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Bright Source Subtraction Requirements for Redshifted 21 cm Measurements

Datta, A. and Bowman, J. D. and Carilli, C. L. (2010) Bright Source Subtraction Requirements for Redshifted 21 cm Measurements. Astrophysical Journal, 724 (1). pp. 526-538. ISSN 0004-637X.

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The H I 21 cm transition line is expected to be an important probe into the cosmic dark ages and epoch of reionization. Foreground source removal is one of the principal challenges for the detection of this signal. This paper investigates the extragalactic point source contamination and how accurately bright sources (≳ Jy) must be removed in order to detect 21 cm emission with upcoming radio telescopes such as the Murchison Widefield Array. We consider the residual contamination in 21 cm maps and power spectra due to position errors in the sky model for bright sources, as well as frequency-independent calibration errors. We find that a source position accuracy of 0.1 arcsec will suffice for detection of the H I power spectrum. For calibration errors, 0.05% accuracy in antenna gain amplitude is required in order to detect the cosmic signal. Both sources of subtraction error produce residuals that are localized to small angular scales, k⊥ ≳ 0.05 Mpc^(–1), in the two-dimensional power spectrum.

Item Type:Article
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Carilli, C. L.0000-0001-6647-3861
Additional Information:© 2010 American Astronomical Society. Received 2010 May 21; accepted 2010 September 17; published 2010 November 3. A.D. and C.L.C. are grateful for support from the Max- Planck Society and the Alexander von Humboldt Foundation through the Max Planck Forshungspreise 2005. J.D.B. is supported by NASA through Hubble Fellowship grant HF- 01205.01-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS 5-26555. The National Radio Astronomy Observatory is operated by Associated Universities, Inc., under cooperative agreement with the National Science Foundation. A.D. is grateful for support from NRAO through the graduate-intern program.
Funding AgencyGrant Number
Max-Planck SocietyUNSPECIFIED
Alexander von Humboldt FoundationMax Planck Forshungspreise 2005
NASAHubble Fellowship grant HF- 01205.01-A
Space Telescope Science InstituteUNSPECIFIED
Subject Keywords:early universe; intergalactic medium; methods: data analysis; radio lines: general; techniques: interferometric
Issue or Number:1
Classification Code:PACS: 98.58.Hf; 98.62.Ra; 98.62.Py; 95.30.Ky; 98.80.-k
Record Number:CaltechAUTHORS:20101206-095846998
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Official Citation:A. Datta et al 2010 ApJ 724 526 doi: 10.1088/0004-637X/724/1/526
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:21170
Deposited By: Jason Perez
Deposited On:06 Dec 2010 23:49
Last Modified:03 Oct 2019 02:20

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