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Balloon Flight 2001 of the HERO Engineering Test Payload
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The spring 2001 balloon flight from the National Scientific Balloon Facility
in Ft. Sumner, NM completed May 24, 2001. Three hard X-ray astronomical objects, the Crab Nebula and Pulsar (left), Cygnus X-1 (below left), and GRS 1915 (below right)
were successfully imaged during the flight. The balloon
reached an altitude of 128,000 ft, well above most of Earth's X-ray-absorbing
atmosphere.
These images represent the first successful hard X-ray focussing optics experiment,
part of the HERO High Energy Replicated Optics program, ever achieved. Here is the
NASA press release story.
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The pictures are smoothed false-color images combining data from both telescope/detector modules.
Each are ~12.5 arcmin across
with colors ranging from black/blue representing the lowest significance (<2 sigma) up to
white corresponding to 7-8 sigma in the 20-45 keV hard X-ray band
(for GRS 1915 the significance is about 5.9 sigma).
The data have been binned at a 1 arcminute scale and smoothed with a 1 arcminute
filter giving an artificial width to the sources. Without smoothing, most of
the flux falls within single ~1 arcmin pixels consistent with the 3/4 arcminute
measured resolution. Integration times are ~1 to 2 hours per target. The
highly variable source GRS 1915 was not seen during the first 1.25 hours of observation, but is
clearly there over the remaining 3/4 hour.
More information on the HERO program and an associated NASA Science News story are available.
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Cygnus X-1
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GRS 1915
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Solar System Objects