Box/Peanut and Bar structures in edge-on and face-on SDSS nearby galaxies I. Catalogue

TL;DR

This study catalogs Box/Peanut and bar structures in SDSS galaxies, analyzing their frequency, strength, and relation, supporting the idea that Box/Peanut structures are edge-on views of bars.

Contribution

It provides a large catalog of Box/Peanut and bar structures in nearby galaxies, with detailed classification and analysis of their properties and prevalence.

Findings

22% of edge-on galaxies have Box/Peanut structures.

33% of face-on galaxies have bar structures.

Box/Peanut strength correlates slightly with bulge-to-total ratio.

Abstract

We investigate Box/Peanut and bar structures in image data of edge-on and face-on nearby galaxies taken from SDSS (Sloan Digital Sky Survey) to present catalogues containing the surface brightness parameters and the morphology classification. About 1700 edge-on galaxies and 2600 face-on galaxies are selected from SDSS DR7 in g, r and i-band. The images of each galaxy are fitted with the model of 2-dimensional surface brightness of S\'{e}rsic bulge and exponential disk. After removing some irregular data, Box/Peanut, bar and other structures are easily distinguished by eye using residual (observed minus model) images. We find 292 Box/Peanut structures in the 1329 edge-on samples and 630 bar structures in 1890 face-on samples in i-band, after removing some irregular data. Then the fraction of Box/Peanut galaxies is about 22 percent against the edge-on samples, and that of bar is about 33 percent (about 50 percent if 629 elliptical galaxies are removed) against the face-on samples. Furthermore the strengths of the Box/Peanut and bar are evaluated as "Strong", "Standard" and "Weak". We find that the strength increases slightly with increasing $B/T$ (Bulge-to-Total flux ratio), and that the fraction of Box/Peanut is generally about a half of that of bar irrespective of the strength and the $B/T$. Our result supports the idea that the Box/Peanut is bar seen edge-on.