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You are here: Home Research Activities Galaxies and Cosmology Origin and evolution of the galaxies and structure

The evolution of galaxies

In the standard cold dark matter model, galaxy formation occurs hierarchically. At least this is what happens to the dark matter component, that collects into ever-larger structures (the halos mentioned above) via a process of gravitational interaction and successive merger. Although driven gravitationally by dark matter, what happens to the baryonic component could be very different. In general it is thought that the latter collapses in the potential wells created by dark matter, in what is called dissipative collapse, converting primordial gas into stars. This could be the origin of the most massive galaxies, the ellipticals, and in general of the spheroidal component observed in spiral galaxies. In this latter case, the disks form around the spheroid as the result of a slow and continuous acquisition of gas from the regions around the galaxy. This gas acquires angular momentum and contributes to the formation of the younger stellar population, as well as providing the fuel for successive generations. In this process, both the initial mass of the dark matter halo in which the galaxy forms and the environment in which it finds itself play an important role. It is well established, for example, that in galaxy clusters, or in regions of high density, the fraction of spiral galaxies is very low. The last 15 years have seen great progress in this field, with an important contribution from the Italian astronomical community both through the above mentioned surveys, VVDS and COSMOS-ZCOSMOS, and other projects (for example GMASS and GOODS), equally important for the understanding of the evolutionary phenomena that guide the history of the galaxies. On this qualitative picture there is general agreement, even if details such as the epoch of formation of disks or the relative role of mass and environment in defining the properties of forming galaxies are still poorly defined, also due to the dearth of available samples at redshift z>1.5-2.

First detection of the simplest organic acid in the protoplanetary disk surrounding a Sun-like young star

Jul 16, 2018

First detection of the simplest organic acid in the protoplanetary disk surrounding a Sun-like young star Using ALMA, an international group of astronomers have reported the first detection of formic acid towards the TW Hydrae protoplanetary disk, located at only 190 light years from our Sun

The Governor-General of Australia visits INAF in Rome

Jun 27, 2018

The Governor-General of Australia visits INAF in Rome His Excellency the Governor-General of the Commonwealth of Australia, Sir Peter Cosgrove, and his wife, Lady Cosgrove, today visited the Headquarters of INAF, the Italian National Institute for Astrophysics

THESEUS: a new window on the early Universe and the multi-messenger transient sky

May 10, 2018

THESEUS: a new window on the early Universe and the multi-messenger transient sky The European Space Agency announced the three space missions selected for ESA’s fifth medium class mission in its Cosmic Vision science programme. One of them is THESEUS, in which the Italian National Institute for Astrophysics plays a major role