White dwarfs stripped by massive black holes: sources of coincident gravitational and electromagnetic radiation

TL;DR

White dwarfs inspiraling into massive black holes can lose mass periodically, producing detectable gravitational waves and electromagnetic signals, enabling dual observations of these cosmic events.

Contribution

This paper introduces the concept that white dwarf-black hole inspirals involve mass loss and electromagnetic emission, providing a new potential source for multi-messenger astronomy.

Findings

White dwarf mass loss occurs during inspiral near massive black holes.

Mass loss can last thousands of orbits, producing periodic signals.

Electromagnetic luminosity can reach near the Eddington limit.

Abstract

White dwarfs inspiraling into black holes of mass $\MBH\simgt 10^5M_\odot$ are detectable sources of gravitational waves in the LISA band. In many of these events, the white dwarf begins to lose mass during the main observational phase of the inspiral. The mass loss starts gently and can last for thousands of orbits. The white dwarf matter overflows the Roche lobe through the $L_1$ point at each pericenter passage and the mass loss repeats periodically. The process occurs very close to the black hole and the released gas can accrete, creating a bright source of radiation with luminosity close to the Eddington limit, $L\sim 10^{43}$~erg~s$^{-1}$. This class of inspirals offers a promising scenario for dual detections of gravitational waves and electromagnetic radiation.