The influence of the cluster environment on the large-scale radio continuum emission of 8 Virgo cluster spirals

TL;DR

This study examines how the environment, especially ram pressure, influences the radio continuum emission of Virgo cluster spiral galaxies, revealing large-scale magnetic field effects without significantly altering star formation rates.

Contribution

It provides detailed radio polarization observations of Virgo spirals, linking ram pressure effects to large-scale magnetic field structures and emission features.

Findings

Ram pressure causes sharp edges in total power emission coinciding with HI edges.

Asymmetric polarization gradients reveal ram pressure wind directions.

Local star formation and small-scale magnetic fields are not significantly affected.

Abstract

The influence of the environment on the polarized and total power radio continuum emission of cluster spiral galaxies is investigated. We present deep scaled array VLA 20 and 6 cm observations including polarization of 8 Virgo spiral galaxies. These data are combined with existing optical, HI, and Halpha data. Ram pressure compression leads to sharp edges of the total power distribution at one side of the galactic disk. These edges coincide with HI edges. In edge-on galaxies the extraplanar radio emission can extend further than the HI emission. In the same galaxies asymmetric gradients in the degree of polarization give additional information on the ram pressure wind direction. The local total power emission is not sensitive to the effects of ram pressure. The radio continuum spectrum might flatten in the compressed region only for very strong ram pressure. This implies that neither the local star formation rate nor the turbulent small-scale magnetic field are significantly affected by ram pressure. Ram pressure compression occurs mainly on large scales (>=1 kpc) and is primarily detectable in polarized radio continuum emission.