Stars as Laboratories for Fundamental Physics - MPP Theory Group

466 Chapter 12
Fig. 12.7. Event rates measured in the Gamma Ray Spectrometer (GRS)
of the Solar Maximum Mission (SMM) satellite encompassing the observed
neutrino burst of SN 1987A (the dashed line is for the first neutrinos observed
in the IMB detector). The time interval for each bin is 2.048 s. The rates to
the left of the dashed line are used to determine the background while the
ones to the right would include photons from neutrino decay. (Figure from
Oberauer et al. 1993 with permission.)
Table 12.1. GRS 3σ upper fluence limits.
Channel Energy Band γ Fluence Limit [cm −2 ]
[MeV] (10 s) a (223.2 s) b
1 4.1−6.4 0.9 6.11
2 10−25 0.4 1.48
3 25−100 0.6 1.84
a Chupp, Vestrand, and Reppin (1989)
b Oberauer et al. (1993)
For the 10 s and 223.2 s time intervals one can compute an average
flux limit (cm −2 s −1 ) for each channel. Then one expects that for the
longer time interval it is more restrictive by the ratio of (∆t) 1/2 , i.e. by
(10 s/223.2 s) 1/2 = 0.21. This expectation is approximately borne out
by the data in Tab. 12.1, confirming their consistency.