Brief program summary and its significance:

  Giant arcs and arclets in clusters of galaxies (C. Oliveira)

   High redshift clusters of galaxies can be used as ``gravitational
telescopes'' through which we can study distant field galaxies that
have been gravitationaly lensed.  The study of the properties of field
galaxies at medium redshift can be addressed by observing arcs towards
rich clusters of galaxies at different redshifts.  These could then be
compared with the properties of galaxies at low redshifts to search for
evolutionary effects.

   We plan to obtain near-infrared and optical images of giant arcs and
arclets of known redshifts to study the properties (colours and
sizes) of the field galaxy population which is being
lensed.

   We also plan to obtain low-resolution spectroscopy of samples of
arcs for which no redshift is known, in order to enhance the sample
for the above colour/structure study.

  The observations involve low resolution spectroscopy and
high-resolution imaging in the NIR and optical.

Required minimum field of view (arcmin): 10" for spectroscopy, 1' 
for imaging

Required psf (FWHM, profile details): as small as possible (< 0.5")

Typical target separation if multiple targets per exposure: < 1' 

Signal/noise required per resolution element: $\sim$ 5 for spectroscopy,
enough to obtain the redshift of the arc

Typical exposure time for this S/N & lunar phase: 4-5 hours for
spectroscopy, dark moon. About 2-4 hours imaging, dark moon (B,R). 

Anticipated photometric dynamic range required: high 
(will have bright central cluster members close to the arcs we would 
like to image)

What additional photometric calibrations are required?
twilight flats,  night sky flats, standard photometric calibrations,
flux calibrators.

If IR, is tip/tilt feasible (consider isoplanatic patch)? yes

Anticipated number of separate pointings to complete program: 10

Can this program execute in a queue? yes, but many hours of observation

Anticipated post-focus instrumentation requirements (filters, gratings,
etc.):

Required instruments (spectral R, filters, wavelength range):
spectroscopy R<1000, 3700-10000 A. Imaging: filters B, R, K

How soon might you need to revisit this target with another instrument?
Not immediately.

Why can't this program execute on the Blanco 4m? It needs high spatial
resolution. A typical giant arc has a width of 0.5" and smaller

References (for non-mainstream applications):

Fort, B. and Mellier, Y. 1994, A&A Rev., 5, 239

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Brief program summary and its significance:

    Dwarf galaxies formed in Interacting Systems (C. Oliveira)

    Merging events involving at least one gas-rich system may trigger
the birth of dwarf galaxies formed out of recycled material from the
parent galaxies.  Only a few of such cases of possible ongoing galaxy
formation have been studied in detail.  We would like to obtain
spectroscopy (with an IFU?) of candidate dwarf galaxies around nearby
galaxies in compact groups to determine the fraction of dwarfs in
groups formed through this process.

  The observations involve medium-resolution optical spectroscopy.

Required minimum field of view (arcmin): 30" 

Required psf (FWHM, profile details): as small as possible (< 0.5")

Typical target separation if multiple targets per exposure: < 30" 

Signal/noise required per resolution element: $\sim$ 20 

Typical exposure time for this S/N & lunar phase: 1-3 hours for
spectroscopy, grey moon. 

Anticipated photometric dynamic range required: high 

What additional photometric calibrations are required? 
flat fields, flux calibration

If IR, is tip/tilt feasible (consider isoplanatic patch)? 

Anticipated number of separate pointings to complete program: 10

Can this program execute in a queue? yes

Anticipated post-focus instrumentation requirements (filters, gratings,
etc.):

Required instruments (spectral R, filters, wavelength range):
spectroscopy R$\sim$5000, 3700-10000 A

How soon might you need to revisit this target with another instrument?
Not immediately.

Why can't this program execute on the Blanco 4m? It needs high spatial
resolution to resolve the faint/small dwarf galaxies in the tails of the
interacting galaxies.

References (for non-mainstream applications):

Duc, P.A., Mirabel, I.F. 1994, A&A 289, 83