The core flux of the brightest 10 micron galaxies in the southern sky

TL;DR

This study provides high-resolution mid-infrared images of the brightest southern sky galaxies at 8.9, 11.9, and 12.9 microns, identifying unresolved cores suitable for VLTI MIDI observations and comparing flux measurements with existing data.

Contribution

It offers the first near diffraction-limited images of these sources, establishing core fluxes and positions, aiding future interferometric studies with VLTI MIDI.

Findings

15 AGNs have unresolved core fluxes < 300mJy at 11.9 microns

Most sources are promising targets for VLTI MIDI observations

Extended sources' images are characterized and discussed

Abstract

Aims. Near diffraction-limited images have been taken at 8.9, 11.9, and 12.9 micron 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 400mJy. We used the TIMMI2 Mid Infrared instrument mounted on the ESO's 3.6m 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 < 300mJy at 11.9 micron, making them promising targets for MIDI at the VLTI. For extended sources, near diffraction-limited images are presented and discussed.