Dark Matter Dominance and Disk Stability in the Dwarf Irregular Galaxy NGC 3741

Authors: Efe Yenice, Ahmet Selim Çevirgen, Aslıhan Kalender Bozkurt

Abstract

We present a detailed analysis of the dark matter distribution and disk stability of the dwarf irregular galaxy NGC 3741 using multi-wavelength observations. HI, optical, and near-ultraviolet (NUV) imaging data were retrieved from the SkyView Virtual Observatory, providing a comprehen- sive view of both the gaseous and stellar components.

Using the HI surface density and rotation curve data available from the literature, we estimate the dynamical mass distribution, revealing a total dark matter mass of ∼ 3.1 × 10⁹ M⊙ within the observed HI disk, corresponding to a dark matter to baryon ratio of ∼18. The extended HI disk permits the calculation of the Toomre stability parameter, showing that the gas disk is broadly stable against axisymmetric collapse (Q > 1). Turbulent pressure, estimated from the observed HI velocity dispersion (σg ∼ 8 km s⁻¹), contributes significantly to this stability, consistent with the low star formation efficiency observed in this system.

Our results demonstrate that NGC 3741 is dark matter dominated, and that turbulence and differential rotation provide sufficient support to stabilize its extended gaseous disk. This study highlights the importance of multi-wavelength observations in understanding the dynamical structure and internal pressure support mechanisms in gas-rich dwarf irregular galaxies.

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