Program: RADPROF
Purpose: Solves the radial surface density distribution from a strip
integral of the brightness distribution. USE PROGRAM
RADIAL AS FRONT END FOR RADPROF.
Category: ANALYSIS, FITTING, PROFILES, RADIO
File: radprof.shl
Author: M.G.R. Vogelaar
(Initial code: Myung-Hyun Rhee, Rob Swaters)
Keywords: See radial.dc1
PA= Position angle (deg) of galaxy:
INCL= Inclination (deg) of galaxy:
Inclination of 90.0 degrees not allowed.
GUESS= Enter initial estimate: [L]
Enter one of: L = Linear Regression
E = Exponential Decreasing
G = Gaussian Distribution
F = Flat Distribution
**IDENT= Give integer to identify output: [0]
SCF= Give scale factor for density: [1]
SIGMA= Give noise in your data points: [1]
ITMAX= Maximum number of iterations: [10]
BEAM= Half power beam width (arcsec): [0.0]
POS= Positions of data points (arcsec):
First position must be zero and positions must be
equally spaced.
EAST= Values at east side:
WEST= Values at west side:
TABLEFILE= Enter output filename for densities: [RADIAL.DAT]
This file contains the observed and fitted
integrated flux for east, west and the average profile,
and the fitted surface densities.
Description: RADPROF solves the radial surface density distribution from
a strip integral of the brightness distribution of a galaxy.
The method is simular to the one decribed by Lucy,
(The Astronomical Journal, Vol. 79, Number 6, June 1974).
The geometry of the problem is determined by the inclination
and the position angle of the galaxy together with the position
angle of the resolution axis of the strip integral.
The method of Lucy takes care of the existence of noise
in the data and used an iterative scheme to take that into
account.
Algorithm: 1. read in the observational data of observation 1
from the data file for both the east and west side
2. convert the positions on the resolution (=position)
axis to radial distances in the plane of the galaxy
3. make an inital guess of the radial distribution
4. start lucy iterative scheme to compute the true
radial distribution
5. print and plot the results of the observation
Array's
R (input) distance to centre along the resolution axis
R (out) distance in the plane of the galaxy
V (out) radial distr. east and west (solar masses/pc**2)
S (out) radial distr. east and west (cumulative perc.)
T (out) average radial distr. (solar masses/pc**2)
U (out) average radial distr. (cum. perc.)
This program is usually started by program RADIAL which
serves as a front-end to RADPROF.
For a further description of the method see:
Warmels, R.H., 1988b, A&AS 72, 427
Updates: Jul 30, 1999: VOG, Document created.