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http://hdl.handle.net/20.500.12386/32540
Title: | First Results from HERA Phase I: Upper Limits on the Epoch of Reionization 21 cm Power Spectrum | Authors: | Abdurashidova, Zara Aguirre, James E. Alexander, Paul Ali, Zaki S. Balfour, Yanga Beardsley, Adam P. BERNARDI, GIANNI Billings, Tashalee S. Bowman, Judd D. Bradley, Richard F. BULL, PHILIP Burba, Jacob Carey, Steve Carilli, Chris L. Cheng, Carina DeBoer, David R. Dexter, Matt de Lera Acedo, Eloy Dibblee-Barkman, Taylor Dillon, Joshua S. Ely, John Ewall-Wice, Aaron Fagnoni, Nicolas Fritz, Randall Furlanetto, Steven R. Gale-Sides, Kingsley Glendenning, Brian Gorthi, Deepthi Greig, Bradley Grobbelaar, Jasper Halday, Ziyaad Hazelton, Bryna J. Hewitt, Jacqueline N. Hickish, Jack Jacobs, Daniel C. Julius, Austin Kern, Nicholas S. Kerrigan, Joshua Kittiwisit, Piyanat Kohn, Saul A. Kolopanis, Matthew Lanman, Adam La Plante, Paul Lekalake, Telalo Lewis, David Liu, Adrian MacMahon, David Malan, Lourence Malgas, Cresshim Maree, Matthys Martinot, Zachary E. Matsetela, Eunice Mesinger, Andrei Molewa, Mathakane Morales, Miguel F. Mosiane, Tshegofalang Murray, Steven G. Neben, Abraham R. Nikolic, Bojan Nunhokee, Chuneeta D. Parsons, Aaron R. Patra, Nipanjana Pascua, Robert Pieterse, Samantha Pober, Jonathan C. Razavi-Ghods, Nima Ringuette, Jon Robnett, James Rosie, Kathryn Sims, Peter Singh, Saurabh Smith, Craig Syce, Angelo Thyagarajan, Nithyanandan Williams, Peter K. G. Zheng, Haoxuan HERA Collaboration |
Issue Date: | 2022 | Journal: | THE ASTROPHYSICAL JOURNAL | Number: | 925 | Issue: | 2 | First Page: | 221 | Abstract: | We report upper limits on the Epoch of Reionization 21 cm power spectrum at redshifts 7.9 and 10.4 with 18 nights of data (~36 hr 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 ~10<SUP>9</SUP> with respect to the peak foreground power. This yields a 95% confidence upper limit on the 21 cm power spectrum of ${{\rm{\Delta }}}_{21}^{2}\leqslant {(30.76)}^{2}\ {\mathrm{mK}}^{2}$ at k = 0.192 h Mpc<SUP>-1</SUP> at z = 7.9, and also ${{\rm{\Delta }}}_{21}^{2}\leqslant {(95.74)}^{2}\ {\mathrm{mK}}^{2}$ at k = 0.256 h Mpc<SUP>-1</SUP> 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 <SUB>∥</SUB> modes, at high k <SUB>∥</SUB> 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 subreflections, 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. | URI: | http://hdl.handle.net/20.500.12386/32540 | URL: | https://iopscience.iop.org/article/10.3847/1538-4357/ac1c78 https://api.elsevier.com/content/abstract/scopus_id/85125844909 |
ISSN: | 0004-637X | DOI: | 10.3847/1538-4357/ac1c78 | Bibcode ADS: | 2022ApJ...925..221A | Fulltext: | open |
Appears in Collections: | 1.01 Articoli in rivista |
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HERA_II_22.pdf | Pdf editoriale | 4.63 MB | Adobe PDF | View/Open |
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