SwePub - sökning: L773:9290928638

Numrering	Referens	Omslagsbild	Hitta
1.	Larsson, S., et al. (författare) The Background of the INTEGRAL SPI Anticoincidence Shield and the Observations of GRBs 2004 Ingår i: PROCEEDINGS OF THE 5TH INTEGRAL WORKSHOP ON THE INTEGRAL UNIVERSE. - : European Space Agency. - 9290928638 ; , s. 649-652 Konferensbidrag (refereegranskat)abstract The anti-coincidence shield, ACS, of the spectrometer, SPI (Vedrenne et al., 2003), on INTEGRAL provides the possibility to study temporal properties of gamma-ray bursts (GRBs) with high resolution (Rau et al. 2004). To correctly interpret the results of the analysis, a good understanding of the back,ground and noise levels of the instrument is required. The back-round noise of the ACS, oil timescales up to the length of a GRB, has a Gaussian distribution and its power is independent of frequency, that is, it is white noise. However, it does not follow a Poisson statistic since on average the variance is similar to 1.6 times larger than the mean, and varies significantly. We find a systematic relation between the mean count rate and its variance. The ratio, variance/mean, decreases as the mean count rate increases. As well as helping to understand the cause of this effect, this characterisation is useful when modelling the time variability of GRBs. To illustrate the discussion we present some GRB light curves detected by the SPI/ACS and shortly discuss the analysis that has been made of them.

Larsson, S., et al. (författare)
The Background of the INTEGRAL SPI Anticoincidence Shield and the Observations of GRBs
2004
Ingår i: PROCEEDINGS OF THE 5TH INTEGRAL WORKSHOP ON THE INTEGRAL UNIVERSE. - : European Space Agency. - 9290928638 ; , s. 649-652
Konferensbidrag (refereegranskat)abstract
- The anti-coincidence shield, ACS, of the spectrometer, SPI (Vedrenne et al., 2003), on INTEGRAL provides the possibility to study temporal properties of gamma-ray bursts (GRBs) with high resolution (Rau et al. 2004). To correctly interpret the results of the analysis, a good understanding of the back,ground and noise levels of the instrument is required. The back-round noise of the ACS, oil timescales up to the length of a GRB, has a Gaussian distribution and its power is independent of frequency, that is, it is white noise. However, it does not follow a Poisson statistic since on average the variance is similar to 1.6 times larger than the mean, and varies significantly. We find a systematic relation between the mean count rate and its variance. The ratio, variance/mean, decreases as the mean count rate increases. As well as helping to understand the cause of this effect, this characterisation is useful when modelling the time variability of GRBs. To illustrate the discussion we present some GRB light curves detected by the SPI/ACS and shortly discuss the analysis that has been made of them.

Träfflista för sökning "L773:9290928638 "