Our NASA Astrophysics Theory Program (ATP) Grant Proposal 17-ATP17-0047 (Exploring Extreme Gravity with LISA: Developing a Science Case for Tests of General Relativity) (PI: Emanuele Berti, Co-PI: Nicolás Yunes) was recommended for funding. The total award amount is $815,554 over 3 years. This is the proposal summary:
This proposal is focused on developing the experimental-relativity science case for the Laser Interferometer Space Antenna (LISA). We propose to explore tests of General Relativity with LISA gravitational wave data using different astrophysical population models and astrophysical sources to forecast what will be possible in the era of space-based detectors. We will create and develop tools to carry out consistency checks of Einstein’s theory and to search for modified gravity anomalies with LISA data. We will explore how the strength of these tests varies with population models and with astrophysical sources, mapping out the theory space that will be constrainable with LISA. We will also explore the strength of combining LISA data with ground-based gravitational wave observations to carry out tests of Einstein’s theory with multi-wavelength observations.
The proposed work is of direct relevance to NASA’s strategic mission to better understand the universe through observation, and to NASA’s mission of discovery and knowledge. The region of the universe where gravity is very strong and dynamically changing (the extreme gravity universe) is one of the last unturned stones. This is in part because extreme gravity objects, like black holes, are difficult to resolve due to their size and distance from Earth. NASA’s investment in space-borne gravitational wave astrophysics as a partner to ESA is aimed at resolving such objects and, for the first time, exploring the extreme gravity universe in detail. The focus of this proposal is to aid in this endeavor by developing the understanding needed to extract the most information about theoretical physics and modified gravity constraints from LISA data.