Foreground: Composite All-Sky H-alpha

Composite all-sky H-alpha (Finkbeiner)

Coordinate System:
Projection Type:
HEALPix, nested, res 10 (Nside=1024) and res 9 (Nside=512)
6 arcmin
Original Data Source:
Download Links:

D. Finkbeiner (see 2003 reference below) has assembled a full sky Halpha map using data from several surveys: the Wisconsin H-Alpha Mapper (WHAM), the Virginia Tech Spectral-Line Survey (VTSS), and the Southern H-Alpha Sky Survey Atlas (SHASSA). The composite map can be used to provide limits on free-free foreground emission.

The H-alpha data products provided here are direct copies of the version 1.1 products distributed on D. Finkbeiner's website (see below). The data are available in three projections: HEALPix Nside=1024, HEALPix Nside=512, and Cartesian 8640 x 4320 projection (2.5 arcmin pixels). For each pixelization, three files are available: the H-alpha map itself, a 'mask' map indicating how each pixel in the composite map was processed, and an estimated error map. Note that the data are undersampled at the HEALPix Nside=512 pixelization (pixel size 6.9 arcmin). HEALPix Nside=256 products are available from Finkbeiner's website.

More details can be found in:

"A Full-Sky H-alpha Template for Microwave Foreground Prediction",
Finkbeiner, 2003

D. Finkbeiner's skymap website

WHAM website

VTSS website

SHASSA website

Release Notes:

25 Jan 2003:
Initial release of V1.1 (Finkbeiner)

27 Jul 2003:
FITS headers revised to standard, data content unchanged.
Release version still V1.1 (Finkbeiner).

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