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Name

runvelfitss07 - frontend to run Spekkens & Sellwood's 2007 velfit code

Synopsis

runvelfitss07 [parameter=value]

Description

runvelfitss07 is a NEMO frontend to velfitss07, and fits a non-parametric non-axisymmetric flow to a planar disk galaxy velocity field. Radial (m=0) flow can be fitted by setting flags(4) , whereas bisymmetric (m=2) or lobsided (m=1) flow with flags(5) (see flags= below). The code is usually not well converging when fitting both. For more details and a full explanation of the parameters, see Spekkens and Sellwood (2007ApJ...664..204S) and the Users Guide on the VELFIT website.

Parameters

The following parameters are recognized in any order if the keyword is also given:
in=
input velocity field. The first 4 lines are completely ignored, each subsequent data line must be X,Y,V,DV in 4F10.2 format. Note X is positive to the west. Up to 50,000 points can be read in the default compilation. No default.
out=
output model field. No default.
par=
output parameter file. No default.
center=xc,yc
center of velocity field. Note X is positive to the west [0,0].
vsys=
systemic velocity [0]
pa=
(kinematic) position angle of disk (E of N), the usual convention applies where this means the receding side of the disk [0]
inc=
inclination angle of disk [0]
rmsism=
ISM turbulence [0]
flags=f1,f2,f3,f4,f5,f6
Siz flags which to be fitted/done: geom (inc and pa), center, vsys, radial (m=0), lobsides/bisymmetric (m=1,2...), error estimates. [1,1,1,0,0,0]
m=
harmonic order of bar perturbation (1 or 2). [2]
seed=
Random Seed [-50]
bootstrap=
Number of bootstrap samples if errors (flags(6) set) are calculated. Note using bootstrap will result in a large runtime. [200]
j=
correlation length, in case bootstrap is used [1.0]
rcirc=
Radius beyond which no non-circular rmotions fitted [50]
radii=rmin:rmax:step
Ring Radii at which velocity field components are are extracted.
exe=
name of VELFITSS07 executable. It will have to be found in the user's $PATH. Note that although the original name of the SS07 is velfit, this conflicts with velfit(1NEMO) and within NEMO we normally rename the SS07 version fo velfitss07. [velfitss07]

Examples

The standard example from the Users Guide can be run as follows: 
runvelfitss07 examp.vels examp.m examp.p vsys=500 pa=80 inc=60 radii=2.5:50:2.5
and the next 3 examples from the Users Guide are run as follows: 
runvelfitss07 examp.vels examp.m examp.p vsys=500 pa=80 inc=60 radii=2.5:50:2.5
flags=1,1,1,1,0,0 rmsism=2.0
runvelfitss07 examp.vels examp.m examp.p vsys=500 pa=80 inc=60 radii=2.5:50:2.5
flags=1,1,1,1,0,1 rmsism=2.0
runvelfitss07 examp.vels examp.m examp.p vsys=500 pa=80 inc=60 radii=2.5:50:2.5
flags=1,1,1,0,1,1 rmsism=2.0

See Also

rotcur(1NEMO) , velfit(1NEMO) , rotcurshape(1NEMO) , rundiskfitss07(1NEMO) 
2007ApJ...664..204S (Spekkens & Sellwood, 2007) - V1 of velfit (SS07)
2010MNRAS.404.1733S (Sellwood & Sanches, 2010) - V2 of velfit (SS10)
WEBSITE: http://www.physics.rutgers.edu/~spekkens/velfit/
2010ascl.soft10021S:  http://ascl.net/1010.021

Files


NEMO/usr/spekkens/velfit    - original SS07 code/examples (see their WEBSITE)
NEMOBIN/velfitss07    - SS07 executable (see also exe=)
NEMO/src/image/rotcur    - NEMO frontend

Caveats

The parameter file (velfit.inc) is in the local run directory, and is silently overwritten. This will hamper running the program in parallel.

This version will only run V1, i.e. the SS07 code. The SS10 (V2) of the code has major user interface changes to allow reading FITS files, and is handles through a new frontend, see runvelfitss10(1NEMO) .

Examples

Below is an example snippet C-shell code to output the table in the format velfitss07 needs: 
#! /bin/csh -f
#
#  create an example input file for velfitss07 from a MIRIAD dataset
#  1) select the inner 40x40 arcsec
#  2) select points where flux mom0 map > 1.0
set region="arcsec,box(-20,-20,20,20)"
set map=mom0a
set vel=mom1a
set sig=mom2a
imtab in=$map region="$region" > tmp.map1.tab
imtab in=$vel region="$region" > tmp.vel1.tab
tail -n +3 tmp.map1.tab | grep -v Found > tmp.map2.tab
tail -n +3 tmp.vel1.tab | grep -v Found > tmp.vel2.tab
#  here's a simple example of constant errors and only use mom0 and mom1
echo "# input file for velfitss07:  $0" 
echo "#      X          Y       VEL       EVEL"
echo "#     asec       asec    km/s       km/s"
echo "#----------------------------------------"
paste tmp.map2.tab tmp.vel2.tab |
  awk '{ if ($3 > 1.0) printf("%10.2f%10.2f%10.2f%10.2f0,$1,$2,$6,5.0)}'

Author

Peter Teuben

Update History


27-oct-2008    V1.0 : frontend for velfitss07 V1.0 (oct 2008)    PJT

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