Synthetic HI observations of a simulated spiral galaxy

Abstract

Using the Torus radiative transfer code we produce synthetic observations of the 21 cm neutral hydrogen line from an SPH simulation of a spiral galaxy. The SPH representation of the galaxy is mapped onto an AMR grid, and a ray tracing method is used to calculate 21 cm line emission for lines of sight through the AMR grid in different velocity channels and spatial pixels. The result is a synthetic spectral cube which can be directly compared to real observations. We compare our synthetic spectral cubes to observations of M31 and M33 and find good agreement, whereby increasing velocity channels trace the main disc of the galaxy. The synthetic data also show kinks in the velocity across the spiral arms, evidence of non-circular velocities. These are still present even when we blur our data to a similar resolution as the observations, but largely absent in M31 and M33, indicating those galaxies do not contain significant spiral shocks. Thus the detailed velocity structure of our maps better represent previous observations of the grand design spiral M81.

MNRAS accepted; 13 pages; 11 figures, 4 in colour

References in corpus (18)

• SPLASH: An interactive visualisation tool for Smoothed Particle Hydrodynamics simulations
• The VLA Galactic Plane Survey
• What is Driving the HI Velocity Dispersion?
• Simulating the formation of molecular clouds. I. Slow formation by gravitational collapse from static initial conditions
• Star Formation in Disk Galaxies. I. Formation and Evolution of Giant Molecular Clouds via Gravitational Instability and Cloud Collisions
• HI kinematics and dynamics of Messier 31
• Simulations of the grand design galaxy M51: a case study for analysing tidally induced spiral structure
• GMC formation by agglomeration and self gravity
• The formation of molecular clouds in spiral galaxies
• Giant Molecular Clouds in M31: I - Molecular Cloud Properties
• The ISM in spiral galaxies: can cooling in spiral shocks produce molecular clouds?
• The origin of large peculiar motions of star-forming regions and spiral structures of our Galaxy
• The Star-Forming Molecular Gas in High Redshift Submillimeter Galaxies
• Instabilities of Spiral Shocks -- II. A quasi-steady State in the multi-phase inhomogeneous ISM
• Magnetic fields and the dynamics of spiral galaxies
• Panchromatic Spectral Energy Distributions of Dusty Galaxies with RADISHE. I. Predictions for Herschel: Correlating Colors with Galactic Energy Sources
• Modelling circumstellar discs with 3D radiation hydrodynamics
• Topology of HI in the Large Magellanic Cloud

Cited by in corpus (11)

• Radiation hydrodynamics of triggered star formation: the effect of the diffuse radiation field
• The morphology of the Milky Way - I. Reconstructing CO maps from simulations in fixed potentials
• TORUS-3DPDR: A self-consistent code treating three-dimensional photoionization and photodissociation regions
• Synthetic observations of star formation and the interstellar medium
• How do different spiral arm models impact the ISM and GMC population?
• On the accuracy of HI observations in molecular clouds -- More cold HI than thought?
• Testing diagnostics of triggered star formation
• Assessing molecular line diagnostics of triggered star formation using synthetic observations
• The structure of HI in galactic disks: Simulations vs observations
• Analysis of the spiral structure in a simulated galaxy
• Giant molecular clouds: star factories of the galaxy