2015/05/19 by Anwar Saleh AlMuhammad, AlMuhammad, Anwar Saleh
Earth and Planetary Sciences · Physics and Astronomy · #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #Geophysics and Gravity Measurements #astro-ph.CO #gr-qc
paper · pdf · doi:10.48550/arxiv.1505.05204
25 pages, 13 figures, Prepared for submission to JCAP
arxiv created 2015/05/19 · openalex publication_date 2015/05/19 · arxiv updated 2015/05/21 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We study the primordial magnetic field generated by the simple model f2 FF in Starobinsky, R2-inflationary, model. The scale invariant PMF is achieved at relatively high power index of the coupling function, | α| ≈ 7.44. This model does not suffer from the backreaction problem as long as, the rate of inflationary expansion, H, is in the order of or less than the upper bound reported by Planck (≤ 3.6 × 10-5 M_\rmPl) in both de Sitter and power law expansion, which show similar results. We calculate the lower limit of the reheating parameter, R_\rmrad > 6.888 in R2-inflation. Based on the upper limit obtained from CMB, we find that the upper limits of magnetic field and reheating energy density as, (ρ_B_\rmend )_\rmCMB < 1.184 × 10-20 M_\rmPl4 and (ρ_\rmreh )_\rmCMB < 8.480 × 10-22 M_\rmPl4. All of foregoing results are well more than the lower limit derived from WMAP7 for both large and small field inflation. By using the Planck inflationary constraints, 2015 in the context of R2-inflation, the upper limit of reheating temperature and energy density for all possible values of w _\rmreh are respectively constrained as, T_\rmreh < 4.32 × 1013 \rmGeV and ρ_\rmreh < 3.259 × 10-18 M_\rmPl4 at n_\rms ≈ 0.9674. This value of spectral index is well consistent with Planck, 2015 results. Adopting T_\rmreh, enables us to constrain the reheating e-folds number, N_\rmreh on the range 1 < N_\rmreh < 8.3, for - 1/3 < w_\rmreh < 1. By using the scale invariant PMF generated by f2 FF, we find that the upper limit of present magnetic field, B0 < 8.058 × 10-9 \rmG.