## 1/f noise in WMAP 3yr data

carlos monteserin
Posts: 1
Joined: February 08 2007
Affiliation: IFCA (Santander,Spain)

### 1/f noise in WMAP 3yr data

Hello!

white noise dispersion maps are approximately sqrt(3) times lower in WMAP coadded 3yr than in single 1yr maps.

somebody knows how much is this factor for the 1/f noise?

Thanks

Tom Crawford
Posts: 8
Joined: December 29 2004
Affiliation: University of Chicago

### 1/f noise in WMAP 3yr data

There are only two reasons why the 1/f contributions wouldn't also be $\sqrt{3}$ lower:

1) The amplitude of the 1/f sources changed appreciably over years two and three.

2) The sources of 1/f aren't really noise (i.e., they're coherent in some basis that matters to the instrument), and so they don't integrate down as $\sqrt{N}$.

Given the observed stability of the instrument, I think 1) is unlikely, and 2) is something that I think the WMAP team has checked pretty thoroughly. So I think you're probably safe in assuming that the 1/f scales the same way the white noise does.

(Of course, I'm not on the WMAP team, so there may be something important that I'm missing.)