Astronomy and Astrophysics – Astrophysics
Scientific paper
2006-01-19
Astrophys.J. 643 (2006) 1-7
Astronomy and Astrophysics
Astrophysics
22 pages, 7 figures, accepted for publication in the Astrophysical Journal
Scientific paper
10.1086/502709
We compute the power spectrum of the Cosmic Microwave Background temperature anisotropies generated by the Intergalactic Medium. To estimate the electron pressure along the line of sight and its contribution to the Sunyaev-Zeldovich component of the CMB anisotropies, we assume the non-linear baryonic density contrast is well described by a log-normal distribution. For model parameters in agreement with observations and for an experiment operating in the Rayleigh-Jeans regime, the largest IGM contribution is expected at scales corresponding to multipole numbers of about 2000. The amplitude is rather uncertain and could be as large as 100-200 [mikroK]^2, comparable to the contribution of galaxy clusters. The actual value is strongly dependent on the gas polytropic index and the amplitude of the matter power spectrum sigma_8. At all redshifts, the largest contribution comes from scales very close to the comoving baryon Jeans length. This scale is not yet resolved in numerical simulations that follow the evolution of gas on cosmological scales. The anisotropy generated by the Intergalactic Medium could make compatible the excess of power measured by Cosmic Background Imager (CBI) on scales of l > 2000 with sigma_8=0.9. Taking the CBI result as an upper limit, the polytropic index can be constrained to < 1.5 at 2-sigma level at redshifts z ~ 0.1-0.4. With its large frequency coverage, the PLANCK satellite will be able to measure the secondary anisotropies coming from hot gas. Cluster and Intergalactic Medium contributions could be separated by cross correlating galaxy/cluster catalogs with CMB maps. This measurement will determine the state of the gas at low and intermediate redshifts.
Atrio-Barandela Fernando
Muecket Jan P.
No associations
LandOfFree
The Contribution of the Intergalactic Medium to Cosmic Microwave Background Anisotropies 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 Contribution of the Intergalactic Medium to Cosmic Microwave Background Anisotropies, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Contribution of the Intergalactic Medium to Cosmic Microwave Background Anisotropies will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-449120