ENGINEERING

N-Body simulation based on data compiled by David R. Law et al. Here the simulation is shown intersecting wedge 82. For the stream animation click here.

For those interested in learning more about the origin of the Sagittarius Stream, the above animation is based on data from an N-Body simulation created by David R. Law et al. which shows how the stream may have formed.

The simulation was rendered using the same engine that will be used in the MilkyWay@Home screensaver. A MilkWay@Home team member, Ben Willet has written a brief summary about the simulation and what our next MilkyWay@Home project will be! This visualization shows the two different components of the Milkyway@home project. The circular wedge that you see is a 2.5 degree wide stripe of SDSS data. The bright overdensity in the stripe is composed of stars that have been torn off of the Sagittarius Dwarf Galaxy (Sgr) as it orbits around the Milky Way. The main goal of the project is to analyze this data stripe to determine the most likely parameters of those stars (e.g. how wide the overdensity is, where it is going, and how many stars are in it). To accomplish this goal, each user's computer analyzes a stripe with a certain parameter set, and determines how well those parameters match the data. These results are fed into the BOINC platform, which takes actions to decide the next parameter values, and chooses the best answer. The rest of the visualization is a prelude to an upcoming BOINC project. The stars in motion are taken from an N-body simulation of the Sgr Dwarf Galaxy. We take the currently known position and velocity of the Sgr Dwarf Galaxy and run it back in time for anywhere between 3 and 6 billion years within a gravitational field that approximates the Milky Way. We then place a spherical group of stars at that predicted location, and run it forward to the current day. The Milky Way's gravity tears apart the dwarf, causing it to flow out into long streams of stars. It is these stars that are contained within the data wedges. The ultimate goal of this project is to utilize N-body simulations over BOINC to find the best fit model for the Milky Way's gravitational field.

The ability to do N-body simulations over BOINC is currently being developed by a team of astronomers and computer scientists, and will soon be available to users.