Details
| Originalsprache | Englisch |
|---|---|
| Aufsatznummer | 019 |
| Fachzeitschrift | JCAP |
| Jahrgang | 2022 |
| Ausgabenummer | 10 |
| Publikationsstatus | Veröffentlicht - 7 Okt. 2022 |
| Extern publiziert | Ja |
Abstract
In view of the growing tension between the dipole anisotropy of number counts of cosmologically distant sources and of the cosmic microwave background (CMB), we investigate the number count dipole induced by primordial perturbations with wavelength comparable to or exceeding the Hubble radius today. First, we find that neither adiabatic nor isocurvature superhorizon modes can generate an intrinsic number count dipole. However a superhorizon isocurvature mode does induce a relative velocity between the CMB and the (dark) matter rest frames and thereby affects the CMB dipole. We revisit the possibility that it has an intrinsic component due to such a mode, thus enabling consistency with the galaxy number count dipole if the latter is actually kinematic in origin. Although this scenario is not particularly natural, there are possible links with other anomalies and it predicts a concommitant galaxy number count quadrupole which may be measurable in future surveys. We also investigate the number count dipole induced by modes smaller than the Hubble radius, finding that subject to CMB constraints this is too small to reconcile the dipole tension.
ASJC Scopus Sachgebiete
- Physik und Astronomie (insg.)
- Astronomie und Astrophysik
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in: JCAP, Jahrgang 2022, Nr. 10, 019, 07.10.2022.
Publikation: Beitrag in Fachzeitschrift › Artikel › Forschung › Peer-Review
}
TY - JOUR
T1 - Galaxy number-count dipole and superhorizon fluctuations
AU - Domènech, Guillem
AU - Mohayaee, Roya
AU - Patil, Subodh P.
AU - Sarkar, Subir
N1 - Publisher Copyright: © 2022 IOP Publishing Ltd and Sissa Medialab.
PY - 2022/10/7
Y1 - 2022/10/7
N2 - In view of the growing tension between the dipole anisotropy of number counts of cosmologically distant sources and of the cosmic microwave background (CMB), we investigate the number count dipole induced by primordial perturbations with wavelength comparable to or exceeding the Hubble radius today. First, we find that neither adiabatic nor isocurvature superhorizon modes can generate an intrinsic number count dipole. However a superhorizon isocurvature mode does induce a relative velocity between the CMB and the (dark) matter rest frames and thereby affects the CMB dipole. We revisit the possibility that it has an intrinsic component due to such a mode, thus enabling consistency with the galaxy number count dipole if the latter is actually kinematic in origin. Although this scenario is not particularly natural, there are possible links with other anomalies and it predicts a concommitant galaxy number count quadrupole which may be measurable in future surveys. We also investigate the number count dipole induced by modes smaller than the Hubble radius, finding that subject to CMB constraints this is too small to reconcile the dipole tension.
AB - In view of the growing tension between the dipole anisotropy of number counts of cosmologically distant sources and of the cosmic microwave background (CMB), we investigate the number count dipole induced by primordial perturbations with wavelength comparable to or exceeding the Hubble radius today. First, we find that neither adiabatic nor isocurvature superhorizon modes can generate an intrinsic number count dipole. However a superhorizon isocurvature mode does induce a relative velocity between the CMB and the (dark) matter rest frames and thereby affects the CMB dipole. We revisit the possibility that it has an intrinsic component due to such a mode, thus enabling consistency with the galaxy number count dipole if the latter is actually kinematic in origin. Although this scenario is not particularly natural, there are possible links with other anomalies and it predicts a concommitant galaxy number count quadrupole which may be measurable in future surveys. We also investigate the number count dipole induced by modes smaller than the Hubble radius, finding that subject to CMB constraints this is too small to reconcile the dipole tension.
KW - cosmic flows
KW - cosmological perturbation theory
KW - galaxy surveys
KW - Inflation and CMBR theory
UR - http://www.scopus.com/inward/record.url?scp=85150277305&partnerID=8YFLogxK
U2 - 10.1088/1475-7516/2022/10/019
DO - 10.1088/1475-7516/2022/10/019
M3 - Article
VL - 2022
JO - JCAP
JF - JCAP
IS - 10
M1 - 019
ER -