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
STScI is an International Year of Astronomy 2009 (IYA 2009) program partner.
Tracing aromatic molecules in the early universe
23.03.2017 | University of California - Riverside
New study maps space dust in 3-D
23.03.2017 | DOE/Lawrence Berkeley National Laboratory
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
23.03.2017 | Life Sciences
23.03.2017 | Power and Electrical Engineering
23.03.2017 | Earth Sciences