# Prospects of detection of subsolar mass primordial black hole and white dwarf binary mergers

**Authors:** Takahiro S. Yamamoto, Ryoto Inui, Yuichiro Tada, Shuichiro Yokoyama  
**arXiv:** [2401.00044](https://arxiv.org/abs/2401.00044)  
**Date:** 2023-12-29  
**Summary page:** https://www.summarizepaper.com/en/arxiv-id/2401.00044v1/

## Key points

- The study focuses on detectability of subsolar mass primordial black hole (PBH) and white dwarf (WD) binary mergers using space-borne gravitational wave interferometers like DECIGO.
- Research explores formation of binaries between PBHs and ordinary astrophysical objects, such as WDs, through gravitational wave bremsstrahlung.
- Conservative assessment indicates expected event number for WD-PBH binary mergers in three years by DECIGO is on the order of $10^{-6}$ for a PBH mass of approximately 0.1 solar masses.
- Paper estimates merger rate of WD-PBH binaries and compares it with that of WD-WD binaries to determine distinguishability based on their inspiral waveforms.
- Distinguishing binaries becomes challenging for certain ranges of WD masses, necessitating consideration of merger waveforms beyond the scope of current analysis.
- Study discusses how enhancements in WD-PBH binary formation mechanisms could potentially increase event rate detected by gravitational wave interferometers.
- Researchers explore scenarios where significant enhancements associated with WDs are required to detect WD-PBH merger events without conflicting with existing constraints on PBH-PBH mergers detected by ground-based detectors.
- Overall, research sheds light on prospects and challenges associated with detecting subsolar mass PBH and WD binary mergers using advanced gravitational wave observatories like DECIGO.

## Summary

The study focuses on the detectability of subsolar mass primordial black hole (PBH) and white dwarf (WD) binary mergers using space-borne gravitational wave interferometers like DECIGO. The research explores the formation of binaries between PBHs and ordinary astrophysical objects, such as WDs, through gravitational wave bremsstrahlung. The conservative assessment indicates that the expected event number for WD-PBH binary mergers in three years by DECIGO is on the order of $10^{-6}$ for a PBH mass of approximately 0.1 solar masses. The paper delves into estimating the merger rate of WD-PBH binaries and compares it with that of WD-WD binaries to determine distinguishability based on their inspiral waveforms. It is noted that distinguishing binaries becomes challenging for certain ranges of WD masses, necessitating the consideration of merger waveforms beyond the scope of the current analysis. Furthermore, the study discusses how enhancements in WD-PBH binary formation mechanisms could potentially increase the event rate detected by gravitational wave interferometers. The researchers explore scenarios where significant enhancements associated with WDs are required to detect WD-PBH merger events without conflicting with existing constraints on PBH-PBH mergers detected by ground-based detectors. Overall, this research sheds light on the prospects and challenges associated with detecting subsolar mass PBH and WD binary mergers using advanced gravitational wave observatories like DECIGO. The findings contribute valuable insights into understanding these unique astrophysical phenomena and pave the way for future studies in this field.