Visualizing the Number of Existing and Future Gravitational-Wave Detections from Merging Double Compact Objects (2303.17628v2)

Abstract: How many gravitational-wave observations from double compact object mergers have we seen to date? This seemingly simple question surprisingly yields a somewhat ambiguous answer that depends on the chosen data-analysis pipeline, detection threshold and other underlying assumptions. To illustrate this we provide visualizations of the number of existing detections from double compact object mergers by the end of the third observing run (O3) based on recent results from the literature. Additionally, we visualize the expected number of observations from future-generation detectors, highlighting the possibility of up to millions of detections per year by the time next-generation ground-based detectors like Cosmic Explorer and Einstein Telescope come online. We present a publicly available code that highlights the exponential growth in gravitational-wave observations in the coming decades and the exciting prospects of gravitational-wave (astro)physics.

• The paper examines the current variability in gravitational wave detection counts across different data analysis pipelines and catalogs due to varying thresholds and assumptions.
• Forecasts predict a substantial increase in detections with observing runs O4 and O5, and potentially hundreds of thousands to millions annually with next-generation detectors like Einstein Telescope and Cosmic Explorer.
• The projected exponential increase in future detections will provide significantly more precise and expansive data, enhancing our understanding of compact object populations and advancing gravitational wave astronomy.

Overview of Gravitational Wave Detections: Current and Future Prospects

The paper "Visualizing the Number of Existing and Future Gravitational--Wave Detections from Merging Double Compact Objects" offers a rigorous examination of the status and outlook on gravitational wave (GW) detections from double compact object (DCO) mergers. It is geared towards quantitatively summarizing the current landscape of GW detections, while also projecting future possibilities with the advancement of detector technology.

Current Detection Landscape

The paper begins by addressing the ambiguity that surrounds the current number of GW detections. This is largely due to the variations in data-analysis pipelines, detection thresholds, and underlying assumptions chosen in different studies. As of the third observing run (O3), the cumulative detection counts across several catalogs such as the GWTC (Gravitational Wave Transient Catalog) by the LVK (LIGO-Virgo-KAGRA) collaboration, 4-OGC, and others, show variations in the number of binary black hole (BHBH), black hole-neutron star (BHNS), and binary neutron star (NSNS) events detected. Figures such as Figure~\ref{fig-ch8:known-detections-different-pipelines} in the source document illustrate these discrepancies, showcasing cumulative detections of 90 to 125 GW events from these mergers depending on the analytical approach.

Significantly, different criteria for assigning astrophysical 'significance' to detections, such as the false-alarm rate (FAR) and the astrophysical probability p_, contribute to varying reported counts. For instance, while the LVK reports 90 detections with p_ > 0.5, the 4-OGC catalog records 94 detections using a slightly different threshold for significance.

Projections for Future Detections

The paper forecasts an exciting future for GW astronomy, driven by enhancements in detection capabilities. Observing runs O4 and O5, commencing in the coming years with improved sensitivities and extended observation periods, are expected to substantially increase detection numbers. For instance, forecasts suggest detecting around 320 to over a thousand events annually during O5.

The anticipation is even greater further in the future with next-generation detectors like the Einstein Telescope (ET) and Cosmic Explorer (CE). Estimates project the potential for hundreds of thousands to millions of detections per year. These projections underscore the transformational nature of future GW observations, highlighting capabilities that will transcend mere numeric counting. Enhanced sensitivity and range will allow scientists to better understand the properties and evolution of compact object populations within the universe's distant reaches, essentially mapping a previously unexplored territory.

Conclusion

The document provides a comprehensive visualization and discussion of existing and expected future GW detections. The results imply not only an expansion in the number of observed events but also significant improvements in precision and range, yielding richer data for astrophysical investigations. As technology advances, gravitational wave astronomy is poised to significantly deepen our understanding of the dynamic cosmos, making it a critical area of research for the coming decade and beyond. The exponential increase in detection numbers will be pivotal in developing insights into the characteristics and distribution of compact objects across the universe. These findings open new prospects for theoretical developments and observational synergies in the field of astrophysics.