| Type |
Journal Article |
| Names |
Jungyeon Cho, A. Lazarian, Peter T. Timbie |
| Publication |
The Astrophysical Journal |
| Volume |
749 |
| Issue |
2 |
| Pages |
164 |
| Date |
April 1, 2012 |
| URL |
http://adsabs.harvard.edu/abs/2012ApJ...749..164C |
| Library Catalog |
NASA ADS |
| Abstract |
One of the main challenges for future 21 cm observations is to remove
foregrounds which are several orders of magnitude more intense than the
H I signal. We propose a new technique for removing foregrounds of the
redshifted 21 cm observations. We consider multi-frequency
interferometer observations. We assume that the 21 cm signals in
different frequency channels are uncorrelated and the foreground signals
change slowly as a function of frequency. When we add the visibilities
of all channels, the foreground signals increase roughly by a factor of
~N because they are highly correlated. However, the 21 cm signals
increase by a factor of {\sim} \sqrt{N} because the signals in different
channels contribute randomly. This enables us to obtain an accurate
shape of the foreground angular power spectrum. Then, we obtain the 21
cm power spectrum by subtracting the foreground power spectrum obtained
this way. We describe how to obtain the average power spectrum of the 21
cm signal. |
| Tags |
ISM: General, cosmology: observations, large-scale structure of Universe, turbulence |