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RIT’s Center for Computational Relativity and Gravitation at the dawn of new age of gravitational wave astrophysics –> Now that gravitational waves have been detected, what’s next? We transform gravitational waves into a tool for astronomical discovery!

• The unexpected: Einstein’s theory says any time-varying mass (quadrupole) radiates gravitational waves…so the universe is full of sources, some of which we may not have imagined.

• Coalescing binary black holes: LIGO will detect many more, soon, and measure their properties equally if not more precisely. We can build a large census of “heavy” black holes in the local universe – a census we can correlate against other experience. We know how stars evolve; we see similar black holes (and their progenitors) in our own galaxy; and new large-scale surveys will complement insights from LIGO into binary star evolution. (We’ll make a census of binaries including neutron stars too.)

Next-generation instruments, if they have your support, can enhance our reach dramatically, enabling exquisitely precise measurements of hundreds of thousands of coalescing binaries per year. We’ll see so many binaries, from all over the univese, that we can directly measure the formation rate versus time!

• Simultaneously seeing and hearing explosions: Multimessenger astronomy: The inspiral and merger of neutron stars, if sufficiently close by, can be detected via their gravitational waves too. But this merger often tears the neutron star apart, throwing highly radioactive material to large distances while releasing an enormous amount of gravitational energy. So we should be able to see it with telescope…and probably have: short gamma ray bursts and kilonovae.

In other words, nature’s provided us with a cosmic collider, throwing neutron stars onto other compact objects. Gravitational waves can tell telescopes where to look and identify what happened, particularly the inputs to the coalescence; electromagnetic observations tell us what comes out. Using these two probes, we’ll be able to disassemble and reassemble the physics underlying these two longstanding cosmic mysteries, in a controlled fashion. And we’ll learn quite a bit about nuclear physics, too.

• Neutron stars as a source and detector of gravitational waves: With roughly one billion in our galaxy, the closest and most persistent relics of stellar death are neutron stars, which uniquely are useful both as sources and detectors of gravitational waves:

Neutron stars as souces: If neutron stars irregular enough – and all calculations suggest they could and indeed should be – then we’ll be able to detect these steady-state sources too. The strength of their gravitational wave signal will provide another perspective into nuclear physics.

• The Milky Way as a detector? Neutron stars are often periodic radio sources: pulsars. The regular arrival time of these pulses can be distorted by an intervening gravitational wave. So, by timing sources, we can tell if nearby galaxies contain hidden supermassive black hole binaries: if so, we’ll see distinctive patterns in their radiation.