Details
| Original language | English |
|---|---|
| Article number | 150 |
| Number of pages | 8 |
| Journal | Astrophysical Journal |
| Volume | 831 |
| Issue number | 2 |
| Early online date | 4 Nov 2016 |
| Publication status | Published - 10 Nov 2016 |
Abstract
We use time-domain electromagnetic simulations to determine the spectral characteristics of the Hydrogen Epoch of Reionization Arrays (HERA) antenna. These simulations are part of a multi-faceted campaign to determine the effectiveness of the dish's design for obtaining a detection of redshifted 21 cm emission from the epoch of reionization. Our simulations show the existence of reflections between HERA's suspended feed and its parabolic dish reflector that fall below -40 dB at 150 ns and, for reasonable impedance matches, have a negligible impact on HERA's ability to constrain EoR parameters. It follows that despite the reflections they introduce, dishes are effective for increasing the sensitivity of EoR experiments at a?relatively low cost. We find that electromagnetic resonances in the HERA feed's cylindrical skirt, which is intended to reduce cross coupling and beam ellipticity, introduces significant power at large delays (-40 dB at 200 ns), which can lead to some loss of measurable Fourier modes and a modest reduction in sensitivity. Even in the presence of this structure, we find that the spectral response of the antenna is sufficiently smooth for delay filtering to contain foreground emission at line-of-sight wave numbers below kP 2.2 h Mpc-1, in the region where the current PAPER experiment operates. Incorporating these results into a Fisher Matrix analysis, we find that the spectral structure observed in our simulations has only a small effect on the tight constraints HERA can achieve on parameters associated with the astrophysics of reionization.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Astronomy and Astrophysics
- Earth and Planetary Sciences(all)
- Space and Planetary Science
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In: Astrophysical Journal, Vol. 831, No. 2, 150, 10.11.2016.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Einstein@Home discovery of a Double-Neutron Star Binary in the PALFA Survey
AU - Lazarus, P.
AU - Freire, P. C.C.
AU - Allen, B.
AU - Aulbert, C.
AU - Bock, O.
AU - Bogdanov, S.
AU - Brazier, A.
AU - Camilo, F.
AU - Cardoso, F.
AU - Chatterjee, S.
AU - Cordes, J. M.
AU - Crawford, F.
AU - Deneva, J. S.
AU - Eggenstein, H. B.
AU - Fehrmann, H.
AU - Ferdman, R.
AU - Hessels, J. W.T.
AU - Jenet, F. A.
AU - Karako-Argaman, C.
AU - Kaspi, V. M.
AU - Knispel, B.
AU - Lynch, R.
AU - Van Leeuwen, J.
AU - MacHenschalk, B.
AU - Madsen, E.
AU - McLaughlin, M. A.
AU - Patel, C.
AU - Ransom, S. M.
AU - Scholz, P.
AU - Seymour, A.
AU - Siemens, X.
AU - Spitler, L. G.
AU - Stairs, I. H.
AU - Stovall, K.
AU - Swiggum, J.
AU - Venkataraman, A.
AU - Zhu, W. W.
PY - 2016/11/10
Y1 - 2016/11/10
N2 - We use time-domain electromagnetic simulations to determine the spectral characteristics of the Hydrogen Epoch of Reionization Arrays (HERA) antenna. These simulations are part of a multi-faceted campaign to determine the effectiveness of the dish's design for obtaining a detection of redshifted 21 cm emission from the epoch of reionization. Our simulations show the existence of reflections between HERA's suspended feed and its parabolic dish reflector that fall below -40 dB at 150 ns and, for reasonable impedance matches, have a negligible impact on HERA's ability to constrain EoR parameters. It follows that despite the reflections they introduce, dishes are effective for increasing the sensitivity of EoR experiments at a?relatively low cost. We find that electromagnetic resonances in the HERA feed's cylindrical skirt, which is intended to reduce cross coupling and beam ellipticity, introduces significant power at large delays (-40 dB at 200 ns), which can lead to some loss of measurable Fourier modes and a modest reduction in sensitivity. Even in the presence of this structure, we find that the spectral response of the antenna is sufficiently smooth for delay filtering to contain foreground emission at line-of-sight wave numbers below kP 2.2 h Mpc-1, in the region where the current PAPER experiment operates. Incorporating these results into a Fisher Matrix analysis, we find that the spectral structure observed in our simulations has only a small effect on the tight constraints HERA can achieve on parameters associated with the astrophysics of reionization.
AB - We use time-domain electromagnetic simulations to determine the spectral characteristics of the Hydrogen Epoch of Reionization Arrays (HERA) antenna. These simulations are part of a multi-faceted campaign to determine the effectiveness of the dish's design for obtaining a detection of redshifted 21 cm emission from the epoch of reionization. Our simulations show the existence of reflections between HERA's suspended feed and its parabolic dish reflector that fall below -40 dB at 150 ns and, for reasonable impedance matches, have a negligible impact on HERA's ability to constrain EoR parameters. It follows that despite the reflections they introduce, dishes are effective for increasing the sensitivity of EoR experiments at a?relatively low cost. We find that electromagnetic resonances in the HERA feed's cylindrical skirt, which is intended to reduce cross coupling and beam ellipticity, introduces significant power at large delays (-40 dB at 200 ns), which can lead to some loss of measurable Fourier modes and a modest reduction in sensitivity. Even in the presence of this structure, we find that the spectral response of the antenna is sufficiently smooth for delay filtering to contain foreground emission at line-of-sight wave numbers below kP 2.2 h Mpc-1, in the region where the current PAPER experiment operates. Incorporating these results into a Fisher Matrix analysis, we find that the spectral structure observed in our simulations has only a small effect on the tight constraints HERA can achieve on parameters associated with the astrophysics of reionization.
UR - http://www.scopus.com/inward/record.url?scp=84994491828&partnerID=8YFLogxK
U2 - 10.48550/arXiv.1608.08211
DO - 10.48550/arXiv.1608.08211
M3 - Article
AN - SCOPUS:84994491828
VL - 831
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 2
M1 - 150
ER -