______________________________________________________________________________ RG RADGAL is a module which performs a nonlinear least squares fit to surface brightness data in a file of type 1 and derives the parameters of a chosen surface brightness formula and their errors. It can take into account blurring from the atmosphere by using the actual point spread function of a star (or averge of many stars). ______________________________________________________________________________ Enter an option: 22-OCT-1991 13:59:32.32 OPTION=RG RADGAL, Version 1 Open the data file Enter the file name: (default = last entry) FILE_21=R022152 ....This the data file of type 1 which was produced by option PR. Enter the ID of the object: (default = last galaxy entry) ID=129 ....The data file can hold many different galaxies Do you wish to plot the first estimate of the Hubble "a" against radius? (default = N) ....This is quick way to get a rough value for the radius parameter PLOT= F Enter the surface brightness law: G = Gaussian H = Hubble HV = Hubble with variable power in denominator I = Inverse radius K = Constant L = Straight line M = Modified Hubble (default) MC = Modified Hubble plus modified Hubble for cluster ML = Fixed modified Hubble with color gradient, linear in log(r) MR = Fixed modified Hubble with color gradient, linear in r SI = Sum of K/r and K'/r**2 T = Tapered Hubble V = de Vaucouleurs VC = de Vaucouleurs plus de Vaucouleurs for cluster E3 = Extrafocal photometry of E3 galaxies ....There are lots of choices CHOICE=V Do you wish to solve for the sky level also? (default = Y) SOLVE= T ....Normally, one does not know the sky ahead of time. Obtaining an accurate sky level is important for getting an accurate total magnitude. Do you wish to convolve the surface brightness law with a smearing distribution? (default = Y) CONVOLVE= T ....It is essential to do this for most images. Open the file containing the smearing function Enter the file name: (default = last entry) FILE_22=S022152 ....This was prepared with option PR on stars in the field Enter the ID of the smearing object: (default = last smearing entry) ID=STARS ....Several stars were added together for more accuracy with option ED Enter the convolving factor: (default = 75.0) CONVOLVE_FACTOR= 75.0000 ....This factor controls the stepsize for convolution. A large factor produces a smaller stepsize near the center of the galaxy. This gives more accuraccy, but takes longer to compute. We choose the default here. Enter the starting and ending radii for the least squares fit: (default = the entire range of the data file) RADII= 0.000000E+00 90.0000 Enter the outer radius to where convolution is to be done: (default = previous fitting outer radius RADIUS=40 ....By not convolving out to the edge of the data file we save computing time and do not loose accuracy. Enter the estimates for the surface brightness at 1/2 the total light (ADU), the corresponding radius (pixels), and the sky level (ADU): PARAMETERS=100 10 491 ....A reasonable guess Select the weighting scheme: R = Weight equal to circumference/(noise)**2 (default) S = Weight equal to the square root of the circumference N = Weight equal to 1/(noise)**2 P = Weight equal to weight from file/(constant*noise**2) WEIGHT_SCHEME= R Enter the readout noise in electrons and the gain in electrons per ADU: (defaults = 63.9 21.3) NOISE_PARAMETERS= 63.9000 21.3000 ....These will depend on the instrument Select the iteration scheme: M = Manual (default) A = Automatic selection of fractional increment with maximum searching B = Automatic selection of fractional increment with minimum searching C = Automatic selection of fractional increment with no searching ITERATION_SCHEME= M ....We choose M here so as to illustrate the behavior of the iteration. Normally, this operation can be submitted as a batch job and A (for good data) or B (for noisier data) chosen. Enter the fractional increment: (default = 1.0) FRACTIONAL_INCREMENT= 1.00000 ....If the answer starts to oscillate, we can decrease this value. When A is chosen, the increment is adjusted downward as needed automatically. For the initial guess: Mean error for an observation of average weight = 27.9963 +- 2.11030 For the solution: Mean error for an observation of average weight = 4.21510 +- 0.317725 and in magnitudes it is = 1.35730 +- 0.102310 Effective surface brightness = 52.48601 +- 4.79713 Effective radius = 8.78313 +- 0.31946 Sky surface brightness = 490.70779 +- 0.47116 Do you wish to iterate 1 more time? (default = Y) ITERATE= T Enter the fractional increment: (default = 0.67xlast value) FRACTIONAL_INCREMENT=1 ....We'll try keeping this high for now Enter the new estimates: (default = best values) PARAMETERS= 52.4860 8.78313 490.708 For the solution: Mean error for an observation of average weight = 1.01237 +- 0.763099E-01 and in magnitudes it is = 1.32065 +- 0.995480E-01 Effective surface brightness = 58.41388 +- 1.37615 Effective radius = 6.91855 +- 0.14996 Sky surface brightness = 490.73038 +- 0.11192 Do you wish to iterate 1 more time? (default = Y) ITERATE= T Enter the fractional increment: (default = 0.67xlast value) FRACTIONAL_INCREMENT=1 Enter the new estimates: (default = best values) PARAMETERS= 58.4139 6.91855 490.730 For the solution: Mean error for an observation of average weight = 0.886601 +- 0.668301E-01 and in magnitudes it is = 1.30982 +- 0.987316E-01 Effective surface brightness = 69.91505 +- 1.67909 Effective radius = 6.10233 +- 0.12451 Sky surface brightness = 490.79819 +- 0.09649 Do you wish to iterate 1 more time? (default = Y) ITERATE= T Enter the fractional increment: (default = 0.67xlast value) FRACTIONAL_INCREMENT= 0.670000 ....To prevent the solution from bouncing around too much, we'll let the fractional increment decrease on each iteration. Enter the new estimates: (default = best values) PARAMETERS= 69.9151 6.10233 490.798 For the solution: Mean error for an observation of average weight = 0.821715 +- 0.619391E-01 and in magnitudes it is = 1.22094 +- 0.920321E-01 Effective surface brightness = 74.94466 +- 1.86721 Effective radius = 5.88179 +- 0.09985 Sky surface brightness = 490.83908 +- 0.08886 Do you wish to iterate 1 more time? (default = Y) ITERATE= T Enter the fractional increment: (default = 0.67xlast value) FRACTIONAL_INCREMENT= 0.448900 Enter the new estimates: (default = best values) PARAMETERS= 74.9447 5.88179 490.839 For the solution: Mean error for an observation of average weight = 0.887865 +- 0.669254E-01 and in magnitudes it is = 1.20830 +- 0.910789E-01 Effective surface brightness = 77.77221 +- 2.13163 Effective radius = 5.75739 +- 0.10164 Sky surface brightness = 490.85941 +- 0.09585 Do you wish to iterate 1 more time? (default = Y) ITERATE= T Enter the fractional increment: (default = 0.67xlast value) FRACTIONAL_INCREMENT= 0.300763 Enter the new estimates: (default = best values) PARAMETERS= 74.9447 5.88179 490.839 For the solution: Mean error for an observation of average weight = 0.846092 +- 0.637766E-01 and in magnitudes it is = 1.22517 +- 0.923505E-01 Effective surface brightness = 76.83912 +- 2.03134 Effective radius = 5.79844 +- 0.09685 Sky surface brightness = 490.85269 +- 0.09134 . . . . . . ....We have let it iterate a few more times Do you wish to iterate 1 more time? (default = Y) ITERATE= T Enter the fractional increment: (default = 0.67xlast value) FRACTIONAL_INCREMENT= 0.606071E-01 Enter the new estimates: (default = best values) PARAMETERS= 74.9447 5.88179 490.839 For the solution: Mean error for an observation of average weight = 0.822191 +- 0.619750E-01 and in magnitudes it is = 1.22255 +- 0.921532E-01 Effective surface brightness = 75.32642 +- 1.97396 Effective radius = 5.86499 +- 0.09412 Sky surface brightness = 490.84183 +- 0.08876 Do you wish to iterate 1 more time? (default = Y) ITERATE=N ....The solution seems to have converged For a perfect fit: Mean error for an observation of average weight = 0.337123 +- 0.254116E-01 Covariance(1,1) = 3.8965144 Covariance(1,2) = -0.18082026 ....This is expected to be negative Covariance(2,2) = 0.88583706E-02 Covariance(1,3) = 0.28629743E-01 Covariance(2,3) = -0.16628597E-02 Covariance(3,3) = 0.78780372E-02 The average weight = 0.019394 The reduced chi squared = 5.9480 The integral from radius = 0.0 to radius = 90.0 = 44849.835182 In magnitudes it is 18.370598 The integral from radius = 91.0 to the limit of 2212.5 = 718.027778 In magnitudes it is 22.859648 The total is 45567.862960 and in magnitudes it is 18.353354 ....Note that the total magnitude is only slightly brighter than the aperture magnitude out to 90 pixels. Do you wish to plot the residuals? (default = Y) PLOT= T ....This is a good way to see how good the fit actually is. Enter the plot devices: G = Graphics terminal (VT100/Retrographics and Visual 550, default) G1 = Graphics terminal (GraphOn) G2 = Graphics terminal (Codonics) G3 = Graphics terminal (Micro-term) F = File T = Tektronix 4662 flat bed plotter (1200 baud) DEVICES= G ....The first plot is in linear units Enter the plot devices: G = Graphics terminal (VT100/Retrographics and Visual 550, default) G1 = Graphics terminal (GraphOn) G2 = Graphics terminal (Codonics) G3 = Graphics terminal (Micro-term) F = File T = Tektronix 4662 flat bed plotter (1200 baud) DEVICES= G ....This plot is in logarithmic units Do you wish to store the results? (default = N) STORE=Y Add the results to an existing file? (default = N) OLD= F Enter the file name: (default = last entry) FILE_24=RESULTS_FILE More objects to analyze in this file? (default = N) MORE= F Enter an option: 22-OCT-1991 14:08:47.06 OPTION=EX ______________________________________________________________________________