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Fig. 2:
High-spatial resolution images of the two components of the T Tau
system, from near- to mid-IR. The JHK and 3.42µm images have
been obtained with IRCAM3, while the frames from 4.7 µm to
20.6 µm were taken with MAX. The strong silicate features
in absorption in the IRC (T Tau S) are particularly evident.
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nents. As can
be seen in Fig. 3, the silicate feature is seen in emission in the
primary, while the secondary shows a deep, and broader, absorption
feature. These data allowed us to model the emission and therefore
to constrain the basic parameters of the system.
Solar System minor bodies
One of the faintest object observed with MAX is the asteroid 1997
CU26: Jewitt and Kalas (1998) used previously available photometry
and mid-IR data taken with MAX to determine the diameter and albedo
of this object. The 20 µm magnitude of 1997 CU26 turned out
to be [Q]=5.6, that is 60 mJy. The picture in Fig. 4 is the result
of coadding thousands of single frames to obtain a total integration
time of 5400 s.
The derived parameters show that this asteroid is extremely “dark”:
the albedo is only 0.045 ± 0.010. The effective diameter,
on the other hand, is 300 ± 30 km. This diameter
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Fig. 3:
Resolved spectrophotometry of the T Tau system
made 1997 CU26 the largest Centaurus object known to date.
Fig. 4:
MAX image of the Centaurus object 1997 CU26 in the Q filter. The
total exposure time was 5400 s
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Fig. 5:
the BN/KL region observed at 10 µm. Some of the previously
known sources are labelled.
The reduction of the Orion map data is still underway; the main
problem has been to overcome the effects of chopping and nodding
in fields characterized by strong extended emission. Since the reference
beam, which should see only an empty sky region, is actually pointing
at a region with strong emission, the subtraction of the reference
beam from the science frame shows a negative contribution in addition
to the positive image of the sources in the main beam.
A complex algorithm able to solve, at least partially, this problem
has been realized by a group of mathematicians which started a collaboration
with our team (Robberto et al. 2000). Since this is a common problem
in thermal IR observations, this algorithm represents a very important
tool for the users of 8 meter-class telescopes.
An example of the application of the algorithm is shown in Fig.
5. This 10 µm image of the BN/KL region (Robberto et al. 2001)
is characterized by an unprec-
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Embedded HII regions: BN/KL and W51
One of the major projects for MAX has been the mapping at 10 and
20 µm of the Trapezium region in Orion. The field of view
and pixel size of our camera allow one to obtain maps of extended
regions with a reasonable number of fields, while the good seeing
and the tip-tilt correction made it possible to reach the diffraction
limit. The pixel size is, in addition, optimized to correctly sample
the PSF in these conditions.
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