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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.

K2-3: A system of three likely sub-Neptunes

Mar 22, 2018

K2-3: A system of three likely sub-Neptunes A team led by astronomers from INAF presented a new study aimed at determining accurate masses for the three planets in orbit aroud the M-dwarf star K2-3

INAF hosts the preliminary round to set up the Cherenkov Telescope Array Observatory-ERIC

Feb 14, 2018

INAF hosts the preliminary round to set up  the Cherenkov Telescope Array Observatory-ERIC At Headquarters of the Italian National Institute for Astrophysics INAF, the kick-off round of the multilateral negotiations to establish an ERIC organization to the manage the Cherenkov Telescope Array project as part of the EU’s ESFRI infrastructure roadmap had take place

Extrasolar planets: Italy to lead the construction of the SHARK instruments on the LBT

Jan 24, 2018

Extrasolar planets: Italy to lead the construction of the SHARK instruments on the LBT The Italian institutes involved in the construction of SHARK are the INAF Observatories of Padua and Rome, responsible for the two channels, together with the Observatories of Arcetri, Milan and Trieste and the Department of Physics and Astronomy of the University of Padua