Accretion phenomena and theories
Accretion phenomena and theories
Accretion phenomena and theories
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Origin of accreted matter<br />
• Given M/R, luminosity produced depends on<br />
accretion rate, dm/dt:<br />
L acc = dE acc /dt = GM (dm/dt)/R . = (R sch /R)(dm/dt)c 2<br />
• Consider a neutron star with an observed X-<br />
ray luminosity of 10 38 .<br />
ergs/s, the required<br />
mass accretion rate dm/dt = 10 -8 M sun /year<br />
• Where does accreted matter come from?<br />
– Companion? Yes.<br />
– ISM? Too small to explain observed accreting<br />
compact objects of stellar masses. But enough for<br />
AGNs --- accreting supermassive black holes with<br />
masses 10 6 -10 10 M sun
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