UKIRT to offer Michelle in Semester 01B
Tom Kerr and Andy Adamson
Joint Astronomy Centre, Hilo, Hawaii
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observing modes at the UKIRT for Semester 01B. Although some examples
for sensitivity are given below, please refer to the observation
planning applet for more detailed information on sensitivity
and observing modes.
Spectroscopy
Grating specifications
Michelle contains five gratings offering a wide selection of resolutions
and wavelengths. Any grating can be selected in a few seconds so
observers are not limited to one or two gratings per run. Each can
be used with different slits, 1, 2, 3, 4, 8 and 16-pixels (0".18,
0".36 and 0.”54 etc.) wide, all
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of which are approximately 91 arcseconds long. Table 1 summarizes
the available gratings.
Sensitivity
For broad band spectroscopy (R=200) of an extended continuum source
using the 2-pixel (0".36) slit, the nominal 1 sigma 1 minute
sensitivity is 34-mJy/arcsec2 and for a point source is 19-mJy in
the centre of the N band. For R=3000 spectroscopy of an extended
source, the 1 sigma 1 minute sensitivity is 120-mJy/arcsec2, again
in the centre of the N band. The 1 sigma 1 minute sensitivity for
echelle spectroscopy of a spatially and spectrally unresolved line
source at 10.5 microns, R=20000 and using a 0".36 arcsec slit
is 2.6x10-18 W/m-2. Overheads for chopping and nodding have not
been included in the above estimates which remain provisional
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Subject to upcoming acceptance tests, UKIRT will be offering Michelle
for PATT observing in a service and shared-risks mode in Semester
01B. Michelle is an infrared imager/spectrometer which uses a SBRC
Si:As 320x240-pixel array and operates between 8 and 25 microns.
Michelle offers many observing modes, including:
· Imaging (67.2 x 50.4 arcsec field of view at 0.21 arcsecs
per pixel)
· Imaging polarimetry
· Spectroscopy (R=200 to 30000, a ~91 arcsec long slit,
0.38 arcsec per pixel)
· Spectropolarimetry
ATC
Michelle webpages but what follows is a brief description of
the expected performance and availability of
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