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nam, runam- Numerical Action Method integrator



runam [parameter=value]


NOTE:: This is work in progress, the code is not yet available within NEMO.x


Some abstracts from papers to give an idea what we do here:

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.


There are the NEMO command line parameters for runam:
Input catalog of ra,dec,z,D,dz. No default.


PARAMETER.DAT    basic input parameters (see below for details)


The following example uses ...
   % runam ....


The standard benchmark is ....
You can run the command either as:
   % time runam ....

Data Conversion

If snapshots are requested..
tabtos ..


The input catalog is

See Also



Ed Shaya, Jim Peebles, Alan Peel ...


2006    original version + NEMO integration    xxx/PJT

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