PPT Slide

• Number of electrons = luminosity/power = 1.6 x 10 / 6 x 10 = 2.6 x 10

• Synchrotron lifetime, t =5 x 10 B E s = 30 years Thus in 900yrs since SN explosion, must be 30 replenishments of electrons and these must be produced by the pulsar.

• Total no. electrons = 2.6 x 10 x 30 ~ 8 x 10 each with E = 5 x 10 J

30

-15

44

-13

-2

-1

syn

44

45

e-

-6

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We thus calculate the number of electrons by dividing the luminosity by the power radiated per electron, which gives us 2.6e44 electrons.

From synchrotron section, we already know that the synchrotron lifetime,

tau_syn = 5e13 B^-2 E-1 seconds

which is 30 years for the Crab. So the electrons must have been replenished 30 times since the explosion, so 8e45 electrons must have been produced each with an electron energy of 5e-6 J.