Authors:
(1) Hyosun park, Department of Astronomy, Yonsei University, Seoul, Republic of Korea;
(2) Yongsik Jo, Artificial Intelligence Graduate School, UNIST, Ulsan, Republic of Korea;
(3) Seokun Kang, Artificial Intelligence Graduate School, UNIST, Ulsan, Republic of Korea;
(4) Taehwan Kim, Artificial Intelligence Graduate School, UNIST, Ulsan, Republic of Korea;
(5) M. James Jee, Department of Astronomy, Yonsei University, Seoul, Republic of Korea and Department of Physics and Astronomy, University of California, Davis, CA, USA.
Table of Links
2 Method
2.1. Overview and 2.2. Encoder-Decoder Architecture
2.3. Transformers for Image Restoration
4 JWST Test Dataset Results and 4.1. PSNR and SSIM
4.3. Restoration of Morphological Parameters
4.4. Restoration of Photometric Parameters
5.2. Restoration of Multi-epoch HST Images and Comparison with Multi-epoch JWST Images
6 Limitations
6.1. Degradation in Restoration Quality Due to High Noise Level
6.2. Point Source Recovery Test
6.3. Artifacts Due to Pixel Correlation
7 Conclusions and Acknowledgements
Appendix: A. Image restoration test with Blank Noise-Only Images
4.3. Restoration of Morphological Parameters
Although one can characterize galaxy morphologies in various ways, we employ best-fit Sersic parameters to quantify the comparison. Specifically, we compare the two ellipticity components: e1 and e2, Sersic index n, half-light radius R50, and the intensity at R50.
The two components of the ellipticity are motivated by the weak lensing convention, which utilizes not only the absolute ellipticity e of a galaxy but also its position angle θ as follows:
The ellipticity e is defined as (a − b)/(a + b), where a and b are the semi-major and -minor axes, respectively.
Figure 6 compares the five morphological parameters. Across all parameters, the RS images exhibit stronger correlations with the GT images in terms of the scatter and slope of the correlations. The ellipticity comparison shows that the LQ galaxies are systematically rounder than the GT galaxies, which is not surprising because they are generated by convolving the GT galaxies with the circular HST PSF. This bias nearly disappears in the RS images. The improvement in the Sersic index n is remarkable. The scatter is reduced by more than a factor of 3. Also, the Pearson correlation coefficient improves from 0.61 to 0.90. Given that the Sersic index n is one of the most difficult parameters to restore, its recovery showcases the stability of the restoration performance. The R50 recovery is also noteworthy with the reduction of the scatter by more than a factor of 4 and the increase of the Pearson correlation coefficient by ∼48%. Finally, the I(R50) intensity comparison shows a scatter reduction of ∼46% and an increase of the correlation by ∼9%.
This paper is available on arxiv under CC BY 4.0 Deed license.
