We confront Yukawa modified cosmology, proposed in [Jusufi et al. arXiv:2304.11492], with data from Supernovae Type Ia (SNe Ia) and Hubble parameter (OHD) observations. Yukawa cosmology is obtained from a Yukawa-like gravitational potential, with coupling parameter α and wavelength parameter λ, which gives rise to modified Friedmann equations. We show that the agreement with observations is very efficient, and within 1σ confidence level we find the best-fit parameters λ=2693−1262+1191Mpc, α=0.416−0.326+1.137, and a graviton mass of mg=2.374−0.728+2.095×10−42GeV. Additionally, we establish a connection between the effective dark matter and dark energy density parameters and the angular radius of the black hole shadow of the SgrA and M87 black holes in the low-redshift limit, consistent with the Event Horizon Telescope findings. 

Observational constraints on Yukawa cosmology and connection with black hole shadows

One of main sources of uncertainty in modern cosmology is the present rate of the universe’s expansion, H0, called the Hubble constant. Once again, different observational techniques bring about different results, causing new “Hubble tension”. In the present work, we review the historical roots of the Hubble constant from the beginning of the twentieth century, when modern cosmology originated, to the present. We develop the arguments that gave rise to the importance of measuring the expansion of the Universe and its discovery, and we describe the different pioneering works attempting to measure it. There has been a long dispute on this matter, even in the present epoch, which is marked by high-tech instrumentation and, therefore, in smaller uncertainties in the relevant parameters. It is, again, currently necessary to conduct a careful and critical revision of the different methods before one invokes new physics to solve the so-called Hubble tension.

The Unsettled Number: Hubble’s Tension

We confront Yukawa modified cosmology, proposed in arXiv:2304.11492 by Jusufi et al., with data from Supernovae Type Ia (SNe Ia) and Hubble parameter (OHD) observations. Yukawa cosmology is obtained from a Yukawa-like gravitational potential, with coupling parameter $\alpha$ and wavelength parameter $\lambda$, which gives rise to modified Friedmann equations. We show that the agreement with observations is very efficient, and within $1\sigma$ confidence level we find the best-fit parameters $\lambda=2693_{-1262}^{+1191}\, \rm Mpc$, and $\alpha=0.416_{-0.326}^{+1.137}$, and a graviton mass of approximately $m_g \simeq 5.6\times 10^{-43}$ GeV. Additionally, we establish a connection between the effective dark matter and dark energy density parameters and the angular radius of the black hole shadow of the SgrA and M87 black holes in the low-redshift limit, which is consistent with the findings of the Event Horizon Telescope.

Observational Constraints on Yukawa Cosmology and Connection with Black Hole Shadows

Gravitational lensing of luminous matter that surrounds a black hole or some other sufficiently compact object produces an infinite sequence of images. Besides the direct (or primary) image, it comprises demagnified and deformed replicas of the original known as photon rings which are progressively nearing the boundary of the socalled shadow. In the present paper, we present analytical approximation formulas for higher-order photon rings for an asymptotically flat, static, spherically symmetric spacetime that admits a photon sphere. We consider a geometrically thin disk of light sources in the equatorial plane and an observer at arbitrary inclination far away from the center. Fixing the emission radius and leveraging the strong deflection limit, which provides an analytical logarithmic approximation for the deflection angle, we find the deformed shape of higher-order photon rings in the form of a polar equation on the observer's screen. It has been suggested by other authors to use the relative size of photon rings for characterizing the underlying spacetime. In particular, the relative separation between two neighboring photon rings, which we call"gap parameter", was considered. We analytically calculate the gap parameter of higher-order photon rings for metrics of the considered class that may depend on multiple parameters. The advantage of using this quantity is in the fact that, to within the assumed approximations, it is independent of the mass of the central object (or of some other characteristic parameter if the mass is zero) and of the distance of the observer. Measurements of the gap parameter, which may become possible in the near future, will restrict the spacetime models that are in agreement with the observations. Even without knowing the inner and outer radii of the shining disk, it will conclusively rule out some metrics. Some examples are provided.

Constraining spherically symmetric metrics by the gap between photon rings

In the context of the Fab-Four theory of gravity in a Friedmann-Lemaître-Robertson-Walker background, in this work we use the cosmography approach to study a particular self-tuning filter solution focused on a zero-curvature fixed point to study the H0 tension. In this scheme, the equations restrict the universe’s evolution to certain scenarios, including radiation-like expansion, matter-like expansion, and late-time acceleration. Furthermore, we build the cosmographic series of the Fab-Four theory to obtain the kinematic parameters as the Hubble constant H0 and the deceleration parameter q0 for all the scenarios mentioned. Finally, we compare our results to find that it is possible to alleviate the current discrepancy on H0 by considering specific requirements on the free parameters of the Fab-Four theory through a self-tuning filter.

/pdf/fab-four-cosmography-to-tackle-the-hubble-tension-2m61da2g.pdf

Fab-Four Cosmography to Tackle the Hubble Tension

Cosmological tensions in current times have opened a wide door to study new probes to constrain cosmological parameters, specifically, to determine the value of the Hubble constant H0 through independent techniques. The two standard methods to measure/infer H0 rely on: (i) anchored observables for the distance ladder, and (ii) establishing the relationship of the H0 to the angular size of the sound horizon in the recombination era assuming a standard Cosmological Constant Cold Dark Matter (ΛCDM) cosmology. However, the former requires a calibration with observables at nearby distances, while the latter is not a direct measurement and is model-dependent. The physics behind these aspects restrains our possibilities in selecting a calibration method that can help minimise the systematic effects or in considering a fixed cosmological model background. Anticipating the possibility of deeply exploring the physics of new nearby observables such as the recently detected black hole shadows, in this paper we propose standard rules to extend the studies related to these observables. Supermassive black hole shadows can be characterised by two parameters: the angular size of the shadow and the black hole mass. We found that it is possible to break the degeneracy between these parameters by forecasting and fixing certain conditions at high(er) redshifts, i.e., instead of considering the ≈10% precision from the EHT array, our results reach a ≈4%, a precision that could be achievable in experiments in the near future. Furthermore, we found that our estimations provide a value of H0=72.89±0.12 km/s/Mpc and, for the baryonic mass density, Ωm=0.275±0.002, showing an improvement in the values reported so far in the literature. We anticipate that our results can be a starting point for more serious treatments of the physics behind the SMBH shadow data as cosmological probes to relax tension issues.

/pdf/h0-tension-on-the-light-of-supermassive-black-hole-shadows-21jii2jd.pdf

H0 Tension on the Light of Supermassive Black Hole Shadows Data

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Rubén Torres Castillejos

Author Tools

Chat about Author

Papers

H0 Tension on the Light of Supermassive Black Hole Shadows Data