Hey everyone,

The last set of NBody runs have just converged beautifully. We are currently working on writing the paper to publish these results. In the meantime, we will be replacing these runs with another set:
-de_nbody_07_29_2020_v176_40k__data__4
-de_nbody_07_29_2020_v176_40k__data__5
-de_nbody_07_29_2020_v176_40k__data__6

Thank you all so much for your support. We would not be able to write this paper without your continued assistance.

-Eric

Good Afternoon,

I was just curious on what these calcs were for and was the projects expectation correct?

Many Thanks,

Robert Cowger

MilkyWay@home calculates the mass and radial profile of The Orphan Stream based off of its tidal debris and stellar distribution. This is useful because it gives us a measure of the dark matter content within the stream. It works by testing random sets of parameters against the tidal stream and seeing which parameter set gives the best fit. Each computer on this project receives a parameter set and performs an Nbody simulation. Good or bad, the computer sends a likelihood score back to the main server, and we use a differential evolution algorithm to generate more accurate parameter sets to be tested. We keep running this algorithm until our population of parameter sets converges to a maximum likelihood.

One of the big hurdles regarding this project was determining whether the dark matter content could even be determined from stellar data alone. However, testing of the code on MW@home shows that given a test tidal stream generated from predetermined parameters, MW@home could indeed return back those parameters. In addition, our most recent set of runs is returning parameter sets that make sense as a whole. So, yes. Our project's expectations were correct.

Thank you for taking interest in our research.