Choudhuri, S and Ghosh, A and Roy, N and Bharadwaj, S and Intema, HT and Saiyad Ali, Sk (2020) All-sky angular power spectrum - I. Estimating brightness temperature fluctuations using the 150-MHz TGSS survey. In: Monthly Notices of the Royal Astronomical Society, 494 (2). pp. 1936-1945.
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Abstract
Measurements of the Galactic synchrotron emission are important for the 21-cm studies of the epoch of reionization. The study of synchrotron emission is also useful for quantifying the fluctuations in the magnetic field and the cosmic-ray electron density of the turbulent interstellar medium (ISM) of our Galaxy. Here, we present the all-sky angular power spectrum (Cl) measurements of the diffuse synchrotron emission obtained using the TIFR GMRT Sky Survey (TGSS) at 150 MHz. We estimate Cl using visibility data both before and after subtracting the modelled point sources. The amplitude of the measured Cl decreases significantly after subtracting the point sources, and it is slightly higher in the Galactic plane for the residual data. The residual Cl is most likely to be dominated by theGalactic synchrotron emission. The amplitude of the residual Cl decreases significantly away from the Galactic plane. We find that the measurements are quite symmetric in the Northern and Southern hemispheres except in the latitude range 15°-30°, which is the transition region from the discdominated to the diffuse halo-dominated region. A comparison between this interferometric measurement and the scaled version of the Haslam rms map at 150 MHz shows that the correlation coefficient (r) is greater than 0.5 for most of the latitude ranges considered here. This indicates that the TGSS is quite sensitive to the diffuse Galactic synchrotron radiation.
| Item Type: | Journal Article |
|---|---|
| Publication: | Monthly Notices of the Royal Astronomical Society |
| Publisher: | Oxford University Press |
| Additional Information: | The copyright for this article belongs to the Author(s). |
| Keywords: | Cosmology; Galaxies; Interferometry; Power spectrum; Synchrotron radiation; Synchrotrons, All-sky; Angular power spectrum; Dark age, reionization, first star; Methods. Data analysis; Methods:statistical; Radio continuum: galaxies; Radio continuum: general; Reionization; Synchrotron emission; Technique: interferometric, Surveys |
| Department/Centre: | Division of Physical & Mathematical Sciences > Physics |
| Date Deposited: | 23 Jan 2023 07:24 |
| Last Modified: | 23 Jan 2023 07:24 |
| URI: | https://eprints.iisc.ac.in/id/eprint/79256 |
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