Search for strongly lensed counterpart images of binary black hole mergers in the first two LIGO observing runs

Understand

Strong gravitational lensing can produce multiple images of the same gravitational-wave signal, each arriving at different times and with different magnification.

• Previous work has explored if lensed pairs exist among the known high-significance events and found no evidence of this.
• However, the possibility remains that weaker counterparts of these events are present in the data, unrecovered by previous searches.
• We conduct a targeted search specifically looking for sub-threshold lensed images of known binary black hole (BBH) observations.