Contents of: VI/111/./abstract/RGENZEL_MPEXGAL3.abs

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SCIENTIFIC ABSTRACT
Exploration of the nature, physical conditions and evolution of the nuclear
regions of luminous external galaxies is the main purpose of the SWS CP
Proposal: GALACTIC NUCLEI. We propose to carry out multi-line spectroscopy for
a detailed study of the circum-nuclear interstellar media and for a better
determination of the properties of the central energy source(s). We will first
explore the global character of the circum-nuclear gas by observing the
brightest infrared lines in a sample of about 60 galaxies of all classes,
including normal, starburst and distant luminous IRAS galaxies, as well as
Seyferts, Liners and AGN/QSOs. In a next step we will then study physical
properties and excitation of the circumnuclear regions of a selected group of
galaxies in more detail by observing a wide range of ionic, atomic and molecular
infrared lines. Due to the large gain in sensitivity and the full wavelength
coverage, such a program will only become possible with the advent of ISO.
With the help of theoretical modeling and comparison to nearby,
prototypical `template' sources, these measurements will determine the physical
processes in and constrain current evolutionary models of galactic nuclei.

OBSERVATION SUMMARY
We plan to take advantage of the spectroscopic capabilities of ISO over its
full wavelength range, using the following AOTs:
SWS: Medium resolution spectroscopy with the AOTs SWS01,SWS02,SWS06
LWS: Medium resolution spectroscopy with AOTs LWS01,LWS02
PHT: Low resolution spectra with AOT PHT40

For a small number of `template' sources, we will perform scans over the
full ISO wavelength range.

For all our program galaxies, we will obtain a survey of some of the
brightest or most important lines:
Species  Lambda
[Mg V]   5.608
[Ar III] 8.991
[Ne V]  14.320  (only in IR-luminous galaxies+N5253+N6764+IIZw40+IZw1+Mk463)
[S III] 18.713
[O IV]  25.913
[S III] 33.480
[Si II] 34.814
[O III] 51.815   (Or LWS full scan)
[O I]   63.184         ''
[C II] 157.741         ''
PHT-S Spectrum

A subset of starburst galaxies will be studied in detail in a large number of
lines characterizing various phases of the ISM:
Species  Lambda
Br alpha 4.052
[MgV]    5.608
H2 S(5)  6.910
Pf alpha 7.460
[NeVI]   7.642
[ArIII]  8.991
[SIV]   10.511
H2 S(2) 12.279
[NeII]  12.814
[NeV]   14.320
[NeIII] 15.555
H2 S(1) 17.035
[SIII]  18.713
[ArIII] 21.842
[FeIII] 22.930
[FeI]   24.042
[NeV]   24.300
[SI]    25.249
[OIV]   25.913
[FeII]  25.988
H2 S(0) 28.219
[SIII]  33.480
[SiII]  34.814
[FeII]  35.349
[NeIII] 36.020
H2O     40.337
[O III] 51.815   (From LWS full scan)
[N III] 57.317         ''
[O I]   63.184         ''
[O III] 88.356         ''
[N II] 121.898         ''
[O I]  145.526         ''
[C II] 157.741         ''

A search for molecular hydrogen emission (S(0) and S(2)) in galactic disks
will be done for a number of mostly edge-on galaxies.

The OH 34.6 line will be observed in the megamaser galaxies Arp 220, Mrk 231
and NGC3690A/BC, in coordination with LWS.

H3+ emission from X-ray illuminated gas will be searched for in NGC 6240 and
NGC 1068.

A subset of active galactic nuclei will be observed in the following lines
tracing the NLR, CLR, partially ionized and molecular zones:
Species  Lambda
[SiIX]   2.585
[Mg VIII]3.028
[SiIX]   3.935
[MgIV]   4.488
[MgVII]  5.500
[MgV]    5.608
[SiVII]  6.515
S(5)     6.910
[NeVI]   7.642
[MgVII]  9.030
[SIV]   10.511
S(2)    12.279
[NeII]  12.814
[MgV]   13.540
[NeV]   14.320
[NeIII] 15.555
S(1)    17.035
[SIII]  18.713
[FeIII] 22.930
[FeI]   24.042
[NeV]   24.300
[OIV]   25.913
[FeII]  25.988
S(0)    28.219
[FeII]  35.349
[NeIII] 36.020
For the two Liners studied in detail, high excitation lines will be skipped

We deviate from the philosophy to use both SWS and LWS by dropping LWS
observations for those sources in which the LWS consortium will obtain
equivalent data.

Concatenation is asked for only in a limited number of cases where the same AOT
is used at several positions, e.g. of an interacting system. A number of very
long observations with AOT SWS02 have been split. These are deliberately not
concatenated to allow efficient scheduling.

For details see the scientific justification below. In particular, the
`quick overview of observations' indicates, for both positions of the hole,
which sources are observed, to which level of detail, and the corresponding
priority.

The scientific justification contains also a list of requested S/N values for
the various projects. In bright sources, these are often exceeded by large
factors within the shortest possible integration times for the respective AOTs.
For some faint lines in faint sources, the requested S/N cannot be
met within the time limit of 1280s pure integration per line we have adopted
for most sources. Details on integration time per line for each source by far
exceed the size limits imposed  for this file. They are available on request.

Version March 7, 1994