Center for Astrophysical Research in Antarctica
CARA Science: SPIFI
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Summary
The South Pole Imaging Fabry-Perot Interferometer (SPIFI) is an imaging
Fabry Perot for use in the far-infrared and submillimeter
(200, 350, 450 micron) windows available to the AST/RO telescope at
the South Pole. SPIFI employs a 5x5 element array
of monolithic silicon bolometers cooled to 60 mK with an adiabatic
demagnetization refrigerator (ADR). The array is fed by Winston cones
with 1.2 
/D
entrance apertures set in a rectangular grid
separated by 1.4 /D in
the focal plan, resulting in a 315''x315'' field of view on AST/RO.
SPIFI's resolving power is fully tunable from R ~ 300 to
10,000 and its resolving power and sensitivity are uniform over the
entire field of view. SPIFI's sensitivity is consistent with the
background limit at all resolving powers.
The primary science drivers for SPIFI are mapping in the
CO (7-6) (371 micron) rotational line, and the [CI]
(J = 2 - 1) (370 micron) fine structure
lines in the Galactic Center, nearby galaxies including low metalicity
dwarfs, distant starburst galaxies, and ultraluminous infrared galaxies.
We also hope to detect
redshifted [CII] line emission from galaxies at z > 1 with SPIFI.
These lines
trace the physical conditions of the gas associated with regions of active
star formation and can be used to probe the hardness and strength of the
ambient far-UV radiation fields.
Results
SPIFI had first light on the James Clark Maxwell
Telescope (JCMT) on Mauna Kea in April 1999.
(see Figures 2 and
3).
There were
15 pixels installed in the array, of which 13 were working. The
resolving power employed corresponded to a velocity
resolution of about 70 km/s
Since this was the first run, the SPIFI team was rather conservative and
focused on the brighter and easier to calibrate CO (7-6) line.
The SPIFI system sensitivity was quite good. No evidence was found for
excess noise at the telescope and the sensitivity was equivalent to a
double side-band receiver temperature of 100 K.
A second test run is scheduled for the JCMT from September 14 to 27,
1999. The final pixels are installed in the array, so
it is expected that the full 5 by 5 array will be operational.
The reimaging lens system has also been improved
to increase the sensitivity per pixel.
Pictures
For more information
See the group's website at
http://astrosun.tn.cornell.edu/research/projects/spifi.html
SPIFI is based at Cornell University. For more information, conatct
Gordon Stacey, stacey@astrosun.tn.cornell.edu .
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agreement, grant number NSF OPP 89-20223.
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Last modified Thursday, 28-Oct-1999 09:31:30 CDT
http://astro.uchicago.edu/cara/research/submm/spifi.html