Properties of 3D HI Filaments in the Smith High Velocity Cloud

Abstract

We present findings of 3D filamentary structures in the Smith Cloud, a high-velocity cloud (HVC) located at $l=38^{\circ }$, $b=-13^{\circ }$. We use data from the Galactic Arecibo L-Band Feed Array \ion{H}{i} (GALFA-\ion{H}{i}) along with our new filament detection algorithm, \texttt{fil3d}, to characterize these structures. In this paper, we also discuss how different input parameters affect the output of \texttt{fil3d}. We study filaments in the local ISM and compare them to those found in the Smith Cloud. Based on thermal linewidth estimations we find supporting evidence that the Smith Cloud filaments are part of its warm neutral medium. We also find a relationship between thermal linewidth and the $v_{LSR}$ of the filaments. We study the plane-of-sky magnetic field as traced by Planck 353 GHz polarized dust emission along the line of sight and find the HI filaments in this region are not aligned with the magnetic field. This is likely related to their location close to dynamic processes in the Galactic Plane and/or the low column density of the filaments relative to emission in the Plane. The results show the HI filaments are found in a wide range of Galactic environments and form through multiple processes.

Accepted to MNRAS

References in corpus (18)

• Array Programming with NumPy
• HI4PI: A full-sky HI survey based on EBHIS and GASS
• The link between turbulence, magnetic fields, filaments, and star formation in the Central Molecular Zone cloud G0.253+0.016
• Distances to Galactic high-velocity clouds. I. Cohen Stream, complex GCP, cloud g1
• A new, large-scale map of interstellar reddening derived from HI emission
• An Accurate Distance to High-Velocity Cloud Complex C
• Smith's Cloud: A High-velocity Cloud Colliding with the Milky Way
• Mapping the Magnetic Interstellar Medium in Three Dimensions Over the Full Sky with Neutral Hydrogen
• Magnetically Dominated Strands of Cold Hydrogen in the Riegel-Crutcher Cloud
• The FAST all sky HI survey (FASHI): The first release of catalog
• Ionized Gas in the Smith Cloud
• Initial Conditions for Star Formation: A Physical Description of the Filamentary ISM
• The Galactic dynamics revealed by the filamentary structure in atomic hydrogen emission
• Constraining the Magnetic Field of the Smith High Velocity Cloud using Faraday rotation
• Magnetic field draping around clumpy high-velocity clouds in galactic halo
• Simulating the impact of the Smith Cloud
• The Kinematic Structure of Magnetically Aligned HI Filaments
• HI filaments as potential compass needles? Comparing the magnetic field structure of the Small Magellanic Cloud to the orientation of GASKAP-HI filaments

Cited by in corpus (2)

• Probing large-scale structures with the two-point function and the power spectrum: insights into cosmic clustering evolution
• Simulating High-Velocity Clouds in the Observational Plane: An Initial Study with the Smith Cloud