Using eagle simulations to study the effect of observational constraints on the determination of H i asymmetries in galaxies. Issue 4 (3rd May 2022)

• Record Type: Journal Article
• Authors: Bilimogga, Pooja V; Oman, Kyle A; Verheijen, Marc A W; van der Hulst, Thijs
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 513:Issue 4(2022)
• Page Start: 5310
• Page End: 5327
• Publication Date: 2022-05-03
• Subjects: methods: data analysis -- methods: miscellaneous -- galaxies: structure; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stac1213
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: We investigate the effect of observational constraints such as signal-to-noise (S/N) ratio, resolution, and column density level on the H i morphological asymmetry ( A mod ) and the effect of noise on the H i global profile ( A flux ) asymmetry indices. Using mock galaxies from the eagle simulations, we find an optimal combination of the observational constraints that are required for a robust measurement of the A mod value of a galaxy: a column density threshold of 5 × 10 19 cm −2 or lower at a minimal S/N of 3 and a galaxy resolved with atleast 11 beams. We also use mock galaxies to investigate the effect of noise on the A flux values and conclude that a global profile with S/N greater than 6 is required to achieve a robust measurement of asymmetry. We investigate the relation between A mod and A flux indices and find them to be uncorrelated, which implies that A flux values cannot be used to predict morphological asymmetries in galaxies.