TY - UNPB
T1 - Euclid Quick Data Release (Q1). The active galaxies of Euclid
AU - Euclid Collaboration
AU - Matamoro Zatarain, T.
AU - Fotopoulou, S.
AU - Ricci, F.
AU - Bolzonella, M.
AU - La Franca, F.
AU - Viitanen, A.
AU - Zamorani, G.
AU - Taylor, M. B.
AU - Mezcua, M.
AU - Laloux, B.
AU - Bongiorno, A.
AU - Stevens, G.
AU - Shaw, R. A.
AU - Fu, Y.
AU - Bremer, M. N.
AU - Wang, L.
AU - Alexander, D.~M.
AU - Scott, D.
AU - Selwood, M.
AU - Chambers, K.~C.
AU - Da Silva, A.
AU - Duncan, C.~A.~J.
AU - George, K.
AU - Holmes, W.
AU - Massey, R.
AU - Masters, D.~C.
AU - Nightingale, J.~W.
AU - Rhodes, J.
AU - Riccio, G.
AU - Sánchez, A.~G.
PY - 2025/3/19
Y1 - 2025/3/19
N2 - We present a catalogue of candidate active galactic nuclei (AGN) in the Euclid Quick Release (Q1) fields. For each Euclid source we collect multi-wavelength photometry and spectroscopy information from Galaxy Evolution Explorer (GALEX), Gaia, Dark Energy Survey (DES), Wise-field Infrared Survey Explorer (WISE), Spitzer, Dark Energy Survey (DESI), and Sloan Digital Sky Survey (SDSS), including spectroscopic redshift from public compilations. We investigate the AGN contents of the Q1 fields by applying selection criteria using Euclid colours and WISE-AllWISE cuts finding respectively 292,222 and 65,131 candidates. We also create a high-purity QSO catalogue based on Gaia DR3 information containing 1971 candidates. Furthermore, we utilise the collected spectroscopic information from DESI to perform broad-line and narrow-line AGN selections, leading to a total of 4392 AGN candidates in the Q1 field. We investigate and refine the Q1 probabilistic random forest QSO population, selecting a total of 180,666 candidates. Additionally, we perform SED fitting on a subset of sources with available Zspec , and by utilizing the derived AGN fraction, we identify a total of 7766 AGN candidates. We discuss purity and completeness of the selections and define two new colour selection criteria (J H_IEY and IEH_gz) to improve on purity, finding 313,714 and 267,513 candidates respectively in the Q1 data. We find a total of 229,779 AGN candidates equivalent to an AGN surface density of 3641 deg-2 for 18< IE ≤ 24.5, and a subsample of 30,422 candidates corresponding to an AGN surface density of 482 deg-2 when limiting the depth to 18< IE ≤ 22. The surface density of AGN recovered from this work is in line with predictions based on the AGN X-ray luminosity functions.
AB - We present a catalogue of candidate active galactic nuclei (AGN) in the Euclid Quick Release (Q1) fields. For each Euclid source we collect multi-wavelength photometry and spectroscopy information from Galaxy Evolution Explorer (GALEX), Gaia, Dark Energy Survey (DES), Wise-field Infrared Survey Explorer (WISE), Spitzer, Dark Energy Survey (DESI), and Sloan Digital Sky Survey (SDSS), including spectroscopic redshift from public compilations. We investigate the AGN contents of the Q1 fields by applying selection criteria using Euclid colours and WISE-AllWISE cuts finding respectively 292,222 and 65,131 candidates. We also create a high-purity QSO catalogue based on Gaia DR3 information containing 1971 candidates. Furthermore, we utilise the collected spectroscopic information from DESI to perform broad-line and narrow-line AGN selections, leading to a total of 4392 AGN candidates in the Q1 field. We investigate and refine the Q1 probabilistic random forest QSO population, selecting a total of 180,666 candidates. Additionally, we perform SED fitting on a subset of sources with available Zspec , and by utilizing the derived AGN fraction, we identify a total of 7766 AGN candidates. We discuss purity and completeness of the selections and define two new colour selection criteria (J H_IEY and IEH_gz) to improve on purity, finding 313,714 and 267,513 candidates respectively in the Q1 data. We find a total of 229,779 AGN candidates equivalent to an AGN surface density of 3641 deg-2 for 18< IE ≤ 24.5, and a subsample of 30,422 candidates corresponding to an AGN surface density of 482 deg-2 when limiting the depth to 18< IE ≤ 22. The surface density of AGN recovered from this work is in line with predictions based on the AGN X-ray luminosity functions.
KW - Astrophysics - High Energy Astrophysical Phenomena
KW - Astrophysics - Astrophysics of Galaxies
U2 - 10.48550/arXiv.2503.15320
DO - 10.48550/arXiv.2503.15320
M3 - Preprint
BT - Euclid Quick Data Release (Q1). The active galaxies of Euclid
PB - arXiv.org
ER -