Polar-ring galaxies: the SDSS view on the symbiotic galaxies

Polar-ring galaxies (PRGs) are multispin systems, showing star formation in a blue late-type component, perpendicular to a red early-type one, revealing how galaxy formation can sometimes occur in successive steps. We perform two-dimensional decomposition in the g, r, i bandpasses of 50 PRGs from th...

Full description

Saved in:
Bibliographic Details
Published in:Monthly notices of the Royal Astronomical Society 2015-03, Vol.447 (3), p.2287-2287
Main Authors: Reshetnikov, V, Combes, F
Format: Article
Language:English
Subjects:
Astrophysics
Clouds
Color
Comparative analysis
Dimensional analysis
Discs
Disks
Galaxies
Luminosity
Physics
Quenching
Sky surveys (astronomy)
Star & galaxy formation
Star formation
Symbols
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Polar-ring galaxies (PRGs) are multispin systems, showing star formation in a blue late-type component, perpendicular to a red early-type one, revealing how galaxy formation can sometimes occur in successive steps. We perform two-dimensional decomposition in the g, r, i bandpasses of 50 PRGs from the Sloan Digital Sky Survey. Each object was fit with a Sersic host galaxy and a Sersic ring. Our general results are: (i) the central (host) galaxies of the PRGs are non-dwarf sub-L* galaxies with colours typical for early-type galaxies. (ii) Polar structures in our sample are, on average, fainter and bluer than their host galaxies. (iii) In most galaxies, the stellar mass M* of the polar component is not negligible in comparison with that of the host. (iv) The distributions of the host galaxies on the size -- luminosity and Kormendy diagrams are shifted by ~1 mag to fainter magnitudes in comparison with E/S0 galaxies. It means that the PRGs hosts are more similar to quenched discs than to ordinary early-type galaxies. (v) All the PRGs in our sample are detected in mid-infrared by WISE, and we derive from the 22 ...m luminosity their star formation rate (SFR). Their SFR/M* ratio is larger than for the early-type galaxy sample of Atlas..., showing that the star-forming disc brings a significant contribution to the new stars. Globally, PRGs appear frequently on the green valley in the mass-colour diagram, revealing the symbiotic character between a red-sequence host and a blue cloud ring. (ProQuest: ... denotes formulae/symbols omitted.)
ISSN:0035-8711
1365-2966
DOI:10.1093/mnras/stu2604