Problem Set #2
Reading: Chapters 4 and 5 of the text
1. In 1977 the German X-ray astronomer J. Trumper observed the neutron star Hercules X-1. He found two emission lines, one at 55keV and the other at 110keV. He interpreted these as cyclotron emission from charged particles near the surface of a magnetized neutron star.
a) Derive the strength of the magnetic field at the surface of the
2. The Crab Nebula is observed to emit x-rays having an energy of at least 100keV from an extended region.
A) Assume we know that the magnetic field is 10-4 Gauss and that the radiation is synchrotron. Compute the energy, lifetime, and Larmor radius of
the electrons producing this radiation.
3. The great cluster of galaxies in Coma Berenices exhibits 5x1044 ergs/s of x-ray emission from 108
K gas trapped in the potential well of the cluster. It has a radius of 2x1024cm.
Assuming a uniform distribution of gas, compute