A New Perspective on Galaxy Clustering as a Cosmological Probe: General Relativistic Effects
Jaiyul Yoo
Harvard/CfA
October 12, 2009, 4PM, Steward N210
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.
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