High Energy Astrophysics -
Fall
2006
Homework #2 - due September 12
1. Assuming the Hubble constant is 72 km/s/Mpc, estimate the age of the
Universe. Explain.
2. Derive an equation which gives the approximate lifetime of a star as
a function of its mass.
3. A quasar has a luminosity of 1012 solar luminosities and
varies by a factor of 2 on a time scale of 10,000 seconds. If the
quasar is producing blackbody radiation, what the minimum possible
temperature for that radiation? What sort of radiation does the
quasar produce?
4. Attach a printout of the ds9 image from data analysis excerise #1
showing the photon map and your source and background regions.
5. Attach a printout showing your best fit spectrum for 3C273 along
with the fit parameters and the quality of the fit.