Dipole of the Epoch of reionization 21-cm signal
- Brookhaven National Lab. (BNL), Upton, NY (United States)
The motion of the Solar System with respect to the cosmic rest frame modulates the monopole of the epoch of reionization 21-cm signal into a dipole. This dipole has a characteristic frequency dependence that is dominated by the frequency derivative of the monopole signal. We argue that although the signal is weaker by a factor of ~100, there are significant benefits in measuring the dipole. Most importantly, the direction of the cosmic velocity vector is known exquisitely well from the cosmic microwave background and is not aligned with the galaxy velocity vector that modulates the foreground monopole. Furthermore, an experiment designed to measure a dipole can rely on differencing patches of the sky rather than making an absolute signal measurement, which helps with some systematic effects.
- Research Organization:
- Brookhaven National Laboratory (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), High Energy Physics (HEP)
- Grant/Contract Number:
- SC00112704; 16-038
- OSTI ID:
- 1368677
- Alternate ID(s):
- OSTI ID: 1351053
- Report Number(s):
- BNL-114019-2017-JA; PRLTAO; TRN: US1702753
- Journal Information:
- Physical Review Letters, Vol. 118, Issue 15; ISSN 0031-9007
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Dipole Anisotropy as an Essential Qualifier for the Monopole Component of the Cosmic-dawn Spectral Signature, and the Potential of Diurnal Pattern for Foreground Estimation
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journal | October 2018 |
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