| NSF Org: |
OISE Office of International Science and Engineering |
| Recipient: |
|
| Initial Amendment Date: | May 29, 2014 |
| Latest Amendment Date: | May 29, 2014 |
| Award Number: | 1415111 |
| Award Instrument: | Fellowship Award |
| Program Manager: |
Anne Emig
OISE Office of International Science and Engineering O/D Office Of The Director |
| Start Date: | June 1, 2014 |
| End Date: | May 31, 2015 (Estimated) |
| Total Intended Award Amount: | $5,070.00 |
| Total Awarded Amount to Date: | $5,070.00 |
| Funds Obligated to Date: |
|
| History of Investigator: |
|
| Recipient Sponsored Research Office: |
Honolulu HI US 96822-2450 |
| Sponsor Congressional District: |
|
| Primary Place of Performance: |
Tokyo JA |
| Primary Place of
Performance Congressional District: |
|
| Unique Entity Identifier (UEI): |
|
| Parent UEI: |
|
| NSF Program(s): |
EAPSI, EPSCoR Co-Funding |
| Primary Program Source: |
|
| Program Reference Code(s): |
|
| Program Element Code(s): |
|
| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.079 |
ABSTRACT
Physicists and astronomers have conclusively determined that a large percent of the matter within our universe is dark and of unknown composition. While computer simulations which model this dark matter over billions of years produce a universe in agreement with observation at sizes larger than galaxies, disagreement with data remains at the size of individual galaxies. Recent extensions to Einstein's description of gravity have produced a new type of dark matter which agrees with data at the size of individual galaxies. Through supercomputer simulations, in collaboration with Dr. Naoki Yoshida jointly at University of Tokyo and Kavli Institute on the Physics and Mathematics of the Universe (IPMU) in Japan, this study will investigate whether this form of dark matter can also produce a universe in agreement with data at sizes larger than galaxies. This study has the potential to resolve a long-standing disagreement between astronomers and astrophysicists, and could point toward more fruitful extensions to Einstein's gravity.
N-body simulation of point-like dark matter agrees well with the galactic power spectrum as inferred from comprehensive sky surveys. Yet, at the scale of a single galaxy, N-body simulations predict densities that diverge toward galactic centers, while observational evidence strongly suggests constant densities. There have emerged extensions to Einstein gravity that predict a dark matter candidate with Newtonian gravitational interactions at large separation but which diminish linearly to zero at small separation. The N-body code GADGET-2 will be augmented to permit distinct gravitational interactions between particles, with focus on deviations from point-mass behavior as predicted by recent models featuring multiple metric tensors. The effect of these deviations on large-scale structure will be compared against existing sky surveys. Research outcomes will either lessen tension between large-scale and small-scale dark matter observations, or exclude these specific models. This NSF EAPSI award is funded in collaboration with the Japan Society for the Promotion of Science.
PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
More than ninety percent of the matter and energy within our universe does not emit or block any light. Though evidence for this mysterious dark matter and dark energy comes from many distinct observations, much of it comes from astronomical observation where the force of gravity reigns supreme. For this reason, present-day researchers in cosmology are actively extending Einstein's understanding gravity, just as Einstein extended Newton's understanding of universal attraction a century ago. Yet Einstein's equations are already so sophisticated that only the simplest scenarios can be directly investigated with pencil and paper. Thus, computer simulations have become an integral part of testing the predictions of Einstein's theory, and its modern extensions, against the vast quantities of data collected by astronomers.
This project has developed, and publicly released, an enhanced version of a leading simulation tool, GADGET-2. Our extension, named "ngravs," enables study of physical scenarios where more than one kind of gravitational force can coexist. The ngravs extension now enables us, for example, to ask the question: "If I find a galaxy here on the night sky, how likely is it that I will find another one nearby?" Each extension to Einstein's theory will produce its own simulated night sky, but comparison against the reality observed in our actual night sky will now constrain and eliminate some of these extensions.
Simulations can further be used to produce striking visualizations, and this project engaged Hawaiian island high school students with growing universes in red-blue 3D. These presentations were combined with hands-on activities designed to give an intuitive understanding of how long a computer takes to actually compute these simulations. As a result, students learned just how much time and money can be saved by creative solutions to seemingly straight-forward problems.
Last Modified: 02/28/2015
Modified by: Kevin A Croker
Please report errors in award information by writing to: awardsearch@nsf.gov.
