(Press-News.org) Astronomers using the NASA/ESA Hubble Space Telescope have solved the 40-year-old mystery of the origin of the Magellanic Stream, a long ribbon of gas stretching nearly halfway around the Milky Way. New Hubble observations reveal that most of this stream was stripped from the Small Magellanic Cloud some two billion years ago, with a smaller portion originating more recently from its larger neighbour.
The Magellanic Clouds, two dwarf galaxies orbiting our galaxy, are at the head of a huge gaseous filament known as the Magellanic Stream. Since the Stream's discovery in the early 1970s, astronomers have wondered whether this gas comes from one or both of the satellite galaxies. Now, new Hubble observations show that most of the gas was stripped from the Small Magellanic Cloud about two billion years ago -- but surprisingly, a second region of the stream was formed more recently from the Large Magellanic Cloud.
A team of astronomers determined the source of the gas filament by using Hubble's Cosmic Origins Spectrograph (COS), along with observations from ESO's Very Large Telescope, to measure the abundances [1] of heavy elements, such as oxygen and sulphur, at six locations along the Magellanic Stream. COS detected these elements from the way they absorb the ultraviolet light released by faraway quasars as it passes through the foreground Stream. Quasars are the brilliant cores of active galaxies.
The team found low abundances of oxygen and sulphur along most of the stream, matching the levels in the Small Magellanic Cloud about two billion years ago, when the gaseous ribbon was thought to have been formed.
In a surprising twist, the team discovered a much higher level of sulphur in a region closer to the Magellanic Clouds. "We're finding a consistent amount of heavy elements in the stream until we get very close to the Magellanic Clouds, and then the heavy element levels go up," says Andrew Fox, a staff member supported by ESA at the Space Telescope Science Institute, USA, and lead author of one of two new papers reporting these results. "This inner region is very similar in composition to the Large Magellanic Cloud, suggesting it was ripped out of that galaxy more recently."
This discovery was unexpected; computer models of the Stream predicted that the gas came entirely out of the Small Magellanic Cloud, which has a weaker gravitational pull than its more massive cousin.
"As Earth's atmosphere absorbs ultraviolet light, it's hard to measure the amounts of these elements accurately, as you need to look in the ultraviolet part of the spectrum to see them," says Philipp Richter of the University of Potsdam, Germany, and lead author on the second of the two papers. "So you have to go to space. Only Hubble is capable of taking measurements like these."
All of the Milky Way's nearby satellite galaxies have lost most of their gas content -- except the Magellanic Clouds. As they are more massive than these other satellites they can cling on to this gas, using it to form new stars. However, these Clouds are approaching the Milky Way and its halo of hot gas. As they drift closer to us, the pressure of this hot halo pushes their gas out into space. This process, together with the gravitational tug-of-war between the two Magellanic Clouds, is thought to have formed the Magellanic Stream [2].
"Exploring the origin of such a large stream of gas so close to the Milky Way is important," adds Fox. "We now know which of our famous neighbours, the Magellanic Clouds, created this gas ribbon, which may eventually fall onto our own galaxy and spark new star formation. It's an important step forward in figuring out how galaxies obtain gas and form new stars."
INFORMATION:
Notes
[1] The "abundance" of an element is a measure of how common it is in its environment relative to other elements.
[2] The Magellanic Clouds can be used as a good testing ground for theories on how galaxies strip gas from one another and form new stars. This process seems episodic rather than smooth, without a continuous, slow stream of gas being stripped away from a small galaxy by a larger one. As both of the Magellanic Clouds are approaching our own galaxy, the Milky Way, they can be used to explore the dynamics of this process.
Notes for editors
The Hubble Space Telescope is a project of international cooperation between ESA and NASA.
These results are presented in a set of two papers, both published in the 1 August issue of The Astrophysical Journal.
The first of these papers is entitled "The COS/UVES absorption survey of the Magellanic Stream: I. One-tenth solar abundances along the body of the stream".
The international team of astronomers in this study consists of A. J. Fox (STScI, USA; ESA), P. Richter (University of Potsdam; Leibniz Institute for Astrophysics, Potsdam, Germany), B. P. Wakker (University of Wisconsin- Madison, USA), N. Lehner (University of Notre Dame, USA), J. C. Howk (University of Notre Dame, USA), N. B. Bekhti (University of Bonn, Germany),
J. Bland-Hawthorn (University of Sydney, Australia), S. Lucas (University College London, UK).
The second of these papers is entitled "The COS/UVES absorption survey of the Magellanic Stream: II. Evidence for a complex enrichment history of the stream from the Fairall 9 sightline".
The international team of astronomers in this study consists of P. Richter (University of Potsdam; Leibniz Institute for Astrophysics, Potsdam, Germany), A. J. Fox (STScI, USA; ESA), B. P. Wakker (University of Wisconsin-Madison, USA), N. Lehner (University of Notre Dame, USA), J. C. Howk (University of Notre Dame, USA), J. Bland-Hawthorn (University of Sydney, Australia), N. B. Bekhti (University of Bonn, Germany), C. Fechner (University of Potsdam, Germany).
More information
Image credit: David L. Nidever, et al., NRAO/AUI/NSF and Mellinger, LAB Survey, Parkes Observatory, Westerbork Observatory, and Arecibo Observatory.
Links
Images of Hubble - http://www.spacetelescope.org/images/archive/category/spacecraft/
Research Paper I - http://www.spacetelescope.org/static/archives/releases/science_papers/heic1314a.pdf
Research Paper II - http://www.spacetelescope.org/static/archives/releases/science_papers/heic1314b.pdf
Contacts
Philipp Richter
University of Potsdam
Postdam, Germany
Tel: +49-331-977-1841
Email: prichter@astro.physik.uni-potsdam.de
Andrew Fox
Space Telescope Science Institute & ESA
Baltimore, USA
Tel: +1-410-338-5083
Email: afox@stsci.edu
Nicky Guttridge
Hubble/ESA
Garching bei München, Germany
Tel: +49-89-3200-6855
Email: nguttrid@partner.eso.org
Hubble finds source of Magellanic Stream
Astronomers explore origin of gas ribbon wrapped around our galaxy
2013-08-08
ELSE PRESS RELEASES FROM THIS DATE:
Study shows elementary and middle schools can get students moving, not just thinking
2013-08-08
BLOOMINGTON, Ind. -- Despite widespread cuts to physical education classes and recess, an Indiana University study has shown that schools can play an important role in helping their students live healthier lives. Schools that implemented coordinated school health programs saw increases in students' physical activity.
"With support from teachers, administrators and parents, our schools can become healthier places," said Mindy Hightower King, evaluation manager at the Indiana Institute on Disability and Community at IU Bloomington. "Despite budget cuts and increasing emphasis ...
Increase in woodpecker populations linked to feasting on emerald ash borer
2013-08-08
MORGANTOWN, W.Va., August 8, 2013 – The scourge of forests, the emerald ash borer, or EAB, is usually described with words like "destructive" and "pest." A recent study based on data collected by citizen scientists suggests that one more adjective might apply, at least from a bird's perspective: "delicious."
In a study published this week in the journal Biological Invasions, U.S. Forest Service entomologist Andrew Liebhold and Cornell University scientist Walter Koenig and others document how an EAB invasion fueled a population boom for four species of birds in the Detroit ...
Capturing live tumor cells in the blood
2013-08-08
WASHINGTON D.C., August 8, 2013 -- Tumor cells circulating within a patient's bloodstream can carry cancer from a primary tumor site to distant sites of the body, spreading the disease.
Now a team of researchers in China has developed a new microfluidic chip that can quickly and efficiently segregate and capture live circulating tumor cells (CTCs) from a patient's blood, with potential applications for cancer screenings and treatment assessments. The researchers describe their technique in the journal Biomicrofluidics, which is produced by AIP Publishing.
Many currently ...
Immigration bill offers big economic boost but no major health benefits
2013-08-08
WASHINGTON—A landmark immigration bill passed by the Senate would create new pathways to citizenship and provide a much-needed boost to the U.S. economy but would do little to ease immigration-related disparities in health care, according to a new report.
"The Senate bill represents the most significant bipartisan effort to reform immigration in many years," says Leighton Ku, PhD, MPH, the author of the new report and the director of the Center for Health Policy Research at the George Washington University School of Public Health and Health Services (SPHHS). "It would ...
Ozone hole might slightly warm planet
2013-08-08
WASHINGTON, DC—A lot of people mix up the ozone hole and global warming, believing the hole is a major cause of the world's increasing average temperature. Scientists, on the other hand, have long attributed a small cooling effect to the ozone shortage in the hole.
Now a new computer-modeling study suggests that the ozone hole might actually have a slight warming influence, but because of its effect on winds, not temperatures. The new research suggests that shifting wind patterns caused by the ozone hole push clouds farther toward the South Pole, reducing the amount of ...
Study suggests way to fight therapy resistant leukemia by blocking DNA repair
2013-08-08
CINCINNATI – New research posted online by the Nature journal Leukemia suggests blocking part of a DNA repair complex that helps some types of leukemia resist treatment can increase the effectiveness of chemotherapy and enhance survival.
Scientists from Cincinnati Children's Hospital Medical Center report that their experimental combination treatment strategy – using a small molecular inhibitor along with chemotherapy – was particularly effective at stopping a stubborn leukemia called T-cell acute lymphoblastic leukemia, or T-ALL. The study involved laboratory cell lines ...
UNC-Malawi cancer pathology laboratory is a model for Sub-Saharan Africa
2013-08-08
Since 2011, the University of North Carolina has partnered with the government of Malawi to establish a pathology laboratory in the nation's capital, building on an existing decades-long collaboration. The laboratory has provided an invaluable service to patients and has also built capacity at a national teaching hospital, according to an analysis of the first 20 months of operation published (date) online by PLOS ONE.
"A robust platform for cancer care and research now exists in a setting where it did not previously, and can serve as a model for similar interventions ...
Use digital signal processing engineering to prevent a flash crash, says NJIT prof
2013-08-08
NJIT Associate Professor Ali Akansu, PhD, wants to prevent another flash crash on Wall Street. An electrical and computing engineer who is an expert in the relatively new field of adapting signal processing to strengthen the security of finance markets, he fights to be heard. Among his weapons are frequent talks to colleagues at IEEE events. He believes that by using new technology—like digital signal processing (DSP) engineering--another flash crash, like the one in 2010 that almost destroyed world-wide financial markets, need never happen again.
"There are DSP engineering ...
Nutritional values established in 3 new, high-energy protein ingredients fed to weanling pigs
2013-08-08
URBANA, Ill. – The use of soybean meal in diets fed to weanling pigs is limited due to the presence of anti-nutritional factors that young pigs can't tolerate. Therefore, other sources of protein, such as fish meal and plasma, are used in nursery pig diets. But there are other ingredients available to producers as well. Researchers at the University of Illinois have determined the nutritional value of three new protein products that have recently become available as feed ingredients for pigs.
Hans H. Stein, a U of I professor of animal sciences, and his team measured ...
Robot treats brain clots with steerable needles
2013-08-08
Surgery to relieve the damaging pressure caused by hemorrhaging in the brain is a perfect job for a robot.
That is the basic premise of a new image-guided surgical system under development at Vanderbilt University. It employs steerable needles about the size of those used for biopsies to penetrate the brain with minimal damage and suction away the blood clot that has formed.
The system is described in an article accepted for publication in the journal IEEE Transactions on Biomedical Engineering. It is the product of an ongoing collaboration between a team of engineers ...
LAST 30 PRESS RELEASES:
Insulin resistance is linked to over 30 diseases – and to early death in women, study of people in the UK finds
Innovative semaglutide hydrogel could reduce diabetes shots to once a month
Weight loss could reduce the risk of severe infections in people with diabetes, UK research suggests
Long-term exposure to air pollution and a lack of green space increases the risk of hospitalization for respiratory conditions
Better cardiovascular health in early pregnancy may offset high genetic risk
Artificial intelligence method transforms gene mutation prediction in lung cancer: DeepGEM data releases at IASLC 2024 World Conference on Lung Cancer
Antibody–drug conjugate I-DXd shows clinically meaningful response in patients with extensive-stage small cell lung cancer
IASLC Global Survey on biomarker testing reveals progress and persistent barriers in lung cancer biomarker testing
Research shows pathway to developing predictive biomarkers for immune checkpoint inhibitors
Just how dangerous is Great Salt Lake dust? New research looks for clues
Maroulas appointed Associate Vice Chancellor, Director of AI Tennessee
New chickadee research finds cognitive skills impact lifespan
Cognitive behavioral therapy enhances brain circuits to relieve depression
Terasaki Institute awarded $2.3 Million grant from NIH for organ transplantation research using organs-on-a-chip technology
Atoms on the edge
Postdoc takes multipronged approach to muon detection
Mathematical proof: Five satellites needed for precise navigation
Scalable, multi-functional device lays groundwork for advanced quantum applications
Falling for financial scams? It may signal early Alzheimer’s disease
Integrating MRI and OCT for new insights into brain microstructure
Designing a normative neuroimaging library to support diagnosis of traumatic brain injury
Department of Energy announces $68 million in funding for artificial intelligence for scientific research
DOE, ORNL announce opportunity to define future of high-performance computing
Molecular simulations, supercomputing lead to energy-saving biomaterials breakthrough
Low-impact yoga and exercise found to help older women manage urinary incontinence
Genetic studies reveal new insights into cognitive impairment in schizophrenia
Researcher develops technology to provide cleaner energy and cleaner water
Expect the unexpected: nanoscale silver unveils intrinsic self-healing abilities
nTIDE September 2024 Jobs Report: Gains in employment for people with disabilities appear to level off after reducing gaps with non-disabled workers
Wiley enhances NMR Spectral Library Collection with extensive new databases
[Press-News.org] Hubble finds source of Magellanic StreamAstronomers explore origin of gas ribbon wrapped around our galaxy