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Validating a novel angular power spectrum estimator using simulated low frequency radio-interferometric data

Choudhuri, Samir and Roy, Nirupam and Bharadwaj, Somnath and Ali, Saiyad SK and Ghosh, Abhik and Dutta, Prasun (2017) Validating a novel angular power spectrum estimator using simulated low frequency radio-interferometric data. In: NEW ASTRONOMY, 57 . pp. 94-103.

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Official URL: http://doi.org/10.1016/j.newast.2017.06.010

Abstract

The ``Tapered Gridded Estimator'' (TGE) is a novel way to directly estimate the angular power spectrum from radio-interferometric visibility data that reduces the computation by efficiently gridding the data, consistently removes the noise bias, and suppresses the foreground contamination to a large extent by tapering the primary beam response through an appropriate convolution in the visibility domain. Here we demonstrate the effectiveness of TGE in recovering the diffuse emission power spectrum through numerical simulations. We present details of the simulation used to generate low frequency visibility data for sky model with extragalactic compact radio sources and diffuse Galactic synchrotron emission. We then use different imaging strategies to identify the most effective option of point source subtraction and to study the underlying diffuse emission. Finally, we apply TGE to the residual data to measure the angular power spectrum, and assess the impact of incomplete point source subtraction in recovering the input power spectrum C-t of the synchrotron emission. This estimator is found to successfully recovers the C-t of input model from the residual visibility data. These results are relevant for measuring the diffuse emission like the Galactic synchrotron emission. It is also an important step towards characterizing and removing both diffuse and compact foreground emission in order to detect the redshifted 21 cm signal from the Epoch of Reionization. (C) 2017 Elsevier B.V. All rights reserved.

Item Type: Journal Article
Additional Information: Copy right for this article belongs to the ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Depositing User: Id for Latest eprints
Date Deposited: 16 Sep 2017 06:29
Last Modified: 21 Feb 2019 05:16
URI: http://eprints.iisc.ac.in/id/eprint/57780

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