papers

Publications (205)

astro-ph.CO2024

Euclid preparation: XLVIII. The pre-launch Science Ground Segment simulation framework

Euclid Collaboration, S. Serrano, P. Hudelot +274

The European Space Agency's Euclid mission is one of the upcoming generation of large-scale cosmology surveys, which will map the large-scale structure in the Universe with unprece…

astro-ph.CO2021

Euclid preparation: I. The Euclid Wide Survey

R. Scaramella, J. Amiaux, Y. Mellier +238

Euclid is an ESA mission designed to constrain the properties of dark energy and gravity via weak gravitational lensing and galaxy clustering. It will carry out a wide area imaging…

astro-ph.CO2021

preparation: XV. Forecasting cosmological constraints for the and CMB joint analysis

Euclid Collaboration, S. Ilić, N. Aghanim +207

The combination and cross-correlation of the upcoming data with cosmic microwave background (CMB) measurements is a source of great expectation since it will provide the l…

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.GA2026

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

A. U. Kapoor, R. Smith, A. J. Zuiderwijk +133

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 galaxi…

astro-ph.GA2026

Euclid: Scaled-up little red dots and other sources with v-shaped spectral energy distributions at z>4

Euclid Collaboration, A. A. Tumborang, K. I. Caputi +169

Little Red Dots (LRDs) are some the most intriguing galaxy populations recently identified at z>~4 with JWST. They constitute the most extreme class of a more abundant population o…

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.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.GA2024

Euclid preparation. The Cosmic Dawn Survey (DAWN) of the Euclid Deep and Auxiliary Fields

Euclid Collaboration, C. J. R. McPartland, L. Zalesky +288

Euclid will provide deep NIR imaging to 26.5 AB magnitude over 59 deg in its deep and auxiliary fields. The Cosmic DAWN survey complements the deep Euclid data with…

astro-ph.CO2025

Euclid: Systematic uncertainties from the halo mass conversion on galaxy cluster number count data analyses

T. Gayoux, P. -S. Corasaniti, T. R. G. Richardson +153

The large catalogues of galaxy clusters expected from the Euclid survey will enable cosmological analyses of cluster number counts that require accurate cosmological model predicti…

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.GA2025

Euclid: The Early Release Observations Lens Search Experiment

J. A. Acevedo Barroso, C. M. O'Riordan, B. Clément +206

We investigated the ability of the Euclid telescope to detect galaxy-scale gravitational lenses. To do so, we performed a systematic visual inspection of the Eucl…

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.CO2026

Euclid: Precise inference of defocus wavefront error from image diffraction spike measurements

D. Neumann, L. Miller, H. Hoekstra +146

The success of the Euclid cosmological weak lensing measurements requires unprecedented knowledge of the point spread function (PSF) shape. Defocus wavefront errors induce variatio…

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.GA2022

Euclid preparation. XXV. The Euclid Morphology Challenge -- Towards model-fitting photometry for billions of galaxies

Euclid Collaboration, E. Merlin, M. Castellano +218

The ESA Euclid mission will provide high-quality imaging for about 1.5 billion galaxies. A software pipeline to automatically process and analyse such a huge amount of data in real…

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.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: A machine-learning search for dual and lensed AGN at sub-arcsec separations

L. Ulivi, F. Mannucci, M. Scialpi +189

Cosmological models of hierarchical structure formation predict the existence of a widespread population of dual accreting supermassive black holes (SMBHs) on kpc-scale separations…

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.GA2026

Euclid: A blue galaxy population and a brightest cluster galaxy in the making in a MaDCoWS2 galaxy cluster candidate

A. Trudeau, A. H. Gonzalez, S. A. Stanford +152

We present an example cluster follow-up study with Euclid. Our target, a candidate cluster nicknamed the 'Puddle', was initially discovered by the Massive and Distant…

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.IM2026

Euclid: An automated system to match Rubin transient alerts to Euclid observations

C. Duffy, I. M. Hook, C. M. Gutierrez +150

The Vera C. Rubin observatory is expected to produce 10 million transient alerts per night in ugrizy filters, whilst Euclid is a visible to near-infrared space telescope engaged in…

astro-ph.GA2025

Euclid: Early Release Observations -- Interplay between dwarf galaxies and their globular clusters in the Perseus galaxy cluster

T. Saifollahi, A. Lançon, Michele Cantiello +183

We present an analysis of globular clusters (GCs) of dwarf galaxies in the Perseus galaxy cluster to explore the relationship between dwarf galaxy properties and their GCs. Our foc…

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) -- Dual AGN in low-mass galaxies

M. Mezcua, B. Laloux, M. Scialpi +164

Dual active galactic nuclei (AGNs) are expected in hierarchical galaxy evolution models, in which low-mass galaxies merge to build more massive ones. While observational evidence f…

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.GA2025

Euclid: Early Release Observations -- The Intracluster Light of Abell 2390

A. Ellien, M. Montes, S. L. Ahad +183

Intracluster light (ICL) provides a record of the dynamical interactions undergone by clusters, giving clues on cluster formation and evolution. Here, we analyse the properties of…

astro-ph.CO2024

Euclid preparation. Modelling spectroscopic clustering on mildly nonlinear scales in beyond-CDM models

Euclid Collaboration, B. Bose, P. Carrilho +229

We investigate the approximations needed to efficiently predict the large-scale clustering of matter and dark matter halos in beyond-CDM scenarios. We examine the normal branch…

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): 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.GA2024

Euclid preparation. LVIII. Detecting globular clusters in the Euclid survey

Euclid Collaboration, K. Voggel, A. Lançon +270

Extragalactic globular clusters (EGCs) are an abundant and powerful tracer of galaxy dynamics and formation, and their own formation and evolution is also a matter of extensive deb…

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.GA2025

Euclid: Quick Data Release (Q1) -- A census of dwarf galaxies across a range of distances and environments

F. R. Marleau, R. Habas, D. Carollo +204

The Euclid Q1 fields were selected for calibration purposes in cosmology and are therefore relatively devoid of nearby galaxies. However, this is precisely what makes them interest…

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.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.CO2025

Euclid: Optimising tomographic redshift binning for 32pt power spectrum constraints on dark energy

J. H. W. Wong, M. L. Brown, C. A. J. Duncan +136

We present a simulation-based method to explore the optimum tomographic redshift binning strategy for 3x2pt analyses with Euclid, focusing on the expected configuration of its firs…

astro-ph.IM2023

The PAU Survey: Narrow-band image photometry

S. Serrano, E. Gaztañaga, F. J. Castander +22

PAUCam is an innovative optical narrow-band imager mounted at the William Herschel Telescope built for the Physics of the Accelerating Universe Survey (PAUS). Its set of 40 filters…

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.IM2024

Euclid. IV. The NISP Calibration Unit

Euclid Collaboration, F. Hormuth, K. Jahnke +332

The near-infrared calibration unit (NI-CU) on board Euclid's Near-Infrared Spectrometer and Photometer (NISP) is the first astronomical calibration lamp based on light-emitting dio…

astro-ph.GA2025

Euclid preparation: LXXXI. The impact of nonparametric star formation histories on spatially resolved galaxy property estimation using synthetic Euclid images

Euclid Collaboration, A. Nersesian, Abdurro'uf +283

We analyzed the spatially resolved and global star formation histories (SFHs) for a sample of 25 TNG50-SKIRT Atlas galaxies to assess the feasibility of reconstructing accurate SFH…

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.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.CO2025

Euclid: Exploring observational systematics in cluster cosmology -- a comprehensive analysis of cluster counts and clustering

A. Fumagalli, M. Costanzi, T. Castro +168

This study explores the impact of observational and modelling systematic effects on cluster number counts and cluster clustering and provides model prescriptions for their joint an…

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.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.CO2025

Euclid preparation. LXXIV. Euclidised observations of Hubble Frontier Fields and CLASH galaxy clusters

Euclid Collaboration, P. Bergamini, M. Meneghetti +263

We present HST2EUCLID, a novel Python code to generate Euclid realistic mock images in the , , , and photometric bands based on panchro…

astro-ph.GA2026

Euclid: Early Release Observations -- The star-formation history of massive early-type galaxies in the Perseus cluster

S. Martocchia, A. Boselli, J. -C. Cuillandre +157

The Euclid Early Release Observations (ERO) programme targeted the Perseus galaxy cluster in its central region over 0.7deg. We combined the exceptional image quality and depth…

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.CO2026

Euclid: The linear-construction covariance and cosmology

V. Lindholm, E. Sihvola, J. Valiviita +137

We study the properties of galaxy cluster 2-point correlation function covariance matrices estimated using the linear-construction (LC) method, which is computationally up to 20 ti…

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.SR2024

Euclid: High-precision imaging astrometry and photometry from Early Release Observations. I. Internal kinematics of NGC 6397 by combining Euclid and Gaia data

M. Libralato, L. R. Bedin, M. Griggio +175

The instruments at the focus of the Euclid space observatory offer superb, diffraction-limited imaging over an unprecedented (from space) wide field of view of 0.57 deg. This e…

astro-ph.GA2026

Euclid: Discovery of 31 new quasars at

D. Yang, J. F. Hennawi, F. Guarneri +211

We report the discovery of 31 new high- quasars in the redshift range . These quasars were selected from approximately 3000 deg of sky covered during the firs…

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.CO2025

Euclid preparation: The flat-sky approximation for the clustering of Euclid's photometric galaxies

Euclid Collaboration, W. L. Matthewson, R. Durrer +277

We compare the performance of the flat-sky approximation and Limber approximation for the clustering analysis of the photometric galaxy catalogue of Euclid. We study a 6 bin config…

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.CO2026

Euclid: Photometric redshift calibration with the clustering redshifts technique

W. d'Assignies, M. Manera, C. Padilla +172

Aims: The precision of cosmological constraints from imaging surveys hinges on accurately estimating the redshift distribution of tomographic bins, especially their mean r…

astro-ph.GA2026

Euclid: A UV-faint quasar in a highly luminous star-forming host galaxy at

S. Belladitta, R. Decarli, E. Bañados +180

Constraining the co-evolution of supermassive black holes and their host galaxies in the first billion years after the Big Bang is essential for understanding the formation of the…

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.GA2024

Euclid Preparation XXXIII. Characterization of convolutional neural networks for the identification of galaxy-galaxy strong lensing events

Euclid Collaboration, L. Leuzzi, M. Meneghetti +216

Forthcoming imaging surveys will potentially increase the number of known galaxy-scale strong lenses by several orders of magnitude. For this to happen, images of tens of millions…

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.CO2024

Euclid preparation: TBD. The impact of line-of-sight projections on the covariance between galaxy cluster multi-wavelength observable properties -- insights from hydrodynamic simulations

Euclid Collaboration, A. Ragagnin, A. Saro +240

Cluster cosmology can benefit from combining multi-wavelength studies, which can benefit from characterising the correlation coefficients between different mass-observable relation…

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.CO2024

Euclid Preparation. XXXVII. Galaxy colour selections with Euclid and ground photometry for cluster weak-lensing analyses

Euclid Collaboration, G. F. Lesci, M. Sereno +238

We derived galaxy colour selections from Euclid and ground-based photometry, aiming to accurately define background galaxy samples in cluster weak-lensing analyses. Given any set o…

astro-ph.CO2021

Euclid preparation: XII. Optimizing the photometric sample of the Euclid survey for galaxy clustering and galaxy-galaxy lensing analyses

Euclid Collaboration, A. Pocino, I. Tutusaus +157

The accuracy of photometric redshifts (photo-zs) particularly affects the results of the analyses of galaxy clustering with photometrically-selected galaxies (GCph) and weak lensin…

astro-ph.CO2021

Euclid preparation: XI. Mean redshift determination from galaxy redshift probabilities for cosmic shear tomography

Euclid Collaboration, O. Ilbert, S. de la Torre +162

The analysis of weak gravitational lensing in wide-field imaging surveys is considered to be a major cosmological probe of dark energy. Our capacity to constrain the dark energy eq…

astro-ph.GA2024

Euclid preparation. Optical emission-line predictions of intermediate-z galaxy populations in GAEA for the Euclid Deep and Wide Surveys

Euclid Collaboration, L. Scharré, M. Hirschmann +239

In anticipation of the Euclid Wide and Deep Surveys, we present optical emission-line predictions at intermediate redshifts from 0.4 to 2.5. Our approach combines a mock light cone…

astro-ph.GA2024

Euclid preparation. XLIII. Measuring detailed galaxy morphologies for Euclid with machine learning

Euclid Collaboration, B. Aussel, S. Kruk +255

The Euclid mission is expected to image millions of galaxies with high resolution, providing an extensive dataset to study galaxy evolution. We investigate the application of deep…

astro-ph.CO2020

Euclid preparation: IX. EuclidEmulator2 -- Power spectrum emulation with massive neutrinos and self-consistent dark energy perturbations

Euclid Collaboration, M. Knabenhans, J. Stadel +131

We present a new, updated version of the EuclidEmulator (called EuclidEmulator2), a fast and accurate predictor for the nonlinear correction of the matter power spectrum. Percent-l…

astro-ph.SR2025

Euclid: Quick Data Release (Q1) -- A photometric search for ultracool dwarfs in the Euclid Deep Fields

M. Žerjal, C. Dominguez-Tagle, N. Vitas +178

We present a catalogue of 5306 new ultracool dwarf (UCD) candidates in the three Euclid Deep Fields in the Q1 data release. They range from late M to late T dwarfs, and include 120…

astro-ph.CO2024

Euclid preparation. Simulations and nonlinearities beyond CDM. 1. Numerical methods and validation

Euclid Collaboration, J. Adamek, B. Fiorini +268

To constrain models beyond CDM, the development of the Euclid analysis pipeline requires simulations that capture the nonlinear phenomenology of such models. We present an over…

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.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.CO2011

Euclid Definition Study Report

R. Laureijs, J. Amiaux, S. Arduini +216

Euclid is a space-based survey mission from the European Space Agency designed to understand the origin of the Universe's accelerating expansion. It will use cosmological probes to…

astro-ph.GA2019

Euclid preparation: V. Predicted yield of redshift 7<z<9 quasars from the wide survey

Euclid Collaboration, R. Barnett, S. J. Warren +126

We provide predictions of the yield of quasars from the Euclid wide survey, updating the calculation presented in the Euclid Red Book in several ways. We account for revisi…

astro-ph.CO2024

Euclid preparation. XXXIX. The effect of baryons on the Halo Mass Function

Euclid Collaboration, T. Castro, S. Borgani +220

The Euclid photometric survey of galaxy clusters stands as a powerful cosmological tool, with the capacity to significantly propel our understanding of the Universe. Despite being…

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.CO2025

Euclid: Forecasts on CDM consistency tests with growth rate data

I. Ocampo, D. Sapone, S. Nesseris +156

The large-scale structure (LSS) of the Universe is an important probe for deviations from the canonical cosmological constant and cold dark matter (CDM) model. A statistic…

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.CO2024

Euclid: Field-level inference of primordial non-Gaussianity and cosmic initial conditions

A. Andrews, J. Jasche, G. Lavaux +147

A primary target of the \Euclid space mission is to constrain early-universe physics by searching for deviations from a primordial Gaussian random field. A significant detection of…

astro-ph.CO2024

Euclid preparation. Sensitivity to neutrino parameters

Euclid Collaboration, M. Archidiacono, J. Lesgourgues +246

The Euclid mission of the European Space Agency will deliver weak gravitational lensing and galaxy clustering surveys that can be used to constrain the standard cosmological model…

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.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…

astro-ph.CO2023

Euclid preparation. XXXI. The effect of the variations in photometric passbands on photometric-redshift accuracy

Euclid Collaboration, Stéphane Paltani, J. Coupon +214

The technique of photometric redshifts has become essential for the exploitation of multi-band extragalactic surveys. While the requirements on photo-zs for the study of galaxy evo…

astro-ph.IM2025

Euclid Quick Data Release (Q1). From simulations to sky: Advancing machine-learning lens detection with real Euclid data

Euclid Collaboration, N. E. P. Lines, T. E. Collett +301

In the era of large-scale surveys like Euclid, machine learning has become an essential tool for identifying rare yet scientifically valuable objects, such as strong gravitational…

astro-ph.GA2026

Euclid preparation. 3D reconstruction of the cosmic web with simulated Euclid Deep spectroscopic samples

Euclid Collaboration, K. Kraljic, C. Laigle +321

The ongoing Euclid mission aims to measure spectroscopic redshifts for approximately two million galaxies using the H line emission detected in near-infrared slitless spectros…

astro-ph.CO2025

Cosmology Likelihood for Observables in \Euclid (CLOE). 1. Theoretical recipe

Euclid Collaboration, V. F. Cardone, S. Joudaki +323

As the statistical precision of cosmological measurements increases, the accuracy of the theoretical description of these measurements needs to increase correspondingly in order to…

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.CO2025

Euclid: Relativistic effects in the dipole of the 2-point correlation function

F. Lepori, S. Schulz, I. Tutusaus +130

Gravitational redshift and Doppler effects give rise to an antisymmetric component of the galaxy correlation function when cross-correlating two galaxy populations or two different…

astro-ph.IM2024

Euclid. III. The NISP Instrument

Euclid Collaboration, K. Jahnke, W. Gillard +434

The Near-Infrared Spectrometer and Photometer (NISP) on board the Euclid satellite provides multiband photometry and R>=450 slitless grism spectroscopy in the 950-2020nm wavelength…

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…