LECTURE QUIZ 6
Having two LIGO detectors by 3000 km is important because
a & c: only true astrophysical signals would be observed in both detectors & the time of arrival of signals can be used to find the position of the sources
The object(s) created by the merger of two black holes is
a single black hole with mass slightly lower than the sum of the merging ones
The 170817 even demonstrated that neutron star mergers
all of the above: produce gamma ray bursts, produce gravitational waves, produce most of the heavy elements on earth, produce kilonova afterglows
When laser beans in an interferometer combine
an interference pattern of bright and dark light is formed
After traveling 140 million light years from the 170817 neutron star merger, gravitational waves and gamma rays
arrived at earth at almost exactly the same time
The gravitational wave signal from merging black holes is called a "chirp" because
as the black holes get closer, the signal frequency and amplitude increase
The term "multi-messenger astronomy" refers to
combining electromagnetic and gravitational wave observations
Current measurements of the Hubble constant H0
disagree on the method used
What is a key reason that gravitational waves are so much are harder to detect than electromagnetic waves?
gravitational wavs are much weaker than electromagnetic waves, and therefore require very, very precise equipment to detect
Gravitational waves produce motions of the interferometer mirrors in LIGO
much smaller than a proton diameter
We know that most heavy elements such as gold are produced in
neutron star mergers
Merging black holes can be observed
only by their gravitational wave emission
The core of neutron stars consists of
super-nuclear density matter in a form we don't know for sure
How did observations show that gamma-ray bursts were not coming from the Milky Way Galaxy?
the gamma-rays came from all over the sky, not just the plane of the Galaxy
In the first direct detection of gravitational waves by LIGO in 2015, the waves came from
the merger of two black holes
The speed that gravitational waves travel is
the speed of light
Astronomers now have a good idea for explaining how the short-duration gamma-ray bursts come about. Which of the follow is part of their explanantion?
these bursts come from the merger of two neutron stars
The location of the 170817 neutron star merger was first determined using
three gravitational wave detectors
In the 2015 gravitational wave discovery event, the two black holes
were each about 30 solar masses
