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Fig. 1:
Planck image of the sky in microwaves. The dust emission of
the Milky Way is visible as broad, horizontal band. Near the galactic
north and south pole, at the top and bottom of this sky projection,
the temperature variations of the cosmic background radiation are
visible. With a detailed measurement and characterization of the
galactic foreground emission, this signal can be subtracted from the
map to reveal light from the early universe.
Image: ESA / Planck Collaboration
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Fig. 2:
The 15 000 objects in the ”Early Release Compact
Source Catalogue“, where galactic objects — mainly compact
dust clouds — are shown in green, and extragalactic objects
— mainly radio galaxies and galaxies with a large thermal
emission from dust — are shown in yellow. The larger yellow blob
to the lower right is the Large Magellanic Cloud, a dwarf galaxy
orbiting the Milky Way.
Image: ESA / Planck Collaboration
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Fig. 3:
A galaxy super cluster discovered by Planck due to the
Sunyaev-Zeldovich effect (left) and its confirmation due to the X-ray
emission of the hot gas in the galaxy cluster with the XMM-Newton
X-ray telescope (right).
Image: ESA / Planck Collaboration
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Fig. 4:
In these regions, the cosmic far infrared background was
studied, as the galactic foreground emission there is pretty
weak. Each small image shows the grainy emission due to myriad
contributing galaxies. In part this emission is from epochs when the
universe was only 2 billion years old, its present age is about 14
billion years.
Image: ESA / Planck Collaboration
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Fig. 5:
These nine images show temperature maps of the whole sky as measured by
Planck through its nine frequency channels, after the signal due to the
Cosmic Microwave Background (CMB) has been removed. The dominant feature in
all maps is evidently the diffuse emission from the Milky Way, which differs
over the wide spectral range probed by Planck. In the case of the highest
frequencies probed by Planck, above 100 GHz, these are the first full-sky
high-resolution maps ever recorded.
Image: ESA / Planck Collaboration
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Already the start of the mission was very promising: Following 10
years of preparation, the Planck collaboration, which includes a team
at the Max Planck Institute for Astrophysics, observed a launch right
out of the textbook on 14th May 2009. As the satellite reached its
operating position some 1.5 million kilometres outside the
Earth’s atmosphere in summer 2009, right on schedule the
sensitive instruments had been cooled to their working temperature of
in some cases only 0.1 degrees above absolute zero. This means that
they are able not only to observe the 2.7 Kelvin emission of the very
early universe, right after the Big Bang, but also to produce precise
maps of its tiny temperature variations of just a few millionths of a
degree. These temperature variations are the first indicators of all
observable structure in the universe, stars, galaxies and galaxy
clusters. Even though Planck can only look back to a time about 380
000 years after the Big Bang, from its data the scientists glean
insights into the first few fractions of a second, when the cosmic
structures were seeded, some 14 billion years ago.
Planck’s primary aim is the measurement of these temperature
fluctuations with unprecedented accuracy. For this, Planck scans the
sky in nine frequencies, ranging from high-frequency radio waves at 30
gigahertz (GHz) to the far infrared with 857 GHz. The scientists need
this broad frequency range as Planck observes not only the primordial
emission but also noise from galaxies. This interfering signal,
however, has a different spectral distribution, which can be
identified, measured and subtracted due to the multi-frequency
measurements with Planck. And while this foreground signal is an
annoyance to cosmologists who want to look back to the cosmic nursery,
as by-product it provides valuable information to galaxy researchers.
The largest part of this foreground light comes from our own galaxy,
the Milky Way. As we are inside the galactic disk, we see the
interstellar medium all around us, either due to the thermal radiation
of dust clouds at high frequencies or due to the radio emission of
electrons moving nearly with the speed of light in the galactic
magnetic field.
So far, Planck has produced three complete scans of the whole sky,
thus fulfilling its primary objective. However, as it continues to
function perfectly, it will probably stay in operation until the start
of 2012 and continue to provide data. The results gained from the
first year of Planck data were first presented on 11th January 2011,
where many of these results are based on the ”Early Release
Compact Source Catalogue“ with some 15 000 compact sources. The
early release of this data enables scientists to arrange for detailed
follow-up observations with other telescopes such as the Herschel
space telescope with operates at similar wavelengths.
At the same time as the catalogue, 25 scientific papers are published
with topics covering many orders of magnitude and objects and ranging
from studies of individual objects in the catalogue and analyses of
galactic emission to the first cosmological results on galaxy clusters
and the light of early galaxies. Highlights of these papers include:
- confirmation of the galactic anomalous microwave radiation which is probably
due to the fast rotation of small, electrically charged dust particles;
- a map of a dark gaseous component in our galaxy, only visible in
microwaves;
- the precise measurement of 189 galaxy clusters and the discovery of
30 new galaxy clusters with the Suyaev-Zeldovich effect, arising
from the interaction of the cosmic background radiation with the hot
gas (up to 100 million degrees) in the atmosphere of galaxy
clusters;
- the first measurement of the theoretically predicted
Suyaev-Zeldovich effect also in smaller galaxy clusters, which now
makes possible a nearly complete inventory of the previously
invisible gas in the universe;
- a detailed measurement of the far infrared emission of all star
forming galaxies in the universe. The scientists can now observe the
history of galaxy formation, looking back to an epoch when the
universe was only 2 billion years old, just one sevenths of its
present age.
The results presented at this Planck conference mainly cover the
astrophysical by-products of the Planck mission. The data related to
Planck’s primary goal, the cosmic microwave background, the
resulting conclusions regarding the age, structure and composition of
the universe as well as insights into its origins will probably be
published in 2013. Until then, the noise signal from space but also
from the instruments has to be understood in more detail. The team at
the Max Planck Institute for Astrophysics will contribute to this
effort — their software for simulating and processing the data
will continue to be in daily use. At the same time, the institute, in
particular the Planck co-investigators Simon White and Rashid Sunyaev,
who predicted the Suyaev-Zeldovich effect in 1969, as well as Torsten
Enßlin, the head of the German contribution to Planck, and their
groups, will help to increase the scientific gain of the mission.
Contact:
Local contact:
Dr. Torsten Enßlin
Max Planck Institute for Astrophysics, Garching
Tel.: +49 89 30000-2243
email: tensslin mpa-garching.mpg.de
Dr. Hannelore Hämmerle
Press Officer
Max Planck Institute for Astrophysics, Garching
Tel. +49 89 30000-3980
E-mail: hhaemmerlempa-garching.mpg.de
For more detailed information on the Planck mission:
 ESA press release
http://www.esa.int/planck
For further information, please contact:
ESA Media Relations Office
Tel: +33 1 53 69 72 99
Fax: +33 1 53 69 76 90
Email: mediaesa.int
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