Answer the following about the NANOGrav collaboration’s recent discoveries, for 10 points each:
[10e] In June 2023, NANOGrav announced the discovery of a “stochastic” background of these phenomena. These disturbances in spacetime are produced by compact object mergers and are studied by LIGO.
ANSWER: gravitational waves [or gravitational radiation; accept stochastic gravitational wave background; prompt on SGWB; reject “gravity waves”]
[10m] NANOGrav uses a “timing array” of these objects to detect gravitational waves. These degenerate objects emit radio waves at regular intervals, typically hundreds of times per second.
ANSWER: pulsars [accept pulsar timing array; accept binary pulsars; accept millisecond pulsars; accept magnetars; prompt on neutron stars]
[10h] NANOGrav hopes to show that the stochastic gravitational wave background comes from supermassive black hole mergers by finding that it has this property. A mission named for probing this property succeeded the COBE mission.
ANSWER: anisotropy [or anisotropic; accept Wilkinson Microwave Anisotropy Probe, prompt on WMAP]
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