以BICEP/Keck陣列及南極望遠鏡數據規範宇宙暴脹

以BICEP/Keck陣列及南極望遠鏡數據規範宇宙暴脹


Seminar:- Constraining Inflation with BICEP/Keck Array and the South Pole Telescope

Inflation generically predicts a background of primordial gravitational waves, which generate a primordial B-mode component in the polarization of the cosmic microwave background (CMB). The measurement of such a B-mode signature would lend significant support to the paradigm of inflation and be important for development of quantum gravity theories. Observed B modes also contain a component from the gravitational lensing of primordial E modes, which can obscure the measurement of the primordial B modes. If the amplitude of primordial B modes is sufficiently small, the lensing component will need to be cleaned using a process called ‘delensing.’ Delensing has been studied theoretically and with simulations but has not been demonstrated with data until recently. The speaker will present delensing of a measurement of the CMB B-mode power spectrum from SPTpol using data from Herschel as a tracer of the lensing potential. The measured B-mode power is reduced by 28 percent on sub-degree scales, in agreement with predictions from simulations, and the null hypothesis of no delensing is ruled out at 6.9 sigma (arXiv: 1701.04396). Then the speaker will give an update on the current delensing effort on the BICEP/Keck data. This analysis will reduce the uncertainty in the constraint in the primordial B modes (parameterized through the tensor-to-scalar ratio, r ). The speaker will provide an outlook of constraining inflation with the upcoming experiments BICEP3, BICEP Array, and SPT-3G through delensing. Finally, she will conclude with the reach and capabilities of the next generation ground-based CMB experiment CMB-S4. 
 
時間:2017.12.20(三) 14:30 ~ 15:15
地點:香港中文大學 科學館北座G25室
講者:巫惠玲 博士 Dr. Kimmy WU(Kavli Institute of Cosmological Physics The University of Chicago, USA)
語言:英語

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