General Astronomy -
Spring
2011
Homework #12 - due May 6
Circle the correct answer.
1. (2 pt) The distribution of gamma-ray bursts on the sky is: a)
isotropic, b) concentrated along the Galactic plane, c) correlated
with
the local group of galaxies, d) lumpy.
2. (2 pt) The measured
distribution
of fluxes,
log(N>S) versus log(S) where S is the source flux
and N
is the number of sources, has an exponent of -3/2 for a homogeneous
distribution of sources. The log(N>S) versus log(S)
distribution for gamma-ray bursts: a) follows a -3/2 power law, b)
follows a -3/2 power at high fluxes, but falls below at low fluxes,
c)
follows a -3/2 power at high fluxes, but lies above at low fluxes.
3. (2 pt) The first optical counterpart to a gamma-ray burst was
identified using an X-ray position for the gamma-ray burst measured
by:
a) Vela, b) BATSE, c) BeppoSAX, d) Swift.
4. (2 pt) Detection of the first optical counterpart to a gamma-ray
burst greatly advanced the field because it was then possible to: a)
find the progenitor star of the gamma-ray burst, b) determine where
in
the Milky Way the gamma-ray burst originated, c) measure the red
shift
to the gamma-ray burst, d) the public likes nice optical pictures.
5. (2 pt) The locations of long gamma-ray bursts: a) trace the
distribution of star light in the host galaxy, b) are often outside
the
host galaxy, c) all point to known supernova remnants, d) are
impossible to determine.
6. (2 pt) Long gamma-ray bursts are thought to be related to: a)
mergers of neutron stars, b) elliptical galaxies, c) supernovae, d)
Kate and William.
7. (2 pt) Short gamma-ray bursts are thought to be produced by: a)
mergers of neutron stars, b) collapse of massive stars, c) failed
long
GRBs, d)
Kate and William.
8. (2 pt) The gamma-ray emission from GRBs is thought to be: a)
isotropic, b) beamed, c) chocolate.
9. (2 pt) The highest red shift observed for a GRB is: a) 0.03, b)
1.7,
c) 2.7, d) 8.2.
10. (2 pt) Radiation emitted by matter moving towards us with a
Lorentz
factor Γ is: a) blue shifted by a factor of Γ, b) confined to a cone
with an opening angle of 1/Γ radians, c) all of the above, d) none
of
the above.