The Pursuit of Non-Gaussian Fluctuations in the Cosmic Microwave Background

Details The Pursuit of Non-Gaussian Fluctuations in the Cosmic Microwave Background The Pursuit of Non-Gaussian Fluctuations in the Cosmic Microwave Background

2002-06-04

arxiv.org/abs/astro-ph/0206039v1

Astronomy and Astrophysics

Astrophysics

129 pages, 38 figures, Ph.D. thesis at Tohoku University (September 2001)

Scientific paper

We present theoretical and observational studies of non-Gaussian fluctuations in CMB, by using the angular bispectrum and trispectrum. We predict the primary angular bispectrum from inflation, and forecast how well we can measure the primordial non-Gaussian signal. In addition to that, secondary anisotropy sources in the low-redshift universe also produce non-Gaussianity, so do foreground emissions from extragalactic or interstellar microwave sources. We study how well we can measure these non-Gaussian signals, including the primordial signal. We find that slow-roll inflation produces too small bispectrum to be detected by any experiments; thus, any detection strongly constrains this class of models. We also find that the secondary bispectrum from coupling between the SZ effect and the weak lensing effect, and the foreground bispectrum from extragalactic point sources, give detectable non-Gaussian signals on small angular scales. We test Gaussianity of the COBE DMR sky maps, by measuring all the modes of the angular bispectrum down to the DMR beam size. We find no significant signal of the bispectrum. We also find that the previously reported detection of the bispectrum is consistent with a statistical fluctuation. By fitting the theoretical prediction to the data for the primary bispectrum, we put a constraint on non-linearity in inflation. We conclude that the angular bispectrum finds no significant non-Gaussian signals in the DMR data. We present the first measurement of the angular trispectrum on the DMR sky maps, further testing Gaussianity of the DMR data. We find no significant non-Gaussian signals in the trispectrum. Therefore, the angular bispectrum and trispectrum show that the DMR sky map is comfortably consistent with Gaussianity.

Affiliated with

Also associated with

No associations

Rating

The Pursuit of Non-Gaussian Fluctuations in the Cosmic Microwave Background 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 The Pursuit of Non-Gaussian Fluctuations in the Cosmic Microwave Background, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Pursuit of Non-Gaussian Fluctuations in the Cosmic Microwave Background will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-96197