Haslam 408 MHz All-Sky Map
Product attributes (unless otherwise noted**)
HEALPix, ring, res 9 (Nside=512)
Original Data Source:
Remazeilles et al. 2014 have re-evaluated and re-processed the rawest Haslam 408 MHz data, available from the Max Planck Institute for Radioastronomy Survey Sampler website, to produce an improved source-subtracted and destriped 408 MHz all-sky map. Large-scale striations associated with correlated low-frequency noise in the scan direction are reduced using a Fourier-based filtering technique. The most important improvement results from the removal of extra-galactic sources. An iterative combination of two techniques − two-dimensional Gaussian fitting and minimum curvature spline surface inpainting − are used to remove the brightest sources (with flux density larger than 2 Jy). Four products are made publicly available. They are described below. The sky maps are generated using the HEALPix sky pixelization scheme.
For a full discussion refer to Remazeilles et al. (2014).
This is the main product. A re-processing of the data downloaded from the Max Planck Institute for Radioastronomy Survey Sampler website has been performed to improve both the removal of strong baseline striping and the removal of strong extra-galactic radio sources in the Haslam map. An iterative combination of two techniques − two-dimensional Gaussian fitting and minimum curvature spline surface inpainting − have been used for desourcing. In the 2014 Haslam map we get rid of the source residual artifacts that are still present in the LAMBDA post-processed 2003 version of the Haslam map. Note that the brightest Galactic sources have been retained in the map.
An image of this map is shown on LAMBDA Foreground Data Images Page.
Desourced destriped Haslam 408 MHz with small scales added
** Projection Type: HEALPix, ring, res 11 (Nside=2048) / Resolution: 0 arcmin
This is a high-resolution (Nside=2048, beam FWHM=0 arcmin) template of the desourced destriped 408 MHz all-sky map, in which small-scale fluctuations have been artificially added. This template is made available for the simulations of high resolution CMB and 21 cm intensity mapping experiments. Higher Nside maps with small-scales added are available on request from the authors.
Destriped Haslam 408 MHz
A destriped-only version of the 408 MHz radio continuum all-sky map, with no desourcing, is also made available. Strong baseline striping has been reduced to 1 K but the extra-galactic sources have not been subtracted.
Bitmask Haslam 408 MHz
This is the bitmask of the extra-galactic sources that have been subtracted. Each bit indicates the processing technique applied to the source (bit 0: Gaussian fitting, bit 1: Inpainting).
More details can be found in
"An improved source-subtracted and destriped 408 MHz all-sky map", Remazeilles, M., Dickinson, C., Banday, A. J., Bigot-Sazy, M.-A., Ghosh, T., 2014, arXiv:1411.3268
Previous Haslam 408 MHz Data Products
Haslam 408 MHz
HEALPix, nested, res 9 (Nside=512)
Original Data Source:
The 408 MHz radio continuum all-sky map of Haslam et al. (see references below) combines data from four different surveys. The map is dominated by synchrotron emission.
Two versions of the map are supplied:
More details can be found in: