Molecular gas in powerful radio galaxies: major or minor mergers?

We will discuss the detection of CO(1-0) and CO(2-1) emission, with the IRAM-30m telescope, from the central regions (5-10 kpc) of powerful radio galaxies. Their individual CO emission exhibits a double-horned line profile that is characteristic of an inclined rotating disk with a central depression at the rising part of its rotation curve. The inferred disk or ring distributions of the molecular gas is consistent with the observed presence of dust disks or rings detected optically in the cores of the galaxies. Despite their relatively large molecular-gas masses and other peculiarities, as well as many other powerful radio galaxies in the (revised) 3C catalog, they are known to lie within the fundamental plane of normal elliptical galaxies. We will develop our preferred scenario for the origin of molecular gas: cannibalism of gas-rich galaxies which provides a simpler explanation for the origin of molecular gas in the elliptical hosts of radio galaxies rather than the merging of two gas-rich galaxies. We will discuss briefly the line ratio properties and the connection with higher redshift radio-galaxies.

 

Date: 
15/11/2000 - 13:00
Speaker: 
Stephane Leon
Filiation: 
Universidad de Colonia (Alemania)


Seminars