The Quanta Podcast After Black Holes Collide, a Puzzling Flash
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Mar 10, 2016 A satellite caught a brief flash just as gravitational waves arrived from two black holes colliding. Scientists puzzle over how light could accompany a merger and debate rare scenarios like charged black holes, leftover accretion disks, or mergers inside a dying star. Researchers weigh conflicting detections and plan simulations while awaiting more gravitational-wave events.
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Surprising Gamma-Ray Signal With LIGO Event
- Fermi detected a faint gamma-ray burst 0.4 seconds after LIGO's black hole merger signal, challenging expectations that black hole mergers are dark.
- If real, this suggests surrounding matter or new physics can produce electromagnetic counterparts to black hole mergers.
Detection Is Plausible But Not Conclusive
- The Fermi burst was extremely dim and rare, appearing roughly once every 10,000 seconds, so coincidence with LIGO remains possible.
- Independent non-detection by INTEGRAL and the three-sigma significance keep the association uncertain.
Why Black Holes Should Be Dark
- Standard theory says black hole mergers in vacuum can't make light because no charged particles or magnetic fields exist.
- The Fermi observation forced theorists to propose scenarios that leave matter around merging black holes.
