Astronomy & Astrophysics (A&A)

Open Access

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

Euclid Collaboration, H. Aussel, I. Tereno, M. Schirmer, G. Alguero, B. Altieri, E. Balbinot, T. de Boer, P. Casenove, P. Corcho-Caballero et al. (400 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202554610

Open Access

Euclid Quick Data Release (Q1) - II. VIS processing and data products

Euclid Collaboration, H. J. McCracken, K. Benson, C. Dolding, T. Flanet, C. Grenet, O. Herent, P. Hudelot, C. Laigle, G. Leroy et al. (370 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202554594

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

Euclid Collaboration, G. Polenta, M. Frailis, A. Alavi, P. N. Appleton, P. Awad, A. Bonchi, R. Bouwens, L. Bramante, D. Busonero et al. (360 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202554657

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Euclid Quick Data Release (Q1) - IV. From images to multi-wavelength catalogues: The Euclid MERge processing function

Euclid Collaboration, E. Romelli, M. Kümmel, H. Dole, J. Gracia-Carpio, E. Merlin, S. Galeotta, Y. Fang, M. Castellano, F. Caro et al. (338 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202554586

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

Euclid Collaboration, M. Tucci, S. Paltani, W. G. Hartley, F. Dubath, N. Morisset, M. Bolzonella, S. Fotopoulou, F. Tarsitano, C. Saulder et al. (337 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202554588

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Euclid Quick Data Release (Q1) - VI. From spectrograms to spectra: The SIR spectroscopic processing function

Euclid Collaboration, Y. Copin, M. Fumana, C. Mancini, P. N. Appleton, R. Chary, S. Conseil, A. L. Faisst, S. Hemmati, D. C. Masters et al. (341 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202554627

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

Euclid Collaboration, V. Le Brun, M. Bethermin, M. Moresco, D. Vibert, D. Vergani, C. Surace, G. Zamorani, A. Allaoui, T. Bedrine et al. (336 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202554607

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

Euclid Collaboration, L. Quilley, I. Damjanov, V. de Lapparent, A. Paulino-Afonso, H. Domínguez Sánchez, A. Ferré-Mateu, M. Huertas-Company, M. Kümmel, D. Delley et al. (326 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202554585

Open Access

Euclid Quick Data Release (Q1) - IX. First visual morphology catalogue

Euclid Collaboration, M. Walmsley, M. Huertas-Company, L. Quilley, K. L. Masters, S. Kruk, K. A. Remmelgas, J. J. Popp, E. Romelli, D. O’Ryan et al. (346 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202555140

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

Euclid Collaboration, F. R. Marleau, R. Habas, D. Carollo, C. Tortora, P.-A. Duc, E. Sola, T. Saifollahi, M. Fügenschuh, M. Walmsley et al. (300 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202554547

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Euclid Quick Data Release (Q1) - XI. A first look at the fraction of bars in massive galaxies at z < 1

Euclid Collaboration, M. Huertas-Company, M. Walmsley, M. Siudek, P. Iglesias-Navarro, J. H. Knapen, S. Serjeant, H. J. Dickinson, L. Fortson, I. Garland et al. (329 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202554606

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

Euclid Collaboration, F. Gentile, E. Daddi, D. Elbaz, A. Enia, B. Magnelli, J.-B. Billand, P. Corcho-Caballero, C. Cleland, G. De Lucia et al. (315 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202557633

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

Euclid Collaboration, M. Siudek, M. Huertas-Company, M. J. Smith, G. Martínez-Solaeche, F. Lanusse, S. Ho, E. Angeloudi, P. A. C. Cunha, H. Domínguez Sánchez et al. (314 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202554611

Open Access

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

Euclid Collaboration, A. Enia, L. Pozzetti, M. Bolzonella, L. Bisigello, W. G. Hartley, C. Saulder, E. Daddi, M. Siudek, G. Zamorani et al. (341 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202554576

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

Euclid Collaboration, P. Corcho-Caballero, Y. Ascasibar, G. Verdoes Kleijn, C. C. Lovell, G. De Lucia, C. Cleland, F. Fontanot, C. Tortora, L. V. E. Koopmans et al. (311 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202554582

Open Access

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

Euclid Collaboration, W. Roster, M. Salvato, J. Buchner, R. Shirley, E. Lusso, H. Landt, G. Zamorani, M. Siudek, B. Laloux et al. (309 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202554616

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

Euclid Collaboration, A. La Marca, L. Wang, B. Margalef-Bentabol, L. Gabarra, Y. Toba, M. Mezcua, V. Rodriguez-Gomez, F. Ricci, S. Fotopoulou et al. (327 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202554579

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

Euclid Collaboration, B. Margalef-Bentabol, L. Wang, A. La Marca, V. Rodriguez-Gomez, A. Humphrey, S. Fotopoulou, F. Ricci, Y. Toba, G. Stevens et al. (324 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202554583

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

Euclid Collaboration, F. Tarsitano, S. Fotopoulou, M. Banerji, J. Petley, A. L. Faisst, M. Tucci, S. Tacchella, Y. Toba, H. Landt et al. (315 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202554591

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

Euclid Collaboration, T. Matamoro Zatarain, S. Fotopoulou, F. Ricci, M. Bolzonella, F. La Franca, A. Viitanen, G. Zamorani, M. B. Taylor, M. Mezcua et al. (348 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202554619

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

Euclid Collaboration, G. Stevens, S. Fotopoulou, M. N. Bremer, T. Matamoro Zatarain, K. Jahnke, B. Margalef-Bentabol, M. Huertas-Company, M. J. Smith, M. Walmsley et al. (264 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202554612

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

Euclid Collaboration, G. Girardi, G. Rodighiero, L. Bisigello, A. Enia, A. Grazian, E. Dalla Bontà, E. Daddi, S. Serjeant, G. Gandolfi et al. (319 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202554615

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

Euclid Collaboration, R. Hill, A. Abghari, D. Scott, M. Bethermin, S. C. Chapman, D. L. Clements, S. Eales, A. Enia, B. Jego et al. (295 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202557514

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

Euclid Collaboration, L. Bisigello, G. Rodighiero, S. Fotopoulou, F. Ricci, K. Jahnke, A. Feltre, V. Allevato, F. Shankar, P. Cassata et al. (341 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202554537

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Euclid Quick Data Release (Q1) - XXV. Hunting for luminous z > 6 galaxies in the Euclid Deep Fields – Forecasts and the first bright detections

Euclid Collaboration, N. Allen, P. A. Oesch, R. A. A. Bowler, S. Toft, J. Matharu, J. R. Weaver, C. J. R. McPartland, M. Shuntov, D. B. Sanders et al. (302 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202557785

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Euclid Quick Data Release (Q1) - XXVI. The Strong Lensing Discovery Engine A – System overview and first lens sample

Euclid Collaboration, M. Walmsley, P. Holloway, N. E. P. Lines, K. Rojas, T. E. Collett, A. Verma, T. Li, J. W. Nightingale, G. Despali et al. (365 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202555141

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Euclid Quick Data Release (Q1) - XXVII. 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, J. A. Acevedo Barroso, J. W. Nightingale, D. Stern, L. A. Moustakas, S. Schuldt, G. Despali, A. Melo et al. (330 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202554605

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

Euclid Collaboration, N. E. P. Lines, T. E. Collett, M. Walmsley, K. Rojas, T. Li, L. Leuzzi, A. Manjón-García, S. H. Vincken, J. Wilde et al. (343 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202554542

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Euclid Quick Data Release (Q1) - XXIX. The strong-lensing discovery engine D: Double-source-plane lens candidates

Euclid Collaboration, T. Li, T. E. Collett, M. Walmsley, N. E. P. Lines, K. Rojas, J. W. Nightingale, W. J. R. Enzi, L. A. Moustakas, C. Krawczyk et al. (328 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202554543

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Euclid Quick Data Release (Q1) - XXX. The Strong Lensing Discovery Engine E – Ensemble classification of strong gravitational lenses: lessons for Data Release 1

Euclid Collaboration, P. Holloway, A. Verma, M. Walmsley, P. J. Marshall, A. More, T. E. Collett, N. E. P. Lines, L. Leuzzi, A. Manjón-García et al. (336 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202554617

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Euclid Quick Data Release (Q1) - XXXI. LEMON – LEns MOdelling with Neural networks. Automated and fast modelling of Euclid gravitational lenses with singular isothermal ellipsoid mass profile

Euclid Collaboration, V. Busillo, C. Tortora, R. B. Metcalf, J. W. Nightingale, M. Meneghetti, F. Gentile, R. Gavazzi, F. Zhong, R. Li et al. (305 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202554538

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

Euclid Collaboration, N. E. P. Lines, T. E. Collett, P. Holloway, K. Rojas, S. Schuldt, R. B. Metcalf, T. Li, A. Verma, G. Despali et al. (294 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202558456

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

Euclid Collaboration, P. Bergamini, M. Meneghetti, A. Acebron, B. Clément, M. Bolzonella, C. Grillo, P. Rosati, D. Abriola, J. A. Acevedo Barroso et al. (368 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202554577

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

Euclid Collaboration, S. Bhargava, C. Benoist, A. H. Gonzalez, M. Maturi, J.-B. Melin, S. A. Stanford, E. Munari, M. Vannier, C. Murray et al. (344 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202554937

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

Euclid Collaboration, C. Gouin, C. Laigle, F. Sarron, T. Bonnaire, J. G. Sorce, N. Aghanim, M. Magliocchetti, L. Quilley, P. Boldrini et al. (330 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202554655

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

Euclid Collaboration, C. Laigle, C. Gouin, F. Sarron, L. Quilley, C. Pichon, K. Kraljic, F. Durret, N. E. Chisari, U. Kuchner et al. (335 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202554651

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

M. Žerjal, C. Dominguez-Tagle, N. Vitas, N. Sedighi, E. L. Martín, M. R. Zapatero Osorio, J. Olivares, S. Muñoz Torres, S. Tsilia, J.-Y. Zhang et al. (171 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202556980

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Euclid: Quick Data Release (Q1) – Photometric studies of known transients

C. Duffy, E. Cappellaro, M. T. Botticella, I. M. Hook, F. Poidevin, T. J. Moriya, A. A. Chrimes, V. Petrecca, K. Paterson, A. Goobar et al. (167 more)

Published online: 30 June 2026

DOI: https://doi.org/10.1051/0004-6361/202554600