Another look at the size of the low-surface brightness galaxy VCC 1661 in the Virgo Cluster

TL;DR

This study provides new measurements of the size of the low-surface brightness galaxy VCC 1661 in the Virgo Cluster, showing it is consistent with typical dwarf galaxies and not tidally disrupted.

Contribution

The paper offers updated size estimates for VCC 1661, clarifying its nature and challenging previous claims of it being unusually large or tidally disturbed.

Findings

New radius measurement of VCC 1661: 24.1 arcseconds.

VCC 1661's appearance is smooth and consistent with typical dwarf galaxies.

No evidence of tidal disruption in VCC 1661.

Abstract

We present new wide-field images of the low-surface brightness Virgo Cluster dwarf galaxy VCC 1661. The extant literature lists a broad range of radii for this object, covering a factor of more than four, depending on the filters used and the details of the analyses. While some studies find a radius typical of other Virgo dwarfs and note the normality of this object, any larger spatial extent, taken at face value, would render this galaxy the largest dwarf in the Virgo Cluster samples. Confirmation of a large extent of dwarf galaxies has often led to the discovery of tidal tails and would then, also in VCC 1661, indicate a severe state of tidal disruption. Given the importance of galactic sizes for assessing tidal interactions of the satellites with their hosts, we thus combine our surface brightness profile with data from the literature to investigate further the nature of this galaxy. However, our new characteristic radius for VCC 1661 of $r_e=24.1$"$\pm7.7$" and the previously noted smooth appearance of its isophotes are fully consistent with the remainder of the ACSVCS dwarf galaxy population without any need to invoke tidal perturbations.