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arXiv · 2610.30309

The PAU Survey: Active galactic nucleus galaxies in galaxy pairs

F. Duplancic·M. Siudek·D. Navarro-Gironés·E. J. Gonzalez·F. Rodriguez·S. Alonso·I. V. Daza-Perilla·D. G. Lambas·E. Gaztañaga·A. L. O'Mill·M. Eriksen·J. Carretero·R. Casas·F. J. Castander·J. García-Bellido·H. Hildebrandt·M. Mezcua·R. Miquel·C. Padilla·P. Renard·E. Sánchez·S. Serrano·I. Sevilla-Noarbe·P. Tallada-Crespí
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Abstract

Aims. Leveraging the high-precision photometric redshifts of the Physics of the Accelerating Universe Survey (PAUS), we aim to investigate the connection between active galactic nuclei (AGNs) and galaxy pairs up to redshifts of $\sim1.0$. Methods. We identified 16,824 galaxy pairs with projected separations of $r_p < 100$ kpc and radial-velocity differences of $ΔV < 3500$ km s$^{-1}$. AGNs were selected by cross-matching PAUS galaxies with multi-wavelength AGN catalogues, yielding 270 AGNs in pairs out of a parent sample of 8,880 AGNs in PAUS. We constructed control samples of isolated AGNs; non-AGNs in pairs; and isolated non-AGNs matched in redshift, absolute magnitude, and environment. Results. Active galactic nuclei in pairs show progressively redder rest-frame colours with increasing redshift, particularly at redshifts of $z\gtrsim 0.5$, whereas isolated AGNs and non-AGNs in pairs show no significant colour evolution and remain at $\mathrm{M_g-M_r}\sim0.65$. Pairs hosting AGNs are also preferentially morphologically disturbed interacting systems found at smaller projected separations and velocity offsets, consistent with more dynamically advanced interactions. Conclusions. These results provide evidence of a redshift-dependent link between galaxy interactions and AGN activity, suggesting that interactions play an increasingly important role in triggering nuclear activity at intermediate redshifts. This study highlights the unique capability of PAUS to probe AGN-galaxy interaction connections beyond the local Universe with unprecedented statistical power.

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F. Duplancic, M. Siudek, D. Navarro-Gironés, E. J. Gonzalez, F. Rodriguez, S. Alonso, I. V. Daza-Perilla, D. G. Lambas, E. Gaztañaga, A. L. O'Mill, M. Eriksen, J. Carretero, R. Casas, F. J. Castander, J. García-Bellido, H. Hildebrandt, M. Mezcua, R. Miquel, C. Padilla, P. Renard, E. Sánchez, S. Serrano, I. Sevilla-Noarbe, P. Tallada-Crespí. 2026-10-21. The PAU Survey: Active galactic nucleus galaxies in galaxy pairs. https://doi.org/10.1051/0004-6361%2F202556897

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