51 research outputs found
VHE gamma-ray spectral properties of the blazars Mrk 501 and Mrk 421 from CAT observations in 1997 and 1998
The Very High Energy (VHE) gamma-ray emission of the BL Lacertae objects
Markarian 501 and Markarian 421 has been observed by the CAT Imaging
Atmospheric Cherenkov Telescope in 1997 and 1998. The spectrum extraction
method is presented, and the spectral properties of both sources are compared
in different activity states. Theoretical implications for jet astrophysics are
discussed.Comment: 4 figures, 6 pages. To appear in the proceedings of the GeV-TeV Gamma
Ray Astrophysics Workshop "Towards a Major Atmospheric Cherenkov Detector
VI", Snowbird, Utah, August 13-16, 199
Calibration of the CAT Telescope
Due to the lack of test-beams in ground-based gamma-ray astronomy, detector
calibration has been a major challenge in this field. However, with the use of
Cherenkov ring-images due to cosmic-ray muons and of strong gamma-ray signals,
the CAT telescope could be rather well monitored and understood. Here we
present a few oustanding aspects of this work.Comment: 5 pages, 5 figures. To appear in the proceedings of the GeV-TeV Gamma
Ray Astrophysics Workshop "Towards a Major Atmospheric Cherenkov Detector
VI", Snowbird, Utah, August 13-16, 199
Lasers à boites quantiques sur InP, de très faibles courants de seuil et émettant à 1.55 µm
National audienc
Ultra low threshold at room temperature on 1.55 µm InAs/InP(311)B laser with an active zone based on a single quantum dot layer
International audienceFor the first time, a laser emission at 1.55 mu m telecommunication wavelength is obtained on a single quantum dots (QD) layer laser at room temperature with a threshold current density as low as 320A/cm(2)
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