Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Spitzer Space Telescope finds bright infrared galaxies


Cornell University-led team operating the Infrared Spectrograph (IRS), the largest of the three main instruments on NASA’s Spitzer Space Telescope, has discovered a mysterious population of distant and enormously powerful galaxies radiating in the infrared spectrum with many hundreds of times more power than our Milky Way galaxy. Their distance from Earth is about 11 billion light years, or 80 percent of the way back to the Big Bang.

Virtually everything about this new class of objects is educated speculation, the researchers say, since the galaxies are invisible to ground-based optical telescopes with the deepest reach into the universe. "We think we have an idea of what they are, but we are not necessarily correct," says Cornell senior research associate in astronomy Dan Weedman.

Among the more probable ideas are that these mysterious bodies are ultraluminous infrared galaxies, powered either by an active galactic nuclei (AGN) or by a starburst, a massive burst of star formation. AGNs are powered by the in-fall of matter to a massive black hole, while massive starbursts often are triggered by the collision of two or more galaxies. What makes the objects studied by the Spitzer team stand out is that previously known AGNs are "not nearly as powerful, far away, or as dust-enshrouded" as these bodies are, says Weedman.

The Cornell Spitzer team’s discovery is published in the March 1 issue of the Astrophysical Journal Letters (ApJL), published by the American Astronomical Society. The Spitzer telescope, which went into an Earth-trailing orbit around the sun in August 2003, is the last of NASA’s Great Observatories, the Hubble being the first. Spectra spread light out into its basic parts, like a prism turning sunlight into a rainbow. They contain the signatures, or "fingerprints," of molecules that contribute to an object’s light. This galaxy’s spectrum reveals the fingerprint for silicate dust (large dip at right), a planetary building block like sand, only smaller. This particular fingerprint is important because it helped astronomers determine how far away the galaxy lies, or more specifically, how much the galaxy’s light had stretched, or "redshifted," during its journey to Spitzer’s eyes. This galaxy was found to have a redshift of 1.95, which means that its light took about 11 billion years to get here. The silicate fingerprint is also significant because it implies that galaxies were ripe for planetary formation 11 billion years ago Ð back to a time when the universe was 3 billion years old. The universe is currently believed to be 13.5 billion years old. This is the furthest back in time that silicate dust has been detected around a galaxy. These data were taken by Spitzer’s infrared spectrograph in July, 2004. NASA/JPL-Caltech/Cornell Click on the image for a high-resolution version (3000 x 2400 pixels, 1351K) The IRS team used data obtained by the National Science Foundation’s telescopes at Kitt Peak National Observatory, for the National Optical Astronomy Observatory (NOAO) Deep Wide-Field Survey. The team also used a catalog of infrared sources obtained in a survey in early 2004 by another of the Spitzer telescope’s instruments, the Multiband Imaging Photometer for Spitzer (MIPS). From the thousands of MIPS sources in a three-degree square patch of the sky -- about one-fourth the size of the bowl of the Big Dipper -- in the constellation Boötes the Herdsman, the IRS team selected and observed 31 that are quite bright in the infrared but invisible in the NOAO survey.

"The NOAO Deep Wide-Field Survey is the best available optical survey for comparing to our data," Weedman says. "It would have been much more difficult to make this discovery without such a wide area of comparison. These NOAO data allowed us to compare the sky at infrared and optical wavelengths and find things that had never been seen before."

The Boötes area was chosen by the NOAO team because of the absence of obscuring dust in our galaxy, presenting a clear view of the distant sky. The presence of these mysterious, infrared, bright, but optically invisible, objects was first hinted at in 1983 in a paper by James Houck, Cornell’s Kenneth A. Wallace Professor of Astronomy and principal investigator for the IRS. Houck was interpreting data from another space probe he was involved with, the Infrared Astronomical Satellite (IRAS), the first astronomy mission devoted to searching the heavens for infrared sources. More than a decade later these strange objects were again recorded by the European Space Agency’s Infrared Space Observatory. "Spitzer is more than 100 times more sensitive than IRAS for detecting objects at infrared wavelengths," says Houck. "These celestial bodies are so far from our Milky Way galaxy that we detect them as they were when the universe was just 20 percent of its current age," says Sarah Higdon, a research associate in Cornell’s Department of Astronomy, who led the group that developed the software package for analyzing Spitzer data.

In addition to their incredible distance, these objects also are enshrouded by a great deal of dust, which Cornell astronomy research associate Jim Higdon describes as being "the size of smoke particles made of silicates."

Other authors of the ApJL paper are: from Cornell, Terry Herter and Vassilis Charmandaris; from the Spitzer Space Science Center, L. Armus, H.I. Teplitz and B.T. Soifer; from NOAO, M.J.I Brown (now at Princeton University), A. Dey and B.T. Jannuzi; from Steward Observatory, University of Arizona, E. Le Floc’h and M. Rieke; and from Leiden Observatory, Holland, Bernhard Brandl.

The IRS, the most sensitive infrared spectrograph to be sent into space, is a collaborative venture between Cornell and Ball Aerospace and funded by NASA through the Jet Propulsion Laboratory (JPL) and Ames Research Center. JPL manages the Spitzer Space Telescope for NASA. NOAO is operated by the Association of Universities for Research in Astronomy Inc., under a cooperative agreement with the National Science Foundation.

Reported and written for Cornell News Office by freelancer Larry Klaes.

Related World Wide Web sites: The following sites provide additional information on this news release. Some might not be part of the Cornell University community, and Cornell has no control over their content or availability.

David Brand | EurekAlert!
Further information:

More articles from Physics and Astronomy:

nachricht Engineering team images tiny quasicrystals as they form
18.08.2017 | Cornell University

nachricht Astrophysicists explain the mysterious behavior of cosmic rays
18.08.2017 | Moscow Institute of Physics and Technology

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>



Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

Latest News

Nagoya physicists resolve long-standing mystery of structure-less transition

21.08.2017 | Materials Sciences

Chronic stress induces fatal organ dysfunctions via a new neural circuit

21.08.2017 | Health and Medicine

Scientists from the MSU studied new liquid-crystalline photochrom

21.08.2017 | Materials Sciences

More VideoLinks >>>