相关论文: Vesto Slipher and the First Galaxy Redshifts
Recent analyses of Cepheid distances to spiral galaxies have led to an announcement of a Hubble constant of $H_0 = 72 \pm 8$ km/sec/Mpc. The new Cepheid distances, however, show that there are numerous redshift distances with large excesses…
The redshift drift is a small, dynamic change in the redshift of objects following the Hubble flow. Its measurement provides a direct, real-time, model-independent mapping of the expansion rate of the Universe. It is fundamentally different…
Data from the SPectroscopic IDentification of ERosita Sources (SPIDERS) are searched for a detection of the gravitational redshifting of light from $\sim\!20\,000$ galaxies in $\sim\!2500$ galaxy clusters using three definitions of the…
The light that we receive from clusters of galaxies is redshifted by the presence of the clusters' gravitational potential. This effect, known as gravitational redshift, was first detected from a sample of stacked clusters in 2011, by…
Significant progress has been made during the last 10 years toward resolving the debate over the expansion rate of the Universe. The current value of the Hubble parameter, Ho, is now arguably known with an accuracy of 10%, largely due to…
I examine the interpretation of photon redshifts in curved spacetime, as being gravitational or Doppler in origin. In Friedmann-Lema\^itre-Robertson-Walker spacetime, redshifts between comoving observers are often attributed to "expanding…
Edwin Hubble is often credited with discovering the expanding Universe based on spectra taken by him. This statement is incorrect and we feel that it is the responsibility of those who are aware of the historical facts to set the record…
The VIMOS Public Extragalactic Redshift Survey (VIPERS) is an ongoing ESO Large Programme to map in detail the large-scale distribution of galaxies at 0.5 < z <1.2. With a combination of volume and sampling density that is unique for these…
We consider the proposal by many scholars and by the International Astronomical Union to rename Hubble's law as the Hubble-Lemaitre law. We find the renaming questionable on historic, scientific and philosophical grounds. From a historical…
It is widely believed that the cosmological redshift is not a Doppler shift. However, Bunn & Hogg have recently pointed out that to settle properly this problem, one has to transport parallelly the velocity four-vector of a distant galaxy…
When did galaxies start forming stars? What is the role of distant galaxies in galaxy formation models and the epoch of reionization? What are the conditions in typical star-forming galaxies at redshifts >~4? Why is galaxy evolution…
Redshift is not a shift, it is defined as a fractional change in wavelength. Nevertheless, it is a fairly common misconception that Delta-z c represents a velocity where Delta-z is the redshift separation between two galaxies. When…
We consider some aspects of the perturbation to the luminosity distance $d(z)$ that are of relevance for SN1a cosmology and for future peculiar velocity surveys at non-negligible redshifts. 1) Previous work has shown that the correction to…
By correcting the redshift--dependent distances for peculiar motions through a number of peculiar velocity field models, we recover the true distances of a wide, all-sky sample of nearby galaxies (~ 6400 galaxies with velocities cz<5500…
For 100 years since galaxies were found to be flying apart from each other, astronomers have been trying to determine how fast. The expansion, characterized by the Hubble constant, H0, is confused locally by peculiar velocities caused by…
Hubble's announcement of the magnitude-redshift relation \cite{Hub29} brought about a major change in our understanding of the Universe. After tracing the pre-history of Hubble's work, and the hiatus in our understanding which his…
Recent observations of the luminosity-redshift in Type Ia supernovae suggest an accelerated inflation of the Universe (open Universe) as well as the observed matter density showed to be less than the critical one, suggesting that a large…
In a recent article in {\em Modern Physics Letters} {\bf A}, Gentry proposed a new static cosmological model that seeks to explain the Hubble relation as a combination of gravitational and Doppler red shifts. We show that Gentry's model,…
We show that the observed upper bound on the line-of-sight velocity dispersion of the stars in an early-type galaxy, sigma<400km/s, may have a simple dynamical origin within the LCDM cosmological model, under two main hypotheses. The first…
In homogeneous cosmological models the wavelength $\lambda$ of a photon exchanged between two fundamental observers changes in proportion to expansion of the space $D$ between them, so $\Delta\log(\lambda / D) = 0$. This is exactly the same…