EDP Sciences
Free access
Volume 396, Number 3, December IV 2002
Page(s) 857 - 866
Section Extragalactic astronomy
DOI http://dx.doi.org/10.1051/0004-6361:20021462

A&A 396, 857-866 (2002)
DOI: 10.1051/0004-6361:20021462

HST images of B2 radio galaxies: A link between circum-nuclear dust and radio properties?

H. R. de Ruiter1, 2, P. Parma2, A. Capetti3, R. Fanti4, 2 and R. Morganti5

1  Osservatorio Astronomico di Bologna, via Ranzani, 1, 40127 Italy
2  Istituto di Radioastronomia, via Gobetti 101, 40129, Bologna, Italy
3  Osservatorio Astronomico di Torino, Strada Osservatorio 25, 10025 Pino Torinese, Italy
4  Istituto di Fisica, University of Bologna, via Irnerio 46, 40126 Bologna, Italy
5  Netherlands Foundation for Research in Astronomy, Postbus 2, 7990 AA, Dwingeloo, The Netherlands

(Received 5 April 2002 / Accepted 1 October 2002 )

Almost 60% of the B2 low luminosity radio galaxies have been observed with the Hubble Space Telescope. We present an analysis of the dust features, which are often present in the form of circum-nuclear disks or lanes, and show that there are correlations between radio source and dust properties. It is found that nearby radio sources in which a jet has been detected tend to have dust more often than sources without jets; the dust is often in the form of disks or lanes. Moreover the radio jets are close to perpendicular to the disk or lane in the weaker radio sources (with P < 1024 WHz -1). In stronger sources the orientation effect appears to be weak or even absent. Also the dust masses found in the weaker radio sources are smaller than in the stronger ones ( $\log M/M_{\sun} \sim 3$ against 5 respectively). More generally it appears that there is a correlation between dust mass and total radio power (for those sources in which dust has been detected); we show that this correlation is not induced by redshift.

Key words: galaxies: active -- galaxies: elliptical and lenticulars -- galaxies: nuclei

Offprint request: H. R. de Ruiter, deruiter@bo.astro.it

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