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Primeur weekly 2014-02-10

The Cloud

European Cloud Testing Environment to be offered free of charge during 2014 ...

IBM opens access to SaaS portfolio to help African Universities with next-generation IT skills ...

IBM and Actifio add powerful new data virtualization solutions to IBM Cloud portfolio ...

Numericable Group teams with IBM's SoftLayer to develop a unique High Performance Cloud offer in France ...

HP Autonomy extends market-leading eDiscovery platform to the Cloud ...

IBM's SoftLayer and DataHotel help Japanese companies expand globally ...

IBM fuels innovation and entrepreneurship in Africa ...

Oracle extends the power of modern HR in the Cloud with updates to Oracle HCM Cloud ...

Desktop Grids

New CONVECTOR project studies mechanical engineering problems ...

EuroFlash

MSc in High Performance Computing organized at Edinburgh Parallel Computing Centre ...

PRACE Preparatory Access passes 3-year cap in bloom ...

EPSRC calls for Quantum Technology Hubs to put UK in super position ...

2nd International Conference on Research Infrastructures to launch Call for Contributions ...

Netherlands joins international Elixir Consortium on biological data ...

USFlash

IBM Brings Watson to Africa ...

SGI and Cognilytics partner to bring advanced analytics to enterprise Big Data ...

Mellanox releases Ethernet Switch Application Programing Interface (API) to the community as part of the Open Ethernet initiative ...

Mellanox releases world's first 40 Gigabit Ethernet NIC based on Open Compute Project (OCP) designs ...

Mellanox announces launch of Mellanox Capital ...

Computer models help decode cells that sense light without seeing ...

Heavy metal in the early cosmos ...

Scientists use 'voting' and 'penalties' to overcome errors in quantum optimization ...

2013 International Science and Engineering Visualization Challenge winners announced ...

New IBM virtualization solution to speed Software Defined Networking deployments ...

NEC contributes Network Virtualization to OpenDaylight's Hydrogen release ...

Diamond defect boosts quantum technology ...

Oracle and Pluribus Networks collaborate on OpenStack plug-ins for Software Defined Networking products ...

Solving a 30-year-old problem in high mass star formation ...

IBM named an innovation leader in Big Data in Sub-Saharan Africa, notes Frost & Sullivan ...

Solving a 30-year-old problem in high mass star formation

5 Feb 2014 Atlanta - Some 30 years ago, astronomers found that regions of ionized gas around young high mass stars remain small - under a third of a light-year - for ten times longer than they should if they were to expand as expected in simple models. Recent supercomputer simulations predicted that these regions actually flicker in brightness over this period rather than grow continuously. Observations from a team of researchers using the Jansky Very Large Array (VLA) over a 23-year period have confirmed that such flickering actually occurs.

The lives of stars like the Sun are relatively easy to understand, because they are numerous, and live for billions of years. High mass stars, however, are rare and live for only a few million years. As a result, understanding their early evolution has been a challenge. Simple models would suggest that when high mass stars become hot enough to ionize the gas around them, heating it to thousands of degrees, the gas will quickly expand. However, as this happens, the massive stars continue to collect material via their gravitational attraction. As a result, the regions of ionized gas around a star may not simply grow, but instead interact with the infalling material, causing them to flicker in size and brightness during the main assembly phase of the massive stars.

The new observations confirming the occurrence of such flickering were published recently inThe Astrophysical Journal (Letters)by a collaboration of theorists and observers at Agnes Scott College, Universität Zürich, American Museum of Natural History, Harvard-Smithsonian Center for Astrophysics, National Radio Astronomy Observatory, European Southern Observatory, and Universität Heidelberg.

Since the VLA was dedicated in 1980, astronomers have observed a large number of regions of ionized hydrogen - so-called H II regions - around high-mass stars that were very small, so small they were termed ultracompact. These early observations conflicted with existing models, which predicted that only the very youngest regions should be so small, and hence, they should be rarely seen. Several models have been proposed to explain this discrepancy, but the recent numerical work made a testable prediction that differed from the other models. If the cause of the small size was the continued infall of material, these radio sources should flicker and the changes in brightness should be detectable over a 20-year period.

"In astronomy it is a rare occurrence to see sources vary on such short timescales", stated Thomas Peters from Universität Zürich, who led the numerical simulations. "But the regions we predicted to change are huge, almost a thousand times larger than the Solar System."

The researchers, led by Chris De Pree, professor of astronomy and director of the Bradley Observatory at Agnes Scott College, used VLA observations of the Sagittarius B2 region made in 1989 and again in 2012. This massive star forming region located near the Galactic centre contains many small regions of ionized gas around high mass stars, providing a large number of candidates for flickering.

"In the old theoretical model, a high-mass star forms, the HII region lights up and begins to expand, everything was neat and tidy", Chris De Pree stated. "But the group of theorists I am working with were running numerical models that showed accretion was continuing during star formation, and that material was continuing to fall in toward the star after the HII region had formed."

Chris De Pree's group chose Sagittarius B2 because the region contains more than 40 ultracompact HII regions. “Since there are so many sources, you can look for changes in relative brightness", Chris De Pree stated. Between 1989 and 2012, four of the HII regions indeed changed in brightness significantly.

"The long term trend is still the same, that HII regions expand with time", Chris De Pree stated. "But in detail, they get brighter or get fainter and then recover. Careful measurements over time can observe this more detailed process."

C. G. De Pree, T. Peters, M.-M. Mac Low, D. J. Wilner, W. M. Goss, R. Galván-Madrid, E. R. Keto, R. S. Klessen, and A. Monsrud are the authors of the paper titled "Flickering of 1.3 cm Sources in Sgr B2: Toward a Solution to the Ultracompact H II Region Lifetime Problem", which appears inThe Astrophysical Journal Letters, vol. 781, L36, 2014, doi:10.1088/2041-8205/781/2/L36.
Source: Agnes Scott College

Back to Table of contents

Primeur weekly 2014-02-10

The Cloud

European Cloud Testing Environment to be offered free of charge during 2014 ...

IBM opens access to SaaS portfolio to help African Universities with next-generation IT skills ...

IBM and Actifio add powerful new data virtualization solutions to IBM Cloud portfolio ...

Numericable Group teams with IBM's SoftLayer to develop a unique High Performance Cloud offer in France ...

HP Autonomy extends market-leading eDiscovery platform to the Cloud ...

IBM's SoftLayer and DataHotel help Japanese companies expand globally ...

IBM fuels innovation and entrepreneurship in Africa ...

Oracle extends the power of modern HR in the Cloud with updates to Oracle HCM Cloud ...

Desktop Grids

New CONVECTOR project studies mechanical engineering problems ...

EuroFlash

MSc in High Performance Computing organized at Edinburgh Parallel Computing Centre ...

PRACE Preparatory Access passes 3-year cap in bloom ...

EPSRC calls for Quantum Technology Hubs to put UK in super position ...

2nd International Conference on Research Infrastructures to launch Call for Contributions ...

Netherlands joins international Elixir Consortium on biological data ...

USFlash

IBM Brings Watson to Africa ...

SGI and Cognilytics partner to bring advanced analytics to enterprise Big Data ...

Mellanox releases Ethernet Switch Application Programing Interface (API) to the community as part of the Open Ethernet initiative ...

Mellanox releases world's first 40 Gigabit Ethernet NIC based on Open Compute Project (OCP) designs ...

Mellanox announces launch of Mellanox Capital ...

Computer models help decode cells that sense light without seeing ...

Heavy metal in the early cosmos ...

Scientists use 'voting' and 'penalties' to overcome errors in quantum optimization ...

2013 International Science and Engineering Visualization Challenge winners announced ...

New IBM virtualization solution to speed Software Defined Networking deployments ...

NEC contributes Network Virtualization to OpenDaylight's Hydrogen release ...

Diamond defect boosts quantum technology ...

Oracle and Pluribus Networks collaborate on OpenStack plug-ins for Software Defined Networking products ...

Solving a 30-year-old problem in high mass star formation ...

IBM named an innovation leader in Big Data in Sub-Saharan Africa, notes Frost & Sullivan ...