Gravitational transitions via the explicitly broken symmetron screening mechanism

Perivolaropoulos, Leandros; Skara, Foteini

doi:10.48550/arxiv.2203.10374

Cited by 4 publications

(5 citation statements)

References 121 publications

(166 reference statements)

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“…If this possible SnIa luminosity inhomogeneity in the Pantheon+ and SH0ES samples is due to a physics transition [77,[79][80][81][82][83][84][85][86][87][88][89][90] (e.g. gravitational transition [73,[91][92][93][94][95]), it may have implications for other calibration parameters like the color and stretch parameters. It would therefore be of interest to extend the present analysis in such directions by testing the homogeneity of the Pantheon+ sample with respect to possible differences of the best fit values of such parameters when these are allowed to change among different subsamples of the full Pantheon+ sample.…”

Section: Conclusion-discussionmentioning

confidence: 99%

On the homogeneity of SnIa absolute magnitude in the Pantheon+ sample

Perivolaropoulos¹,

Skara²

2023

Preprint

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We have analysed the Pantheon+ sample using a new likelihood model that replaces the single SnIa absolute magnitude parameter M used in the standard likelihood model of Brout et. al. [1] with two absolute magnitude parameters M<, M> and a transition distance dcrit that determines the distance at which M changes from M< to M>. The use of this likelihood dramatically changes the quality of fit to the Pantheon+ sample for a ΛCDM background by ∆χ 2 = −19.6 (∆AIC = −15.5 for two additional parameters). The tension between the M< and M> best fit values is at a level more than 3σ with a best fit dcrit very close to 20M pc. The origin of this improvement of fit and M< − M> tension is that the new likelihood model, successfully models two signals hidden in the data: 1. The well known systematic effect called volumetric redshift scatter bias which is due to asymmetric peculiar velocity variations at redshifts z < 0.01 induced by unequal projected volumes at lower and higher distances compared to a given distance and 2. A mild signal for a change of intrinsic SnIa luminosity at about 20M pc. This interpretation of the results is confirmed by truncating the z < 0.01 Hubble diagram data from the Pantheon+ data where the above systematic is dominant and showing that the M< − M> tension decreases from above 3σ to a little less than 2σ. It is also confirmed by performing a Monte Carlo simulation to compare the merged SnIa absolute luminosities Mi of SnIa+Cepheid hosts, obtained from the SH0ES data, with the anticipated luminosities in the context of a homogeneous single absolute magnitude M . This simulation shows that the maximum significance of the SnIa luminosity transition (Σ ≡ |M>−M<|

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Section: Conclusion-discussionmentioning

confidence: 99%

On the homogeneity of SnIa absolute magnitude in the Pantheon+ sample

Perivolaropoulos¹,

Skara²

2023

Preprint

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“…Physical motivation is an important factor for the evaluation of any new modeling degree of freedom, especially if it is favored by the data. A transition of the SnIa luminosity at a particular recent cosmic time could be induced by a sudden change of the value of a fundamental physics constant, e.g., the gravitational constant in the context of a recent firstorder phase transition [166][167][168] to a new vacuum of a scalar-tensor theory, or in the context of a generalization of the symmetron screening mechanism [143]. A similar first-order transition was implemented in early dark energy models [169], attempting to change the last scattering sound horizon scale without affecting other well-constrained cosmological observables.…”

Section: Discussionmentioning

confidence: 99%

“…A fourth approach related to the previous one is based on a possible change of the physical laws (e.g., a gravitational transition [142,143]) during the past 200 Myrs (z 0.01) when the light of the Cepheid calibrator hosts was emitted [143][144][145][146][147][148][149][150][151][152]. In this context, new degrees of freedom should be allowed for the modeling of either Cepheid calibrators and/or SnIa to allow for the possibility of this physics change.…”

mentioning

confidence: 99%

A Reanalysis of the Latest SH0ES Data for H0: Effects of New Degrees of Freedom on the Hubble Tension

Perivolaropoulos

Skara

2022

Universe

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We reanalyze in a simple and comprehensive manner the recently released SH0ES data for the determination of H0. We focus on testing the homogeneity of the Cepheid+SnIa sample and the robustness of the results in the presence of new degrees of freedom in the modeling of Cepheids and SnIa. We thus focus on the four modeling parameters of the analysis: the fiducial luminosity of SnIa MB and Cepheids MW and the two parameters (bW and ZW) standardizing Cepheid luminosities with period and metallicity. After reproducing the SH0ES baseline model results, we allow for a transition of the value of any one of these parameters at a given distance Dc or cosmic time tc, thus adding a single degree of freedom in the analysis. When the SnIa absolute magnitude MB is allowed to have a transition at Dc≃50 Mpc (about 160 Myrs ago), the best-fit value of the Hubble parameter drops from H0=73.04±1.04 km s−1 Mpc−1 to H0=67.32±4.64 km s−1 Mpc−1 in full consistency with the Planck value. Additionally, the best-fit SnIa absolute magnitude MB> for D>Dc drops to the Planck inverse distance ladder value MB>=−19.43±0.15, while the low distance best fit MB< parameter remains close to the original distance ladder calibrated value MB<=−19.25±0.03. Similar hints for a transition behavior is found for the other three main parameters of the analysis (bW, MW and ZW) at the same critical distance Dc≃50 Mpc, even though in that case, the best-fit value of H0 is not significantly affected. When the inverse distance ladder constraint on MB> is included in the analysis, the uncertainties for H0 reduce dramatically (H0=68.2±0.8 km s−1 Mpc−1), and the MB transition model is strongly preferred over the baseline SH0ES model (Δχ2≃−15, ΔAIC≃−13) according to the AIC and BIC model selection criteria.

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“…A novel approach which appears to be consistent with both geometric and dynamical cosmological probes involves a rapid transition of the absolute luminosity of type Ia supernovae (SnIa) to a value lower by about 10% occurring within the last 50 to 150 Myrs (redshift z < 0.01) [63][64][65]. Such a transition could be induced by a sudden decrease of the gravitational constant for objects observed beyond a critical distance [66,67] about 20-40 Mpc (light emitted from them 50-150Myrs ago) which is consistent (or even favored in some cases) with current astrophysical probes [65,[67][68][69] and with solar system chronology [70].…”

Section: Opportunities For Further Involvement Of Greece In Lisamentioning

confidence: 98%

The Laser Interferometer Space Antenna mission in Greece White Paper

Karnesis¹,

Stergioulas²,

Pappas³

et al. 2022

Preprint

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The Laser Interferometer Space Antenna (LISA) mission, scheduled for launch in the mid-2030s, is a gravitational wave observatory in space designed to detect sources emitting in the millihertz band. LISA is an ESA flagship mission, currently entering the Phase B development phase. It is expected to help us improve our understanding about our Universe by measuring gravitational wave sources of different types, with some of the sources being at very high redshifts z ∼ 20. On the 23rd of February 2022 we organized the 1 st LISA in Greece Workshop. This workshop aimed to inform the Greek scientific and tech industry community about the possibilities of participating in LISA science and LISA mission, with the support of the Hellenic Space Center (HSC). In this white paper, we summarize the outcome of the workshop, the most important aspect of it being the inclusion of 15 Greek researchers to the LISA Consortium, raising our total number to 22. At the same time, we present a road-map with the future steps and actions of the Greek Gravitational Wave community with respect to the future LISA mission.https://indico.physics.auth.gr/event/11/ a. The shape and organization of this document, have been inspired by the work of our Canadian Colleagues.

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Gravitational transitions via the explicitly broken symmetron screening mechanism

Cited by 4 publications

References 121 publications

On the homogeneity of SnIa absolute magnitude in the Pantheon+ sample

On the homogeneity of SnIa absolute magnitude in the Pantheon+ sample

A Reanalysis of the Latest SH0ES Data for H0: Effects of New Degrees of Freedom on the Hubble Tension

The Laser Interferometer Space Antenna mission in Greece White Paper

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