Since its commissioning in fall 1996, the stereoscopic system of Imaging Atmospheric Cherenkov Telescopes (IACTs) of HEGRA, with an energy flux sensitivity ν Fν at 1 TeV of 10−11 erg cm−2 s−1 for one hour of observation time, has been used to monitor the BL Lac object Mkn 421 on a regular basis. In this paper, we report detailed temporal and spectral information about the TeV characteristics of...

We have observed Markarian 421 during an extraordinarily high state in January and March 2001 with the CANGAROO-II imaging Cherenkov telescope. From 14 hours observations at a large zenith angle of ∼70◦, a signal of 298± 52 gamma-ray–like events was detected at E > 10 TeV with 5.7 σ significance. Under the assumption of power-law spectrum, we derived a steep energy spectrum of photon index ∼4.0...

A simple procedure for purification of ferredoxin from a green alga, Scenedesmus, is described. Crystalline ferredoxin had an absorption spectrum with maxima at 276, 330, 421, and 464 rnp and with minima at 255, 293, 390, and 445 rnp. The ratios of the optical densities at 421 and 330 rnp to that at 276 rnp were 0.651 and 0.883, respectively. The substance was shown to be pure by disc electroph...

We present a new calculation of the intergalactic γ-ray pair-production absorption coefficient as a function of both energy and redshift up to the redshift of 3C279, z = 0.54. In reexamining this problem, we make use of new observational data on the intergalactic infrared radiation field (IIRF), together with recent theoretical models of the galactic spectral energy distributions of the IIRF fr...

We propose that TeV γ-ray emission from blazars is produced by collisions near the line of sight of high energy jet protons with gas targets (“clouds”) from the broad emission-line region (BLR). Intense TeV γ-ray flares (GRFs) are produced when BLR clouds cross the line of sight close to the black hole. The model reproduces the observed properties of the recently reported very short and intense...

A simple procedure for purification of ferredoxin from a green alga, Scenedesmus, is described. Crystalline ferredoxin had an absorption spectrum with maxima at 276, 330, 421, and 464 rnp and with minima at 255, 293, 390, and 445 rnp. The ratios of the optical densities at 421 and 330 rnp to that at 276 rnp were 0.651 and 0.883, respectively. The substance was shown to be pure by disc electroph...

Karl-Dirk KAMMEYER and Dirk NIKOLAI Univ. of Bremen, Dept. of Telecommunications1 , P.O. Box 33 04 40, D-28334 Bremen, Germany Tel.: ++(49)-421/218-2453, Fax: ++(49)-421/218-3341, E-mail: [email protected] Abstract2: In this paper, we present a novel transmission scheme with application to Direct Sequence Code Division Multiple Access (DSCDMA) combining M -ary orthogonal and PSK modula...