Related papers: Standardizing reverberation-measured Mg II time-la…
We study the frequency of Mg II absorption in the outer haloes of galaxies at z = 0.6 - 1.4 (with median z = 0.87), using new spectra obtained of ten background quasars with galaxy impact parameters of b < 100 kpc. The quasar sightlines…
Fast Radio Bursts (FRBs) have emerged as a powerful tool for cosmological studies, particularly through the dispersion measure-redshift ($\mathrm{DM}-z$) relation. This work proposes a novel calibration method for FRBs using the…
Assuming the existence of standard rulers, standard candles and standard clocks, requiring only the cosmological principle, a metric theory of gravity, a smooth expansion history, and using state-of-the-art observations, we determine the…
In this paper, we firstly calibrate the Amati relation (the $E_{\rm p}-E_{\rm iso}$ correlation) of gamma ray bursts (GRBs) at low redshifts ($z<0.8$) via Gaussian process by using the type Ia supernovae samples from Pantheon+ under the…
We present an initial survey of Mg II absorption characteristics in the halos of a carefully constructed, volume-limited subsample of galaxies embedded in the spectroscopic part of the Sloan Digital Sky Survey. We observed quasars near…
Strongly lensed quasars with time-delay measurements are well known to provide the "time-delay distances" $D_{\Delta t}=(1+z_L)D_LD_S/D_{LS}$ and the angular diameter distances to lens galaxies $D_L$. These two kinds of distances give…
A model-independent test of the cosmic curvature parameter $\Omega_k$ is very important in cosmology. In order to estimate cosmic curvature from cosmological probes like standard candles, one has to be able to measure the luminosity…
We cross-correlate a low-contamination subset of the VST ATLAS g < 22.5 quasar catalogue with g < 21.5 galaxy clusters, r < 21 galaxies and r < 19.5 Luminous Red Galaxies (LRGs) to probe their halo mass profiles via quasar magnification…
From regular monitoring of the Double Quasar QSO 0957+561 A,B there is now general agreement on a time delay of about 416 days. This has made it possible to determine the microlensing residual in the light-curve, see Pelt et al. (1998). We…
Combining cosmological probes has consolidated the standard cosmological model with percent precision, but some tensions have recently emerged when certain parameters are estimated from the local or primordial Universe. The origin of this…
The non-linear relationship between the monochromatic X-ray and UV luminosities in quasars offers the possibility of using high-z quasars as standard candles for cosmological testing. In this paper, we use a high-quality catalog of 1598…
High redshift quasars can be used to deduce the distribution of dark energy in the Universe, as a complementary tool to SN Ia. The method is based on determination of the size of the Broad Line Region from the emission line delay,…
We search for the most suitable set of cosmological parameters that describes the observable universe. The search includes the possibility of quintessential flat universes, i.e., the analysis is restricted to the determination of the…
We report 6 yr monitoring of a distant bright quasar CTS C30.10 (z = 0.90052) with the Southern African Large Telescope (SALT). We measured the rest-frame time-lag of $562\pm 2$ days between the continuum variations and the response of the…
We simultaneously constrain cosmology and galaxy bias using measurements of galaxy abundances, galaxy clustering and galaxy-galaxy lensing taken from the Sloan Digital Sky Survey. We use the conditional luminosity function (which describes…
With the distance sum rule in the Friedmann-Lema\^{\i}tre-Robertson-Walker metric, model-independent constraints on both the Hubble constant $H_0$ and spatial curvature $\Omega_{K}$ can be obtained using strong lensing time-delay data and…
We propose a model-independent way to determine the cosmic curvature using the Hubble parameter $H(z)$ measured with cosmic chronometers and the comoving distance $D(z)$ inferred from HII galaxies. We employ Gaussian processes to smooth the…
We here propose a new model-independent technique to overcome the circularity problem affecting the use of Gamma-Ray Bursts (GRBs) as distance indicators through the use of $E_{\rm p}$--$E_{\rm iso}$ correlation. We calibrate the $E_{\rm…
Current observational bounds on dark energy depend on assumptions about the curvature of the universe. We present a simple and efficient method for incorporating constraints from CMB anisotropy data, and use it to derive constraints on…
In this paper we consider constraints on the cosmological density parameters from the spatial power spectrum of QSOs. We first review an analytic approach to the spatial power spectrum of QSOs, then we compare the result of the analytic…