Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Hubble Resolves Puzzle about Loner Starburst Galaxy

21.11.2008
Astronomers have long puzzled over why a small, nearby, isolated galaxy is pumping out new stars faster than any galaxy in our local neighborhood.

Now NASA's Hubble Space Telescope has helped astronomers solve the mystery of the loner starburst galaxy, called NGC 1569, by showing that it is one and a half times farther away than astronomers thought.

The extra distance places the galaxy in the middle of a group of about 10 galaxies centered on the spiral galaxy IC 342. Gravitational interactions among the group's galaxies may be compressing gas in NGC 1569 and igniting the star-birthing frenzy.

"Now the starburst activity seen in NGC 1569 makes sense, because the galaxy is probably interacting with other galaxies in the group," said the study's leader, Alessandra Aloisi of the Space Telescope Science Institute in Baltimore, Md., and the European Space Agency. "Those interactions are probably fueling the star birth."

The farther distance not only means that the galaxy is intrinsically brighter, but also that it is producing stars two times faster than first thought. The galaxy is forming stars at a rate more than 100 times higher than in the Milky Way. This high star-formation rate has been almost continuous for the past 100 million years.

Discovered by William Herschel in 1788, NGC 1569 is home to three of the most massive star clusters ever discovered in the local universe. Each cluster contains more than a million stars.

"This is a prime example of the type of massive starbursts that drive the evolution of galaxies in the distant and young universe," said team member Roeland van der Marel of the Space Telescope Science Institute. "Starburst galaxies can only be studied in detail in the nearby universe, where they are much rarer. Hubble observations of our galactic neighborhood, including this study, are helping astronomers put together a complete picture of the galaxies in our local universe. Put the puzzle pieces in the right place, as for NGC 1569, and the picture makes much more sense."

Aloisi and her team actually discovered the new distance by accident. They were using Hubble's Advanced Camera for Surveys to hunt in NGC 1569 for the kind of red giant stars (stars near the ends of their lives) that shine because of fusion of helium nuclei in their cores. These stars are dimmer than bright red giants without helium burning, but when detected, they can be used to estimate the galaxy's age.

"When we found no obvious trace of them, we suspected that the galaxy was farther away than originally believed," said Aaron Grocholski of the Space Telescope Science Institute and the lead author on a paper describing the results. "We could only see the brightest red giant stars, but we were able to use these stars to recalibrate the galaxy's distance." Bright red giants are reliable "standard candles" for measuring distance because they all shine at the same brightness. Once astronomers know a star's true brightness, they can calculate its distance from earth.

Previous estimates of the galaxy's distance made with ground-based telescopes were unreliable because they looked at the galaxy's crowded core and were unable to resolve individual red giant stars.

The Hubble study observed both the galaxy's cluttered core and its sparsely populated outer fringes. The sharpness of Hubble's Advanced Camera pinpointed individual red giants, which led to a precise distance to the galaxy. Astronomers measured the galaxy's distance at nearly 11 million light-years away, about 4 million light-years farther than the old distance.

"This was a serendipitous discovery," Aloisi said. "Hubble didn't go deep enough to see the faintest red giant stars we were hunting for because the galaxy is farther away than we thought. However, by capturing the entire population of the brightest red giant stars, we were able to calculate a precise distance to NGC 1569 and resolve the puzzle about the galaxy's extreme starburst activity."

The results were published in the Oct. 20 issue of the Astrophysical Journal Letters.

The science team for the NGC 1569 observations consists of Alessandra Aloisi and Marco Sirianni (STScI/ESA), Aaron Grocholski, Jennifer Mack, and Roeland van der Marel (STScI), Luca Angeretti, Donatella Romano, and Monica Tosi (INAF-OAB), and Francesca Annibali, Laura Greggio, and Enrico Held (INAF-OAP).

For images and more information about NGC 1569, visit:

http://hubblesite.org/news/2008/38
http://heritage.stsci.edu/2008/38
The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency (ESA) and is managed by NASA's Goddard Space Flight Center (GSFC) in Greenbelt, Md. The Space Telescope Science Institute (STScI) conducts Hubble science operations. The institute is operated for NASA by the Association of Universities for Research in Astronomy, Inc., Washington, D.C.

STScI is an International Year of Astronomy 2009 (IYA 2009) program partner.

Donna Weaver | Newswise Science News
Further information:
http://hubblesite.org/news/2008/38
http://heritage.stsci.edu/2008/38
http://www.stsci.edu

More articles from Physics and Astronomy:

nachricht DGIST develops 20 times faster biosensor
24.04.2017 | DGIST (Daegu Gyeongbuk Institute of Science and Technology)

nachricht New quantum liquid crystals may play role in future of computers
21.04.2017 | California Institute 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: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

DGIST develops 20 times faster biosensor

24.04.2017 | Physics and Astronomy

Nanoimprinted hyperlens array: Paving the way for practical super-resolution imaging

24.04.2017 | Materials Sciences

Atomic-level motion may drive bacteria's ability to evade immune system defenses

24.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>