Broken blue-tilted inflationary gravitational waves: a joint analysis of NANOGrav 15-year and BICEP/Keck 2018 data
| Autor: | Jiang, Jun-Qian, Cai, Yong, Ye, Gen, Piao, Yun-Song |
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| Rok vydání: | 2023 |
| Předmět: | |
| Zdroj: | JCAP 05 (2024) 004 |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1088/1475-7516/2024/05/004 |
| Popis: | Recently, the pulsar timing array (PTA) collaborations have reported the evidence for a stochastic gravitational wave background (SGWB) at nano-Hertz band. The spectrum of inflationary gravitational wave (IGW) is unknown, which might exhibit different power law at different frequency-bands, thus if the PTA signal is primordial, it will be significant to explore the underlying implications of current PTA and CMB data on IGW. In this paper, we perform a joint Markov Chain Monte Carlo analysis for a broken power-law spectrum of IGW with the NANOGrav 15-year and BICEP/Keck 2018 data. It is found that though the bestfit spectral tilt of IGW at PTA band is $n^\text{PTA}_\text{T} =2.42^{+0.32}_{-0.91}$, at CMB band the bestfit is $n^\text{CMB}_\text{T} =0.55^{+0.37}_{-0.10}$ while a detectable amplitude of $r$ with $n^\text{CMB}_\text{T} \simeq 0$ is still compatible. The implication of our results for inflation is also discussed. Comment: 19 pages, 3 figures |
| Databáze: | arXiv |
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