Scientists hunt for dark matter stars that mimic black holes

• Scientists are analyzing gravitational wave data from the LIGO-Virgo-KAGRA network to identify "exotic objects" such as boson stars, rather than conventional black holes.
• The 2019 event GW190521 is being re-examined, as it may be better explained by the collision of hypothetical boson stars than by a black hole merger.
• The EU-funded NewFunFiCO project, running until 2026, aims to use these observations to uncover the true nature of dark matter.

Research Background and Objectives

• Gravitational waves provide a new medium to explore cosmic mysteries by measuring tiny distortions in space-time.
• Since 2015, over 150 black hole mergers have been identified; however, the O4 observation campaign (May 2023 – November 2025) identified approximately 250 candidate events that do not perfectly align with black hole models.

Exotic Objects and Dark Matter

• Boson stars: Hypothetical ultra-compact objects lacking an event horizon, theorized to be filled with ultralight dark matter particles like axions.
• Mixed stars: Dense objects, such as neutron stars, containing a core of dark matter.
• Gravastars: Exotic structures that mimic black holes but lack both an event horizon and a singularity at their center.

Project Impact and Technological Spillovers

• NewFunFiCO is an international collaboration involving researchers from Spain, Portugal, Italy, Germany, Mexico, Brazil, and China.
• The pursuit of detecting minuscule space-time distortions has pushed advancements in laser interferometry, vibration isolation, and ultra-precise optics.
• These scientific instruments have yielded practical spin-offs in fields such as precision manufacturing, medical imaging, and global navigation systems.