Morfometryka
We present an extended morphometric system to automatically classify
galaxies from astronomical images. The new system includes the
original and modified versions of the CASGM coefficients
(Concentration $C_1$, Asymmetry $A_3$, and Smoothness $S_3$), and the
new parameters entropy, $H$, and spirality $\sigma_\psi$. The new
parameters $A_3$, $S_3$ and $H$ are better to discriminate galaxy
classes than $A_1$, $S_1$ and $G$, respectively. The new parameter
$\sigma_\psi$ captures the amount of non-radial pattern on the image
and is almost linearly dependent on T-type. Using a sample of spiral
and elliptical galaxies from the Galaxy Zoo project as a training set,
we employed the Linear Discriminant Analysis (LDA) technique to
classify \citet[4478 galaxies]{EFIGI}, \citet[14123 galaxies]{NA}
and SDSS Legacy (779,235 galaxies) samples. The cross-validation test
shows that we can achieve an accuracy of more than 90\% with our
classification scheme. Therefore, we are able to define a plane in the
morphometric parameter space that separates the elliptical and spiral
classes with a mismatch between classes smaller than 10\%. We use the
distance to this plane as a morphometric index (M$_{\rm i}$) and we
show that it follows the human based T-type index very closely. We
calculate morphometric index M$_{\rm i}$ for $\sim$780k galaxies from
SDSS Legacy Survey - DR7. We discuss how M$_{\rm i}$ correlates with
stellar population parameters obtained using the spectra available
from SDSS-DR7.
Rio Grande, RS - Brasil | 24 Mar 2023, 00h47m | your IP: 44.200.168.16 |