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Low-frequency observations of the moon with the murchison widefield array

Citation

McKinley, B and Briggs, F and Kaplan, DL and Greenhill, LJ and Bernardi, G and Bowman, JD and De Oliveira-Costa, A and Tingay, SJ and Gaensler, BM and Oberoi, D and Johnston-Hollitt, M and Arcus, W and Barnes, D and Bunton, JD and Cappallo, RJ and Corey, BE and Deshpande, A and Desouza, L and Emrich, D and Goeke, R and Hazelton, BJ and Herne, D and Hewitt, JN and Kasper, JC and Kincaid, BB and Koenig, R and Kratzenberg, E and Lonsdale, CJ and Lynch, MJ and McWhirter, SR and Mitchell, DA and Morales, MF and Morgan, E and Ord, SM and Pathikulangara, J and Prabu, T and Remillard, RA and Rogers, AEE and Roshi, A and Salah, JE and Sault, RJ and Udaya Shankar, N and Srivani, KS and Stevens, J and Subrahmanyan, R and Wayth, RB and Waterson, M and Webster, RL and Whitney, AR and Williams, A and Williams, CL and Wyithe, JSB, Low-frequency observations of the moon with the murchison widefield array, Astronomical Journal, 145, (1) Article 23. ISSN 0004-6256 (2013) [Refereed Article]


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Copyright 2013 The American Astronomical Society

DOI: doi:10.1088/0004-6256/145/1/23

Abstract

A new generation of low-frequency radio telescopes is seeking to observe the redshifted 21cm signal from the epoch of reionization (EoR), requiring innovative methods of calibration and imaging to overcome the difficulties of wide-field low-frequency radio interferometry. Precise calibration will be required to separate the expected small EoR signal from the strong foreground emission at the frequencies of interest between 80 and 300MHz. The Moon may be useful as a calibration source for detection of the EoR signature, as it should have a smooth and predictable thermal spectrum across the frequency band of interest. Initial observations of the Moon with the Murchison Widefield Array 32 tile prototype show that the Moon does exhibit a similar trend to that expected for a cool thermally emitting body in the observed frequency range, but that the spectrum is corrupted by reflected radio emission from Earth. In particular, there is an abrupt increase in the observed flux density of the Moon within the internationally recognized frequency modulated (FM) radio band. The observations have implications for future low-frequency surveys and EoR detection experiments that will need to take this reflected emission from the Moon into account. The results also allow us to estimate the equivalent isotropic power emitted by the Earth in the FM band and to determine how bright the Earth might appear at meter wavelengths to an observer beyond our own solar system.

Item Details

Item Type:Refereed Article
Keywords:dark ages, reionization, first stars – extraterrestrial intelligence – Moon – techniques: interferometric Online-only material: color figures
Research Division:Physical Sciences
Research Group:Astronomical and Space Sciences
Research Field:Galactic Astronomy
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Physical Sciences
Author:Stevens, J (Dr Jamie Stevens)
ID Code:88389
Year Published:2013
Web of Science® Times Cited:11
Deposited By:Mathematics and Physics
Deposited On:2014-01-31
Last Modified:2014-05-26
Downloads:0

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