Astronomy and Astrophysics, volume 516, A1-1 (2010/6-2)
Parsec-scale properties of brightest cluster galaxies.
LIUZZO E., GIOVANNINI G., GIROLETTI M. and TAYLOR G.B.
Abstract (from CDS):
We present new VLBI observations at 5GHz of a complete sample of brightest cluster galaxies (BCGs) in nearby Abell clusters (distance class <3). Combined with data from the literature, we provide parsec-scale information for 34 BCGs. Our analysis of the parsec-scale radio emission of BCGs and the cluster X-ray properties finds a possible dichotomy between BCGs in cool-core clusters and those in non-cool-core clusters. Among resolved sources, those in cool-core clusters tend to have two-sided parsec-scale jets, while those in less relaxed clusters have predominantly one-sided parsec-scale jets. We suggest that this difference is caused by the interplay between the jets and the surrounding medium. The one-sided structure in non-cool-core clusters may be due to Doppler boosting effects in relativistic, intrinsically symmetric jets whereas two-sided morphology in cool core clusters is probably related to the presence of heavy and mildly relativistic jets that have been decelerated on the parsec-scale. Evidence of recurrent activity is also found in BCGs in cool-core clusters.
galaxies: clusters: general - galaxies: nuclei - galaxies: jets - galaxies: structure - radio continuum: galaxies