On the nature of IC 3328, an early-type dwarf galaxy with weak spiral structure

TL;DR

This study investigates the dynamical properties of the early-type dwarf galaxy IC 3328, which exhibits weak spiral features, to understand its relation to classical dwarf ellipticals and spiral galaxies.

Contribution

It provides a detailed dynamical analysis of IC 3328, incorporating asymmetric drift correction and stability considerations, highlighting the presence of a hot component alongside the disk.

Findings

Presence of a significant hot component in IC 3328

Weak spiral arms in a gas-devoid dwarf galaxy

Further data needed for definitive conclusions

Abstract

Various early-type dwarf galaxies with disk features were identified in the Virgo cluster, including objects that display weak grand-design spiral arms despite being devoid of gas. Are these still related to the classical dEs, or are they a continuation of ordinary spiral galaxies? Kinematical information of acceptable quality is available for one of these galaxies, IC 3328. We perform an investigation of its dynamical configuration, taking into account the effect of asymmetric drift, and using the Toomre parameter as well as density wave considerations. The derived mass-to-light ratios and rotational velocities indicate the presence of a significant dynamically hot component in addition to the disk. However, unambiguous conclusions need to await the availability of further data for this and other early-type dwarfs with spiral structure.