The Herschel Virgo Cluster Survey: VII. Dust in cluster dwarf elliptical galaxies

TL;DR

This study reports the first far-infrared detections of dust in cluster early-type dwarf galaxies, revealing that dust removal processes in dense environments are highly efficient, comparable to gas removal.

Contribution

It presents the first possible far-infrared detections of dust in Virgo cluster dwarf elliptical galaxies, highlighting the efficiency of dust removal mechanisms.

Findings

Detected dust in two dwarf ellipticals at 10 sigma in SPIRE 250 micron.

Dust masses are around 10^5 solar masses with temperatures near 20K.

Detection rate is less than 1%, indicating efficient dust removal in cluster environment.

Abstract

We use the Science Demonstration Phase data of the Herschel Virgo Cluster Survey to search for dust emission of early-type dwarf galaxies in the central regions of the Virgo Cluster as an alternative way of identifying the interstellar medium.We present the first possible far-infrared detection of cluster early-type dwarf galaxies: VCC781 and VCC951 are detected at the 10 sigma level in the SPIRE 250 micron image. Both detected galaxies have dust masses of the order of 10^5 Msun and average dust temperatures ~20K. The detection rate (less than 1%) is quite high compared to the 1.7% detection rate for Hi emission, considering that dwarfs in the central regions are more Hi deficient. We conclude that the removal of interstellar dust from dwarf galaxies resulting from ram pressure stripping, harassment, or tidal effects must be as efficient as the removal of interstellar gas.