• Prospects of Measuring the Angular Power Spectrum of the Diffuse Galactic Synchrotron Emission with SKA1 Low

• # Fulltext

https://www.ias.ac.in/article/fulltext/joaa/037/04/0035

• # Keywords

Methods: statistical, data analysis; techniques: interferometric; cosmology: diffuse radiation.

• # Abstract

The Diffuse Galactic Syncrotron Emission (DGSE) is the most important diffuse foreground component for future cosmological 21-cm observations. The DGSE is also an important probe of the cosmic ray electron and magnetic field distributions in the turbulent interstellar medium (ISM) of our galaxy. In this paper we briefly review the Tapered Gridded Estimator (TGE) which can be used to quantify the angular power spectrum $C_\ell$ of the sky signal directly from the visibilities measured in radio-interferometric observations. The salient features of the TGE are: (1) it deals with the gridded data which makes it computationally very fast, (2) it avoids a positive noise bias which normally arises from the system noise inherent to the visibility data, and (3) it allows us to taper the sky response and thereby suppresses the contribution from unsubtracted point sources in the outer parts and the side lobes of the antenna beam pattern. We also summarize earlier work where the TGE was used to measure the $C_\ell$ of the DGSE using 150 MHz GMRT data. Earlier measurements of $C_\ell$ are restricted to $\ell \le \ell _{\max } \sim 10^{3}$ for the DGSE, the signal at the larger $\ell$ values is dominated by the residual point sources after source subtraction. The higher sensitivity of the upcoming SKA1 Low will allow the point sources to be subtracted to a fainter level than possible with existing telescopes. We predict that it will be possible to measure the $C_\ell$ of the DGSE to larger values of $\ell _{\max }$ with SKA1 Low. Our results show that it should be possible to achieve $\ell _{\max }\sim 10^{4}$ and $∼10^5$ with 2 minutes and 10 hours of observations respectively.

• # Author Affiliations

1. Department of Physics, Jadavpur University, Kolkata 700 032, India.
2. Department of Physics and Centre for Theoretical Studies, Indian Institute of Technology Kharagpur, Kharagpur 721 302, India.
3. Kapteyn Astronomical Institute, P.O. Box 800, 9700 AV Groningen, The Netherlands.
4. Department of Physics, Indian Institute of Science, Bangalore 560 012, India.

• # Journal of Astrophysics and Astronomy

Volume 41, 2020
All articles
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• # Continuous Article Publication

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