A Catalog of Edge-on Disk Galaxies: From Galaxies with a Bulge to Superthin Galaxies

TL;DR

This study compiles a large, uniform catalog of edge-on disk galaxies from SDSS data, revealing the prevalence of bulgeless and flat galaxies and providing insights into their distribution and characteristics.

Contribution

It presents a new, extensive catalog of edge-on disk galaxies classified into detailed morphological types, including a significant number of bulgeless and flat galaxies, improving upon previous optical catalogs.

Findings

Approximately 15% of the catalog are flat galaxies.

Bulgeless disks constitute about one third of the sample.

The catalog contains nearly four times more bulgeless galaxies than previous surveys.

Abstract

The formation and evolution of disk-dominated galaxies is difficult to explain, yet these objects exist. We therefore embarked on a study aimed at a better understanding of these enigmatic objects. We used data from the SDSS DR1 in order to identify edge-on galaxies with disks in a uniform, reproducible, automated fashion. We identified 3169 edge-on disk galaxies, which we subdivided into disk galaxies with bulge, intermediate types, and simple disk galaxies without any obvious bulge component. We subdivided these types further into subclasses: Sa(f), Sb(f), Sc(f), Scd(f), Sd(f), Irr(f), where the (f) indicates that these galaxies are seen edge-on. A number of incompleteness effects affect our catalog, but it contains almost a factor of four more bulgeless galaxies with prominent simple disks (flat galaxies) within the area covered here than previous optical catalogs, which were based on the visual selection from photographic plates. We find that approximately 15% of the edge-on disk galaxies in our catalog are flat galaxies, demonstrating that these galaxies are fairly common, especially among intermediate-mass star-forming galaxies. Bulgeless disks account for roughly one third of our galaxies when also puffy disks and edge-on irregulars are included.(Abridged)