Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Distant inferno: Cornell astronomer finds galaxies that contain massive young stars in compact, cosmic globs

17.02.2006


The discovery makes the fiery environment within a typical spiral or starburst galaxy look almost pastoral. Cornell researchers using the Spitzer Space Telescope say distant galaxies contain an inferno of very young, massive and violently evolving stars, packed together in tiny but extremely powerful cosmic globs.


Provided
Spectral lines from distant ultra-luminous infrared galaxies, as recorded by the Spitzer Space Telescope’s infrared spectrograph, show the telltale bumps (in green) indicating the presence of crystalline silicates.


Provided
This image illustrates how two galaxies could be torn apart by their mutual attraction, causing whole strains of stars to be catapulted out to form something like antennae. The galaxies’ nuclei would dance around each other and eventually merge to form a single nucleus.



The key to the discovery, paradoxically, is in the presence of delicate, glittery crystalline silicates called Forsterite. These are glassy particles that exist in the debris disks of young stars and in the stellar wind of very old stars, but which have never before been observed in the mass of gas and dust known as the interstellar medium, or ISM, in the Milky Way or in any other galaxy.

The research, led by Cornell astronomer and Spitzer Fellow Henrik Spoon, will appear in the Feb. 20 issue of the Astrophysical Journal.


Using Spitzer’s infrared spectrograph (IRS), an instrument developed by a team led by Cornell professor of astronomy James Houck and built at Cornell, Spoon and colleagues observed dozens of distant galaxies known as ultra-luminous infrared galaxies (ULIRGs). First discovered in large numbers in 1982, most ULIRGs are thought to form as two or more spiral galaxies collide (as our galaxy will, in a few billion years, with the nearby Andromeda galaxy), and their leftover hydrogen gas fuels the fierce, rapid formation of massive stars.

ULIRGs are relative runts in galactic terms (though some have sweeping tidal tails), with the source of their luminosity coming from an area as small as one-hundredth that of typical galaxies. Seen with an optical telescope, they look dusty, chaotic and unspectacular. But in the mid-infrared spectrum, said Spoon, "they are booming," appearing up to 100 times more luminous than a spiral or starburst galaxy.

Silicates are the most common types of minerals in the Milky Way, so their presence in ULIRGs is not surprising. But among the silicates, most (95 percent in the immediate vicinity of rapidly evolving stars and at least 99 percent in the general ISM) are amorphous in structure.

Spoon and his team saw the expected broad absorption features of amorphous silicates in the infrared spectra of the ULIRGs they observed. But they also saw signature narrow dips within the broad bumps indicating the presence of silicates in crystalline form in the general ISM. The concentration of crystalline silicates in at least 21 ULIRGs, Spoon found, is seven to 15 times greater than in any other known environment.

In our galaxy, crystalline silicates have only been observed close to active new stars, which inject them into their immediate environment as they evolve, and in the exhaled winds of dying stars. Subject to heavy pummeling by destructive cosmic and shock-accelerated ions, the silicates quickly lose their ordered, crystalline structure and take an amorphous shape.

"We were surprised to find such delicate little crystals in the centers of some of the most violent places in the universe," said Spoon. "Given the rapid transformation of crystalline silicates to an amorphous state, the injection rate of freshly produced crystalline silicates must be far higher than in our galaxy. We’re probing exotic circumstances."

Spitzer’s IRS, which can record infrared spectra from objects fainter and farther away than ever before, has allowed astronomers to study ULIRGs and other stellar nurseries in new detail.

"Now we can take a good look at what these characteristics are," said Spoon. "It’s like, for the first time, you put on a pair of glasses, and -- wow."

The Spitzer Space Telescope is the last of NASA’s Great Observatories. The Jet Propulsion Laboratory, a division of the California Institute of Technology, manages the Spitzer mission for NASA’s Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at Caltech.

Press Relations Office | EurekAlert!
Further information:
http://www.cornell.edu

More articles from Physics and Astronomy:

nachricht Climate cycles may explain how running water carved Mars' surface features
02.12.2016 | Penn State

nachricht What do Netflix, Google and planetary systems have in common?
02.12.2016 | University of Toronto

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: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>