TY - JOUR
T1 - Cosmic microwave background dipole from an entropy gradient
AU - Langlois, David
AU - Piran, Tsvi
PY - 1996
Y1 - 1996
N2 - It is generally accepted that the observed CMBR dipole arises from the motion of the local group relative to the CMBR frame. An alternative interpretation is that the dipole results from an ultralarge scale (λ>100c/H0) isocurvature perturbation. Recently it was argued that this alternative possibility is ruled out. We examine the growth of perturbations on scales larger than the Hubble radius, and in view of this analysis we show that the isocurvature interpretation is still a viable explanation. If the dipole is due to peculiar motion then it should appear in observations of other background sources provided that they are distant enough.
AB - It is generally accepted that the observed CMBR dipole arises from the motion of the local group relative to the CMBR frame. An alternative interpretation is that the dipole results from an ultralarge scale (λ>100c/H0) isocurvature perturbation. Recently it was argued that this alternative possibility is ruled out. We examine the growth of perturbations on scales larger than the Hubble radius, and in view of this analysis we show that the isocurvature interpretation is still a viable explanation. If the dipole is due to peculiar motion then it should appear in observations of other background sources provided that they are distant enough.
UR - http://www.scopus.com/inward/record.url?scp=0000576809&partnerID=8YFLogxK
U2 - 10.1103/PhysRevD.53.2908
DO - 10.1103/PhysRevD.53.2908
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AN - SCOPUS:0000576809
SN - 1550-7998
VL - 53
SP - 2908
EP - 2919
JO - Physical Review D - Particles, Fields, Gravitation and Cosmology
JF - Physical Review D - Particles, Fields, Gravitation and Cosmology
IS - 6
ER -