Research Note

The core flux of the brightest 10 m galaxies in the southern sky ^*,**

¹ Leiden Observatory, Leiden University, PB 9513, Leiden, 2300 RA, The Netherlands e-mail: raban@strw.leidenuniv.nl
² Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
³ ESO, Karl-Schwarzschild-Str. 2, 85748 Garching bei Muenchen, Germany

Received: 9 March 2007
Accepted: 26 March 2008

Abstract

Aims. Near diffraction-limited images have been taken at 8.9, 11.9, and 12.9 μm for the brightest extragalactic sources in the southern sky, in order to optimally plan N-band observations with MIDI (MID-infrared Interferometric instrument) at the VLTI.

Methods. We have assembled a sample of 21 objects consisting of all the AGNs observable from Paranal observatory, Chile, plus three non-AGN objects, with an estimated N-band flux greater than 400 mJy. We used the TIMMI2 Mid Infrared instrument mounted on the ESO's 3.6 m telescope to obtain near diffraction-limited images in order to establish the unresolved core flux within <0.5 arscsec.

Results. Positions and core total fluxes were obtained for all sources in our sample and compared with similar investigations in the literature. We find that 15 AGN and the nuclear starburst in NGC 253 exhibit an unresolved core flux <300 mJy at 11.9 μm, making them promising targets for MIDI at the VLTI. For extended sources, near diffraction-limited images are presented and discussed.