Related papers: On the time dependency of $a_0$
We investigate the star-formation properties of dynamically relaxed galaxy clusters as a function of cluster mass for 308 low-redshift clusters drawn from the Sloan Digital Sky Survey (SDSS) C4 cluster catalog. It is important to establish…
We show that current clustering observations of quasars and luminous AGN can be explained by a merger model augmented by feedback from outflows. Using numerical simulations large enough to study clustering out to 25 comoving h^{-1} Mpc, we…
We present optical and near infrared spectroscopy obtained at Keck, VLT, and Gemini for a sample of 36 secure strong gravitational lens systems and 17 candidates identified as part of the SL2S survey. The deflectors are massive early-type…
Cosmologists are exploring two possible sets of explanations for the remarkable observation of cosmic acceleration: dark energy fills space or general relativity fails on cosmological scales. We define a null test parameter $\epsilon(k,a)…
We use high-redshift type Ia supernova and compact radio source data in order to test the infrared (IR) fixed point model of the late Universe which was proposed recently. It describes a cosmology with a time dependent cosmological constant…
The geometry of Freedman-Roberston-Walker cosmological models is fixed by the mass density parameter, Omega_M, and the cosmological constant, Omega_Lambda. The classical volume-redshift cosmological relation is a sensitive…
We extend the MOND analysis to a sample of 17 high surface brightness, early-type disc galaxies with rotation curves derived from a combination of 21cm HI line observations and optical spectroscopic data. A number of these galaxies have…
The SPARC sample consists of 175 nearby galaxies with modern surface photometry at $3.6\,\mu m$ and high quality rotation curves. The sample has been constructed to span very wide ranges in surface brightness, luminosity, rotation velocity…
We use the IllustrisTNG cosmological hydrodynamical simulation to study the evolution of star formation rate (SFR)-density relation over cosmic time. We construct several samples of galaxies at different redshifts from $z=2.0$ to $z=0.0$,…
Intermediate-richness galaxy groups are an important test ground for MOND. First, they constitute a distinct type of galactic systems, with their own evolution histories and underlying physical processes; secondly, they probe…
We measure the redshift-space correlation function from a spectroscopic sample of 2783 emission line galaxies from the FastSound survey. The survey, which uses the Subaru Telescope and covers the redshift ranges of $1.19<z<1.55$, is the…
We study the redshift evolution of the dynamical properties of ~180,000 massive galaxies from SDSS-III/BOSS combined with a local early-type galaxy sample from SDSS-II in the redshift range 0.1<z< 0.6. The typical stellar mass of this…
One of the goals of current cosmological studies is the determination of the expansion and acceleration rates of the universe as functions of redshift, and the determination of the properties of the dark energy that can explain these…
At the core of the standard cosmological model lies the assumption that the redshift of distant galaxies is independent of photon wavelength. This invariance of cosmological redshift with wavelength is routinely found in all galaxy spectra…
We present a new, model-independent method to reconstruct the temporal evolution of the speed of light $c(z)$ using astronomical observations. After validating our pipeline using mock datasets, we apply our method to the latest BAO and…
This paper aims to put constraints on the transition redshift $z_t$, which determines the onset of cosmic acceleration, in cosmological-model independent frameworks. In order to perform our analyses, we consider a flat universe and {assume}…
We apply Monte Carlo Markov Chain (MCMC) methods to large-scale simulations of galaxy formation in a LambdaCDM cosmology in order to explore how star formation and feedback are constrained by the observed luminosity and stellar mass…
We revisit the application of Modified Newtonian Dynamics (MOND) to galaxy clusters. We confront the high quality X-ray data for eight clusters of galaxies observed by the \xmm satellite with the predictions of MOND. We obtain a ratio of…
Only by incorporating various forms of feedback can theories of galaxy formation reproduce the present-day luminosity function of galaxies. It has also been argued that such feedback processes might explain the counter-intuitive behaviour…
The possibility that ultra-diffuse galaxies lacking dark matter has recently stimulated interest to check the validity of Modified Newton Dynamics (MOND) predictions on the scale of such galaxies. It has been shown that the External Field…