Probing the nuclear emission structure in the LINER F01364-1042 with the VLTI by

1. Probing the nuclear emission structure in the LINER F01364-1042 with the VLTI by Konstantina & Jürgen Abstract: LINER bear an AGN with unusual properties with respect to dominating Seyfert population: very high Eddington rates, low luminosities, naming low ionization emission lines. -> the nuclear properties appear to differ from Seyferts -> optical long baseline interferometry is the only tool to probe the pc scales of a nuclear star cluster at AGN redshifts -> What is the a geometrical connection / orientation between these innermost scales and the surrounding host -> We propose to use AMBER/PRIMA to investigate directly the circumnuclear NIR emission around a LINER nucleus and search for imprints of the surrounding matter

2. Target selection: Scientific selection: -> at a redshift of z~0.05 the linear scale is 1pc/mas -> right scale -> while Seyferts typically show only a few percent of non-nuclear flux contribution in the inner parsec (Davies et al. 07) the lower luminosity of LINER but higher accretion rate suggest to push this ratio towards higher flux contributions from the nuclear stellar surroundings -> LINERs are ideal to study the stellar morphology around an AGN and search for (a)symmetric structures, merger imprints, and M1-instabilities (Garcia-Burillo et al. 03), enhanced circumnuclear hot gas outflow and star formation due to high Eddington rate LINER background: -> common phenomenon under low-lum active galaxies -> some LINERs are powered by AGN, some by star formation: -> fraction of unresolved flux contribution is an important piece of information (Sturm et al 06) LINER example

3. Target selection: • Technical selection: • -> limiting magnitudes: we assume perfect AMBER-LR/PRIMA: K=11 (FT) and 30” off-axis capabilities for both AO (V=16) and AMBER (K=15) • > coordinates: declination below 35degr • > observability in the next semester (Apr.-Sept.) • > nearby visibilty calibrators: same brightness and guide star distance • Targets: • -> LINER F01364-1042 (K=13.6) and GuideStar (K=8.5, dist=30”) • -> CAL: HD7783 (K=8 with sec. star: dist=24” and K_sec=12); distance to science target = 7.4degrees

4. What do we expect to see? To first order depending on the inclination extended flux should show up as circular or elliptical structure around an unresolved nucleus: -> visibility modeling shows that 10% extended flux contribution at 2-10pc scales can be probed with VLTI baselines. Model: Point source + Gaussian 2mas ext. 10mas ext. 90% flux contribution of point source

5. Probing non-circular symmetry Different PA, same BL If the extended flux distribution contributes more than the assumed 10% in case of circumnuclear starburst, the closure phase of the three telescope experiment becomes an important tool to analyse asymmetries in the flux -> Three baselines (U134) and three AMBER shots are enough to characterize the extended emission around a LINER nucleus in half a night.

6. Observing constraints: delay line range is fine Go for september second half of the night Outlook: Connect the geometry of innermost parsec scale with larger radii is a tool to study the importance of warped discs in these systems. The outcome of this experiment will enable to design future VLTI studies of stellar and gas properties with maximum uv-efficiency. Spectral emission lines from the extended flux around the nucleus can be studied with the higher spectral resolution modes of AMBER.