Color Dependence of Dipole in CatWISE2020 Data

Fuente: arXiv
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Main Authors: Panwar, Mohit, Jain, Pankaj, Omar, Amitesh
Format: Preprint
Published: 2024
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author Panwar, Mohit
Jain, Pankaj
Omar, Amitesh
author_facet Panwar, Mohit
Jain, Pankaj
Omar, Amitesh
contents The signal of dipole anisotropy in quasar number counts is studied using the CatWISE2020 catalog in various color bins. It is found that the dipole signal differs significantly in two color bins, namely, $1.1>W1-W2\ge 0.8$ and $1.4>W1-W2>1.1$. The color bin $1.4>W1-W2>1.1$ appears strongly contaminated, with possibly Galactic contributions and is unreliable for extracting the signal of cosmological dipole. The source of this contamination has not been identified and cannot be attributed to known emissions within the galaxy. Removing this contaminated color bin leads to a strong dipole signal with a direction significantly different from that obtained from full data. If we interpret this dipole as due to our local motion, the extracted velocity turns out to be $900\pm 113$ Kms$^{-1}$, which deviates from the CMB dipole velocity with approximately $4.7$ sigma significance.
format Preprint
id arxiv_https___arxiv_org_abs_2405_16853
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Color Dependence of Dipole in CatWISE2020 Data
Panwar, Mohit
Jain, Pankaj
Omar, Amitesh
Cosmology and Nongalactic Astrophysics
The signal of dipole anisotropy in quasar number counts is studied using the CatWISE2020 catalog in various color bins. It is found that the dipole signal differs significantly in two color bins, namely, $1.1>W1-W2\ge 0.8$ and $1.4>W1-W2>1.1$. The color bin $1.4>W1-W2>1.1$ appears strongly contaminated, with possibly Galactic contributions and is unreliable for extracting the signal of cosmological dipole. The source of this contamination has not been identified and cannot be attributed to known emissions within the galaxy. Removing this contaminated color bin leads to a strong dipole signal with a direction significantly different from that obtained from full data. If we interpret this dipole as due to our local motion, the extracted velocity turns out to be $900\pm 113$ Kms$^{-1}$, which deviates from the CMB dipole velocity with approximately $4.7$ sigma significance.
title Color Dependence of Dipole in CatWISE2020 Data
topic Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2405.16853