The core flux of the brightest 10 $\mathsf{\mu}$m galaxies in the southern sky

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.

Parsec-scale dust distributions in Seyfert galaxies

“…They are well suited for comparison to the MIDI data because of the pointlike nature of the nucleus in 3C 273: neither in our VISIR imaging (cf. Appendix A.6) nor in our observations with TIMMI2 (Raban et al 2008) are there signs for extended emission. Furthermore, the VISIR measurements are consistent with the Spitzer spectra, as are the TIMMI2 measurements.…”

“…Its unresolved near-infrared emission shows a strong bump at 2.2 μm which is interpreted as very hot dust near its sublimation temperature (T ∼ 1200 K), very likely located both in the upper layers of the torus and close to the apex of the polar scattering region (Rodríguez-Ardila & Mazzalay 2006). While the source appears unresolved with a flux of 0.64 ± 0.10 Jy in the TIMMI2 image at 11.9 μm (Raban et al 2008), Gorjian et al (2004) detected an approximately 1 arcsec long extension from the nucleus to the northwest.…”

“…The original list of targets for both the GTO and the SDT (see Table 1) contains those 16 active galaxies from Raban et al (2008), plus NGC 1068, which are well observable from Cerro Paranal (Dec < +25…”

“…The results of the investigation with TIMMI2 were published in Raban et al (2008); those of the investigation with NACO will be presented in Prieto et al (in preparation). The photometric values of the targets at 11.9 μm from Raban et al (2008), for aperture sizes ranging from 1.2 arcsec to 2.6 arcsec, are listed in the last column of Table 1. As the observations progressed, several galaxies from the original target list were released from the GTO protection without being observed. NGC 253, NGC 3256, NGC 3783, Mrk 463E, and NGC 7582 are among these galaxies released.…”

“…The dusty tori are too small to be significantly resolved with single dish telescopes in the thermal infrared (λ > ∼ 3 μm), even Article published by EDP Sciences Notes: the columns are: (1) the name of the galaxy used in this paper; (2) an alternative name for the galaxy; (3) and (4) the coordinates of the nucleus used for the MIDI observations or, if no observations were carried out, the 2MASS coordinates; (5) the galaxy type (from NED); (6) the distance to Earth assuming H 0 = 73 km s −1 Mpc −1 ; (7) the angular size corresponding to 1 pc in the target; (8) the angular distance ψ and (9) the visual magnitude V of the best Coudé guide star (if present); (10) the flux at 11.9 μm from Raban et al (2008). for 10 m class telescopes at the diffraction limit (with or without AO), which implies that the dust distributions are rather compact with sizes < ∼ 10 pc (e.g. Soifer et al 2003;Horst et al 2009).…”