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Appendix B: More on Mkn 421 spectra
Appendix B.1: Available statistics
The statistics used for extracting the Mkn 421 spectra are given in Table B.1. With the same notations
used in this paper, we write:
- the data zenith angle amplitude, and the ON and OFF-source observation durations,
and
;
- for each of the
energy intervals
(in
):
the numbers of events passing the selection cuts in the ON and OFF data,
and
;
the observed number of
events,
,
and its error,
;
the statistical significance
;
- the observed total number of
events,
,
and its error,
.
Appendix B.2: Covariance matrices
Let
and
be the two covariance matrices of spectral parameters for the
and
hypotheses
(see Sect. 2.3), respectively:
The values of these matrices elements are given in Table B.2 for each spectrum of Mkn 421 obtained in this paper.
In the power-law hypothesis, the energy
at which the values of
et
are decorrelated writes:
At this decorrelation energy, the width of the hatched area representing the 68% confidence level contour, is minimum: for
instance, we find
for the 1998 time-averaged spectrum of Mkn 421 shown in Sect. 3.2.
In the curved shape hypothesis, the energy-dependent exponent
has a minimal error at the energy
;
the corresponding value of
writes
and its error
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