Is the Radio Source Dipole from NVSS Consistent with the CMB and ΛCDM?
arxiv(2023)
摘要
The dipole moment in the angular distribution of the cosmic microwave
background (CMB) is thought to originate from the Doppler effect and our motion
relative to the CMB frame. Observations of large-scale structure (LSS) should
show a related “kinematic dipole” and help test the kinematic origin of the
CMB dipole. Intriguingly, many previous LSS dipole studies suggest
discrepancies with the expectations from the CMB. Here we reassess the apparent
inconsistency between the CMB measurements and dipole estimates from the NVSS
catalog of radio sources. We find that it is important to account for the shot
noise and clustering of the NVSS sources, as well as kinematic contributions,
in determining the expected dipole signal. We use the clustering redshift
method and a cross-matching technique to refine estimates of the clustering
term. We then derive a probability distribution for the expected NVSS dipole in
a standard ΛCDM cosmological model including all (i.e., kinematic,
shot-noise and clustering) dipole components. Our model agrees with most of the
previous NVSS dipole measurements in the literature at better than ≲
2σ. We conclude that the NVSS dipole is consistent with a kinematic
origin for the CMB dipole within ΛCDM.
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