High Velocity Clouds Project
The purpose of this project is to make high-sensitivity (rms ~ 0.03K) observations of HVC regions around the Andromeda Galaxy with the Green Bank 20 meter telescope.
Below are some details about the 20 meter's capabilities and about what we hope to learn from this project.
20 Meter Notes and Links
Questions about using the 20-Meter:
- Once I've taken the independent track scans, how do I splice them into a map?
- Other questions will be added as needed.
The Northern Region of M31
Braun and Thilker (2004) mapped a region to the north of M31 with the Westerbork Array and found evidence of HVC's. In 2016, Wolfe et al did some track scans in that same region and found some conflicting results. We hope to figure out what's really going on in that part of the sky, in order to learn more about the origins of HI around M31. Right now, some hypotheses about the origins of the M31 HVCs include:
- The possibility that HVCs are really dwarf galaxies
- They are the baryonic component of dark matter halos
- They are condensations of hot gas in the CGM
- They are the result of past gravitational interactions between M31 and other massive nearby objects (i.e. dwarf galaxies)
By mapping the northern M31 region, we hope to be able to learn something about the HVCs' properties and thus test some of these hypotheses.
Questions I have about the science portion of this project:
- How do you determine the mass of a gas cloud?
- More will be added as I think of them...