TY - JOUR

T1 - Examination of the Functional Form of the Light and Mass Distribution in Spiral Arms

AU - Chugunov, Ilia V.

AU - Marchuk, Alexander A.

AU - Савченко, Сергей Сергеевич

PY - 2025/4/19

Y1 - 2025/4/19

N2 - Spiral arms are a common feature of local galaxies, but the exact form of the distribution of mass and light in them is not well known. In this work, we aim to measure this distribution as accurately as possible, focusing on individual spiral arms and using the so-called slicing method. The sample consists of 19 well-resolved, viewed face-on spiral galaxies from the S4G survey. We work primarily with infrared images at 3.6 μm from the same survey and, secondarily, with ultraviolet data from the GALEX telescope. We derive the properties of the spiral arms step by step, starting from their overall shape, then measuring their brightness profile and width variation along the arm and then examining the fine structure of the profile across the arm, namely, its skewness and Sérsic index. We construct a 2D photometric function of the spiral arm that can be used in further decomposition studies, validate it and identify the most and least important parameters. Finally, we show how our results can be used to unravel the nature of the spiral arms, supporting the evidence that NGC 4535 has a density wave in its disc.

AB - Spiral arms are a common feature of local galaxies, but the exact form of the distribution of mass and light in them is not well known. In this work, we aim to measure this distribution as accurately as possible, focusing on individual spiral arms and using the so-called slicing method. The sample consists of 19 well-resolved, viewed face-on spiral galaxies from the S4G survey. We work primarily with infrared images at 3.6 μm from the same survey and, secondarily, with ultraviolet data from the GALEX telescope. We derive the properties of the spiral arms step by step, starting from their overall shape, then measuring their brightness profile and width variation along the arm and then examining the fine structure of the profile across the arm, namely, its skewness and Sérsic index. We construct a 2D photometric function of the spiral arm that can be used in further decomposition studies, validate it and identify the most and least important parameters. Finally, we show how our results can be used to unravel the nature of the spiral arms, supporting the evidence that NGC 4535 has a density wave in its disc.

KW - galaxies

KW - spiral structure

KW - photometric decomposition

KW - Astrophysics of Galaxies

UR - https://www.mendeley.com/catalogue/424b0611-8e36-3b38-82bd-2cdc46d7741c/

U2 - 10.3390/galaxies13020044

DO - 10.3390/galaxies13020044

M3 - Article

VL - 13

SP - 44

JO - Galaxies

JF - Galaxies

SN - 2075-4434

IS - 2

ER -