Foreground Data


Product Name
Composite all-sky H-alpha (Finkbeiner)
Coord. System
Projection Type
HEALPix, nested, res 9 (Nside=512)
6 arcmin
Original Data Source


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 map provided here is a direct copy of the version 1.1 HEALPix Nside=512 products distributed on D. Finkbeiner's website (see below). Three files are in this package: the H-alpha map itself, a 'mask' map indicating how each pixel in the composite map was processed, and an estimated error map. The HEALPix Nside=512 versions were chosen for distribution here because the projection coincides with that used by WMAP. Note that the data are undersampled at this pixelization. Additional 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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A service of the HEASARC and of the Astrophysics Science Division at NASA/GSFC
Goddard Space Flight Center, National Aeronautics and Space Administration
HEASARC Director: Dr. Alan P. Smale
LAMBDA Director: Dr. Eric R. Switzer
NASA Official: Dr. Eric R. Switzer
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