[AAA] NIRI SPECTROSCOPY + ALTAIR : CALL FOR PROPOSALS FOR SYSTEM VERIFICATION

[Oficina Gemini Argentina]

NIRI SPECTROSCOPY + ALTAIR :  CALL FOR PROPOSALS FOR SYSTEM VERIFICATION

Dear Colleagues,

ALTAIR, Gemini's adaptive optics instrument, is now in frequent use
with NIRI in imaging mode, with image sizes well under 0.10 arcseconds
at H and K being delivered routinely if the natural seeing is not much
worse than average. It is now time for the system verification (SV)
process for ALTAIR with NIRI in spectroscopic mode
(ALTAIR+NIRIsp). Note that ALTAIR+NIRIsp was offered as part of the
2004B Call for Proposals.

We are contacting you because you are either Gemini staff, a member of
the Altair instrument team, or a member of a National Gemini
Office. We strongly encourage you to contact colleagues and
communities and to submit projects. Collaboration is highly encouraged
since there is a limited amount of observing time.

We anticipate using 8-12 clear hours for Altair+NIRIsp SV. Because of
the variation of the seeing with zenith angle, we would prefer to
observe objects within 45 degrees of the zenith (although we do not
absolutely exclude larger zenith angles). This, coupled with the
likely dates of the SV observing, in early June suggests that targets
should have RA's in the range 12-24.

ALTAIR+NIRIsp is conducted at f/32 (0.022 arcsec/pixel) along the slit
direction.  NIRI possesses J, H, and K grisms for use at f/32,
respectively covering the following wavelength intervals: 1.05-1.35,
1.49-1.80, and 1.97-2.41 microns. Each SV program must make use of at
least one of these grisms and of either of the two narrow slits (the 4
or the 7 pixel wide slits, with widths of approximately 0.08 and 0.14
arcsec. Resolving powers typically range from 600 to 1200. The
properties of these grisms and of the slits that they utilize are
given on the NIRI web pages.

A brief discussion of the sensitivity of ALTAIR+NIRIsp is given on the
NIRI "Performance and Use" webpage, but is repeated here. No ITC is
available for this mode.  However,one can obtain a rough estimate of
time requirements by using the NIRI ITC at f/6 with the narrowest (2
pixel wide f/6) slits, best (20%) image quality, and 25x shorter
individual exposures than will actually be used (as the sky and
telescope background per pixel will be 25 times less than at f/6.
E.g., to estimate the S/N in one hour of integration consisting of
twelve 300-second exposures in the low readnoise mode for f/32
spectroscopy, in the ITC one should specify f/6 spectroscopy and 300
exposures of 12 seconds each in low readnoise mode.

Other issues to consider are the limited isoplanatic field of view
delivered by Altair and the extendedness of the target. For best
results the visible AO guide star must be located within about 7
arcseconds of the target.  Sensitivity on objects that are further
separated or too extended will suffer greatly from the small pixel
size used at f/32 without benefiting much from the AO
sharpening. Hence, small objects with spatial structure will be
strongly preferred over highly extended objects.  Note that the OIWFS
will not be used for Altair spectroscopy at this time.

There is additional information on the Altair webpages about the
isoplanatic field of view, guide star requirements and much more.  The
Main ALTAIR, "Performance and Use," and "Commissioning Performance" web
pages are located at:

http://www.gemini.edu/sciops/instruments/altair/altairIndex.html
http://www.gemini.edu/sciops/instruments/altair/altairPerformance.html
and
http://www.gemini.edu/sciops/instruments/altair/altairCommissioningPerformance.html
 
The SV process uses the normal proposal tools. Therefore you must
submit your program (by e-mail, see below), including brief scientific
and technical justifications, observing constraints, target lists, and
instrument configurations using the 2004A Phase I Tool, see

http://www.gemini.edu/sciops/P1help/p1Index.html

Scientific justifications should be brief (maximum 500
words). Technical justifications should be complete enough that
feasibility can be assessed easily.

Data reduction and analysis should be completed 2 to 3 months after
the observations have been obtained.  The data will be made public as
part of the normal SV process.

THE DEADLINE FOR THE SV PHASE I XML FILES IS FRIDAY, MAY 21, 2004. The
XML files must be emailed directly to Chad Trujillo at
trujillo en gemini.edu.  Early submissions will be appreciated. We will
inform PIs of the results of the selection process by the end of
May. At that time we will solicit Phase II files for the selected
projects.  Because of time constraints, PI's will need to be prepared
to act quickly if their proposals are accepted.

Submitting a SV program or even having a SV program selected as high
priority does not guarantee that data will be taken. Selection for SV
will be based not only on scientific and technical merit, but also on
the abilities of the proposers to reduce the data and provide feedback
within a reasonable time. The proprietary period for SV data is two
months.  PIs and their collaborators will need to provide reduced data
for public release.

Sincerely,

Chad Trujillo, Tom Geballe, and Francois Rigaut

Gemini Observatory
670 N. A'ohoku place
University Park
Hilo HI 96720-2700