Related papers: What Hubble really meant by late and early type: s…
Since Edwin Hubble introduced his famous tuning fork diagram more than 70 years ago, spiral galaxies and early-type galaxies (ETGs) have been regarded as two distinct families. The spirals are characterized by the presence of disks of stars…
The present paper presents a discussion of classification systems for galaxies, with special emphasis on possible modifications of the Hubble "tuning fork" diagram, and on galaxy types not included in Hubble's original scheme. Hubble's…
The Hubble tuning fork diagram, based on morphology and established in the 1930s, has always been the preferred scheme for classification of galaxies. However, the current large amount of multiwavelength data, most often spectra, for…
A number of years ago the estimates of astronomers and astrophysicists were that the earliest galaxies took about 2.5 to 3 billion years to form, that is, that they did not appear until 2.5 to 3 billion years after the Big Bang. Those…
Recently much attention has been paid to the discovery of Hubble's law: the linear relation between the rate of recession of the distant galaxies and distance to them. Though we now mention several names associated with this law instead of…
This talk investigates the formation of early-type galaxies from a deliberately observational view point. I begin by reviewing the conclusions that can be reached by comparing the detailed properties of galaxies in present-day clusters,…
Thanks to a technique that reveals galaxies in 3D, astronomers can now show that many galaxies have been wrongly classified. Davor Krajnovi\'c argues that the classification scheme proposed 85 years ago by Edwin Hubble now needs to be…
Hubble's name is associated closely with the idea of an expanding universe as he discovered the relation between the recession velocity and distances of galaxies. Hubble also did a lot of pioneering work on the distribution of galaxies in…
We analyze Hubble's approach to cosmology. In 1929 he accepted a finite expanding universe in order to explain the redshifts of distant galaxies. Later on he turned to an infinite stationary universe due to observational constraints. We…
Edwin Hubble is famous for a number of discoveries that are well known to amateur and professional astronomers, students and the general public. The origins of these discoveries are examined and it is demonstrated that, in each case, a…
We have investigated some statistical properties of integrated spectra of galaxies with principal component analysis. The projection of the spectra onto the plane defined by the first two principal components shows that normal galaxies are…
The secular evolution process, which slowly transforms the morphology of a galaxy over its lifetime, could naturally account for observed properties of the great majority of physical galaxies if both stellar and gaseous accretion processes…
The most recent results and some of the open key questions on the evolution of early-type galaxies are reviewed in the general cosmological context of massive galaxy formation.
Observational cosmology of the first decades of the Twentieth Century was dominated by two giants: Edwin Hubble and Harlow Shapley. Hubble's major contributions were to the study and classification of individual galaxies with large…
Galaxies represent the visible fabric of the Universe and there has been considerable progress recently in both observational and theoretical studies. The underlying goal is to understand the present-day diversity of galaxy forms, masses…
I review recent observational progress concerning the evolution of the morphological distribution of galaxies in the rich cluster environment and in the faint field population. By coupling HST imagery with ground-based spectroscopic…
Phylogenetic approaches are finding more and more applications outside the field of biology. Astrophysics is no exception since an overwhelming amount of multivariate data has appeared in the last twenty years or so. In particular, the…
Light received from a cosmological source is redshifted with an apparent loss of energy, a problem first pointed out by Edwin Hubble in 1936. A new type of energy called Hubble Energy is introduced to restore the principle of energy…
Star forming galaxies represent a valuable tracer of cosmic history. Recent observational progress with Hubble Space Telescope has led to the discovery and study of the earliest-known galaxies corresponding to a period when the Universe was…
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…