First Results from HERA Phase I: Upper Limits on the Epoch of Reionization 21 cm Power Spectrum
Authors
Abdurashidova, Z
Alexander, P
Ali, ZS
Balfour, Y
Billings, TS
Bradley, RF
Burba, J
Carey, S
Cheng, C
Dexter, M
De Lera Acedo, E
Dibblee-Barkman, T
Ely, J
Fagnoni, N
Fritz, R
Gale-Sides, K
Glendenning, B
Grobbelaar, J
Halday, Z
Hewitt, JN
Hickish, J
Julius, A
Lanman, A
La Plante, P
Lekalake, T
Lewis, D
Macmahon, D
Malan, L
Malgas, C
Maree, M
Martinot, ZE
Matsetela, E
Molewa, M
Mosiane, T
Nikolic, B
Parsons, AR
Pascua, R
Pieterse, S
Razavi-Ghods, N
Ringuette, J
Robnett, J
Rosie, K
Smith, C
Syce, A
Zheng, H
Publication Date
2022Journal Title
Astrophysical Journal
ISSN
0004-637X
Publisher
American Astronomical Society
Volume
925
Issue
2
Language
en
Type
Article
This Version
VoR
Metadata
Show full item recordCitation
Abdurashidova, Z., Aguirre, J., Alexander, P., Ali, Z., Balfour, Y., Beardsley, A., Bernardi, G., et al. (2022). First Results from HERA Phase I: Upper Limits on the Epoch of Reionization 21 cm Power Spectrum. Astrophysical Journal, 925 (2) https://doi.org/10.3847/1538-4357/ac1c78
Abstract
We report upper-limits on the Epoch of Reionization (EoR) 21 cm power
spectrum at redshifts 7.9 and 10.4 with 18 nights of data ($\sim36$ hours of
integration) from Phase I of the Hydrogen Epoch of Reionization Array (HERA).
The Phase I data show evidence for systematics that can be largely suppressed
with systematic models down to a dynamic range of $\sim10^9$ with respect to
the peak foreground power. This yields a 95% confidence upper limit on the 21
cm power spectrum of $\Delta^2_{21} \le (30.76)^2\ {\rm mK}^2$ at $k=0.192\ h\
{\rm Mpc}^{-1}$ at $z=7.9$, and also $\Delta^2_{21} \le (95.74)^2\ {\rm mK}^2$
at $k=0.256\ h\ {\rm Mpc}^{-1}$ at $z=10.4$. At $z=7.9$, these limits are the
most sensitive to-date by over an order of magnitude. While we find evidence
for residual systematics at low line-of-sight Fourier $k_\parallel$ modes, at
high $k_\parallel$ modes we find our data to be largely consistent with thermal
noise, an indicator that the system could benefit from deeper integrations. The
observed systematics could be due to radio frequency interference, cable
sub-reflections, or residual instrumental cross-coupling, and warrant further
study. This analysis emphasizes algorithms that have minimal inherent signal
loss, although we do perform a careful accounting in a companion paper of the
small forms of loss or bias associated with the pipeline. Overall, these
results are a promising first step in the development of a tuned,
instrument-specific analysis pipeline for HERA, particularly as Phase II
construction is completed en route to reaching the full sensitivity of the
experiment.
Keywords
310, Galaxies and Cosmology
Identifiers
apjac1c78, ac1c78, aas30632
External DOI: https://doi.org/10.3847/1538-4357/ac1c78
This record's URL: https://www.repository.cam.ac.uk/handle/1810/333711
Rights
Licence:
http://creativecommons.org/licenses/by/4.0/
Statistics
Total file downloads (since January 2020). For more information on metrics see the
IRUS guide.
Recommended or similar items
The current recommendation prototype on the Apollo Repository will be turned off on 03 February 2023. Although the pilot has been fruitful for both parties, the service provider IKVA is focusing on horizon scanning products and so the recommender service can no longer be supported. We recognise the importance of recommender services in supporting research discovery and are evaluating offerings from other service providers. If you would like to offer feedback on this decision please contact us on: support@repository.cam.ac.uk