Power Spectrum of Cosmic String Perturbations on the Microwave Background
Abstract
I review recent progress towards a detailed understanding of the power spectrum of cosmic string perturbations induced on the Microwave Background (CMB). The use of a simple analytic model allows to include important effects that have not been included in previous studies. These effects are potential fluctuations on the last scattering surface (the Sachs-Wolfe effect) and Doppler CMB perturbations. These previously neglected fluctuations are shown to dominate over post-recombination fluctuations (Gott-Kaiser-Stebbins effect) on angular scales less than about $2^\circ$ assuming that no reionization occurs. The effective power spectrum index $n_{eff}$ is calculated on COBE scales and is shown to be somewhat larger than 1 ($1.35 \lsim n_{eff} \lsim 1.5$). After normalizing the model on COBE data and string simulations, I derive the predicted values of $({{\delta T}\over T})_{rms}$ for several ongoing CMB experiments on medium and small angular scales. A comparison is also made with current observations and predictions of models based on inflation.
- Publication:
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arXiv e-prints
- Pub Date:
- June 1994
- DOI:
- 10.48550/arXiv.astro-ph/9406020
- arXiv:
- arXiv:astro-ph/9406020
- Bibcode:
- 1994astro.ph..6020P
- Keywords:
-
- Astrophysics;
- High Energy Physics - Phenomenology
- E-Print:
- Invited Talk at the Global Foundation conference `Unified Symmetry of the Small and the Large', January 27-30 1994, Miami, Florida. To appear in the conference proceedings. 18 pages plus 6 figures (available in postscript from the author). Use LaTeX