Thanks to your suggestions I made some progresses in my work...but now I'm
trying to obtain and fit the radial profile of my normalized psf (I
normalized it following the threads, with dimgcalc):well, after that
operation(i.e. multipyling the psf image by a number) it seems to be
impossible...I mean, I 'm able to obtain the radial profile of the
un-normalized psf...but when I do the same for the normalized one , this
is the error message I see:
(egallo@wasat 144) dmextract
Input event file (psf_5keV_norm.fits[bin sky=@annuli_psf.reg]):
Enter output file name (rprofile_psf_5keV_norm.fits):
# 4753: dmextract:
WARNING: Keywords LIVETIME and EXPOSURE not found:
LIVETIME set to default 1.0
# 4753: dmextract:
WARNING: TLMIN and TLMAX not found for column sky
# 4753: dmextract:
WARNING: Keywords LIVETIME and EXPOSURE not found:
LIVETIME set to default 1.0
# 4753: dmextract:
WARNING: TLMIN and TLMAX not found for column sky
# 4753: signal_handler was invoked
# 4753: Received error signal SIGSEGV-segmentation violation.
# 4753: An invalid memory reference was made.
# 4753: segmentation fault: dmextract (1) is:
exit_upon_error->NULL
Probably I make some mistakes...?
Many thanks in advance!
cheers,
Elena Gallo
> You can use Sherpa to model your image data with the PSF. The Sherpa will give
> you normalization as well as the residuals map. I'm working on the thread which
> should be on the Web somtime this week.
>
> In meantime you can try Sherpa:
>
> ---------
> read data:
>
> data myimage.fits
>
> read psf file:
>
> psffromfile[psf0]
> psf0.file = mypsf.fits
>
> Now you can use psf0 as model to get the normalization and the centroid location, or you can use it as a convolution kernel in fitting your surface brightness model.
>
> use as a model:
>
> source 1 = psf0
>
> or
> use as a convolution kernel:
>
> source 1 = <some model for the surface brightness >
> instrument 1 = psf0
>
> You can get more help on the PSF in online Sherpa help:
> "ahelp psffromfile" and in the Model section of the manual.
>
> -Aneta Siemiginowska
>
>
> __________________________________________________________________________
> Aneta Siemiginowska Chandra X-Ray Center (CXC)
> asiemiginowska@cfa.harvard.edu Harvard-Smithsonian
> Center for Astrophysics
> Phone:(617)-495-7243 60 Garden St. MS-4
> FAX: (617)-495-7356 Cambridge, MA 02138
> __________________________________________________________________________
>
>
>
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