The PAU Survey: Close galaxy pairs identification and analysis

GONZALEZ, ELIZABETH JOHANA; RODRIGUEZ, FACUNDO; NAVARRO-GIRONES; GAZTAÑAGA, ENRIQUE; SIUDEK, MA?GORZATA; LAMBAS, DIEGO GARCÍA; O'MILL, ANA LAURA; RENARD; CABAYOL; CARRETERO; CASAS; DE VICENTE; ERIKSEN; FERNANDEZ

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2023

0035-8711

Galaxy pairs constitute the initial building blocks of galaxy evolution, which is driven through merger events and interactions.Thus, the analysis of these systems can be valuable in understanding galaxy evolution and studying structure formation. In thiswork, we present a new publicly available catalogue of close galaxy pairs identified using photometric redshifts provided bythe Physics of the Accelerating Universe Survey (PAUS). To efficiently detect them we take advantage of the high-precisionphoto−z (σ68 < 0.02) and apply an identification algorithm previously tested using simulated data. This algorithm considersthe projected distance between the galaxies (r p < 50 kpc), the projected velocity difference (ΔV < 3500 km/s) and an isolationcriterion to obtain the pair sample. We applied this technique to the total sample of galaxies provided by PAUS and to a subsetwith high-quality redshift estimates. Finally, the most relevant result we achieved was determining the mean mass for severalsubsets of galaxy pairs selected according to their total luminosity, colour and redshift, using galaxy-galaxy lensing estimates.For pairs selected from the total sample of PAUS with a mean r−band luminosity 1010.6h−2L⊙, we obtain a mean mass ofM200 = 1012.2h−1M⊙, compatible with the mass-luminosity ratio derived for elliptical galaxies. We also study the mass-to-lightratio M/L as a function of the luminosity L and find a lower M/L (or steeper slope with L) for pairs than the one extrapolatedfrom the measurements in groups and galaxy clusters.