Abstract

In this thesis, we present a comprehensive visual analysis of low surface brightness (LSB) structures in edge-on galaxies using two statistically complete samples: 838 galaxies from the SDSS Stripe 82 region (ES82) and 5,745 galaxies from the Edge-on Galaxies in SDSS (EGIS) catalog, both containing galaxies with spectroscopic redshifts out to 𝑧 ∼ 0.2. Using deep imaging data from the SDSS, SDSS Stripe 82, DESI Legacy Imaging Surveys, and the HSC-SSP, we construct RGB and coadded images for comparison and to improve feature detection. Average limiting photometric depth for each survey in the 𝑟 band for the surveys analyzed in this study are, 26.5 mag arcsec−2, 28.6 mag arcsec−2 for SDSS Stripe 82, 28.5 mag arcsec−2 for DESI, and 29.7 mag arcsec−2 for HSC-SSP. For the EGIS sample, additional deep images from the APO 3.5m telescope were incorporated for a subsample of galaxies with dim tidal features, reaching a depth of 29.4 mag arcsec−2 in the 𝑟 band. All images and classifications are compiled into the largest atlas of features around edge-on galaxies to date. A custom semi-automatic pipeline and graphical user interfaces (GUIs) were developed for image analysis and classification refinement. We find that 5.8% of the Stripe 82 galaxies show LSB tidal structures, while only 2.8% of the EGIS sample exhibits such features. These fractions are significantly lower than predictions from most cosmological simulations, which estimate 20–40% incidence at similar surface brightness limits. Our results suggest that the low detection rates may reflect a genuine scarcity of tidal structures rather than limitations in observational depth or sample composition. Furthermore, a large portion of both samples consists of late-type galaxies, which may contribute to the discrepancy, as early-type galaxies more commonly host visible tidal features. This work highlights the need to reassess simulation assumptions and motivates future studies using deeper surveys, such as LSST, to bridge the gap between observation and theory further. Additionally, we classify disk warps as having an angle amplitude ≥ 3° and disk lopsidedness as having a radii ratio ≥ 0.10 at isophotes of 24 and 26 mag arcsec−2, finding occurrence fractions of 42.8% and 34.2% using the 26 mag arcsec−2 isophote, respectively, consistent with prior observational studies. However, unlike previous work, which often finds S-type warps to be more common, we observe a much lower fraction of S-type warps, only 7.1% in the EGIS sample, compared to the ∼ 30% reported by other studies.

Degree

College and Department

Computational, Mathematical, and Physical Sciences; Physics and Astronomy

Rights

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