PSF and the role of medium-band filters

Euclid Collaboration, F. Tarsitano, C. Schreiber +301

Weak lensing surveys require accurate correction for the point spread function (PSF) when measuring galaxy shapes. For a diffraction-limited PSF, as arises in space-based missions,…

astro-ph.CO2026

Euclid preparation. LXXXV. Toward a DR1 application of higher-order weak lensing statistics

Euclid Collaboration, S. Vinciguerra, F. Bouchè +284

This is the second paper in the HOWLS (higher-order weak lensing statistics) series exploring the usage of non-Gaussian statistics for cosmology inference within Euclid. With respe…

astro-ph.IM2025

Euclid Quick Data Release (Q1): From images to multiwavelength catalogues: the Euclid MERge Processing Function

Euclid Collaboration, E. Romelli, M. Kümmel +345

The Euclid satellite is an ESA mission that was launched in July 2023. \Euclid is working in its regular observing mode with the target of observing an area of $14\,000~\text{deg}^…

astro-ph.CO2023

Modelling the next-to-leading order matter three-point correlation function using FFTLog

M. Guidi, A. Veropalumbo, E. Branchini +2

The study of higher-order statistics, particularly three-point statistics, of the Large Scale Structure (LSS) of the Universe provides us with unique information on the biasing rel…

astro-ph.CO2025

Euclid preparation. Review of forecast constraints on dark energy and modified gravity

Euclid Collaboration, N. Frusciante, M. Martinelli +326

The Euclid mission has been designed to provide, as one of its main deliverables, information on the nature of the gravitational interaction, which determines the expansion of the…

astro-ph.CO2025

Euclid Quick Data Release (Q1). First detections from the galaxy cluster workflow

Euclid Collaboration, S. Bhargava, C. Benoist +351

The first survey data release by the Euclid mission covers approximately in the Euclid Deep Fields to the same depth as the Euclid Wide Survey. This paper show…

astro-ph.CO2025

Euclid preparation. Establishing the quality of the 2D reconstruction of the filaments of the cosmic web with DisPerSE using Euclid photometric redshifts

Euclid Collaboration, N. Malavasi, F. Sarron +313

Cosmic filaments are prominent structures of the matter distribution of the Universe. Modern detection algorithms are an efficient way to identify filaments in large-scale observat…

astro-ph.GA2026

Euclid Quick Data Release (Q1): The evolution of the passive-density and morphology-density relations between and

Euclid Collaboration, C. Cleland, S. Mei +320

The extent to which the environment affects galaxy evolution has been under scrutiny by researchers for decades. With the first data from Euclid, we can begin to systematically stu…

astro-ph.GA2026

Euclid preparation. Far-infrared predictions for Euclid galaxy catalogues: cluster, protocluster, and field

Euclid Collaboration, A. Parmar, D. L. Clements +297

The MAMBO mock galaxy catalogue, based on the Millennium Simulation with empirically assigned galaxy properties, provides predictions of FIR fluxes and physical parameters of Eucli…

astro-ph.GA2025

Euclid Quick Data Release (Q1). A probabilistic classification of quenched galaxies

Euclid Collaboration, P. Corcho-Caballero, Y. Ascasibar +318

Investigating what drives the quenching of star formation in galaxies is key to understanding their evolution. The Euclid mission will provide rich data from optical to infrared wa…

astro-ph.CO2026

Testing template-fitting models for the multipoles of the two-point clustering of galaxy clusters

Euclid Collaboration, E. Tsaprazi, A. Fumagalli +274

The \textit{Euclid} satellite will deliver a catalogue of optically-selected galaxy clusters spanning from around deg in Data Release (DR) 1 to around deg

astro-ph.CO2026

Euclid preparation. The impact of redshift interlopers on the two-point correlation function analysis

Euclid Collaboration, I. Risso, A. Veropalumbo +317

The Euclid survey aims to measure the spectroscopic redshift of emission-line galaxies by identifying the H line in their slitless spectra. This method is sensitive to the si…

astro-ph.GA2025

Euclid Quick Data Release (Q1). Optical and near-infrared identification and classification of point-like X-ray selected sources

Euclid Collaboration, W. Roster, M. Salvato +316

To better understand the role of active galactic nuclei (AGN) in galaxy evolution, it is crucial to achieve a complete and pure AGN census. X-ray surveys are key to this, but ident…

astro-ph.GA2026

Euclid Quick Data Release (Q1). AgileLens: A scalable CNN-based pipeline for strong gravitational lens identification

Euclid Collaboration, X. Xu, R. Chen +308

We present an end-to-end, iterative pipeline for efficient identification of strong galaxy--galaxy lensing systems, applied to the Euclid Q1 imaging data. Starting from VIS catalog…

astro-ph.CO2025

Euclid preparation. Methodology for validating the Euclid Catalogue of Galaxy Clusters using external data

Euclid Collaboration, J. -B. Melin, S. A. Stanford +315

We present our methodology for identifying known clusters as counterparts to objects in the Euclid Catalogue of Galaxy Clusters (ECGC). Euclid is expected to detect a large number…

astro-ph.GA2025

Euclid Quick Data Release (Q1). Photometric redshifts and physical properties of galaxies through the PHZ processing function

Euclid Collaboration, M. Tucci, S. Paltani +344

The ESA Euclid mission will measure the photometric redshifts of billions of galaxies in order to provide an accurate 3D view of the Universe at optical and near-infrared wavelengt…

astro-ph.GA2026

Euclid Quick Data Release (Q1). Quenching precedes bulge formation in dense environments but follows it in the field

Euclid Collaboration, F. Gentile, E. Daddi +321

(Abridged) The bimodality between star-forming discs and quiescent spheroids requires the existence of two main processes: the galaxy quenching and the morphological transformation…

astro-ph.IM2025

Euclid Quick Data Release (Q1): From spectrograms to spectra: the SIR spectroscopic Processing Function

Euclid Collaboration, Y. Copin, M. Fumana +348

The Euclid space mission aims to investigate the nature of dark energy and dark matter by mapping the large-scale structure of the Universe. A key component of Euclid's observation…

astro-ph.GA2026

Euclid Quick Data Release (Q1). Searching for radio-selected \Euclid-dark galaxies in the EDF-N

Euclid Collaboration, M. Giulietti, I. Prandoni +308

We present and investigate the properties of a sample of radio-selected, Euclid-dark galaxies, identified from LOFAR HBA observations at 144 MHz within the Euclid Deep Field-North…

astro-ph.GA2025

Euclid Quick Data Release (Q1), A first look at the fraction of bars in massive galaxies at

Euclid Collaboration, M. Huertas-Company, M. Walmsley +336

Stellar bars are key structures in disc galaxies, driving angular momentum redistribution and influencing processes such as bulge growth and star formation. Quantifying the bar fra…

astro-ph.CO2026

Euclid preparation: LXXXVII. Non-Gaussianity of 2-point statistics likelihood: Precise analysis of the matter power spectrum distribution

Euclid Collaboration, J. Bel, S. Gouyou Beauchamps +281

We investigate the non-Gaussian features in the distribution of the matter power spectrum multipoles. Using the COVMOS method, we generate 100\,000 mock realisations of dark matter…

astro-ph.GA2025

Euclid Quick Data Release (Q1). Exploring galaxy morphology across cosmic time through Sersic fits

Euclid Collaboration, L. Quilley, I. Damjanov +333

We present the results of the single-component Sérsic profile fitting for the magnitude-limited sample of \IE galaxies within the 63.1 deg area of the Euclid Quick Data R…

astro-ph.CO2025

Euclid preparation. Cosmology Likelihood for Observables in Euclid (CLOE). 6: Impact of systematic uncertainties on the cosmological analysis

Euclid Collaboration, L. Blot, K. Tanidis +309

Extracting cosmological information from the Euclid galaxy survey will require modelling numerous systematic effects during the inference process. This implies varying a large numb…

astro-ph.CO2026

Euclid preparation: Testing multi-field inflation with galaxy power spectrum and bispectrum

Euclid Collaboration, D. Linde, A. Moradinezhad Dizgah +281

Primordial non-Gaussianity (PNG) is a powerful probe of the origin of cosmic structure. Stage-IV surveys like \Euclid will measure galaxy - and -point clustering at high sign…

astro-ph.IM2025

Euclid Quick Data Release (Q1): VIS processing and data products

Euclid Collaboration, H. J. McCracken, K. Benson +377

This paper describes the VIS Processing Function (VIS PF) of the Euclid ground segment pipeline, which processes and calibrates raw data from the VIS camera. We present the algorit…

astro-ph.GA2026

Euclid Quick Data Release (Q1). The average far-infrared properties of Euclid-selected star-forming galaxies

Euclid Collaboration, R. Hill, A. Abghari +302

The first Euclid Quick Data Release contains millions of galaxies with excellent optical and near-infrared (IR) coverage. To complement this dataset, we investigate the average far…

astro-ph.CO2026

Euclid preparation. CosmoPostProcess: A simulation calibrated framework for weak lensing selection bias in richness-selected galaxy clusters

Euclid Collaboration, R. Ingrao, S. Borgani +280

We present \texttt{CosmoPostProcess}, a simulation-based forward-modelling algorithm calibrated to reproduce Euclid optical cluster observables. Its main deliverable is a correctio…

astro-ph.CO2025

Euclid preparation. 3-dimensional galaxy clustering in configuration space. Part I. 2-point correlation function estimation

Euclid Collaboration, S. de la Torre, F. Marulli +297

The 2-point correlation function of the galaxy spatial distribution is a major cosmological observable that enables constraints on the dynamics and geometry of the Universe. The Eu…

astro-ph.CO2026

Euclid preparation. CII. Non-Gaussianity of 2-pt statistics likelihood: Parameter inference with a non-Gaussian likelihood in Fourier and configuration space

Euclid Collaboration, S. Gouyou Beauchamps, J. Bel +277

In this work we account for this skewness in parameter inference by modelling the likelihood through an Edgeworth expansion which involves the complete skewness tensor, composed of…

astro-ph.CO2026

Euclid preparation. Refining input galaxy shape distributions for shear calibration simulations

Euclid Collaboration, H. Jansen, N. Martinet +282

The Euclid Wide Survey (EWS) will cover the majority of the extragalactic sky with a resolution similar to the Hubble Space Telescope. This unprecedented data set will introduce a…

astro-ph.CO2025

Euclid preparation. Simulating thousands of Euclid spectroscopic skies

Euclid Collaboration, P. Monaco, G. Parimbelli +303

We present two extensive sets of 3500+1000 simulations of dark matter haloes on the past light cone, and two corresponding sets of simulated (`mock') galaxy catalogues that represe…

astro-ph.CO2026

Euclid preparation. Testing analytic models of galaxy intrinsic alignments in the Euclid Flagship simulation

Euclid Collaboration, R. Paviot, B. Joachimi +293

We model intrinsic alignments (IA) in Euclid's Flagship simulation to investigate its impact on Euclid's weak lensing signal. Our IA implementation in the Flagship simulation takes…