All sky angular power spectrum: I. Estimating brightness temperature fluctuations using TGSS 150 MHz survey

Abstract

Measurements of the Galactic synchrotron emission is relevant for the 21-cm studies from the Epoch of Reionization. The study of the synchrotron emission is also useful to quantify 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 $(C_{\ell })$ measurements of the diffuse synchrotron emission using the TIFR GMRT Sky Survey (TGSS) at 150 {\rm MHz}. We estimate $C_{\ell }$ using visibility data both before and after subtracting the modelled point sources. The amplitude of the measured $C_{\ell }$ falls significantly after subtracting the point sources, and it is also slightly higher in the Galactic plane for the residual data. The residual $C_{\ell }$ is most likely to be dominated by the Galactic synchrotron emission. The amplitude of the residual $C_{\ell }$ falls significantly away from the Galactic plane. We find the measurements are quite symmetric in the Northern and Southern hemispheres except in the latitude range $15-30^{\circ }$ which is the transition region from the disk dominated to diffuse halo dominated region. The comparison between this interferometric measurement with the scaled version of the Haslam rms map at 150 {\rm MHz} shows that the correlation coefficient $(r)$ is more than 0.5 for most of the latitude ranges considered here. This signifies the TGSS survey is quite sensitive to the diffuse Galactic synchrotron radiation.

11 pages, 7 figures, Accepted for publication in MNRAS

References in corpus (11)

• Cosmology at Low Frequencies: The 21 cm Transition and the High-Redshift Universe
• First Season MWA EoR Power Spectrum Results at Redshift 7
• All-sky Galactic radiation at 45 MHz and spectral index between 45 and 408 MHz
• The 1.28 GHz MeerKAT DEEP2 Image
• Foregrounds for redshifted 21 cm studies of reionization: GMRT 153 MHz observations
• Characterizing Foreground for redshifted 21-cm radiation: 150 MHz GMRT observations
• GMRT observation towards detecting the Post-reionization 21-cm signal
• The impact of Galactic synchrotron emission on CMB anisotropy measurements. I. Angular power spectrum analysis of total intensity all-sky surveys
• The angular power spectrum measurement of the Galactic synchrotron emission in two fields of the TGSS survey
• Statistics of Galactic Synchrotron and Dust Foregrounds: Spectra, PDFs and Higher-Order Moments
• Clustering properties of TGSS radio sources

Cited by in corpus (19)

• Patterns of primary beam non-redundancy in close-packed 21 cm array observations
• Demonstrating the Tapered Gridded Estimator (TGE) for the Cosmological HI 21-cm Power Spectrum using $150\mathrm{MHz}$ GMRT observations
• Characterizing EoR foregrounds: A study of the Lockman Hole Region at 325 MHz
• A Stimulating Explanation of the Extragalactic Radio Background
• Statistical recovery of the BAO scale from multipoles of the beam-convolved 21cm correlation function
• Probing early universe through redshifted 21-cm signal: Modelling and observational challenges
• Towards 21-cm Intensity Mapping at $z=2.28$ with uGMRT using the Tapered Gridded Estimator I: Foreground Avoidance
• Measurement of the Anisotropy Power Spectrum of the Radio Synchrotron Background
• CII and HI 21-cm line intensity mapping from the EoR: Impact of the light-cone effect on auto and cross-power spectra
• Towards $21$-cm intensity mapping at $z=2.28$ with uGMRT using the tapered gridded estimator III: Foreground removal
• Galaxy power spectrum and biasing results from the LOFAR Two-metre Sky Survey (first data release)
• The Tracking Tapered Gridded Estimator for the 21-cm power spectrum from MWA drift scan observations I: Validation and preliminary results
• Towards $21$-cm intensity mapping at $z=2.28$ with uGMRT using the tapered gridded estimator II: Cross-polarization power spectrum
• Calibration requirements for Epoch of Reionization 21-cm signal observations -- II. Analytical estimation of the bias and variance with time-correlated residual gains
• Diffuse Sources, Clustering and the Excess Anisotropy of the Radio Synchrotron Background
• The Tracking Tapered Gridded Estimator (TTGE) for the power spectrum from drift scan observations
• Large HI optical depth and Redshifted 21-cm signal from cosmic dawn
• Calibration requirement for Epoch of Reionization 21-cm signal observation -- III. Bias and variance in uGMRT ELAIS-N1 field power spectrum
• Removing systematics-induced 21-cm foreground residuals by cross-correlating filtered data