High Resolution H I Distributions and Multi-Wavelength Analyses of Magellanic Spirals NGC 4618 and NGC 4625

Abstract

We present a detailed analysis of high resolution H I observations of the Magellanic spiral galaxies NGC 4618 and NGC 4625. While the H I disk of NGC 4625 is remarkably quiescent with a nearly uniform velocity dispersion and no evidence of H I holes, there is a dynamic interplay between star formation and the distribution of neutral hydrogen in NGC 4618. We calculate the critical density for widespread star formation in each galaxy and find that star formation proceeds even where the surface density of the atomic gas is well below the critical density necessary for global star formation. There are strong spatial correlations in NGC 4618 between UV emission, 1.4 GHz radio continuum emission, and peaks in the H I column density. Despite the apparent overlap of the outer disks of the two galaxies, we find that they are kinematically distinct, indicating that NGC 4618 and NGC 4625 are not interacting. The structure of NGC 4618 and, in particular, the nature of its outer ring, are highly suggestive of an interaction, but the timing and nature of such an interaction remain unclear.

References in corpus (2)

• Are the Magellanic Clouds on their First Passage about the Milky Way?
• Formation of the off-center bar in the Large Magellanic Cloud: A collision with a dark satellite ?

Cited by in corpus (5)

• Magnetic fields and star formation in low-mass Magellanic-type and peculiar galaxies
• Searching for Milky Way twins: Radial abundance distribution as a strict criterion
• A Comparison of the UV and HI Properties of the Extended UV (XUV) Disk Galaxies NGC 2541, NGC 5832 and ESO406-042
• A Multi-Wavelength Study of Star Formation in 15 Local Star-Forming Galaxies
• A pilot study using deep infrared imaging to constrain the star formation history of the XUV stellar populations in NGC 4625