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The angular power spectrum measurement of the Galactic synchrotron emission using the TGSS survey

Published online by Cambridge University Press:  08 May 2018

Samir Choudhuri ,
Somnath Bharadwaj ,
Sk. Saiyad Ali ,
Nirupam Roy ,
H. T. Intema  and
Abhik Ghosh
Samir Choudhuri
Affiliation:
National Centre For Radio Astrophysics, Post Bag 3, Ganeshkhind, Pune 411 007, India Department of Physics, & Centre for Theoretical Studies, IIT Kharagpur, Kharagpur 721 302, India
Somnath Bharadwaj
Affiliation:
Department of Physics, & Centre for Theoretical Studies, IIT Kharagpur, Kharagpur 721 302, India
Sk. Saiyad Ali
Affiliation:
Department of Physics, Jadavpur University, Kolkata 700032, India
Nirupam Roy
Affiliation:
Department of Physics, Indian Institute of Science, Bangalore 560012, India
H. T. Intema
Affiliation:
Leiden Observatory, Leiden University, Niels Bohrweg 2, NL-2333CA, Leiden, The Netherlands
Abhik Ghosh
Affiliation:
Department of Physics and Astronomy, University of the Western Cape, Robert Sobukwe Road, Bellville 7535, South Africa SKA SA, The Park, Park Road, Pinelands 7405, South Africa
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Abstract

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Characterizing the diffuse Galactic synchrotron emission (DGSE) at arcminute angular scales is needed to remove this foregrounds in cosmological 21-cm measurements. Here, we present the angular power spectrum (Cℓ) measurement of the diffuse Galactic synchrotron emission using two fields observed by the TIFR GMRT Sky Survey (TGSS). We apply 2D Tapered Gridded Estimator (TGE) to estimate the Cℓ from the visibilities. We find that the residual data after subtracting the point sources is likely dominated by the diffuse Galactic synchrotron radiation across the angular multipole range 240 ≤ ℓ ≲ 500. We fit a power law to the measured Cℓ over this ℓ range. We find that the slopes in both fields are consistent with earlier measurements. For the second field, however, we interpret the measured Cℓ as an upper limit for the DGSE as there is an indication of a significant residual point source contribution.

Keywords

methods: statisticaldata analysis - techniques: interferometric- cosmology: diffuse radiation
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 12 , Symposium S333: Peering towards Cosmic Dawn , October 2017 , pp. 157 - 161
Copyright
Copyright © International Astronomical Union 2018 

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