Personal tools
Log in
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.

The New Year’s Day meteorite has been found

Jan 07, 2020

The New Year’s Day meteorite has been found For the first time in Italy a meteorite is recovered through systematic monitoring, thanks to the PRISMA network, promoted and coordinated by INAF

ASTRI: a new pathfinder of the arrays of Cherenkov telescopes

Jun 13, 2019

ASTRI: a new pathfinder of the arrays of Cherenkov telescopes On June 12nd 2019, in La Laguna (Tenerife, Spain) Prof. Nichi D’Amico, President of the Italian National Institute for Astrophysics (INAF), and Prof. Rafael Rebolo Lopez, Director of the Instituto de Astrofisica de Canaries, signed a Record of Understanding to enter a detailed negotiation on a technical and programmatic basis aimed to install and operate the ASTRI Mini-Array at the Observatorio del Teide

Giant planets and comets battling in the circumstellar disk around HD 163296

May 23, 2019

Giant planets and comets battling in the circumstellar disk around HD 163296 In a study appearing today on The Astrophysical Journal, an INAF-lead team of researchers explored whether the anomalous features in the dust and gas distributions of HD 163296's disk revealed by ALMA's observations could arise from the interaction of the giant planets with a component of the disk previously unaccounted for: the planetesimals