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a Milky Way dark matter halo simulated with 234 million particles on NASA's Project Columbia supercomputer |
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via lactea in the news
UC Santa Cruz - press releaseNewScientist.com online article, December 2006
NASA Advanced Supercomputing (NAS) Division
Mid-County Post (local newspaper)
NewScientist article about gamma rays, 29 April 2007
and others ...
simulation description (see the press release for a less technical summary)
The simulation was performed with PKDGRAV (principal author Joachim Stadel; Stadel, J. 2001, PhD thesis, U. Washington) and employed multiple mass particle grid initial conditions generated with the GRAFICS package (Bertschinger, E. 2001, ApJSS, 137, 1). The high resolution region is embedded within a periodic box of comoving size 90 Mpc, which is sampled at lower resolution to account for the large scale tidal forces.We adopt the best-fit cosmological parameters from the WMAP three-year data release (Spergel, D. N. et al. 2006): Omega_M = 0.238, Omega_Lambda = 0.762, H_0= 73 km/s/Mpc, n=0.951, and sigma_8=0.74.
The high resolution region was centered on a isolated halo that had no major merger after z=1.7, making it a suitable host for a Milky Way-like disk galaxy. Its mass at z=0 is M_200 = 1.77e12 solar masses within a radius of r_200 = 389 kpc (r_200 is the radius within which the enclosed average density is 200 times the mean matter value).
The "Via Lactea" run features adaptive time-steps as short as the age of the universe divided by 200'000, which is about 68'500 years, a force resolution of 90 pc and particle masses of 20'900 solar masses.
last updated: May 9, 2007, by J. Diemand
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Please acknowledge J. Diemand, M. Kuhlen and P. Madau (UCSC) wherever material from this web site is used. | |||
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