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Primeur weekly 2015-07-06

Special

Moving up to an Open Science Commons ...

HPC in the Baltic region ...

Data Access helps its customers get the most out of their HPC investments ...

The importance of being earnest about the long tail of research ...

Comstor to simply the IP management of clusters ...

Arbor Networks to protect organisations against DDoS attacks ...

Open Science perspective highlighted at e-IRG workshop in Riga ...

Focus on Europe

IBM, NVIDIA and Mellanox launch Design Center for Big Data and High Performance Computing ...

Launch event of SuperMUC Phase 2 on June 29, 2015 ...

Bright welcomes PC Link Egypt to its Partner Network ...

Middleware

OpenMP Device Constructs ...

Bright Computing to release Version 7.1 of Bright Cluster Manager at the ISC High Performance 2015 Conference ...

Agenda announced for PBS Works User Group Meeting ...

Hardware

CoolIT Systems reaches 50th patent milestone ...

DDN outlines strategic vision driving rapid adoption of DDN high performance storage technology throughout the enterprise ...

Nallatech 510T FPGA accelerator disrupts the data centre ...

Japan Atomic Energy Agency chooses SGI ICE X for new supercomputer system ...

ADVA Optical Networking unveils all-new Data Center Interconnect solution ...

ADVA Optical Networking launches new NFV demarcation product family ...

T-Systems and ADVA Optical Networking showcase the future of Terabit networking in unique demonstration ...

DDN object storage usage grows to 200+ billion objects; now world's 2nd largest object platform behind Amazon ...

Applications

Blue Waters simulations suggest there are fewer faint galaxies than expected ...

Researcher discovers groundwater modelling breakthrough ...

Internet of Things Turning New York's Lake George Into “World’s Smartest Lake ...

Producing spin-entangled electrons ...

The quantum middle man ...

New method of quantum entanglement packs vastly more data in a photon ...

The Cloud

Computational scientist Peter Coveney keynotes at ISC Cloud & Big Data ...

Blue Waters simulations suggest there are fewer faint galaxies than expected

1 Jul 2015 Urbana-Champaign - There may be far fewer galaxies further out in the Universe then might be expected, suggests a new study based on simulations conducted using the Blue Waters supercomputer at the National Center for Supercomputing Applications, with resulting data transferred to SDSC Cloud at the San Diego Supercomputer Center at the University of California, San Diego, for future analysis.

The study, published in theAstrophysical Journal Letters, shows the first results from the Renaissance Simulations, a suite of extremely high-resolution adaptive mesh refinement (AMR) calculations of high redshift galaxy formation.

Moreover, these simulations show hundreds of well-resolved galaxies, allowing researchers to make several novel and verifiable predictions ahead of the October 2018 launch of the James Webb Space Telescope (JWST), a new space observatory that succeeds the Hubble Space Telescope.

"Most critically, we show that the ultraviolet luminosity function of our simulated galaxies is consistent with observations of redshift galaxy populations at the bright end of the luminosity function, but at lower luminosities is essentially flat rather than rising steeply", wrote researchers in their paper, called "Probing the Ultraviolet Luminosity Function of the Earliest Galaxies with the Renaissance Simulations".

"Our work suggests that there are far fewer faint galaxies than one could previously infer", stated principal investigator and lead author Brian W. O'Shea, an associate professor at Michigan State University with a joint appointment in the Department of Computational Mathematics, Science and Engineering; the Department of Physics and Astronomy; and the National Superconducting Cyclotron Laboratory. "Observations of high redshift galaxies provide poor constraints on the low-luminosity end of the galaxy luminosity function, and thus makes it challenging to accurately account for the full budget of ionizing photons during that epoch."

"The Hubble Space Telescope can only see what we might call the tip of the iceberg when it comes to taking inventory of the most distant galaxies", stated SDSC Director Michael Norman, who was part of the research team for this study. "A key question is how many galaxies are too faint to see. By analyzing these new ultra-detailed simulations, we find that there are 10 to 100 times fewer galaxies than a simple extrapolation would predict."

Because these simulations are so costly to generate, the team moved the entire output of the Renaissance Simulations to SDSC Cloud - some 100 terabytes of data, or the equivalent of about 150,000 audio compact discs. "A data access portal is being set up so that others can investigate their properties in more detail", added Michael Norman, who also is a distinguished professor of physics at UC San Diego and a faculty member with the Center for Astrophysics & Space Sciences at the university.

"The flattening at lower luminosities is a key finding in the study and significant to researchers' understanding of the reionization of the universe, when the gas in the universe changed from being mostly neutral to mostly ionized", stated John H. Wise, Dunn Family Assistant Professor with the School of Physics at the Georgia Institute of Technology and a member of the research team.

The term "reionized" is used because the universe was ionized immediately after the fiery Big Bang. During that time, ordinary matter consisted mostly of hydrogen atoms with positively charged protons stripped of their negatively charged electrons. Eventually, the universe cooled enough for electrons and protons to combine and form neutral hydrogen. They didn't give off any optical or UV light and without that light, astrophysicists aren't able to see traces of how the cosmos evolved during these Dark Ages using conventional telescopes. The light returned when reionization began.

In an earlier paper, simulations conducted by two researchers who were part of this new study concluded that about 300 million years after the Big Bang, the universe was 20 percent ionized, 50 percent ionized at 550 million years, and fully ionized at 860 million years after its creation.

While the James Webb Space Telescope will give cosmic researchers the ability to view and record substantial numbers of galaxies, that telescope has a relatively small field of view, according to the researchers. As a result, interpretation of any JWST survey must by necessity take into account cosmic variance - the statistical variation in the number of galaxies from place to place. A deeper understanding based on theory may be necessary to correctly interpret high redshift survey results.

These simulations were done on the National Science Foundation-funded Blue Waters supercomputer, which is one of the largest academic supercomputers in the world. "These simulations are physically complex and very large - we simulate thousands of galaxies at a time, including their interactions through gravity and radiation, and that poses a tremendous computational challenge", stated Brian W. O'Shea. "Without the large memory, fast inter-node network, and powerful file system of Blue Waters, this calculation would not have been possible."

In addition to Brian W. O'Shea, John H. Wise, and Michael Norman, the research team also included Hao Xu, a postdoctoral research associate with the Center for Astrophysics & Space Sciences, at the University of California, San Diego. The research was funded by the National Science Foundation and NASA.
Source: National Center for Supercomputing Applications - NCSA

Back to Table of contents

Primeur weekly 2015-07-06

Special

Moving up to an Open Science Commons ...

HPC in the Baltic region ...

Data Access helps its customers get the most out of their HPC investments ...

The importance of being earnest about the long tail of research ...

Comstor to simply the IP management of clusters ...

Arbor Networks to protect organisations against DDoS attacks ...

Open Science perspective highlighted at e-IRG workshop in Riga ...

Focus on Europe

IBM, NVIDIA and Mellanox launch Design Center for Big Data and High Performance Computing ...

Launch event of SuperMUC Phase 2 on June 29, 2015 ...

Bright welcomes PC Link Egypt to its Partner Network ...

Middleware

OpenMP Device Constructs ...

Bright Computing to release Version 7.1 of Bright Cluster Manager at the ISC High Performance 2015 Conference ...

Agenda announced for PBS Works User Group Meeting ...

Hardware

CoolIT Systems reaches 50th patent milestone ...

DDN outlines strategic vision driving rapid adoption of DDN high performance storage technology throughout the enterprise ...

Nallatech 510T FPGA accelerator disrupts the data centre ...

Japan Atomic Energy Agency chooses SGI ICE X for new supercomputer system ...

ADVA Optical Networking unveils all-new Data Center Interconnect solution ...

ADVA Optical Networking launches new NFV demarcation product family ...

T-Systems and ADVA Optical Networking showcase the future of Terabit networking in unique demonstration ...

DDN object storage usage grows to 200+ billion objects; now world's 2nd largest object platform behind Amazon ...

Applications

Blue Waters simulations suggest there are fewer faint galaxies than expected ...

Researcher discovers groundwater modelling breakthrough ...

Internet of Things Turning New York's Lake George Into “World’s Smartest Lake ...

Producing spin-entangled electrons ...

The quantum middle man ...

New method of quantum entanglement packs vastly more data in a photon ...

The Cloud

Computational scientist Peter Coveney keynotes at ISC Cloud & Big Data ...