False positives in gravitational wave campaigns: the electromagnetic perspective

Area of Science:

• Multi-messenger astrophysics
• Gravitational wave astronomy
• Electromagnetic counterparts

Background:

• The first secure detection of a gravitational wave (GW) event (GW170817) with its electromagnetic (EM) counterpart (gamma-ray burst 170817A and kilonova AT2017gfo) highlighted the importance of multi-messenger astronomy.
• Compact binary mergers are key to understanding heavy element nucleosynthesis, but require further EM associations for comprehensive study.
• Current LIGO-Virgo-KAGRA observing runs aim to detect more GW events and their EM counterparts.

Purpose of the Study:

• To outline the process of searching for EM counterparts to GW events.
• To discuss strategies for identifying and ruling out false positive transient sources within large GW localization areas.
• To emphasize the scientific value of studying false positives, even as contaminants, for refining GW-EM association techniques.

Main Methods:

• Review of established and developing techniques for identifying EM counterparts to GW signals.
• Analysis of strategies for distinguishing genuine EM counterparts from serendipitous, unrelated transient sources.
• Discussion on the temporal evolution of light curves from false positive sources to aid rapid exclusion.

Main Results:

• Gravitational wave localizations are vast, necessitating efficient methods to sift through numerous potential transient sources.
• Understanding the characteristics and temporal behavior of false positives is critical for confirming true GW-EM associations.
• False positives, while contaminants, provide valuable data for improving the efficiency and reliability of multi-messenger searches.

Conclusions:

• The search for EM counterparts to GW events is an active and evolving field, crucial for advancing our understanding of cosmic phenomena.
• Effective discrimination between true signals and false positives is paramount for rapid confirmation and scientific discovery.
• Continued research into false positive sources will enhance the capabilities of future multi-messenger gravitational wave astronomy.