55 citations · 98 across the 13 of their papers we have counts for
14 papers
Scalaron Quasinormal and Quasi-Bound Modes of Schwarzschild Black Holes in the Bondi-Sachs Formulation of Metric Gravity
Bishop Mongwane, Didam G. A. Duniya, Seturumane Tema +2
We study scalaron quasinormal modes and quasi-bound states of Schwarzschild black holes directly within the Bondi-Sachs formulation of metric gravity, combining frequency-do…
Hubble tension in k-essence: Evidence for robust tension alleviation
Isaac Opio, Didam Duniya, Bishop Mongwane +1
The Hubble tension has come to stay as a major problem in modern cosmology as it continues to plague the standard cosmological model (CDM). As one of the viable, self-consistent…
Relativistic effects in k-essence
Didam Duniya, Isaac Opio, Bishop Mongwane +1
Relativistic effects are sensitive to subtle changes in dark energy. These effects grow on very large scales and at high redshifts, which will be the reach of upcoming surveys. We…
Investigating the imprint of quintessence in cosmic magnification
Enas Mohamed, Didam Duniya, Hassan Abdalla +1
We study cosmic magnification beyond lensing in a late-time universe dominated by quintessence and cold dark matter. The cosmic magnification angular power spectrum, especially goi…
Quasinormal modes of a Schwarzschild black hole within the Bondi-Sachs framework
Bishop Mongwane, Sipho Nkele, Didam G. A. Duniya +1
Studies of quasinormal modes (QNMs) of black holes have a long and well established history. Predominantly, much research in this area has customarily focused on the equations give…
Cosmic magnification in beyond-Horndeski gravity
Didam Duniya, Bishop Mongwane
Cosmic magnification is able to probe the geometry of large-scale structure on cosmological scales, thereby providing another window for probing theories of the late-time cosmic ac…
Imprint of f(R) gravity in the cosmic magnification
Didam Duniya, Amare Abebe, Alvaro de la Cruz-Dombriz +1
f(R) gravity is one of the simplest viable modifications to General Relativity: it passes local astrophysical tests, predicts both the early-time cosmic inflation and the late-time…
Qualitative probe of interacting dark energy with redshift-space distortions
Didam Duniya
The imprint of interacting dark energy (IDE) needs to be correctly identified in order to avoid bias in constraints on IDE. This paper investigates the large-scale imprint of IDE i…
Which is a better cosmological probe: Number counts or cosmic magnification?
Didam Duniya, Mazuba Kumwenda
The next generation of cosmological surveys will have unprecedented measurement precision, hence they hold the power to put theoretical ideas to the most stringent tests yet. Howev…
Probing beyond-Horndeski gravity on ultra-large scales
Didam Duniya, Teboho Moloi, Chris Clarkson +4
The beyond-Horndeski gravity has recently been reformulated in the dark energy paradigm - which has been dubbed, Unified Dark Energy (UDE). The evolution equations for the given UD…
Understanding the relativistic overdensity of galaxy surveys
Didam Duniya
The main goal of galaxy surveys is to map the distribution of the galaxies, for the purpose of understanding the properties of this distribution and its implications for the conten…
Large-scale imprint of relativistic effects in the cosmic magnification
Didam Duniya
Apart from the known weak gravitational lensing effect, the cosmic magnification acquires relativistic corrections owing to Doppler, integrated Sachs-Wolfe, time-delay and other (l…
Dark energy homogeneity in general relativity: Are we applying it correctly?
Didam Duniya
Thus far, there does not appear to be an agreed (or adequate) definition of homogeneous dark energy (DE). This paper seeks to define a valid, adequate homogeneity condition for DE.…
Probing the imprint of interacting dark energy on very large scales
Didam Duniya, Daniele Bertacca, Roy Maartens
The observed galaxy power spectrum acquires relativistic corrections from lightcone effects, and these corrections grow on very large scales. Future galaxy surveys in optical, infr…