HI 21 cm opacity fluctuations power spectra towards Cassiopeia A

Details HI 21 cm opacity fluctuations power spectra towards Cassiopeia A HI 21 cm opacity fluctuations power spectra towards Cassiopeia A

2010-02-22

arxiv.org/abs/1002.4192v2

2010, MNRAS, 404, L45

Astronomy and Astrophysics

Astrophysics

Galaxy Astrophysics

5 pages, 3 figures. Corrected minor typos. Accepted for publication in MNRAS Letters. The definitive version is available at

Scientific paper

10.1111/j.1745-3933.2010.00831.x

The angular power spectrum of HI 21 cm opacity fluctuations is a useful statistic for quantifying the observed opacity fluctuations as well as for comparing these with theoretical models. We present here the HI 21 cm opacity fluctuation power spectrum towards the supernova remnant Cas A from interferometric data with spacial resolution of 5" and spectral resolution of 0.4 km/s. The power spectrum has been estimated using a simple but robust visibility based technique. We find that the power spectrum is well fit by a power law P_tau(U) = U^{alpha} with a power law index of alpha ~ -2.86 +/- 0.10 (3 sigma error) over the scales of 0.07 - 2.3 pc for the gas in the Perseus spiral arm and 0.002 - 0.07 pc (480 - 15730 au) for that in the Local arm. This estimated power law index is consistent with earlier observational results based on both HI emission over larger scales and absorption studies over a similar range of scales. We do not detect any statistically significant change in the power law index with the velocity width of the frequency channels. This constrains the power law index of the velocity structure function to be beta = 0.2 +/- 0.6 (3 sigma error).

Affiliated with

Also associated with

No associations

Rating

HI 21 cm opacity fluctuations power spectra towards Cassiopeia A does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with HI 21 cm opacity fluctuations power spectra towards Cassiopeia A, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and HI 21 cm opacity fluctuations power spectra towards Cassiopeia A will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-169126