Probing the nuclear emission structure in the LINER

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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. -gt the nuclear properties appear to differ
from Seyferts -gt optical long baseline
interferometry is the only tool to probe the pc
scales of a nuclear star cluster at AGN
redshifts -gt What is the a geometrical connection
/ orientation between these innermost scales
and the surrounding host -gt 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
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Target selection Scientific selection -gt at a
redshift of z0.05 the linear scale is 1pc/mas -gt
right scale -gt 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 -gt 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 -gt common phenomenon under low-lum
active galaxies -gt some LINERs are powered by
AGN, some by star formation -gt
fraction of unresolved flux contribution is
an important piece of information
(Sturm et al 06)
LINER example
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• Target selection
• Technical selection
• -gt limiting magnitudes we assume perfect
  AMBER-LR/PRIMA K11 (FT) and 30 off-axis
  capabilities for both AO (V16) and AMBER (K15)
• gt coordinates declination below 35degr
• gt observability in the next semester (Apr.-Sept.)
• gt nearby visibilty calibrators same brightness
  and guide star distance
• Targets
• -gt LINER F01364-1042 (K13.6) and GuideStar
  (K8.5, dist30)
• -gt CAL HD7783 (K8 with sec. star dist24 and
  K_sec12) distance to science target
  7.4degrees

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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 -gt 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
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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 -gt Three
baselines (U134) and three AMBER shots are enough
to characterize the extended emission
around a LINER nucleus in half a night.
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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.