WASS Archive Access

The Wisconsin All-Sky Survey (WASS) archive includes :
* High level products: The data associated with the WASS are all-sky maps in FITS in the seven different energy band and a FITS table containing the effective area for each of the energy band. The maps are in galactic coodinates using an Aitoff projection and contain cont rate obtained. One of flight 25.045 (Mar 1979) had a mulfuctioning attitude system and data collected in the B and C band were not used.
Counts in each energy band were binned into 0.2 s intervals, when the payload pointing direction moved at most 1.1°, and a dead-time-corrected cosmic-ray background rate was subtracted. The pointing direction was determined for the middle of each interval, and a conical approximation to the collimator response was used to weight all pixels within the field of view. The net counts were then divided up among the pixels according to these weights. The 0.2 s observing time, corrected for electronic dead-time and atmospheric transmission, was similarly divided and stored in a second array. These count rate maps were produced by dividing the counts map by the exposure time map. ( McCammon et al. 1983, ApJ 269,107M)

Strong X-ray discrete source were removed from the maps. These are :

B and C band M1, M2, I,J, 2-6 band
Cygnus Loop Cygnus Loop
Vela-Puppis SNR Vela-Puppis SNR
HZ 43, AM Her, Sco X-1 67 sources brigher than 20 Uhuru count/s from the 4U(a)
U GEM From the 4U catalog (Forman et al, 1978, ApJ Suppl, 38 , 352

The pictures below of the sky maps and effective area link to the FITS image data in the WASS archive at the HEASARC

* Maps

B band (130 - 188 eV) all-sky map from WASS C band (160 - 284 eV) all-sky map from WASS
M1 band (440 - 930 eV) all-sky map from WASS M2 band (0.6 - 1.1 keV) all-sky map from WASS
I band (0.77 - 1.5 keV) all-sky map from WASS J band (1.1 - 2.2 keV) all-sky map from WASS
2-6 keV band (1.8 - 6.3 keV) all-sky map from WASS

* Effective area

Effective Area Solid Angle for WASS spectral bands Effective Area Solid Angle for selected WASS spectral bands

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Last modified: Thursday, 02-Jul-2020 12:23:21 EDT