IFIC makes a key contribution to an emerging field: the Sun as a source of gravitational waves

An international scientific collaboration between the Institute of Corpuscular Physics (IFIC), research centre of the UV Science Park and joint centre of the Higher Council for Scientific Research (CSIC) and the University of Valencia (UV), and the Deutsches Elektronen-Synchrotron (DESY) has achieved the most detailed theoretical prediction to date of gravitational waves generated by the Sun

The results, recently accepted for publication in the prestigious journal Physical Review Letters, suggest that the Sun emits a continuous spectrum of high-frequency gravitational waves. These types of waves would come from small and fast cosmic events, whereas the low-frequency gravitational waves detected so far are produced by large-scale cosmic events. Although the signal generated by the Sun is currently undetectable, it sets a well-defined reference point for future experimental efforts. 

The work developed at the Institute of Corpuscular Physics (IFIC), located in the scientific-academic area of the Science Park of the University of Valencia (PCUV), has been led by Camilo García Cely, researcher Ramón y Cajal, in collaboration with Andreas Ringwald in DESY. "Our speciality is the study of dark matter, in particular axions," explains García Cely. "However, this work led us to explore different aspects of solar physics in depth," he adds.

Current gravitational wave detectors are designed to capture low-frequency signals, such as those generated by the fusion of black holes or neutron stars. However, in recent years a rapidly growing scientific community has begun to focus on the study of high-frequency gravitational waves. According to the commonly accepted assumption, this frequency band is free of astrophysical backgrounds, which would make it especially suitable for detecting signals from the early stages of the Universe. The new theoretical results question this assumption.

"This contribution opens up a new perspective on high-frequency gravitational waves, which had been virtually unnoticed. We now believe that even ordinary stars like the Sun emit gravitational waves in this frequency range, at levels comparable to those expected from early Universe processes", IFIC researcher Camilo García Cely 

"This contribution opens up a new perspective on high-frequency gravitational waves, which had been practically unnoticed," says García Cely. "We now believe that even ordinary stars like the Sun emit gravitational waves in this frequency range, at levels comparable to those expected from early Universe processes," he says.

Also, according to Ringwald, "the Sun does not emit a significant amount of gravitational radiation, but this could actually be an advantage. In fact, it leaves ample scope for exploration by new physics". "It remains to be seen whether this radiation can be detected, but if so, it could become a powerful tool for studying the inner structure of the Sun," stresses the researcher.

"Our contribution has been to extend its legacy, incorporating a greater number of physical effects, obtaining a complete and coherent spectrum of gravitational waves along a wide range of frequencies", Camilo García Cely, IFIC researcher

The IFIC, under the leadership of Camilo García Cely, has played a key role in this field. His contribution is part of a national project coordinated with other groups in Spain, in which he is the principal researcher. The predictions developed by his team are particularly relevant to the initiatives being carried out at DESY, one of the leading international particle physics research centres. Experiments such as ALPS II, BabyIAXO, MADMAX and MAGO, all aimed at detecting axions or high-frequency gravitational waves, are being or will be installed in the near future. 

This work takes up an idea formulated in the 1960s by Steven Weinberg, one of the founding figures of particle physics. Although Weinberg estimated the total power of gravitational waves emitted by the Sun, he did not derive a detailed frequency distribution. "Our contribution has been to extend its legacy, incorporating a greater number of physical effects, obtaining a complete and coherent spectrum of gravitational waves along a wide range of frequencies," concludes García Cely.

Source: IFIC