Search Publications
Phantom dark energy as a natural selection of evolutionary processes a ^ la genetic algorithm and cosmological tensions
Gangopadhyay, Mayukh R.; Sami, M.; Sharma, Mohit K.
We study the late-time cosmological tensions using the low-redshift background and redshift-space distortion data by employing a machine learning (ML) technique. By comparing the generated observables with the standard cosmological scenario, our findings indicate support for the phantom nature of dark energy, which ultimately leads to a reduction …
Constraining resonant dark matter self-interactions with strong gravitational lenses
Bovy, Jo; Gilman, Daniel; Zhong, Yi-Ming
We devise a method to constrain self-interacting dark matter (SIDM) from observations of quadruply imaged quasars, and apply it to five self-interaction potentials with a long-range dark force. We consider several SIDM models with an attractive potential that allows for the formation of quasibound states, giving rise to resonant features in the cr…
Multipole expansion of the local expansion rate
Kalbouneh, Basheer; Marinoni, Christian; Bel, Julien
We design a new observable, the expansion rate fluctuation η , to characterize deviations from the linear relation between redshift and distance in the local universe. We also show how to compress the resulting signal into spherical harmonic coefficients in order to better decipher the structure and symmetries of the anisotropies in the local expa…
Constraining constant and tomographic coupled dark energy with low-redshift and high-redshift probes
Gómez-Valent, Adrià; Kilbinger, Martin; Pettorino, Valeria +1 more
We consider coupled dark energy (CDE) cosmologies, where dark matter particles feel a force stronger than gravity, due to the fifth force mediated by a scalar field which plays the role of dark energy. We perform for the first time a tomographic analysis of coupled dark energy, where the coupling strength is parametrized and constrained in differe…
Hubble constant from the cluster-lensed quasar system SDSS J 1004 +4112 : Investigation of the lens model dependence
Oguri, Masamune; Liu, Yuting; Cao, Shuo
As a fundamental parameter for modern cosmology, the Hubble constant H0 is experiencing a serious crisis. In this paper, we explore an independent approach to measure H0 based on the time-delay cosmography with strong gravitational lensing of a quasar by a galaxy cluster. Specifically we focus on the strong lensing system SDS…
Constraining dark matter interactions mediated by a light scalar with white dwarfs
Ramirez-Quezada, Maura E.
Observations of white dwarfs in dark matter-rich environments can provide strong limits on the strength of dark matter interactions. Here we apply the recently improved formalism of the dark matter capture rate in white dwarfs to a general model in which dark matter interacts with the white dwarf ion components via a light scalar mediator. We comp…
Calibrating the effective magnitudes of type Ia supernovae with a model-independent method
Li, Zhongmu; Chen, Jing; Hu, Jian +2 more
This research explores the correlation between the absolute magnitude and the redshift of type Ia supernovae (SNe Ia) with a model-independent approach. The Pantheon sample of SNe Ia and strong gravitational lensing systems (SGLS) are used. With the cosmic distance-duality relation (CDDR), the evolution parameter of the magnitude, the light curve …