Foreground Data

Foreground Data Images

Composite All-Sky H-alpha Map

Data from WHAM, VTSS and SHASSA have been combined by D. Finkbeiner (2003) to form an all-sky composite H-alpha map. The H-alpha intensity is provided in units of Rayleighs; no correction has been made for extinction effects.

Please acknowledge LAMBDA when using these images.

halpha Composite H-alpha Map
Log scale from .03 to 160 R
PNG (86kb - 256x512 pixels)
PNG (310kb - 512x1024 pixels)
Haslam 408 MHz Map

The Haslam 408 MHz map is derived from 4 separate surveys. Scan striping and contributions from strong point sources have been mitigated (compared to the original map) through the use of filtering in the Fourier domain.

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haslam408 Haslam 408 MHz Map
Log scale from 10 to 250 K
PNG (75kb - 256x512 pixels)
PNG (228kb - 512x1024 pixels)
HI Column Density Map

Composite neutral hydrogen column density, consisting of the 21 cm survey of Hartmann et al. (1997) supplemented with the lower resolution southern sky map constructed by Dickey & Lockman (1990).

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nh N(HI) Map
Log scale from 1.e19 to 2.e22 cm-2
PNG (72kb - 256x512 pixels)
PNG (217kb - 512x1024 pixels)
LAB HI Survey

HEALPIX resampling of Leiden/Argentine/Bonn (LAB) Survey of Galactic HI (from Kalberla et al., 2005).

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HI LAB HI Survey
Column density cm-2
PNG (77kb - 256x512pixels)
PNG (206kb - 512x1024 pixels)
Predicted Dust Emission at 94 GHz

Using a combination of COBE and IRAS data, Finkbeiner, Davis & Schlegel (1999) derived models for thermal dust emission at microwave and submillimeter frequencies. This map is based on their best-fit two-component Model#8.

Please acknowledge LAMBDA when using these images.

Dust 94GHz Model Dust Map, FDS99
Log scale from 0.4 to 400 uK
PNG (86kb - 256x512 pixels)
PNG (316kb - 512x1024 pixels)
Galactic Reddening Maps

Maps of Galactic reddening, E(B-V), in magnitudes, as derived from IRAS and COBE/DIRBE data by Schlegel, Finkbeiner and Davis (1998) and from Pan-STARRS1 stellar photometry by Schlafly et al. (2014).

Please acknowledge LAMBDA when using these images.

ebv Derived E(B-V) Map, SFD98
Log scale from 0.004 to 6.3 mag
PNG (86kb - 256x512 pixels)
PNG (319kb - 512x1024 pixels)
ebv Derived E(B-V) Map, Schlafly et al. 2014
Log scale from 0.004 to 6.3 mag
PNG (68kb - 512x256 pixels)
PNG (261kb - 1024x512 pixels)
Velocity Integrated CO Map

The Dame et al. (2001) composite map of interstellar molecular clouds, as traced by the 115 GHz line of Carbon Monoxide (CO). The CO line intensity has been integrated over all observed velocities.

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w_co Map of W(CO)
Log scale from 1.5 to 200 K km s-1
PNG (12kb - 256x512 pixels)
PNG (43kb - 512x1024 pixels)
PNG (150kb - 1024x2048 pixels)
CMB vs. Foreground Anisotropy

This figure, from Bennett et al. 2013 , shows the rms anisotropy as a function of frequency from the CMB (red line) and sources of foreground emission: synchrotron, free-free, spinning dust, and thermal dust emission. The lower and upper curves for each foreground component show the anisotropy for two sky cuts, retaining 77% and 85% of the sky respectively.

Please acknowledge LAMBDA when using these images.

CMB and foreground anisotropy vs. frequency

PNG (86 kb - 2048x1755 pixels)
PNG (240kb - 4096x3511 pixels)
EPS (75kb)
PDF (6.1 mb)
CMB vs. Foreground Anisotropy and Multipole

This figure, from Bennett et al. 2003 , compares the CMB anisotropy to the foreground anisotropy in frequency space and harmonic space. The WMAP frequency bands were chosen to be near the minimum of the galactic emission. (a) Spectra of the CMB anisotropy and the galactic emission as a function of frequency. (b) Foreground angular power spectra for each WMAP band using the Kp2 sky mask. The spectrum at each frequency is derived as a cross-power spectrum between radiometers minus the WMAP-derived CMB model. In K- and Ka-band, where cross-power spectra are not available, the noise bias has been estimated and subtracted. Point source fits for each band are shown in the dashed lines on the right. The spectra are expected to asymptotically join these lines. Note that the diffuse foreground spectra (excluding point sources) go as C_l ~ l^(-2). (c) The contour plot shows the ratio of the CMB anisotropy to the foreground anisotropy (for the Kp2 mask) as a function of frequency and multipole moment. The ratios are expressed in power units.

Please acknowledge LAMBDA when using these images.

CMB and foreground anisotropy vs. frequency and multipole

PNG (570kb - 685x1500 pixels)
JPG (282kb - 685x1500 pixels)
JPG (99kb - 600x1315 pixels)
EPS (449kb)
PDF (273kb)
IRAS/ISSA 25, 60 and 100 um composite Map

The 25,60 and 100 um IRAS/ISSA plates were used to produce this 3-color composite image of the infrared sky. Unobserved portions of the sky are white. Residuals from removal of the zodiacal light show as stripes parallel to the ecliptic.

Please acknowledge LAMBDA when using these images.

IRAS/ISSA 25, 60 and 100 um composite Map
Logarithmic scale
JPG (15kb - 256x512 pixels)
JPG (43kb - 512x1024 pixels)
JPG (128kb - 1024x2048 pixels)
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. David T. Chuss
NASA Official: Dr. David T. Chuss
Web Curator: Mr. Michael R. Greason