Herschel Space Telescope uncovers the sources of the Cosmic Infrared Background

Dec 16, 2009
Herschel-PACS images of the ‘GOODS-N’ field in the constellation of Ursa Major at far-infrared wavelengths of 100 and 160m. Galaxies at high redshift (i.e. larger cosmological distance) or with colder dust are displayed in red, while nearby galaxies appear in blue. Image: ESA

(PhysOrg.com) -- Using first observations with the PACS Instrument on board ESA’s Herschel Space Telescope, scientists from the Max Planck Institute for Extraterrestrial Physics and other institutions have for the first time resolved more than half of this radiation into its constituting sources. Observations with Herschel open the road towards understanding the properties of these galaxies, and trace the dusty side of galaxy evolution.

In the mid 1990’s, scientists analyzing data from NASA’s COBE spacecraft discovered faint in the far-infrared part of the electromagnetic spectrum that reaches earth with the same intensity from all directions in space. Immediately, they suspected it to be the aggregate emission of many distant galaxies in the , releasing the same amount of energy in the far-infrared as reaches us in visible light from similarly distant galaxies. Whereas visible light tells us about the stars in galaxies, the far-infrared is emitted by cold dust that is hiding the newly formed stars.

Identifying these surprisingly numerous dusty galaxies has proven difficult, though. Space telescopes are needed to detect far-infrared emission, because it is absorbed by the Earth’s atmosphere. Previous infrared space telescopes have detected far-infrared light from only the brightest of the galaxies forming this cosmic background. To glean any information about the fainter objects, astronomers had to rely on indirect evidence based on shorter radiation.

ESA’s Herschel , launched in May 2009, is the largest ever built with a mirror diameter of 3.5m. Its PACS instrument is designed to take high-resolution images of the sky at far-infrared wavelengths of 70 to 160m, exactly where most of the cosmic infrared background emission is received. "After the check-out of our instrument, we were yearning to obtain the first deep far-infrared observations of the sky," says Albrecht Poglitsch, principal investigator of PACS.

For a total of 30 hours in October, PACS has observed a small patch of sky in the constellation of Ursa Major, about a quarter of the size of the full moon. "Already in these first observations, we have resolved about 60% of the cosmic infrared background from this region of sky into individual well-detected sources," says Dieter Lutz from the consortium of scientists from five European institutes that have obtained the data. "And this is just the beginning. Yet more sensitive observations will follow soon, and we will be able to understand in detail the epoch of activity and the properties of the galaxies that produce the cosmic infrared background, now that we have pinned them down."

Explore further: Can astronomy explain the biblical Star of Bethlehem?

add to favorites email to friend print save as pdf

Related Stories

Herschel spacecraft assembly complete

Apr 23, 2008

The mirror of the Herschel telescope has now been assembled with the payload and service module, completing the spacecraft structure - an important milestone in the days following through to launch.

Herschel first images promise bright future

Jul 10, 2009

Herschel has carried out the first test observations with all its instruments, with spectacular results. Galaxies, star-forming regions and dying stars comprised the telescope's first targets. The instruments ...

'Big baby' galaxy found in newborn Universe

Sep 28, 2005

The NASA/ESA Hubble Space Telescope and NASA’s Spitzer Space Telescope have teamed up to 'weigh' the stars in distant galaxies. One of these galaxies is not only one of the most distant ever seen, but it appears to be unusually ...

Cool spacedust survey goes into orbit

Feb 01, 2008

University of Nottingham astronomers will be studying icy cosmic dust millions of light years away — using the biggest space telescope ever built.

Herschel Opens Its Infrared Eyes

Jun 29, 2009

(PhysOrg.com) -- The Herschel Space Observatory has snapped its first picture since blasting into space on May 14, 2009. The mission, led by the European Space Agency with important participation from NASA, ...

Recommended for you

Can astronomy explain the biblical Star of Bethlehem?

Dec 24, 2014

Bright stars top Christmas trees in Christian homes around much of the world. The faithful sing about the Star of Wonder that guided the wise men to a manger in the little town of Bethlehem, where Jesus was ...

Hubbles spies the beautiful galaxy IC 335

Dec 24, 2014

This new NASA/ESA Hubble Space Telescope image shows the galaxy IC 335 in front of a backdrop of distant galaxies. IC 335 is part of a galaxy group containing three other galaxies, and located in the Fornax ...

Image: Multicoloured view of supernova remnant

Dec 22, 2014

Most celestial events unfold over thousands of years or more, making it impossible to follow their evolution on human timescales. Supernovas are notable exceptions, the powerful stellar explosions that make ...

Ultra-luminous X-ray sources in starburst galaxies

Dec 22, 2014

Ultra-luminous X-ray sources (ULXs) are point sources in the sky that are so bright in X-rays that each emits more radiation than a million suns emit at all wavelengths. ULXs are rare. Most galaxies (including ...

When a bright light fades

Dec 22, 2014

Astronomer Charles Telesco is primarily interested in the creation of planets and stars. So, when the University of Florida's giant telescope was pointed at a star undergoing a magnificent and explosive death, ...

User comments : 4

Adjust slider to filter visible comments by rank

Display comments: newest first

yyz
not rated yet Dec 16, 2009
It would be nice if some distances or identifications were given to some of these point sources.
RayCherry
not rated yet Dec 17, 2009
OK... it seems (to me) that popular (layman's) science literature and recent science has once again developed some rather large gaps.

I have been under the misguided impression that the CMB was the remnents or echoes of the big bang itself. Was that not the theory based on the premise that the radiation originates from every direction we can observe from Earth? I remember scientists claimed in was responsible for, (or at least similar to), the static received on radios and TVs when they are not tuned to a station.

The same idea was given in literature and documentaries, but I will have to check which.

Now, however, the CMB is being attributed to an 'infinite' number of ancient/distant galatic sources?

Wow. 8-/

"Stars" really "are but pinholes in the curtain of night" ???
yyz
5 / 5 (3) Dec 17, 2009
RayCherry,

The PR and article should have stated that this was a detection of point sources that contribute to the cosmic infrared background (CIB) as opposed to the separate cosmic microwave background (CMB). COBE and WMAP made observations of both the CMB and the CIB, but of course, the CMB observations got most of the headlines. See Wikipedia for a good summary of the CIB: http://en.wikiped...ckground . Your confusion is understandable.
RayCherry
not rated yet Dec 18, 2009
yyz: Thank you.

Wish more people took the time to explain things so well, and in such a civilised manner.

May I take this opportunity to wish you a Merry, and Happy, Christmas ... and I look forward to your contributions in the new year.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.