J/A+A/632/A128 New fitting concep (Breda+, 2019)
A new fitting concept for the robust determination of Sersic model parameters.
Breda I., Papaderos P., Gomes J.-M., Amarantidis S.
<Astron. Astrophys. 632, A128 (2019)>
=2019A&A...632A.128B 2019A&A...632A.128B (SIMBAD/NED BibCode)
ADC_Keywords: Models ; Galaxies, photometry
Keywords: galaxies: photometry - galaxies: structure -
galaxies: fundamental parameters - techniques: photometric -
galaxies: starburst - galaxies: elliptical and lenticular, cD
Abstract:
We present a new fitting concept (iFIT) that permits a robust
determination of the equivalent SL model for the general case of
galaxies with imperfect SL profiles. iFIT has been extensively tested
on synthetic data with a Sersic index 0.3<η<4.2 and an effective
radius 1≤Reff(")≤20. Applied to non PSF-convolved data, iFIT can
infer the Sersic exponent η with an absolute error of ≤0.2 even
for shallow SBPs. As for PSF-degraded data, iFIT can recover the input
SL model parameters with a satisfactorily accuracy almost over the
entire considered parameter space as long as FWHM(PSF)≤Reff. This
study also includes examples of applications of iFIT to ETGs and local
low-mass starburst galaxies. These tests confirm that iFIT shows
little sensitivity on PSF corrections and SBP limiting surface
brightness, and that subtraction of the best-fitting SL model in two
different bands generally yields a good match to the observed radial
color profile.
Description:
iFIT is a 1D surface photometry tool for the robust determination of
Sersic model parameters, optimally suited for the automated,
non-supervised structural characterization of galaxies. It allows for
correction of PSF convolution effects, offering the user the option of
choosing between a Moffat, Gaussian, or user-supplied PSF. iFIT, which
is a standalone FORTRAN code, can be applied to any SBP that is
provided in ASCII format and it has the capability of convenient
graphical storage of its output. The iFIT distribution package is
supplemented with an auxiliary SBP derivation tool in python.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
ifit_fv.f 512 343 iFit source code (written in FORTRAN)
ifit_fv 512 532 iFit executable
ex_sbp.py 84 111 Algorithm to extract the SBP from an image
cfit.py 111 243 Algorithm to fit isophotes to an image
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Acknowledgements:
Iris Breda, iris.breda(at)astro.up.pt
History:
16-Dec-2019: on-line version
18-Feb-2020: file cfit.py added
(End) Patricia Vannier [CDS] 18-Oct-2019