Timescales for Detecting Magnetized White Dwarfs in Gravitational Wave Astronomy

Surajit Kalita

doi:10.3390/ecu2021-09310

Abstract

Over the past couple of decades, researchers have predicted more than a dozen super-Chandrasekhar white dwarfs from the detections of over-luminous type Ia supernovae. It turns out that magnetic fields and rotation can explain such massive white dwarfs. If these rotating magnetized white dwarfs follow specific conditions, they can efficiently emit continuous gravitational waves and various futuristic detectors, viz. LISA, BBO, DECIGO, and ALIA can detect such gravitational waves with a significant signal-to-noise ratio. Moreover, we discuss various timescales over which these white dwarfs can emit dipole and quadrupole radiations and show that in the future, the gravitational wave detectors can directly detect the super-Chandrasekhar white dwarfs depending on the magnetic field geometry and its strength.

Highlights

We show that the timescale for the emission of the electromagnetic (EM) and quadrupole radiations from these WDs is highly dependent on the magnetic field geometry and its strength
We know that an object possessing a poloidal magnetic field can emit EM radiation, whereas, with a toroidal field, no such EM radiation is possible
If the WD has a strong poloidal field, it will have LD LGW, and since in this case, χ quickly becomes zero, it stops radiating for a long time

Summary

Introduction

The luminosities of type Ia supernovae (SNeIa) have been used as one of the standard candles in cosmology to measure distances of various astronomical objects This is due to the reason that the peak luminosities of all the SNeIa are similar, as they originate from the white dwarfs (WDs) burst around the Chandrasekhar mass-limit (∼1.4M for carbon–oxygen non-rotating non-magnetized WDs [1]). No super-Chandrasekhar WDs have been observed directly in any of the surveys such as GAIA, SDSS, Kepler, etc., as the highly magnetized WDs generally possess very low thermal luminosities [12]. They are difficult observe in the standard electromagnetic (EM) surveys.

Structure of Rotating Magnetized White Dwarfs

Gravitational Radiation Emitting from Rotating Magnetized White Dwarfs

Timescale for Emission of Gravitational Radiation

Conclusions