Article
Astronomy & Astrophysics
Eleonora Di Valentino, Nils A. Nilsson, Mu-In Park
Summary: This study proposes a renormalizable, higher derivative, Lorentz-violating quantum gravity model without ghost problems known as Hoava gravity. Furthermore, a Hoava gravity-based dark energy (HDE) model is proposed by identifying the additional contributions from Lorentz-violating terms as an effective energy-momentum tensor in Einstein equation. The results show a preference for non-flat universes in the cosmic microwave background, baryon acoustic oscillation, and supernova Ia data tests, aligning with the cosmic concordance model.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Weiqiang Yang, Eleonora Di Valentino, Supriya Pan, Yabo Wu, Jianbo Lu
Summary: This article compares various dynamical dark energy models using different observational data and discusses the alleviation of H-0 tension. Bayesian evidence analysis shows that all models perform better than Lambda CDM scenario, with the CPL model being the best in fitting the data and solving H-0 tension. However, the tension reappears when considering the baryon acoustic oscillations data, not supporting the dynamical dark energy solution.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Wenzhong Liu, Luis A. Anchordoqui, Eleonora Di Valentino, Supriya Pan, Yabo Wu, Weiqiang Yang
Summary: In recent cosmological observations, discrepancies have been found in the rate of expansion of the universe and the clustering of matter. A novel model proposes that cold dark matter disintegrates into dark radiation. However, this model fails to solve the discrepancy in the rate of expansion, although it can address the clustering issue under certain conditions. The effectiveness of these models is weakened when intermediate-redshift data is included.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Physics, Multidisciplinary
Rabia Saleem, Shan Ali, M. Israr Aslam
Summary: This paper investigates the cosmological implications of Rastall gravity by using the new Tsallis agegraphic dark energy (NTADE) and Sharma-Mittal holographic dark energy (SMHDE) models. The results show that the equation of state parameter for NTADE lies in the phantom region, while for SMHDE it exhibits quintom and quintessence regions dependent on the model parameter delta. The deceleration parameter shows a phase transition from decelerating to accelerating phases for both models. The omega(D) - omega(D)' pair exhibits freezing and thawing regions for NTADE, and freezing region for SMHDE. The (J, s) pair for SMHDE indicates different dark energy eras, including phantom, quintessence, and Chaplygin gas, while the NTADE model only shows Chaplygin gas behavior. It is concluded that SMHDE is a more efficient model as it approaches the Lambda CDM limit and produces results within a stable region according to graphical analysis of the square speed of sound.
CHINESE JOURNAL OF PHYSICS
(2023)
Article
Astronomy & Astrophysics
Mark S. Linton, Robert Crittenden, Alkistis Pourtsidou
Summary: We investigated two models of interacting dark energy that only interact through momentum exchange. Global fitting of cosmological parameters showed that these models are competitive with ACDM.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Albin Joseph, Rajib Saha
Summary: The next-generation CMB satellite missions can provide precise constraints on cosmological parameters. However, these constraints may weaken without attributing dark energy to a cosmological constant. Models involving interaction between dark energy and dark matter can alleviate the cosmic coincidence problem. In this study, the ability of future CMB and BAO experiments to constrain interacting dark energy models is tested, showing improved constraints when combined with additional data.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
H. R. M. Zarandi, E. Ebrahimi
Summary: This paper studies the cosmic age problem in holographic and generalized ghost dark energy models, and finds that non-linear interactions can alleviate the age problem. By analyzing age tests and data sets, the study also discovers a new bound for a parameter and shows that the generalized ghost dark energy can completely alleviate the cosmic age problem.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Oem Trivedi, Simran Kaur Saggu, Pankaj S. Joshi
Summary: This work investigates three widely recognized non-canonical scalar field dark energy models: phantom, quintom, and DBI dark energy models. By employing a specific procedure, the presence of singularities in both finite and infinite time within these models is demonstrated, which are independent of the system's initial conditions. Furthermore, the study establishes that different types of cosmological singularities can arise in these models.
PHYSICS OF THE DARK UNIVERSE
(2023)
Article
Astronomy & Astrophysics
Mariana Jaber, Gustavo Arciniega, Luisa G. Jaime, Omar Abel Rodriguez-Lopez
Summary: This study explores the hypothesis of accelerated cosmic expansion by introducing additional fields or modifications to General Relativity. A parameterization form is proposed to reproduce the generic behavior of widely used physical models with infrared corrections. Different combinations of data are analyzed to constrain the specific cases embedded in the parameterization form.
PHYSICS OF THE DARK UNIVERSE
(2022)
Article
Astronomy & Astrophysics
Alexander Ganz
Summary: Minimally modified gravity models use auxiliary constraints to maintain a dynamic cosmological background, with results of linear perturbations being insensitive to constraint details, leading to a modified effective gravitational constant or a non-zero dust sound speed.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Rodrigo von Marttens, Dinorah Barbosa, Jailson Alcaniz
Summary: Einstein's equations connect the space-time geometry to the total matter content of the cosmic substratum, but not to individual contributions of the matter species. Therefore, it is difficult to differentiate cases where dark energy interacts with dark matter from a non-interacting scenario using observational data based on time or distance measurements.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Nikita Blinov, Matthew J. Dolan, Patrick Draper, Jessie Shelton
Summary: This study introduces simplified models to explain enhancements in the matter power spectrum at small scales and investigates their impact on dark matter substructure and gravitational observables. The models capture the characteristics of various early Universe scenarios and discuss the sensitivity of gravitational observables to the presence of bumps in the power spectrum.
Article
Astronomy & Astrophysics
G. Parimbelli, C. Carbone, J. Bel, B. Bose, M. Calabrese, E. Carella, M. Zennaro
Summary: This article provides an accurate comparison of different methodologies for modeling the nonlinear matter power spectra in the presence of massive neutrinos and dynamical dark energy. The results show that HMcode and ReACT perform better than HALOFIT, while EuclidEmulator2 agrees remarkably well with the simulated spectra in some scenarios. This study highlights the importance of selecting appropriate methods when modeling complex cosmological scenarios.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Amine Bouali, Imanol Albarran, Mariam Bouhmadi-Lopez, Ahmed Errahmani, Taoufik Ouali
Summary: This paper examines the interaction between three phantom dark energy models, investigating their impact on cosmological parameters and the presence of singularities and abrupt events. The study focuses on distinguishing these models based on their equations of state and explores the potential of interactions between cold dark matter and dark energy to address issues in standard cosmology. Through the use of a MCMC approach, the cosmological parameters of each model are constrained, and comparisons are made using the corrected AIC(c) tool. The perturbative analysis of phantom DE models based on best fit background parameters is also conducted.
PHYSICS OF THE DARK UNIVERSE
(2021)
Article
Astronomy & Astrophysics
A. Hernandez-Almada, Genly Leon, Juan Magana, Miguel A. Garcia-Aspeitia, V Motta, Emmanuel N. Saridakis, Kuralay Yesmakhanova, Alfredo D. Millano
Summary: We study the scenario of Kaniadakis horizon-entropy cosmology and find that it can alleviate the H-0 tension problem. The parameters of the model are constrained around the value where the standard Bekenstein-Hawking is recovered. Moreover, the scenario is statistically equivalent to the Λ cold dark matter one.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Shulei Cao, Joseph Ryan, Narayan Khadka, Bharat Ratra
Summary: The study utilizes various cosmological constraints from different observational data sets, confirming mutual consistency. The results suggest that the universe is undergoing accelerating expansion, with dark energy potentially acting as a cosmological constant and spatial hypersurfaces likely being flat.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Narayan Khadka, Bharat Ratra
Summary: The study found that the parameters of the X-ray and UV luminosities relation for the full QSO data set depend on the cosmological model used. Subset of QSO data with lower redshifts show a relationship between X-ray and UV flux independent of cosmological model, which can be used to constrain cosmological parameters. The cosmological constraints from these lower redshift QSO data subsets are mostly consistent with other measurements but weaker in strength.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Shulei Cao, Joseph Ryan, Bharat Ratra
Summary: By jointly analyzing data from various cosmological models, we obtained model-independent estimates of the Hubble constant and non-relativistic matter density parameter, as well as more restrictive constraints by including data from quasar angular size and H II starburst galaxy measurements.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Shulei Cao, Narayan Khadka, Bharat Ratra
Summary: This study uses three recently compiled GRB data sets correlated with redshift, as well as the best available Amati-correlated GRB data, to constrain cosmological model parameters. The resulting constraints are weak but largely consistent with established data.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Narayan Khadka, Bharat Ratra
Summary: The recent compilation of quasar X-ray and UV flux measurements shows that some of the QSOs do not meet the standardization criteria via the X-ray luminosity and UV luminosity relation, therefore, they should not be used to constrain cosmological model parameters. The largest sub-sample, SDSS-4XMM QSOs, contributes about 2/3 of the total QSOs and its L-X-L-UV relation depends on the assumed cosmological model and redshift, which is also the main cause of the similar issue found in the full QSO compilation. The second and third largest sub-samples, SDSS-Chandra and XXL QSOs, together contribute about 30% of the total QSOs and appear to be standardizable, but they only provide weak constraints on cosmological parameters without contradicting the standard spatially flat Lambda CDM model or constraints from better-established cosmological probes.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Shulei Cao, Joseph Ryan, Bharat Ratra
Summary: This study compares the constraints from two compilations of H II starburst galaxy data and tests the model independence of quasar angular size data. The new data compilation provides tighter constraints and prefers lower cosmological parameters values. The quasar data by themselves give relatively model-independent constraints on the characteristic linear size. The joint analysis provides model-independent summary estimates of the Hubble constant, matter density parameter, and characteristic size.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Shulei Cao, Maria Dainotti, Bharat Ratra
Summary: The study shows that the Platinum gamma-ray burst (GRB) data compilation follows a cosmological-model-independent correlation and can be standardized. Combining the data with others can improve the precision of cosmological constraints based on GRBs. By excluding common GRBs and jointly analyzing the data, more restrictive GRB-only cosmological constraints can be obtained.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Narayan Khadka, Mary Loli Martinez-Aldama, Michal Zajacek, Bozena Czerny, Bharat Ratra
Summary: We utilize 118 H beta quasar observations to investigate the cosmological model parameters and the radius-luminosity relation parameters. The results show that the assumed cosmology does not affect the relation parameters, indicating that the quasars can be standardized through this relation. However, the cosmological constraints obtained are weak and favor a currently decelerating expansion. Extending the relation does not reduce the discrepancy in cosmological constraints.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Shulei Cao, Bharat Ratra
Summary: This study uses a combination of cosmological data to constrain cosmological parameters in six different models. The results provide model-independent determinations of the Hubble constant and the current non-relativistic matter density parameter. The error bars in these determinations are larger than those in the flat Lambda CDM model, but mild dark energy dynamics and a little spatial curvature are not ruled out.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Shulei Cao, Maria Dainotti, Bharat Ratra
Summary: Gamma-ray bursts (GRBs) are important probes of the early Universe in the largely unexplored redshift range of z ≈ 2.7-9.4. This study finds that the 3D Fundamental Plane correlation between peak luminosity, plateau luminosity, and rest-frame duration of GRBs is favored over the 2D correlation between plateau luminosity and duration. Furthermore, the larger sample size of the LGRB95 data leads to tighter constraints on cosmological and GRB-correlation parameters, despite the larger scatter of intrinsic scatter parameter values compared to the Platinum data.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Narayan Khadka, Michal Zajacek, Swayamtrupta Panda, Mary Loli Martinez-Aldama, Bharat Ratra
Summary: We used observations of 66 reverberation-measured Mg II quasars to study the cosmological model parameters and quasar radius-luminosity relation parameters in six different cosmological models. We found that the quasar radius-luminosity relation parameters are independent of the assumed cosmological model and can be standardized. Additionally, using a three-parameter relation did not lead to a reduction in the intrinsic dispersion compared to a two-parameter relation.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Shulei Cao, Michal Zajacek, Swayamtrupta Panda, Mary Loli Martinez-Aldama, Bozena Czerny, Bharat Ratra
Summary: In this study, we used a large sample of C iv quasar (QSO) observations to simultaneously constrain cosmological models and QSO radius-luminosity (R-L) relation parameters. The results show that the R-L relation parameters are independent of the cosmological models, indicating that the R-L relation can be used to standardize C iv QSOs.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Bozena Czerny, Shulei Cao, Vikram Kumar Jaiswal, Vladimir Karas, Narayan Khadka, Mary Loli Martinez-Aldama, Mohammad Hassan Naddaf, Swayamtrupta Panda, Francisco Pozo Nunez, Raj Prince, Bharat Ratra, Marzena Sniegowska, Zhefu Yu, Michal Zajacek
Summary: As Setti and Woltjer pointed out in 1973, quasars can be used to construct the Hubble diagram, but its actual application was not straightforward and required years of progress. Understanding the structure of quasars is crucial for their cosmological use. The issues of gas flow near the black hole and hot or warm corona still complicate the analysis of X-ray reflection. The formation of the low ionization part of the Broad Line Region is proposed as a failed wind powered by radiation pressure.
ASTROPHYSICS AND SPACE SCIENCE
(2023)
Article
Astronomy & Astrophysics
Narayan Khadka, Michal Zajacek, Raj Prince, Swayamtrupta Panda, Bozena Czerny, Mary Loli Martinez-Aldama, Vikram Kumar Jaiswal, Bharat Ratra
Summary: In this study, measurements of 59/58 quasars are used to compare the radius-luminosity (R - L) and X-ray-UV luminosity (L-X - L-UV) relations and their implications for cosmological parameter estimation. Results show that both R - L and L-X - L-UV relations are standardizable but provide weak constraints on cosmological parameters. Moreover, L-X - L-UV relation data tend to favor larger values of the non-relativistic matter density parameter compared to R - L relation data and other measurements. It is concluded that more research is needed to determine if the L-X - L-UV relation can be used as a cosmological probe.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Bharat Ratra
Summary: We construct nonlinear inflaton potential-energy densities and compute tilted primordial spatial inhomogeneity power spectra in closed and open inflation models. These new tilted power spectra differ from the ones previously used in nonflat cosmological models.
