ESO Expanding Horizons White Paper: Electromagnetic counterparts of massive BH mergers with LISA

TL;DR

This white paper discusses strategies to maximize electromagnetic counterpart detections of massive black hole mergers observed by LISA, enhancing multi-messenger astronomy in the millihertz gravitational wave regime.

Contribution

It proposes an optimal observational strategy to increase the detection of electromagnetic counterparts to LISA's massive black hole binary events.

Findings

Potential to identify EM counterparts weeks before merger

Enhanced multi-messenger observation capabilities

Maximized detection rates of EM signals associated with MBHBs

Abstract

The Laser Interferometer Space Antenna (LISA), adopted by ESA and scheduled for the second half of the next decade, will drive a new revolution in the rapidly growing field of gravitational-wave astronomy, by extending GW observations into the hiterto unexplored millihertz regime. One of the key source classes of LISA is merging massive black hole binaries in the 1e4-1e7 Msun mass range detectable to very high redshifts $z\sim 15$. MBHBs lighter than 1e6 Msun can potentially be identified during their inspiral weeks before coalescence, allowing for complementary electromagnetic observations before, during, and after the two MBHs merge. This white paper aims at defining the optimal strategy to maximize the number of detected EM counterparts of LISA MBHB events.