The luminosity function of ringed galaxies

TL;DR

This study analyzes the luminosity functions of rare ringed galaxies, revealing their distribution, dependence on galaxy brightness and color, and increasing density with redshift, using SDSS data.

Contribution

It provides the first detailed luminosity functions for polar-ring and collisional ring galaxies, highlighting their distribution and evolution with redshift.

Findings

LF of both galaxy types shows low-luminosity fall-off

Polar structures are more common around bright, red galaxies

Density of ringed galaxies increases with redshift up to z~1

Abstract

We perform an analysis of the luminosity functions (LFs) of two types of ringed galaxies -- polar-ring galaxies and collisional ring galaxies -- using data from the Sloan Digital Sky Survey (SDSS). Both classes of galaxies were formed as a result of interaction with their environment and they are very rare objects. We constructed LFs of galaxies by different methods and found their approximations by the Schechter function. The luminosity functions of both types of galaxies show a systematic fall-off at low luminosities. The polar structures around bright ($M_r \leq -20^m$) and red ($g-r > +0.8$) galaxies are about twice as common as around blue ones. The LF of collisional rings is shifted towards brighter luminosities compared to polar-ring galaxies. We analysed the published data on the ringed galaxies in several deep fields and confirmed the increase in their volume density with redshift: up to z$\sim$1 their density grows as $(1+z)^m$, where $m \gtrsim 5$.