2005AAS...207.3001P: The Numerical Action Method (NAM) seeks to recreate past orbits of large galaxies and galaxy groups by application of the least action principle. Recent improvements to NAM include: addition of a smooth, constant density background; time-dependent masses for haloes following linear perturbation theory; and solving for present distances and redshifts simultaneously to optimize fitting observations. We show that this improved NAM reconstructs reasonable orbits which agree with a large-scale numerical N-body code and with far less multiplicity than earlier efforts. We present results on the flow of galaxies, groups and clusters within 3000 km/s based on very recent HST TRGB-distance measurements. We can therefore expect to place theoretical constraints on observations of transverse velocities by future astrometric missions such as SIM and GAIA, as well as existing measurements of the proper motion of M33 by VLBI.
2003AAS...202.1904S: We will describe a new technique within the category of Numerical Action Methods in which one solves for acceptable individual total masses of galaxies along with the orbits in an expanding cosmology. We will present calculations done on simulated regions of radius 5 Mpc around the Milky Way that provide an understanding of the sensitivity of mass determinations on errors in distances and redshifts. In preparation for proper motion measurements to be provided by Space Interferometry Mission (SIM), we examine improvements in mass determinations when proper motions further constrain the orbit solutions.
PARAMETER.DAT basic input parameters (see below for details)
% runam ....
P4/1.6 AMD64/ G5/1.6You can run the command either as:
% time runam ....
2006 original version + NEMO integration xxx/PJT
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