Description
Active Galactic Nuclei (AGNs) play a crucial role in galaxy evolution and cosmic structure formation. This study presents an improved AGN selection method by combining the Euclid Q1 data from the Euclid Deep Field Fornax (EDFF) with deep near-infrared imaging from the VISTA telescope. While Euclid’s Near Infrared Spectrometer and Photometer (NISP) provides high-sensitivity photometry in the Y, J, and H bands, its coverage lacks the crucial Ks-band, which is essential for identifying heavily dust-obscured AGNs and refining photometric redshifts.
VISTA’s Ks-band observations fill this gap, offering a vital extension to Euclid’s wavelength range. The Ks-band is particularly effective in probing the thermal emission from AGN-heated dust and distinguishing AGNs from quiescent galaxies at high redshifts. By cross-matching sources detected in both Euclid and VISTA datasets and analyzing their spectral energy distributions, we refine AGN selection criteria, particularly for obscured and high-redshift AGNs. This synergy between Euclid and VISTA enables a more complete census of AGN populations, improving our understanding of their role in cosmic evolution.
