Jaiyul Yoo, CfA, Harvard

"A New Perspective on Galaxy Clustering as a Cosmological Probe: General Relativistic Effects"

We present a general relativistic description of galaxy clustering in a FLRW universe.
The observed redshift and position of galaxies are affected by the matter fluctuations
and the gravity waves between the source galaxies and the observer, and the volume
element constructed by using the observables differs from the physical volume occupied
by the observed galaxies. Therefore, the observed galaxy fluctuation field contains
additional contributions arising from the distortion in observable quantities and these
include tensor contributions as well as numerous scalar contributions. We generalize the
linear bias approximation to relate the observed galaxy fluctuation field to the underlying
matter distribution in a gauge-invariant way. Our full formalism is essential for the
consistency of theoretical predictions. As our first application, we compute the angular
auto correlation of large-scale structure and its cross correlation with CMB temperature
anisotropies. We comment on the possibility of detecting primordial gravity waves using
galaxy clustering and discuss further applications of our formalism.