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The 21 cm Power Spectrum from the Cosmic Dawn: First Results from the OVRO-LWA

Eastwood, Michael W. and Anderson, Marin M. and Monroe, Ryan M. and Hallinan, Gregg and Catha, Morgan and Dowell, Jayce and Garsden, Hugh and Greenhill, Lincoln J. and Hicks, Brian C. and Kocz, Jonathon and Price, Danny C. and Schinzel, Frank K. and Vedantham, Harish and Wang, Yuankun (2019) The 21 cm Power Spectrum from the Cosmic Dawn: First Results from the OVRO-LWA. Astronomical Journal, 158 (2). Art. No. 84. ISSN 1538-3881. doi:10.3847/1538-3881/ab2629.

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The 21 cm transition of neutral hydrogen is opening an observational window into the Cosmic Dawn of the universe—the epoch of first star formation. We use 28 hr of data from the Owens Valley Radio Observatory Long Wavelength Array to place upper limits on the spatial power spectrum of 21 cm emission at z ≈ 18.4 (Δ_(21) ≾ 10^4 mK), and within the absorption feature reported by the EDGES experiment. In the process we demonstrate the first application of the double Karhunen–Loève transform for foreground filtering, and diagnose the systematic errors that are currently limiting the measurement. We also provide an updated model for the angular power spectrum of low-frequency foreground emission measured from the northern hemisphere, which can be used to refine sensitivity forecasts for next-generation experiments.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Eastwood, Michael W.0000-0002-4731-6083
Anderson, Marin M.0000-0003-2238-2698
Hallinan, Gregg0000-0002-7083-4049
Dowell, Jayce0000-0003-1407-0141
Greenhill, Lincoln J.0000-0003-4912-5974
Kocz, Jonathon0000-0003-0249-7586
Price, Danny C.0000-0003-2783-1608
Schinzel, Frank K.0000-0001-6672-128X
Vedantham, Harish0000-0002-0872-181X
Additional Information:© 2019 The American Astronomical Society. Received 2018 November 4; revised 2019 May 20; accepted 2019 May 30; published 2019 July 29. This material is based in part upon work supported by the National Science Foundation under grants AST-1654815 and AST-1212226. The OVRO-LWA project was initiated through the kind donation of Deborah Castleman and Harold Rosen. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration, including partial funding through the President's and Director's Fund Program. This work has benefited from open-source technology shared by the Collaboration for Astronomy Signal Processing and Electronics Research (CASPER). We thank the Xilinx University Program for donations; NVIDIA for proprietary tools, discounts, and donations; and Digicom for collaboration on the manufacture and testing of DSP processors. We thank the Smithsonian Astrophysical Observatory Submillimeter Receiver Lab for the collaboration of its members, and the observatory for research and development funds. Development, adaptation, and operation of the LEDA real-time digital signal-processing systems at OVRO-LWA have been supported in part by NSF grants AST/1106059, PHY/0835713, OIA/1125087, and AST/1616709.
Funding AgencyGrant Number
JPL President and Director's FundUNSPECIFIED
Smithsonian Astrophysical ObservatoryUNSPECIFIED
Subject Keywords:cosmology: observations – dark ages, reionization, first stars
Issue or Number:2
Record Number:CaltechAUTHORS:20190722-111331237
Persistent URL:
Official Citation:Michael W. Eastwood et al 2019 AJ 158 84
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:97322
Deposited By: Tony Diaz
Deposited On:22 Jul 2019 18:25
Last Modified:16 Nov 2021 17:30

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