Related papers: Slipher, galaxies, and cosmological velocity field…
Using the relation between distance modulus $(m - M)$ and redshift $z$, deduced from Friedman- Robertson-Walker (FRW) metric and assuming different values of deceleration parameter $q_0$. We constrained the Hubble parameter $h$. The…
We analyze a morphologically-selected complete sample of 52 late-type (spiral and irregular) galaxies in the Hubble Deep Field North with total K-magnitudes brighter than K=20.47. This sample exploits in particular the ultimate imaging…
The Hubble constant ($H_{0}$) is a measurement to describe the expansion rate of the Universe in the current era. However, there is a $4.4\sigma$ discrepancy between the measurements from the early Universe and the late Universe. In this…
We are experiencing a period of extreme intellectual effervescence in the area of cosmology. A huge volume of observational data in unprecedented quantity and quality and a more consistent theoretical framework propelled cosmology to an era…
The HST snapshot imaging survey of 110 BL Lac objects (Urry et al. 2000) has clearly shown that the host galaxies are massive and luminous ellipticals. The dispersion of the absolute magnitudes is sufficiently small, so that the measurement…
Peculiar velocities change the expansion rate of any observer moving relative to the smooth Hubble flow. As a result, observers in a galaxy like our Milky Way can experience accelerated expansion within a globally decelerating universe,…
We only see a small fraction of the matter in the universe, but the rest gives itself away by the impact of its gravity. The distortions from pure Hubble flow (or peculiar velocities) that this matter creates have the potential to be a…
In this methodological note we discuss several topics related to interpretation of some basic cosmological principles. We demonstrate that one of the key points is the usage of synchronous reference frames. The Friedmann-Robertson-Walker…
The ultimate fate of the universe, infinite expansion or a big crunch, can be determined by measuring the redshifts, apparent brightnesses, and intrinsic luminosities of very distant supernovae. Recent developments have provided tools that…
New distances, larger than previous ones, have been obtained for M 31 and M 81 based on the geometrical zero-point of the Cepheid Period-luminosity relation provided by the HIPPARCOS satellite. By combining them with independent…
We use a recently proposed luminosity distance measure for relatively nearby active galactic nuclei (AGNs) to test the predicted expansion of the Universe in the R_h=ct and LCDM cosmologies. This comparative study is particularly relevant…
Context. Our Local Group of galaxies appears to be moving relative to the cosmic microwave background with the source of the peculiar motion still uncertain. While in the past this has been studied mostly using galaxies as distance…
We study the expansion of the nearby Universe using a sample of Type Ia supernovae at redshifts below 0.08. These supernovae allow peculiar velocities to be measured at unprecedented precision. We have investigated in detail the possibility…
We examine the effect of redshift space distortions on the galaxy two-point correlation function $\xi(r_p,\pi)$ as a function of separations parallel ($r_p$) and perpendicular ($\pi$) to the line of sight. We find that the relative velocity…
We derive explicit and exact expressions for the physical velocity of a free particle comoving with the Hubble flow as measured by a static observer, and for the frequency shift of light emitted by a comoving source and received, again, by…
Extending the spacetime manifold of general relativity (GR) to incorporate the Hubble expansion of space as a specific curvature, generates a modified solution with three additional non-zero Christoffel symbols and a reformulated Ricci…
Although cosmologists have been trying to determine the value of the Hubble constant for nearly 65 years, they have only succeeded in limiting the range of possibilities: most of the current observational determinations place the Hubble…
We present a model for the broad morphological distinction between the disk and spheroidal components of galaxies. Elaborating on the hierarchical clustering scheme of galaxy formation proposed by Cole et al., we assume that galaxies form…
We use the largest sample to date of spectroscopic SN Ia distances and redshifts to look for evidence in the Hubble diagram of large scale outflows caused by local voids suggested to exist at z<0.15. Our sample combines data from the…
According to astrophysical observations value of recession velocity in a certain point is proportional to a distance to this point. The proportionality coefficient is the Hubble constant measured with 5% accuracy. It is used in many…