HI Power Spectrum Analysis

CGPS Science Project
HI Power Spectrum Analysis

People involved

Chris Brunt:
Five College Radio Astronomy Observatory University of Massachusetts
Lederle Research Tower
Amherst, MA 01003
United States
Steve Gibson:
Dept. of physics and astronomy
University of Calgary
2500 University Dr. NW
Calgary AB T2N 1N4
Dave Green:
Mullard Radio Astronomy Observatory
Cavendish Laboratory
Madingley Road
Cambridge CB3 0HE
United Kingdom
Magdalen Normandeau:
Astronomy Department
601 Campbell Hall
University of California
Berkeley CA 94720-3411
United States
Chris Purton:
Box 248
Penticton BC V2A 6K3
Zhang Xi-Zhen:
Beijing Astronomical Observatory
Chinese Academy of Science
15 Zhongguancun
Beijing 100875
People's Republic of China

Outline of the project

While we often tend to think of HI emission in terms of distinct features (e.g. clouds, filaments), it is far from clear that this is an accurate way of characterizing the neutral hydrogen distribution. A better description may be that what we detect are wrinkles in the general HI fabric.

The plan is to investigate the power spectrum of HI along different lines of sight to determine the influence of events such as star formation and supernovae on the shape of the distribution.

Specific plans

Steve, Dave, Magdalen and Chris had a bit of a chat about the power spectrum project while at the Naramata ISM workshop. After sitting through many talks about turbulence etc, we were all convinced that this project is worth doing. We discussed what approach to take to tackle the mounds of data and it was decided that an automated version of the approach Dave used a few years back would probably be the best place to start.

Because it is best to deal only with the SST data (why add in the uncertainty of the single dish scale?) and because we will be looking at something in the visibility plane, we will have to go back to the individual field u-v data files. Dave has tested his software and it now reads and decodes the new (all things being relative) DRAO format .TBL and .HISTORY files for any survey and then the appropriate data and flag files (test only performed for one field so far but nothing is hardwired for that specific field). "I've still got quite a bit of work to do to get the analysis done in annuli in a general way, and then I'll have to do various tests to check things to see if the noise removal will work with the new correlator data as it did previously. In particular I'll test it with the CGPS field near the field I processed before... to ensure I get the same sort of results!" (DAG - 27Apr99)


Commentaires ou suggestions? Comments or suggestions?
Ecrivez à / Write to mnormandeau@astro.berkeley.edu