CosmoVerse@Lisbon

Contribution List

91. Welcome

Jackson Levi Said

30/05/23, 09:30

103. A new constraint on the expansion history of the Universe with cosmic chronometers in VANDELS

Elena TOMASETTI

30/05/23, 09:40

In the era of precision cosmology, exploring new and complementary approaches to measure the expansion history of the Universe is crucial to increase the accuracy in the measurements and keep systematic effects under control. A novel approach that provides cosmology-independent constraints on the Hubble parameter is based on the analysis of the differential age evolution of massive and...

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

Richard WATKINS

30/05/23, 10:05

We present an estimate of the bulk flow in a volume of radii 150 200h−1Mpc using the minimum variance (MV) method with data from the CosmicFlows4 (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−1Mpc relative to the CosmicFlows3 (CF3). This bulk flow has less than a 0.03% chance of occurring in the...

95. Cosmological parameters via HII galaxies and systematic uncertainties

Ricardo CHÁVEZ MURILLO

30/05/23, 11:00

We present independent determinations of cosmological parameters using the distance estimator based on the established correlation between the Balmer line luminosity, L(Hβ), and the velocity dispersion (σ) for HII galaxies (HIIG). We also explore in detail the systematic uncertainties associ- ated with HIIG as a cosmological tracer. These results are based on new VLT-KMOS high spectral...

96. Standard Siren Cosmology with Gravitational Waves from Binary Black Hole Mergers in Active Galaxy Nuclei

Clecio BOM

30/05/23, 11:25

The detection of gravitational Waves (GW) has opened a new window for cosmology. The cur- rent tension between the measurement of the Hubble constant H0 from Cosmic Microwave Back- ground and Supernova analyses makes an independent, standard siren measurement of H0 from gravitational waves particularly interesting. However, up to date the astronomical community has confidently identified only...

97. Building the high-redshift Hubble Diagram with quasars

Matilde SIGNORINI

30/05/23, 11:50

In recent years, quasars have shown to be standardizable candles, allowing us to extend the Hub- ble Diagram from the Supernovae Ia range (z ˜ 0-1.5) up to very high redshift (z ˜ 6), and therefore explore the expansion history of the Universe at previously uninvestigated epochs. This implemen- tation has shown the presence of a strong tension (>4σ) with a standard flat ΛCDM model, and...

105. Dark energy, our faster universe and its breaker' galaxies

Olga MENA

30/05/23, 12:15

We shall review the landscape of dark energy models, focusing on non-minimal cosmologies which exhibit a coupling among the dark sectors of the theory, that is, an energy flow among dark energy and dark matter. Such a very appealing possibility may alleviate the current mismatch in the observations of the Hubble constant. It could also play a non-negligible role in the recent results of the...

98. The Local Value of the Hubble Constant

Adam RIESS

30/05/23, 14:30

I will review local measurements of the Hubble constant using the distance ladder and data from Gaia EDR3, HST, JWST, Pantheon +, SH0ES and a range of techniques and tools.

99. Systematics of stellar standard candles for an accurate distance ladder and H0

Richard ANDERSON

30/05/23, 15:10

The extragalactic distance ladder measures the Hubble constant using type-Ia supernovae whose absolute calibration relies on stellar standard candles, such as classical Cepheids and the TRGB method. Understanding the implications of the Hubble constant tension requires careful consideration of the systematics of stellar standard candles. This presentation reviews recent improvements in the...

100. Minimizing systematics with CLONES (Constrained LOcal & Nesting Environment Simulations)

Jenny SORCE

30/05/23, 16:20

To understand dark matter and energy, large cosmological surveys are designed to reach a few percent precision. To be fully exploited, this large quantity of data needs to be analyzed in light of cosmological simulations. Preliminary analyses brought out tensions between the standard cosmological model and observations. Reaching a 1% precision, systematics of the same order of magnitude, due...

101. Intrinsic tension in the supernovae sector of the local Hubble constant measurement and its implications

Radoslaw WOJTAK

30/05/23, 16:45

I will start my talk with a brief critical review of cosmological proposals put forward as potential so- lutions to the Hubble constant tension. I will argue that the lack of decisive observational evidence supporting any of the current models should motivate our community to reassess the risk-to-gain ratio of this line of research and perhaps restore a balance between the efforts put in...

102. The Pantheon+ Supernova Sample and Cosmological Constraints

Dillon BROUT

30/05/23, 17:10

I will detail leaps of progress in Type Ia Supernova Cosmology (SNIa) that have culminated in the recent Pantheon+ cosmological analysis of 1701 SNIa light curves. While this SN dataset places strong constraints on dark matter, dark energy and solidify Lambda CDM, Pantheon+ is also used in the recent SH0ES constraints of the local value of the Hubble Constant (the current expansion rate of the...

104. The Ups and Downs of Early Dark Energy

Vivian POULIN

31/05/23, 09:00

Early Dark Energy (EDE), an additional component of dark energy active in the decade of redshift before recombination, has emerged as one of the most effective models at resolving the Hubble tension. By reducing the size of the `sound horizon’ that calibrates CMB and BAO observations, it is able to fit a variety of datasets including the variety of high-H0 measurements, and may shed light upon...

93. Observational cosmology with weak gravitational lensing

Marika ASGARI

31/05/23, 09:40

I give a review of weak gravitational lensing by the large scale structures also known as cosmic shear. I will take you through the steps taken to extract cosmological information from data and discuss the results from the recent weak gravitational lensing surveys. I will then discuss the tension in the structure growth parameter when comparing the weak lensing results with the cosmic...

106. Cosmic Tsunamis in Modified Gravity: Disruption of Screening Mechanisms from Scalar Waves

David MOTA

31/05/23, 10:50

Extending general relativity by adding extra degrees of freedom is a popular approach for explaining the accelerated expansion of the Universe and to build high energy completions of the theory of gravity. The presence of such new degrees of freedom is, however, tightly constrained from several observations and experiments that aim to test general relativity in a wide range of scales. The...

107. Assessing the consistency of Cosmic Microwave Background observations to probe new physics

Willam GIARE

31/05/23, 11:15

In this talk I will discuss about the global agreement between the most recent observations of the Cosmic Microwave Background temperature and polarization anisotropies. I will point out some emergent anomalies that cannot be fully understood within the standard ΛCDM model of cosmology, hinting at significant unaccounted-for systematics in the CMB data or at basic missed ingredients in the...

108. Gamma-Ray Burst cosmology and future perspectives

Maria Giovanna DAINOTTI

31/05/23, 11:40

"Cosmological models and their corresponding parameters are widely debated because of the current discrepancy
between the results of the Hubble constant, H0, obtained by SNe Ia, and the Planck data from the cosmic microwave
background radiation. Thus, considering high redshift probes like gamma-ray bursts (GRBs) is a necessary step.
However, using GRB correlations between their physical...

109. Searching for hidden signals or systematics in the Pantheon+ and SH0ES SnIa samples

Leandros PERIVOLAROPOULOS

31/05/23, 14:00

The standard analysis of the Pantheon+ and SH0ES SnIa samples assumes that the SnIa absolute magnitude parameter M can be standardized to a single and isotropic value. If these assumptions are withdrawn and in particular if a transition of M is allowed at some distance scale from M_< at low distances to M_> at high distances then the quality of fit to the Pantheon+ data improves significantly...

110. Reconstructing the Universe properties

Alberto VAZQUEZ

31/05/23, 14:25

"In the absence of a fundamental and well defined theory, several parameterizations of cosmological functions have been suggested to get insights of the general DE behaviour and hence to look for possible deviations from the cosmological constant.
Even though these parametric forms usually provide a better fit to the data, they have the limitation of assuming an a priori functional form which...

130. Stability Conditions for the Horndeski Scalar Field Gravity Model

Cláudio GOMES

31/05/23, 14:50

We constrain the viable models of Horndeski gravity after the GWs events by resorting to the Witten positive energy theorem. We find that the free function G3(ϕ,X) in the Lagrangian is con- strained to be a function solely of the scalar field, G3(ϕ). In addition,relations among the free functions are found. Other criteria for stability are also analysed, such as the attractiveness of gravity,...

112. Is H0 a constant?

Eoin O COLGAIN

31/05/23, 15:15

Using a combination of mathematics and data analysis, I will explain why evolution of the Lambda- CDM cosmological parameters with effective redshift is expected. I will review observations show- ing such trends and explain why they tilt the cosmological tensions debate away from systematics and towards missing physics.

113. Enhanced weak lensing cosmology with the lensing PDF

Benjamin GIBLIN

31/05/23, 16:10

Weak lensing cosmology stands at a crossroads, with cosmological tensions between cosmic shear experiments and those from Planck’s analysis of the CMB hinting at either undiscovered physics or unaccounted-for systematics. In response to this mystery, we present a new weak lensing statis- tic capable of vastly enhancing cosmological inference. The “lensing PDF” - or the distribution of...

114. Current data are consistent with flat spatial hypersurfaces in the LCDM but favor more lensing than the model predicts

Javier DE CRUZ PÉREZ

31/05/23, 16:35

We study the performance of three pairs of tilted ΛCDM cosmological models, two pairs allowing for non-flat spatial hypersurfaces with CMB temperature and polarization power spectrum data (P18) from Planck, P18 lensing (lensing), and non-CMB data (non-CMB). For the six models, we measure cosmological parameters and study whether or not pairs of the data sets are mutually consistent in these...

115. Time Delay Cosmography with Strongly Lensed Quasars

Fred COURBIN

31/05/23, 17:00

The arrival time of photons in the different lensed images of distant quasars can be measured from long and well-sampled light curves. This has been pioneered by the COSMOGRAIL, H0LiCOW and TDCOSMO programs and will soon been follow-up with Rubin-LSST. Time delays are inversely proportional to H0 and agree with local H0 measurements such as SH0ES. I will present some of the recent results from...

116. Tensions in Cosmology: A signal of modified gravity?

Emmanuel SARIDAKIS

01/06/23, 09:00

It is quite possible that the tensions between various observational datasets and theoretical predictions of the Standard Model of Gravity and Cosmology, such as the H0 and S8 tensions, could be a sign that we are approaching New Physics. Among the various possible solutions/alleviations, the ones bases on modifications /extensions of General Relativity may be the most promising.

117. Cosmic Neutrino Background: Status, Perspectives, and Potential Resolution of Current Tensions

Alessandro MELCHIORRI

01/06/23, 09:40

The cosmic neutrino background, a relic of the early universe, represents a fundamental aspect of cosmic particle physics. This talk provides an overview of the current status and perspectives regarding the cosmic neutrino background, while also exploring the possibility of resolving current tensions.

118. Fast test to assess the impact of marginalization in Monte Carlo analyses and its application to cosmology

Adrià GÓMEZ-VALENT

01/06/23, 10:50

Monte Carlo (MC) algorithms are commonly employed to explore high-dimensional parameter spaces constrained by data. All the statistical information obtained in the output of these analyses is contained in the Markov chains, which one needs to process and interpret. The marginaliza- tion technique allows us to digest these chains and compute the posterior distributions for the parameter subsets...

119. Resolving cosmological tensions with a sign-switching cosmological constant

Ozgur AKARSU

01/06/23, 11:15

In this talk, inspired by the recent conjecture originated from graduated dark energy (gDE) that the universe has transitioned from anti-de Sitter vacua to de Sitter vacua in the late universe, we will discuss the superior features of the $\Lambda_{\rm s}$CDM model, which extends the standard $\Lambda$CDM model by a cosmological constant ($\Lambda_{\rm s}$) that switches sign at a certain...

120. Cosmological Tensions in a Coupled Dark Sector

Elsa TEIXEIRA

01/06/23, 11:40

Reconciling the standard model’s theoretical predictions with precision measurements from mul- tiple probes stands as one of the most pressing challenges of modern cosmology. During the last decade, increasing evidence for persistent discrepancies in the value of cosmological param- eters when inferred from model-dependent and -independent probes opened the door for a new paradigm. In this...

121. Cosmological implications of Weyl geometric gravity

Tiberiu HARKO

01/06/23, 14:00

We investigate the dark energy in the Weyl geometric gravity, which is based on the introduction of a Weyl connection to describe the gravitational properties of the space-time. We consider the case in which the Lagrangian is given by the sum of the square of the Weyl scalar, of the strength of the field associated to the Weyl vector, and a conformally invariant geometry-matter coupling term,...

122. Tomographic cross-correlation of the CMB lensing and galaxy clustering - systematic errors from cross-talk between redshift bins of galaxies

Pawel BIELEWICZ

01/06/23, 14:25

The effect of gravitational lensing of the cosmic microwave background (CMB) provides a unique opportunity to obtain a picture of the gravitational potential of the large-scale structure of the Universe at very high redshifts. Tomographic cross-correlation of the gravitational potential with other tracers of the large-scale structure at known redshifts allows tracing the evolution of the...

111. DE models with combined H0⋅rd from BAO and CMB dataset and friends

Denitsa STAICOVA

01/06/23, 14:50

It has been theorized that Dynamical Dark Energy (DDE) could be a possible solution to the Hubble tension. To avoid the degeneracy between the Hubble parameter H0 and the sound horizon scale rd, we use their multiplication as one parameter c/(H0rd). To the BAO points we add the SNIa Pantehon dataset and GRB dataset and the points from the CMB priors. We use different DE parametrizations to...

124. Can the simplest generalizations of the null inertial mass density alleviate the H0 tension?

Nihan KATIRCI

01/06/23, 15:45

"In this talk, we overview dark energy models with negative energy density values in the past can alleviate the H0 tension. We investigate whether two minimal extensions of the ΛCDM model, to- gether or separately, can successfully realize such a scenario: (i) the spatial curvature, which, in the case of spatially closed universe, mimics a negative density source and (ii) graduated and simple-...

125. Varying alpha through the dynamics of dark energy

Vitor DA FONSECA

01/06/23, 16:10

We propose a cosmological model that predicts the variation of the fine structure constant α with redshift, where the electromagnetic sector couples to the kinetics of a canonical scalar field ϕ. This is a generalization of the usual linear dependence of the interaction term on ϕ. This theory can be seen as a disformal coupling with radiation, where the conformal factor depends on the kinetic...

126. The halo mass function in clustering dark energy models as a tool versus the sigma8 tension

Francesco PACE

01/06/23, 16:35

"When N-body simulations deal with dark energy, they consider its effect only at the background level, modifying the Hubble expansion. A notable exception is the K-evolution code which simulates k-essence models with a low sound-speed using the effective field theory approach at the non-linear level. It has been demonstrated that this leads to divergences. Hence, a few authors recently...

127. Galaxy clustering systematic effects in photometric surveys

Ignacio SEVILLA

01/06/23, 17:00

Galaxy clustering is one of the pillars of current cosmological parameter constraints, in particular for understanding the properties of the late universe and how they relate to those predicted from early universe measurements, in combination with cosmic shear observations. In photometric surveys, spurious correlations may be introduced by the spatial distribution of observational con- ditions...

129. Public Talk in Portuguese -- Einstein's greatest mistake? The discovery of the cosmological constant

Elsa TEIXEIRA

01/06/23, 18:30

128. Public talk in English -- Are we approaching a revolution in physics?

Emmanuel SARIDAKIS

01/06/23, 19:00