Investigating the Contribution of Extended Radio Sources to the Epoch of Reionisation Power Spectrum

Abstract

We investigate the contribution of extended radio sources such as Centaurus A, and Galactic supernova remnants (SNRs) to our ability to detect the statistical $21\mathrm{cm}$ signal from the Epoch of Reionisation (EoR) with the Murchison Widefield Array (MWA). These sources are typically ignored because they are in highly attenuated parts of the MWA primary beam, however in aggregate these sources have apparent flux densities of $10\mathrm{Jy}$ on angular scales we expect to detect the $21\mathrm{cm}$ signal. We create bespoke multi-component 2D Gaussian models for Galactic SNRs and for Centaurus A, and simulate the visibilities for two MWA snapshot observations. We grid those visibilities and then Fourier transform them with respect to frequency, averaging them both spherically and cylindrically to produce the 1D and 2D power spectra. We compare the simulated 1D power spectra to the expected $21\mathrm{cm}$ power spectrum. We find that although these extended sources are in highly attenuated parts of the MWA primary beam pattern, collectively they have enough power ($\sim 10^4-10^5\mathrm{m}{\mathrm{K}}^2{h}^{-3}\mathrm{Mp}{\mathrm{c}}^3$) on EoR significant modes ($|\mathbf{k}|\le 0.1h{\mathrm{Mpc}}^{-1}$) to prohibit detection of the $21\mathrm{cm}$ signal ($10^4\mathrm{m}{\mathrm{K}}^2{h}^{-3}\mathrm{Mp}{\mathrm{c}}^3$). We find that $50-90\%$ of sources must be removed in order to reduce leakage to a level of $10-20\%$ of the $21\mathrm{cm}$ power spectrum on EoR significant modes. The effects of widefield extended sources will have implications on the detectability of the $21\mathrm{cm}$ signal for the MWA and with the future Square Kilometre Array (SKA).

arXiv comment17 pages, 8 png figures

References in corpus (49)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• Astropy: A Community Python Package for Astronomy
• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• scikit-image: Image processing in Python
• LOFAR: The LOw-Frequency ARray
• Cosmology at Low Frequencies: The 21 cm Transition and the High-Redshift Universe
• Constraining the Evolution of the Ionizing Background and the Epoch of Reionization with z ~ 6 Quasars II: A Sample of 19 Quasars
• The Murchison Widefield Array: the Square Kilometre Array Precursor at low radio frequencies
• 21-cm cosmology
• 21cmFAST: A Fast, Semi-Numerical Simulation of the High-Redshift 21-cm Signal
• Hydrogen Epoch of Reionization Array (HERA)
• GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey I: A low-frequency extragalactic catalogue
• Reionization and Cosmology with 21 cm Fluctuations
• The Precision Array for Probing the Epoch of Reionization: 8 Station Results
• Bright Source Subtraction Requirements For Redshifted 21 cm Measurements
• Shapelets: I. A Method for Image Analysis
• Science with the Murchison Widefield Array
• The non-coplanar baselines effect in radio interferometry: The W-Projection algorithm
• Four Fundamental Foreground Power Spectrum Shapes for 21 cm Cosmology Observations
• GLEAM: The GaLactic and Extragalactic All-sky MWA survey
• A revised catalogue of 294 Galactic supernova remnants
• Toward Epoch of Reionization Measurements with Wide-Field Radio Observations
• Compact continuum source-finding for next generation radio surveys
• The Phase II Murchison Widefield Array: Design Overview
• Imaging the Epoch of Reionization: limitations from foreground confusion and imaging algorithms
• Deep multi-redshift limits on Epoch of Reionisation 21cm Power Spectra from Four Seasons of Murchison Widefield Array Observations
• Taxing the Rich: Recombinations and Bubble Growth During Reionization
• The impact of point source subtraction residuals on 21 cm Epoch of Reionization estimation
• Calibration Requirements for Detecting the 21 cm Epoch of Reionization Power Spectrum and Implications for the SKA
• Foreground Contamination in Interferometric Measurements of the Redshifted 21 cm Power Spectrum
• Source finding in the era of the SKA (precursors): Aegean 2.0
• Radio emission from Supernova Remnants
• The Cosmic Dawn and Epoch of Reionization with the Square Kilometre Array
• A radio catalog of Galactic HII regions for applications from decimeter to millimeter wavelengths
• Imprint of Inhomogeneous Hydrogen Reionization on the Temperature Distribution of the Intergalactic Medium
• Improving Foreground Subtraction in Statistical Observations of 21 cm Emission from the Epoch of Reionization
• A Size of ~10 Mpc for the Ionized Bubbles at the End of Cosmic Reionization
• The theory of synchrotron emission from supernova remnants
• The kinetic Sunyaev-Zel'dovich signal from inhomogeneous reionization: a parameter space study
• The Importance of Wide-field Foreground Removal for 21 cm Cosmology: A Demonstration With Early MWA Epoch of Reionization Observations
• Calibration and Stokes Imaging with Full Embedded Element Primary Beam Model for the Murchison Widefield Array
• Analysing the impact of far-out side-lobes on the imaging performance of the SKA-LOW telescope
• The jet/wind outflow in Centaurus A: a local laboratory for AGN feedback
• The giant lobes of Centaurus A observed at 118 MHz with the Murchison Widefield Array
• Modelling and peeling extended sources with shapelets: a Fornax A case study
• Interplanetary Scintillation with the Murchison Widefield Array V: An All-sky Survey of Compact Sources using a Modern Low-frequency Radio Telescope
• The Age Evolution of the Radio Morphology of Supernova Remnants
• Validation Solutions to the Full-Sky Radio Interferometry Measurement Equation for Diffuse Emission
• Multi-scale feedback and feeding in the closest radio galaxy Centaurus A

Cited by in corpus (4)

• The Second Radio Synchrotron Background Workshop: Conference Summary and Report
• Ionospheric contributions to the excess power in high-redshift 21-cm power-spectrum observations with LOFAR
• Spectral modelling of Cygnus A between 110 and 250 MHz. Impact on the LOFAR 21-cm signal power spectrum
• Aliasing from Galactic Plane Setting in Widefield Radio Interferometry