Space & astronomy · the experiment
Find the base note
Two gamma-ray flashes 29 years apart, ten milliseconds each, and one shared rhythm. Four questions, from beginner to expert, on how far that rhythm points to a magnetar.
1 · Say what the authors conclude
Beginner
What do the authors conclude about the 1991 flash, GRB 910711?
2 · Find where a coupling puts power
In GRB 910711, the bispectrum links two oscillations: one at 5 × 360 Hz, the other at 6 × 360 Hz.
Intermediate
At what frequency does their coupling create power?
3 · Separate two base frequencies
Over a 10-millisecond spike, frequencies closer than about 100 Hz cannot be told apart: 350 Hz and 360 Hz look the same.
Each overtone is a whole multiple of the base frequency.
Expert
Multiplied by 12, how far apart do 350 Hz and 360 Hz end up?
4 · Read the rising percentage
Fake bursts with the spike's shape but no oscillation: a bump near 360 Hz at least as strong as that of GRB 910711 appears in about 5% of them.
Fake bursts that also carry the kilohertz oscillations already reported and a more realistic background noise: about 15.5%.
Expert
What does this rise suggest about the 360 Hz bump?
Base note found
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