| Speaker: |
Raul Abramo (U. Sao Paulo) |
| Title: |
A robust cosmic standard ruler from the cross-correlation of galaxies and dark sirens |
| Date (JST): |
Thu, Apr 03, 2025, 13:30 - 15:00 |
| Place: |
Seminar Room A |
| Abstract: |
Dark sirens are sources of gravitational waves (typically mergers of black hole binaries) without an electromagnetic counterpart. The gravitational waveform measured by our detectors (LIGO and others) allows us to infer the distance (not the redshift) to those sources. In this talk I will show that by correlating dark sirens and galaxies we can directly draw the Hubble redshift-distance relation, with minimal assumptions about the underlying cosmology. This allows for a direct measurement of the Hubble parameter, which on one hand is free of the types of systematics that affect standard sirens, and on the other hand comes without the model dependence implicit in the Planck constraint. Using this new technique we forecast an accuracy of 4% with run 5 of the LIGO-Virgo-Kagra network of gravitational wave detectors, and less than 1% with the future facility Einstein Telescope. I will also discuss possible issues and challenges for applying the method to existing data sets.
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