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lecture10 - GRBs - the most powerful explosions! SgrA* the...

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GRBs -- the most powerful explosions SgrA * the black hole at the center of our Galaxy Visible wavelength image toward center of Milky Way Infrared image of galactic center GRBs -- gamma ray bursters (100 kev ! ) Vela satellite (1965 arms control veriFcation sat.) Frst detected cosmic ! -ray pulses (sec ==> minutes) BATSE instr. on Compton GRO ==> detected many bursts isotropic on sky Burst Duration Sky distribution w/i burst, msec variations ! Ray ±uxes are enormous -- 1000’s at earth speculation of effects on earth and extinctions -- only 1/gal per 10 7 yrs ? -- are GRBs galactic or extragalactic isotropy ==> extragalactic high intensity ==> galactic ! -ray positions were not accurate enough to identify with optical objects. eventually, x-ray used to localize ==> id with opt. gal. many at redshift z ~ 1 to 4 ==> 7 billion lyr w/ distances, the implied energy release is ~ 10 52-54 ergs similar to a supernova time is much shorter ! long bursts : many show optical light variations
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lecture10 - GRBs - the most powerful explosions! SgrA* the...

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