An improved source-subtracted and destriped 408 MHz all-sky map

By M. Remazeilles, C. Dickinson, A. Banday, M. Bigot-Sazy, T. Ghosh. 2014

248 citations recorded by the source corpus.

The all-sky 408 MHz map of Haslam et al. is one the most important total-power radio surveys. It has been widely used to study diffuse synchrotron radiation from our Galaxy and as a template to remove foregrounds in cosmic microwave background data. However, there are a number of issues associated with it that must be dealt with, including large-scale striations and contamination from extragalactic radio sources. We have re-evaluated and re-processed the rawest data available to produce a new and improved 408 MHz all-sky map. We first quantify the positional accuracy ($\approx 7$ arcmin) and effective beam ($56.0\pm1.0$ arcmin) of the four individual surveys from which it was assembled. Large-scale striations associated with $1/f$ noise in the scan direction are reduced to a level $\ll 1$ K using a Fourier-based filtering technique. The most important improvement results from the removal of extragalactic sources. We have used an iterative combination of two techniques -- two-dimensional Gaussian fitting and minimum curvature spline surface inpainting -- to remove the brightest sources ($\gtrsim 2$ Jy), which provides a significant improvement over previous versions of the map. We quantify the impact with power spectra and a template fitting analysis of foregrounds to the WMAP data. The new map is publicly available and is recommended as the template of choice for large-scale diffuse Galactic synchrotron emission. We also provide a higher resolution map with small-scale fluctuations added, assuming a power-law angular power spectrum down to the pixel scale (1.7 arcmin). This should prove useful in simulations used for studying the feasibility of detecting HI fluctuations from the Epoch of Reionization.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/f9a7d2f05234217b63fa2a3194c1f334e5c68d82

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Citations in the corpus

Cosmology with Phase 1 of the Square Kilometre Array Red Book 2018: Technical specifications and performance forecasts (2018, background): “Current all-sky observations of the foregrounds are sparse in frequency (Reich & Reich 1988) and suffer under high systematic contaminations (Remazeilles et al. 2015) which limit the possibility of template-fitting.”
The CHIME Fast Radio Burst Project: System Overview (2018, methodology): “The sky temperature at the location of the event is interpolated from the reprocessed Haslam 408-MHz sky temperature map (Remazeilles et al. 2015) and scaled to our survey central frequency (600 MHz) using a power-law index of −2.6.”