A new sample of bright galaxy pairs in UZC

¹ Dipartimento di Astronomia, Universitá di Bologna, Italy e-mail: paola.focardi@unibo.it
² INAF - OABO, via Ranzani 1, 40127 Bologna, Italy

Received: 21 March 2006
Accepted: 19 April 2006

Abstract

Aims.We present a new sample of bright galaxy pairs extracted applying an objective selection code to the UZC catalog. The sample is volume-limited to  log  and contains 89 galaxy pairs.

Methods.We analyze the kinematical, morphological, and photometrical properties of galaxies belonging to this sample.

Results.We show that velocity separation, , between pair members is significantly lower in spiral type (S+S) pairs than in early-type (E+E) and mixed (E+S) pairs. This indicates that truly isolated galaxy pairs are more likely to be found among S+S pairs. We show that ellipticals are rare and underluminous in B and that late spirals () are overluminous.

Conclusions.We confirm that the formation of bright ellipticals is a phenomenon linked to group/cluster environment. while galaxy–galaxy interaction may enhance the blue luminosity of disk galaxies through SF phenomena. This last statement is supported by the presence of strong FIR emission from early spirals in this sample and by the high frequency of the AGN/SB phenomenon, revealed mainly in pairs of low relative radial velocity separation showing signs of interaction.