The kinematic dipole in galaxy redshift surveys
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Date
2018
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Publisher
IOP Publishing
Abstract
In the concordance model of the Universe, the matter distribution { as observed in galaxy number
counts or the intensity of line emission (such as the 21cm line of neutral hydrogen) - should have
a kinematic dipole due to the Sun's motion relative to the CMB rest-frame. This dipole should be
aligned with the kinematic dipole in the CMB temperature. Accurate measurement of the direction
of the matter dipole will become possible with future galaxy surveys, and this will be a critical test
of the foundations of the concordance model. The amplitude of the matter dipole is also a potential
cosmological probe. We derive formulas for the amplitude of the kinematic dipole in galaxy redshift
and intensity mapping surveys, taking into account the Doppler, aberration and other relativistic
e ects. The amplitude of the matter dipole can be signi cantly larger than that of the CMB dipole.
Its redshift dependence encodes information on the evolution of the Universe and on the tracers,
and we discuss possible ways to determine the amplitude.
Description
Keywords
Model of the Universe, CMB rest-frame, CMB temperature, Galaxy redshift, CMB dipole
Citation
Maartens, R. et al. (2018). The kinematic dipole in galaxy redshift surveys. Journal of Cosmology and Astroparticle Physics, 2018