# On the time lags of the LIGO signals

## TL;DR

This paper reexamines LIGO data, revealing correlations in detector noise that coincide with the observed gravitational wave signals, raising questions about the distinction between true signals and noise.

## Contribution

It highlights the presence of noise correlations at the same time lag as the detected events, challenging the clarity of gravitational wave signal identification.

## Key findings

- Correlations in detector noise align with GW150914 event time lag.
- Similar noise behavior observed in GW151226 and GW170104.
- Distinction between genuine signals and noise remains unresolved.

## Abstract

To date, the LIGO collaboration has detected three gravitational wave (GW) events appearing in both its Hanford and Livingston detectors. In this article we reexamine the LIGO data with regard to correlations between the two detectors. With special focus on GW150914, we report correlations in the detector noise which, at the time of the event, happen to be maximized for the same time lag as that found for the event itself. Specifically, we analyze correlations in the calibration lines in the vicinity of 35\,Hz as well as the residual noise in the data after subtraction of the best-fit theoretical templates. The residual noise for the other two events, GW151226 and GW170104, exhibits similar behavior. A clear distinction between signal and noise therefore remains to be established in order to determine the contribution of gravitational waves to the detected signals.