MG11 
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The analysis of GRB redshift distribution.

First time the gamma ray burst redshift was defined in 1997 for GRB970228 and it shown that origin of this burst located at cosmology distanse scale. At present time the volume of GRB set with known redshift consists of approximately 80 bursts, most part of them were localised by SWIFT. The GRB redshift distribution is presented and its shape is discussed. Analysis of one peak approximation of GRB redshift distribution have shown that it has very heavy tail which consist of 25% of set of volume. As example of real uniform set the shape of normalized z-distribution for first 604 QSO from 2QZ_6QZ catalog is analysed and it is shown that only 1% of set of volume must be in the tail on the level comparable with tail of GRB redshift distribution. Such shape of distribution allows to make conclusion that this set is not uniform and at least two subgroups present in GRB redshift distribution at 95% confidence level which limited by volume of GRB set with known redshift. This conclusion confirmed by analysis of hi-square for two peak function approximation, which gives more significant result than one peak fit (95% and 80% correspondly).

The GRB detected in low energy gamma-ray band by AVS-F apparatus onboard CORONAS-F satellite in 2001-2005 years.

The AVS-F apparatus onboard CORONAS-F satellite operated from 31.07.2001 up to 06.12.2005. The AVS-F apparatus constitutes the system for data processing from two detectors: SONG-D (CsI(Tl) scintillation detector Æ200 mm and 100 mm height, fully surrounded by plastic anticoincidence shield) and RPS-1 (solid state CdTe detector 4.9 mm ´ 4.9 mm). Despite of this satellite was Solar-oriented, over 30 GRB during August 2001 – December 2005 period were registered in the energy band of ~0.1-20 MeV by preliminary data analysis. The characteristics of GRB detected by AVS-F device are discussed.