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

/ Authors

Euclid Collaboration W. Roster, M. Salvato, J. Buchner, R. Shirley, E. Lusso, H. Landt, G. Zamorani, M. Siudek, B. Laloux, T. M. Zatarain

and 308 more authors

F. Ricci, S. Fotopoulou, A. Ferr'e-Mateu, X. Lopez, N. Aghanim, B. Altieri, A. Amara, S. Andreon, N. Auricchio, H. Aussel, C. Baccigalupi, M. Baldi, A. Balestra, S. Bardelli, P. Battaglia, A. Biviano, A. Bonchi, E. Branchini, M. Brescia, J. Brinchmann, S. Camera, G. Cañas-Herrera, V. Capobianco, C. Carbone, J. Carretero, S. Casas, M. Castellano, G. Castignani, S. Cavuoti, K. Chambers, A. Cimatti, C. Colodro-Conde, G. Congedo, C. Conselice, L. Conversi, Y. Copin, F. Courbin, H. Courtois, M. Cropper, A. Silva, H. Degaudenzi, G. Lucia, A. Giorgio, C. Dolding, H. Dole, F. Dubath, C. Duncan, X. Dupac, S. Dusini, S. Escoffier, M. Fabricius, M. Farina, R. Farinelli, F. Faustini, S. Ferriol, F. Finelli, P. Fosalba, N. Fourmanoit, M. Frailis, E. Franceschi, S. Galeotta, K. George, B. Gillis, C. Giocoli, J. Graciá-Carpio, B. Granett, A. Grazian, F. Grupp, S. Gwyn, S. Haugan, W. Holmes, I. Hook, F. Hormuth, A. Hornstrup, P. Hudelot, K. Jahnke, M. Jhabvala, E. Keihanen, S. Kermiche, A. Kiessling, B. Kubik, M. Kummel, M. Kunz, H. Kurki-Suonio, Q. L. Boulc'h, A. Brun, D. L. Mignant, S. Ligori, P. Lilje, V. Lindholm, I. Lloro, G. Mainetti, D. Maino, E. Maiorano, O. Mansutti, S. Marcin, O. Marggraf, M. Martinelli, N. Martinet, F. Marulli, R. Massey, D. Masters, E. Medinaceli, S. Mei, M. Melchior, Y. Mellier, M. Meneghetti, E. Merlin, G. Meylan, A. Mora, Michele Moresco, L. Moscardini, R. Nakajima, C. Neissner, S. Niemi, J. Nightingale, C. Padilla, S. Paltani, F. Pasian, K. Pedersen, W. Percival, V. Pettorino, S. Pires, G. Polenta, M. Poncet, L. Popa, L. Pozzetti, F. Raison, R. Rebolo, A. Renzi, J. Rhodes, G. Riccio, E. Romelli, M. Roncarelli, R. Saglia, Z. Sakr, A. S'anchez, D. Sapone, B. Sartoris, J. Schewtschenko, M. Schirmer, P. Schneider, T. Schrabback, A. Secroun, G. Seidel, M. Seiffert, S. Serrano, P. Simon, C. Sirignano, G. Sirri, L. Stanco, J. Steinwagner, P. Tallada-Cresp'i, D. Tavagnacco, A. Taylor, I. Tereno, S. Toft, R. Toledo-Moreo, F. Torradeflot, I. Tutusaus, L. Valenziano, J. Valiviita, T. Vassallo, G. Kleijn, A. Veropalumbo, Y. Wang, J. Weller, A. Zacchei, F. Zerbi, I. Zinchenko, E. Zucca, V. Allevato, M. Ballardini, M. Bolzonella, E. Bozzo, C. Burigana, R. Cabanac, A. Cappi, D. Ferdinando, J. Vigo, L. Gabarra, M. Huertas-Company, J. Mart'in-Fleitas, S. Matthew, N. Mauri, R. B. Metcalf, A. Pezzotta, M. Pontinen, C. Porciani, I. Risso, V. Scottez, M. Sereno, M. Tenti, M. Viel, M. Wiesmann, Y. Akrami, I. Andika, S. Anselmi, M. Archidiacono, F. Atrio-Barandela, C. Benoist, K. Benson, D. Bertacca, M. Bethermin, L. Bisigello, A. Blanchard, L. Blot, H. Bohringer, M. L. Brown, S. Bruton, A. Calabrò, F. Caro, C. Carvalho, T. Castro, F. Cogato, A. Cooray, O. Cucciati, S. Davini, F. Paolis, G. Desprez, A. D'iaz-S'anchez, J. Diaz, S. Domizio, J. M. Diego, A. Enia, Y. Fang, A. Ferrari, A. Finoguenov, A. Fontana, A. Franco, K. Ganga, J. Garc'ia-Bellido, T. Gasparetto, V. Gautard, E. Gaztañaga, F. Giacomini, F. Gianotti, G. Gozaliasl, M. Guidi, C. M. Gutiérrez, A. Hall, W. Hartley, S. Hemmati, C. Hern'andez-Monteagudo, H. Hildebrandt, J. Hjorth, J. Kajava, Y. Kang, Vanshika Kansal, D. Karagiannis, K. Kiiveri, C. Kirkpatrick, S. Kruk, J. L. Graet, L. Legrand, M. Lembo, F. Lepori, G. Leroy, G. Lesci, J. Lesgourgues, L. Leuzzi, T. Liaudat, A. Loureiro, J. Macías-Pérez, G. Maggio, M. Magliocchetti, F. Mannucci, R. Maoli, C. Martins, L. Maurin, M. Miluzio, P. Monaco, C. Moretti, G. Morgante, K. Naidoo, A. Navarro-Alsina, S. Nesseris, F. Passalacqua, K. Paterson, L. Patrizii, A. Pisani, D. Potter, S. Quai, M. Radovich, S. Sacquegna, M. Sahl'en, D. Sanders, E. Sarpa, A. Schneider, D. Sciotti, E. Sellentin, F. Shankar, L. Smith, K. Tanidis, G. Testera, R. Teyssier, S. Tosi, A. Troja, M. Tucci, C. Valieri, A. Venhola, D. Vergani, G. Verza, P. Vielzeuf, A. Viitanen, N. A. Walton, E. Soubrié, D. Scott

/ Abstract

To better understand the role of active galactic nuclei (AGN) in galaxy evolution, it is crucial to work with a complete and pure AGN sample. X-ray surveys are key to doing so, but their larger positional uncertainties complicate counterpart (CTP) association, further compounded by the limited availability of deep, uniform multi-wavelength ancillary data. Euclid is revolutionising this identification effort, offering extensive coverage of nearly the entire extragalactic sky, particularly in the near-infrared bands, where AGN are more easily detected. Using the first Euclid Quick Data Release (Q1), we validated the methods for identifying and classifying Euclid CTPs of known point-like sources from major X-ray surveys, including Chandra and eROSITA. Using Bayesian statistics, combined with machine learning (ML), as incorporated in the algorithm NWAY we identified the CTPs of 11,286 X-ray sources from the three X-ray telescopes. For the large majority of 10,194 sources, the association is unique, with the remaining ∼ 10% of multi-CTP cases equally split between and eROSITA. Six percent of the Euclid CTPs are detected in more than one X-ray survey. We then used ML to distinguish between Galactic (8%) and extragalactic (92%) sources. We computed photo-zs using deep learning for the 9259 sources detected in the tenth data release of the DESI Legacy Survey, reaching an accuracy and a fraction of outliers of roughly 5%. Based on their X-ray luminosities, all CTPs identified as extragalactic are classified as AGN, most of which appear as type I AGN according to their hardness ratios. With this paper, we release our catalogue, which includes identifiers, basic X-ray properties, the reliability of the associations, and additional property extensions, such as Galactic- or extragalactic classifications and photometric/spectroscopic redshifts. We also provide probabilities for sub-selecting the sample based on purity and completeness, in order to allow users to tailor the sample according to their specific needs.

Journal: Astronomy & Astrophysics

DOI: 10.1051/0004-6361/202554616