~ 500 to 1000 times per second. The result
is about a 20-fold increase in the area of the
observed patch of sky compared to previous
AO systems, while providing uniform corrections over the entire field from edge-to-edge.
GeMS is a facility instrument, and as such
it can direct its light output to different science instruments installed at the Cassegrain focus of the Gemini South telescope.
The main instrument used to date is GSAOI, a wide-field camera designed to work
at the diffraction limit of the 8-meter telescope in the near-infrared (NIR). In the next
semesters, plans are to couple GeMS with
FLAMINGOS-2 — the near-infrared imager
and long-slit and Multi-Object Spectrograph, currently in commissioning at Gemini
South (see update on page 19 of this issue)
Science Verification:
A Long-awaited Milestone
In August 2012, the GeMS/GSAOI team released a call for System Verification (SV) targets, offering a total observing time of 60
hours for a wide range of science topics. The
SV programs provide an end-to-end test of
a new instrument or capability, from the
proposal process to data delivery, prior to
offering it to the community for general use.
With GeMS/GSAOI, one main objective was
to demonstrate the gain brought by MCAO
on a large variety of science topics, including
extended sources, crowded fields, and faint
targets. We received great feedback, with 23
programs submitted for a total of 138 hours,
from which 13 were selected for execution
between November 2012 and January 2013.
The SV period did not start as expected: In
early November, the power produced by
the sodium laser fell to a level one-half of
what it was a few weeks before, preventing
the team from completing the remaining
commissioning tasks. With the assistance
of Zach Prezkuta (a laser engineer from
July2013
Lockheed Martin Coherent Technologies),
Gemini laser specialist Vincent Fesquet,
worked non-stop for three weeks to recover the laser light to a nominal 50 watts
(W) –– in time for a run in December (Figure 1). Atmospheric seeing and laser conditions were excellent during this period.
The team overcame most of the delays accumulated during commissioning, and SV
observations started before month’s end.
Figure 2.
A three-pointing
GeMS/GSAOI image
of the Orion Nebula’s
Bullets field.
Orion Bullets:
A Dramatic Demonstration
The team selected the Orion Bullets as their
first SV target (Figure 2). These wake-like features in the Orion Nebula are clumps of gas
violently ejected from an unknown event associated w