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Related papers: Color Dependence of Dipole in CatWISE2020 Data

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We study the dipole signal in the spectral index (x) of the differential number counts using quasars in the CatWISE2020 catalog of infrared sources. The index is extracted by using the log-likelihood method. We obtain the value $x=1.579 \pm…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-29 Mohit Panwar , Pankaj Jain

We study the signal of anisotropy in AGNs/quasars of CatWISE2020 catalogue using different observables. It has been reported earlier that this data shows a strong signal of dipole anisotropy in the source number counts. We test this claim…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-06 Rahul Kothari , Mohit Panwar , Gurmeet Singh , Prabhakar Tiwari , Pankaj Jain

We study the large-scale anisotropy of the Universe by measuring the dipole in the angular distribution of a flux-limited, all-sky sample of 1.36 million quasars observed by the Wide-field Infrared Survey Explorer (WISE). This sample is…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-01 Nathan Secrest , Sebastian von Hausegger , Mohamed Rameez , Roya Mohayaee , Subir Sarkar , Jacques Colin

We determine the dipole in the WISE galaxy catalogue. After reducing star contamination to <0.1% by rejecting sources with high apparent motion and those close to the Galactic plane, we eliminate low redshift sources to suppress the…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-30 M. Rameez , R. Mohayaee , S. Sarkar , J. Colin

Our velocity with respect to the cosmic frame of rest leads to a dipole in the number count distribution of galaxies. The dipole depends on the source spectrum, which is usually assumed to be a power law, $S(\nu) \propto \nu^{-\alpha}$ and…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-08 Mohit Panwar , Akash Gandhi , Pankaj Jain

We apply Simulation-Based Inference ('SBI') to the cosmic dipole problem for the first time, measuring the distribution of quasar counts over the sky in the CatWISE2020 ('CatWISE') sample. We show that the quadrupole anisotropy in CatWISE…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-06 Oliver T. Oayda , Geraint F. Lewis

We theoretically analyze the dipole anisotropy observed in the quasar distribution from the CatWISE2020 catalog. The catalog data shows a peak around $z\approx 1$, suggesting the presence of a large-scale dipole component. We explore the…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-16 Gopal Kashyap , Naveen K. Singh , Pankaj Jain

The cosmic dipole anomaly -- the observation of a significant mismatch between the dipole observed in the matter distribution and that expected given the kinematic interpretation of the cosmic microwave background dipole -- poses a serious…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-25 Sebastian von Hausegger , Nathan Secrest , Harry Desmond , Mohamed Rameez , Roya Mohayaee , Subir Sarkar

The Cosmological Principle, that the Universe is homogeneous and isotropic on sufficiently large scales, underpins the standard model of cosmology. However, a recent analysis of 1.36 million infrared-selected quasars has identified a…

Cosmology and Nongalactic Astrophysics · Physics 2023-08-08 Lawrence Dam , Geraint F. Lewis , Brendon J. Brewer

We probe the isotropy of the Universe with the largest all-sky photometric redshift dataset currently available, namely WISE~$\times$~SuperCOSMOS. We search for dipole anisotropy of galaxy number counts in multiple redshift shells within…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-11 C. A. P. Bengaly , C. P. Novaes , H. S. Xavier , M. Bilicki , A. Bernui , J. S. Alcaniz

A conventional explanation of the dipole anisotropy of the cosmic microwave background (CMB) radiation is in terms of the Doppler effect: our galaxy is moving with respect to CMB frame with $ \sim 600 ~ km ~ s^{-1} $. However, as the deep…

Astrophysics · Physics 2007-05-23 M. Jaroszynski , B. Paczynski

A key test of the isotropy of the Universe on large scales consists in comparing the dipole in the Cosmic Microwave Background (CMB) temperature with the dipole in the distribution of sources at low redshift. Current analyses find a dipole…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-27 N. Grimm , M. Pijnenburg , S. Mastrogiovanni , C. Bonvin , S. Foffa , G. Cusin

The largest temperature anisotropy in the cosmic microwave background (CMB) is the dipole. The simplest interpretation of the dipole is that it is due to our motion with respect to the rest frame of the CMB. As well as creating the $\ell$=1…

Cosmology and Nongalactic Astrophysics · Physics 2021-11-25 Raelyn M. Sullivan , Douglas Scott

Our motion through the Universe generates a dipole in the temperature anisotropies of the Cosmic Microwave Background (CMB) and also in the angular distribution of sources. If the cosmological principle is valid, these two dipoles are…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-09 Charles Dalang , Camille Bonvin

The Ellis-Baldwin test probes the cosmological principle by comparing the kinematic Cosmic Microwave Background dipole with the Doppler-driven dipole in the number counts of extragalactic radio sources. Recent analysis of the CatWISE2020…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-28 Masroor Bashir , Pravabati Chingangbam , Stephen Appleby

We test the usual hypothesis that the Cosmic Microwave Background (CMB) dipole, its largest anisotropy, is due to our peculiar velocity with respect to the Hubble flow by measuring independently the Doppler and aberration effects on the CMB…

Cosmology and Nongalactic Astrophysics · Physics 2021-09-06 Pedro da Silveira Ferreira , Miguel Quartin

The dipole anisotropy seen in the {cosmic microwave background radiation} is interpreted as due to our peculiar motion. The Cosmological Principle implies that this cosmic dipole signal should also be present, with the same direction, in…

Cosmology and Nongalactic Astrophysics · Physics 2019-04-24 Carlos A. P. Bengaly , Thilo M. Siewert , Dominik J. Schwarz , Roy Maartens

We study the dipole anisotropy in number counts and flux density weighted number counts {or sky brightness} in the NRAO VLA Sky Survey (NVSS) data. The dipole anisotropy is expected due to our local motion with respect to the CMBR rest…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-29 Prabhakar Tiwari , Rahul Kothari , Abhishek Naskar , Sharvari Nadkarni-Ghosh , Pankaj Jain

We are in motion against the cosmic backdrop. This motion is evidenced by the systematic temperature shift - or dipole anisotropy - observed in the Cosmic Microwave Background radiation (CMB). Because of the Doppler effect, the temperature…

Astrophysics · Physics 2015-06-24 Chris Blake , Jasper Wall

The largest fluctuation in the CMB sky is the CMB dipole, which is believed to be caused by the motion of our observation frame with respect to the CMB rest frame. This motion accounts for the known motion of the Solar System barycentre…

Cosmology and Nongalactic Astrophysics · Physics 2021-11-19 Sayan Saha , Shabbir Shaikh , Suvodip Mukherjee , Tarun Souradeep , Benjamin D. Wandelt
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