Gaussian curve fitting using scripts
Elden Paul Iverson wrote on Jun 09, 2008
Mike-
I am working on a method to photometrically study galaxies and am trying to script the entire process.
So far I have been able to create a histogram of the galaxy's total flux using increasing aperture sizes from r=1 to some user-defined amount. Now comes the hard part. I want to use just the values in the wings of the histogram to compute a gaussian function fit that should approximate the bulge light. Any ideas how I can use IRAF tasks to accomplish this?
Thanks.
-Paul
I am working on a method to photometrically study galaxies and am trying to script the entire process.
So far I have been able to create a histogram of the galaxy's total flux using increasing aperture sizes from r=1 to some user-defined amount. Now comes the hard part. I want to use just the values in the wings of the histogram to compute a gaussian function fit that should approximate the bulge light. Any ideas how I can use IRAF tasks to accomplish this?
Thanks.
-Paul
Mike Fitzpatrick wrote on Jun 09, 2008
Hi Paul,
For fitting gaussians the first task that comes to mind is the NGAUSSFIT task in STSDAS.FITTING, although I admit I'd need to play with it to know whether it could be used if given only data in the wings. Perhaps more promising is the NFIT1D task in the same package that sports a 'function' parameter, one of the allowed values being
You might need to reformat the histogram data into a table but might also be able to use this to fit the entire thing.
Lastly, you might google around for more specific bulge-disc decomposition tasks (tasks like GIM2D and GALMORPH come to mind. can't remember whether GALFIT was iraf based or not).
Cheers,
-Mike
For fitting gaussians the first task that comes to mind is the NGAUSSFIT task in STSDAS.FITTING, although I admit I'd need to play with it to know whether it could be used if given only data in the wings. Perhaps more promising is the NFIT1D task in the same package that sports a 'function' parameter, one of the allowed values being
galaxy brightness profile (bulge and disk),
You might need to reformat the histogram data into a table but might also be able to use this to fit the entire thing.
Lastly, you might google around for more specific bulge-disc decomposition tasks (tasks like GIM2D and GALMORPH come to mind. can't remember whether GALFIT was iraf based or not).
Cheers,
-Mike
Last post on Jun 09, 2008