The Sixth NEON Observing School
Asiago, September 4-18, 2007

The 6th NEON observing school took place at Asiago Observatory (Italy)  from Sept. 4th to 18th. 
Twenty students of 14 different nationalities performed small research programs
under the guidance of experienced  tutors.
These programs covered all aspects of a real observing program,
starting from the preparation of the 
observations to the extraction of the scientific results, 
including the set-up of the instruments,  and the  exploration of
the Astronomical Virtual Observatory Databases to see if other interesting
data were available  on the corresponding topic. 

Asiago Schmidt telescope (+ lecture room)

The group led by E. Giro (Padova), comprising G. Kordopatis (Greece), R. Martinez 
(Spain), S. Sodorne (Hungary) and K. Zloczewski (Poland),
studied the polarisation of galaxies in interacting  groups.
In face-on, spiral galaxies, the polarisation pattern (i.e. magnetic field pattern) usually follows the 
spiral arms, while the situation is more complex in
objects inclined or comprising dust lanes.
Observations of  NGC 7625 at the 1.82m telescope showed this galaxy to be a blue compact dwarf, with a strong
dustlane,a rich  interstellar medium and numerous starforming regions.
While its nucleus had a polarisation of "only" 0.70 %,  the NE part (more disturbed)
has a stronger value of 2.94 +- 0.91, indicating also a stronger magnetic field. 
The instrumental polarisation was of course determined and removed, but
indicated that there was much dust on the  optics!
The analysis  of archival data for ESO 2400-100  showed its polarisation was ranging between 0.11 and 0.30 
percent, small values expected for an elliptical galaxy.
On the contrary, RR24, a dusty, interacting pair, showed  a maximum polarisation of 3.52 +- 0.32 % in the disturbed region. Remaining questions are how the magnetic field  is affected by interactions and what is
the timescale for alignement of particules  with the new field, once a disturbance has occured.

The group of L. Sbordone (Paris), with G. de Rosa (Italy), E. Kundra (Slovakia), 
S. Nasoudi (Sweden) and G. Petrov (Bulgaria), worked on the chemical analysis of various stars.
High-resolution,  VLT/UVES data were reanalysed to master all the problems of echelle spectra.
Synthetic spectra were produced  with first guesses of the stellar parameters,
for comparison with the data and determination of abundances of  various elements like Fe, Na, Ca, etc...
Direct observations of the same stars at the 1.2m telescope, in low dispersion,
allowed a proper flux calibration to be made, to further constrain the model stars.
After several  iterations, the models and observations converged, allowing even the determination of the parameters of the  microturbulence.
Small discrepancies remained in the blue part of the  spectrum, certainly due to the lower  sensitivity of the detector there, 
and to the higher atmospheric dispersion during the observations. 


The group of J. Dietrich (ESO), with R. D'Abrusco (Italy), K. Jordi (Switzerland), J. Sultana (Malta) 
and G. Szasz (Slovakia), searched for galaxies in clusters, using the red-sequence method. 
A series of dithered images in Blue and Red were obtained of the cluster Abell 115 with the 1.82m telescope, 
in a tile of 3x4, and then mosaiced to produce a composite image.
Some of the peculiar features of that instrument  were put into evidence
(gradient in the bias, some charge transfer inefficiency, etc...)
and a proper weight map  was produced for the final image. 
No clear evidence was found for a red sequence of galaxies, but  the scatter 
was large in the colour-magnitude diagram.
A composite B,V,R image of the central part of the cluster however  revealed that the galaxy
CGCG 480-022 was in fact much bluer than the other objects and was in fact a foreground  galaxy.
To complete the program, spectra of some bright galaxies were also obtained with the 1.2m telescope, 
allowing this group to have a complete overview of the most important observing techniques. 

The group of C. Adami (Marseille), including  S. Comeron (Spain), P. Ponente, U. Seemann (Germany) and Y. Wu (China), 
investigated "fossile groups" of galaxies, to determine whether they were indeed the results of former mergers 
of a large number of galaxies.
For this purpose, a cluster with strong X-ray emission had been selected  
and as many as possible redshifts had to be collected, to assess the belonging of individual galaxies to the group 
and put the possible existence of a void (search diameter
of up to 500 Mpc) around the center into evidence. 
The first task was thus a torough analysis of archival data, in particular the Sloan  Digital Sky Survey, 
where 888 possible  galaxies were found, only 432 of them having a redshift.
After eliminating misidentifications,  83 potential targets remained for further spectroscopy.
This was of course too much for the little observing  time available,
but 3 objects could be observed at the 1.2m telescope, and further 2 (fainter ones...) at  the 1.82m.
Spectroscopic reductions have no secret anymore for this group, but the work needs to be pursued 
in the future to finalise the analysis of this cluster. 

Finally, the group of F. Di Mille (Asiago), with  N. Bonhomme (France), O. Ozdarcan (Turky), C. Ruhland (Germany) 
and K. Stoyanov (Bulgaria), searched for  Novae in the neighbourghing galaxy M31. 
Imaging in broad band R, and, more important, with  a narrow H Alpha  filter, was obtained
in several adjacent regions at the 1.82m telescope.
After proper reduction, including  astrometry and recentering of the various images,
a mosaic Halpha image was produced, to be compared with 
previous images obtained in the same region.
In total, 3 recently discovered Novae were found again,
as well  as one pulsating star  and one object presumably a
Planetary Nebula (coincidence in position).
One new  candidate was discovered, but was unfortunately too faint to obtain immediately a spectroscopic confirmation. 
But spectra could be obtained for 2 out of the 3 recent discoveries,
providing the first spectroscopic  confirmation of their nature.
Spectra of the bright, galactic Nova Vulpecula (detected this summer) were also  obtained,
allowing the students to discover the variety, and the variability, of this class of interesting  celestial objects.
Some of these results will be published soon in the appropriate channels for variable objects.