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View Full Version : MOIRCS -- Subaru's new "infrared eye" now open (Forwarded)


Andrew Yee
March 2nd 06, 11:15 PM
Subaru Telescope
National Astronomical Observatory of Japan
Hilo, Hawaii

February 22, 2006

MOIRCS -- Subaru's new "infrared eye" now open

Subaru Telescope opened its doors to astronomers from all over the world
in December, 2000. In the five years since then, the telescope's
capabilities have been further advanced through ongoing development of new
observational instruments. Leading the charge, we now have MOIRCS, the
Multi-Object Infrared Camera and Spectrograph which became available for
general use in February, 2006.

The Widest Field of View for Infrared Imaging and Spectroscopy

Co-developed by Tohoku University and the National Astronomical
Observatory of Japan (NAOJ), MOIRCS has two giant four-million pixel
detectors. With a field of view of 4 arcmin x 7 arcmin (Note 1), MOIRCS
has the widest view of all the infrared instruments on the world's 8 to 10
meter caliber telescopes. This field of view is 8.6 times wider than that
of CISCO, our Cooled Infrared Spectrograph and Camera. In conjunction with
a large primary mirror, such as that of Subaru, a wide field of view is
key to the exploration of objects at the far reaches of the Universe.

MOIRCS' First Light Images

Figure 2 was taken in 2004, in conjunction with the first engineering test
of the instrument. The entire Orion Nebula (Messier 42) fit in just two
MOIRCS images. It would require as many as 17 shots to capture an image
like this with the narrow field of view of CISCO. Compare the image taken
with MOIRCS to a composite of 9 images taken with CISCO in the Image of
Orion Nebula (Subaru First Light Image: January, 1999). This really gives
you a feel for the size of the MOIRCS field of view.

Figure 3 is an image of the center of our Galaxy. The many stars in our
Galaxy and nearby dark clouds create a complex and memorable mix of light
and dark. Infrared light is able to penetrate dark clouds better than
optical light. MOIRCS is thus able to image stars right into the Galaxy's
center. If you compare an optical and infrared image of the Galactic
Center, you can see that many stars do not show up in the optical image.
(A comparison of optical and infrared images of the Galactic Center)

Powerful Infrared Multi-Object Spectrograph

Not only does MOIRCS have a wonderfully large field of view, it also has
the capability to obtain multiple spectra of astronomical objects at the
same time (Note 2). MOIRCS is the first instrument to provide this
capability in the infrared for an 8 to 10 meter class telescope. Earlier
infrared spectrographic instruments such as IRCS and OHS are only able to
analyze the light from one celestial object at a time. MOIRCS dramatically
increases observation efficiency with the ability to perform spectroscopy
with light coming from many objects at the same time.

Overcoming Design Challenges

Anything warm, including an observational instrument, emits light in the
infrared. To observe infrared light coming from celestial objects, the
interior of the instrument must be cooled to minus 150 degrees or below,
including the mask that selects light from objects of interest for any
specific observation. (Note 3) For MOIRCS to be successful, the design
team had to overcome several challenges, such as developing a drive
mechanism for the mask which could withstand cryogenic conditions.
Fortunately, the team was able to overcome all the design challenges and
MOIRCS's spectroscopy function worked flawlessly during its first
observational test in January, 2005. Since then performance testing is
ongoing and preparations for opening for general use in August, 2006 are
on track.

This multi object spectroscopy original data is from a single observation
with MOIRCS (H+K band). Each barcode-like strip of light in the left and
right side of this image is the spectrum of an individual object. This
image shows the spectra of 31 different objects, one of the largest
numbers of infrared spectra in a single observation. The barcode-like
pattern is actually the spectrum of Earths atmosphere. The spectrum of the
astronomical object is the faint line of light running horizontally
through the middle of the barcode pattern. The thick, bright, continuous
lines that run across either the left or right side of the image are from
holes in the mask for aligning the mask with the position of stars. (Click
here for a diagram of the Multi Object Spectrograph.)

Built by Graduate Students

Graduate students from Tohoku University were the main work force on the
MOICS development team. The students moved from Japan to Hawaii and worked
with Subaru Telescope staff for over five years. Ryuji Suzuki, the
graduate student who has been involved the longest, explains, "The
development of a large instrument like MOIRCS includes a great many
different tasks, so it was very important for each individual involved to
take full responsibility for performing their part of the work. "Dr.
Takashi Ichikawa, associate professor of Tohoku University who oversaw the
graduate students while directing the development reflects, "The fact that
they could go from having zero expertise to this great achievement has led
me to raise my expectations for the potential and capabilities of young
researchers."

A Handcrafted Instrument

Many astronomical instruments are special ordered from manufacturers.
MOIRCS, however, was built up part by part from individually procured high
performance parts, each carefully tested as the team built the instrument.
Koji Omata, MOIRCS project manager at Subaru Telescope, explains, "the
significance of MOIRCS's development is that we set a precedent for
instrument development at observatories -- our challenge was to carry out
the project "Quickly" (i.e. on a deadline), "Cheaply" (i.e. on a budget)
and "Well" (i.e. with high performance). I expect that much of the
difficulties we overcame and the experience we gained will prove highly
valuable to future instrument development."

A Dream Come True

As the universe expands, all the visible light emitted by the galaxy
shifts to the infrared region (red shift). Therefore, to study the current
frontier of the distant universe, large-scale telescopes have awaited the
development of multi-object infrared spectroscopic instruments. Tadayuki
Kodama, an associate professor at NAOJ and one of the first users of
MOIRCS, says, "with this revolutionary instrument, we are going to be able
to study the properties of stars in galaxies that existed when the
Universe was only one tenth of its current age. I'm really excited that we
can now study the formation and evolution of galaxies beginning at such
early times."

Since it saw First Light back in September year before last, MOIRCS has
had over a year of continued efficiency upgrades and improvements. What
view into the Universe will be unveiled with this new "infrared eye" that
so dramatically increases the capabilities of the Subaru telescope? Look
for more MOIRCS news to find out.

NOTES

Note 1: 1arcminute equals one sixtieth of one degree.

Note 2: Spectroscopy is the process of resolving light all wavelengths of
light coming from a celestial object and analyzing in detail the physical
properties of that object.

Note 3: Click here for more about the multi-object spectroscopic
observation of FOCAS, the Faint Object Camera And Spectrograph for visible
light observation, and the mask.

For further information on MOIRCS, please go to the Subaru Telescope
MOIRCS Page, or to the MOIRCS Group Page.

MOIRCS Group: Director: Takashi Ichikawa (Astronomical Institute, Tohoku
University); Previous Director: Testuo Nishimura (Subaru Telescope,
National Astronomical Observatory of Japan); Project Manager: Koji Omata
(Subaru Telescope, National Astronomical Observatory of Japan);
Development Members (in alphabetical order): Yuka Katsuno (Subaru
Telescope, National Astronomical Observatory of Japan); Masahiro Konishi
(Tohoku University); Ryuji Suzuki / Ichi Tanaka / Chihiro Tokoku (Subaru
Telescope, National Astronomical Observatory of Japan), Toru Yamada
(Mitaka Campus, National Astronomical Observatory of Japan),
TomohiroYoshikawa (Tohoku University).

Direct inquiries to: Takashi Ichikawa at <ichikawa at astr.tohoku.ac.jp>

[NOTE: Images and weblinks supporting this release are available at
http://subarutelescope.org/Topics/2006/0222/index.html ]