Probing the rest-frame of the Universe with the near-IR cosmic infrared background

Kashlinsky, A.; Atrio-Barandela, F.

doi:10.1093/mnrasl/slac045

Cited by 8 publications

(5 citation statements)

References 58 publications

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“…Succinctly put, if we assume systematics like intrinsic source properties and its evolution over redshift can be controlled, 65 See [630] for an analysis of superhorizon isocurvature modes and the possibility of a non-kinematic contribution to the CMB dipole. 66 See [631] for a recent analysis on a possible non-kinematic, primordial nature of the CMB dipole. any confirmed excess in the radio galaxy or QSO dipole relative to the CMB in the directions of [111,113,127,130], would immediately imply a non-kinematic anisotropy, which, to leading order, would be seen as a dipole.…”

Section: Does Precision Cosmology Based On Flrw Give An Accurate Pict...mentioning

confidence: 99%

Is the observable Universe consistent with the cosmological principle?

Aluri

Cea

Chingangbam

et al. 2023

Class. Quantum Grav.

107

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The Cosmological Principle (CP) -- the notion that the Universe is spatially isotropic and homogeneous on large scales -- underlies a century of progress in cosmology. It is conventionally formulated through the Friedmann-Lema\^{\i}tre-Robertson-Walker (FLRW) cosmologies as the spacetime metric, and culminates in the successful and highly predictive $\Lambda$-Cold-Dark-Matter ($\Lambda$CDM) model. Yet, tensions have emerged within the $\Lambda$CDM model, most notably a statistically significant discrepancy in the value of the Hubble constant, $H_0$. Since the notion of cosmic expansion determined by a single parameter is intimately tied to the CP, implications of the $H_0$ tension may extend beyond $\Lambda$CDM to the CP itself. This review surveys current observational hints for deviations from the expectations of the CP, highlighting synergies and disagreements that warrant further study. Setting aside the debate about individual large structures, potential deviations from the CP include variations of cosmological parameters on the sky, discrepancies in the cosmic dipoles, and mysterious alignments in quasar polarizations and galaxy spins. While it is possible that a host of observational systematics are impacting results, it is equally plausible that precision cosmology may have outgrown the FLRW paradigm, an extremely pragmatic but non-fundamental symmetry assumption.

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Section: Does Precision Cosmology Based On Flrw Give An Accurate Pict...mentioning

confidence: 99%

Is the observable Universe consistent with the cosmological principle?

Aluri

Cea

Chingangbam

et al. 2023

Class. Quantum Grav.

107

View full text Add to dashboard Cite

show abstract

“…This behavior is difficult to explain in the standard cosmological model, particularly since higher order moments of the velocity field do not appear to be larger than expected (Feldman et al 2010). While this behavior is difficult to explain in the standard model, it could be an indication that the particle rest frame of the Universe is not the same as that inferred from the dipole in the cosmic microwave background (CMB) radiation (see e.g., Kashlinsky et al 2008;Ma et al 2011;Kashlinsky & Atrio-Barandela 2022). Indeed, significant evidence that the CMB frame is not the rest frame of the Universe can also be seen in the analyses of the distribution of Quasars on the sky (Secrest et al 2021(Secrest et al , 2022Dam et al 2022).…”

Section: Discussionmentioning

confidence: 97%

Analyzing the Large-Scale Bulk Flow using CosmicFlows4: Increasing Tension with the Standard Cosmological Model

Watkins¹,

Allen²,

Bradford³

et al. 2023

Preprint

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We present an estimate of the bulk flow in a volume of radii 150−200h −1 Mpc using the minimum variance (MV) method with data from the CosmicFlows-4 (CF4) catalog. The addition of new data in the CF4 has resulted in an increase in the estimate of the bulk flow in a sphere of radius 150h −1 Mpc relative to the CosmicFlows-3 (CF3). This bulk flow has less than a 0.03% chance of occurring in the Standard Cosmological Model (ΛCDM) with cosmic microwave background derived parameters. Given that the CF4 is deeper than the CF3, we were able to use the CF4 to accurately estimate the bulk flow on scales of 200h −1 Mpc (equivalent to 266 Mpc for Hubble constant H o = 75 km/s/Mpc) for the first time. This bulk flow is in even greater tension with the Standard Model, having less than 0.003% probability of occurring. To estimate the bulk flow accurately, we introduce a novel method to calculate distances and velocities from distance moduli that is unbiased and accurate at all distances. Our results are completely independent of the value of H o .

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“…) , an amplification that is comparable (Maoz 1994) to that for cosmic rays (CRs; Kachelrieß & Serpico 2006) and the cosmic infrared background (CIB; Kashlinsky 2005a; Kashlinsky & Atrio-Barandela 2022). (2) The clustering (measured to have white noise angular spectrum) component dipole from the unresolved DGB sources would be C F 0.25% ℓ DGB   using measurements from Ackermann et al (2012bAckermann et al ( , 2018 and also here.…”

Section: Introductionmentioning

confidence: 85%

Probing the Dipole of the Diffuse Gamma-Ray Background

Kashlinsky,

Atrio-Barandela,

Shrader

2024

ApJL

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We measured the dipole of the diffuse γ-ray background (DGB), identifying a highly significant time-independent signal coincidental with that of the Pierre Auger UHECR. The DGB dipole is determined from flux maps in narrow energy bands constructed from 13 yr of observations by the Large Area Telescope (LAT) of the Fermi satellite. The γ-ray maps were clipped iteratively of sources and foregrounds similar to that done for the cosmic infrared background. The clipped narrow energy band maps were then assembled into one broad energy map out to the given energy starting at E = 2.74 GeV, where the LAT beam falls below the sky’s pixel resolution. Next we consider cuts in Galactic latitude and longitude to probe residual foreground contaminations from the Galactic plane and center. In the broad energy range 2.74 < E ≤ 115.5 GeV, the measured dipoles are stable with respect to the various Galactic cuts, consistent with an extragalactic origin. The γ-ray sky’s dipole/monopole ratio is much greater than that expected from the DGB clustering component and the Compton–Getting effect origin with reasonable velocities. At ≃(6.5–7)% it is similar to the Pierre Auger UHECRs with E UHECR ≥ 8 EeV, pointing to a common origin of the two dipoles. However, the DGB flux associated with the found DGB dipole reaches parity with that of the UHECR around E UHECR ≤ 1 EeV, perhaps arguing for a non-cascading mechanism if the DGB dipole were to come from the higher-energy UHECRs. The signal-to-noise ratio of the DGB dipole is largest in the 5–30 GeV range, possibly suggesting the γ-photons at these energies are the ones related to cosmic rays.

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Probing the rest-frame of the Universe with the near-IR cosmic infrared background

Cited by 8 publications

References 58 publications

Is the observable Universe consistent with the cosmological principle?

Is the observable Universe consistent with the cosmological principle?

Analyzing the Large-Scale Bulk Flow using CosmicFlows4: Increasing Tension with the Standard Cosmological Model

Probing the Dipole of the Diffuse Gamma-Ray Background

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