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 First Juno science results supported by University of Leicester's Jupiter 'forecast'
26.05.2017 | University of Leicester

nachricht Measured for the first time: Direction of light waves changed by quantum effect
24.05.2017 | Vienna University of 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: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

How herpesviruses win the footrace against the immune system

26.05.2017 | Life Sciences

Water forms 'spine of hydration' around DNA, group finds

26.05.2017 | Life Sciences

First Juno science results supported by University of Leicester's Jupiter 'forecast'

26.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>