313 research outputs found
Very high-energy observations of the two high-frequency peaked BL Lac objects 1ES 1218+304 and H 1426+428
We present results of very-high-energy gamma-ray observations (E > 160 GeV)
of two high-frequency-peaked BL Lac (HBL) objects, 1ES 1218+304 and H 1426+428,
with the Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE). Both
sources are very-high-energy gamma-ray emitters above 100 GeV, detected using
ground-based Cherenkov telescopes. STACEE observations of 1ES 1218+304 and H
1426+428 did not produce detections; we present 99% CL flux upper limits for
both sources, assuming spectral indices measured mostly at higher energies
OSETI with STACEE: A Search for Nanosecond Optical Transients from Nearby Stars
We have used the STACEE high-energy gamma-ray detector to look for fast
blue-green laser pulses from the vicinity of 187 stars. The STACEE detector
offers unprecedented light-collecting capability for the detection of
nanosecond pulses from such lasers. We estimate STACEE's sensitivity to be
approximately 10 photons per square meter at a wavelength of 420 nm. The stars
have been chosen because their characteristics are such that they may harbor
habitable planets and they are relatively close to Earth. Each star was
observed for 10 minutes and we found no evidence for laser pulses in any of the
data sets.Comment: 38 pages, 12 figures. Accepted for publication in Astrobiolog
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