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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.

Classifying Seyfert Galaxies with Deep Learning

Sep 28, 2021

Classifying Seyfert Galaxies with Deep Learning Scientist uses deep learning to identify low luminous Seyfert 1.9 galaxies that are usually missed by human inspection among ten thousands of spectra. These results are published in the Astrophysical Journal Supplement Series by Yen Chen Chen, in the department of physics at Sapienza University of Rome and ICRANet

The long journey of human missions to Mars and back to Earth

Aug 09, 2021

The long journey of human missions to Mars and back to Earth The Embassy of Italy, in collaboration with the Italian Cultural Institute in Sydney and the Australian Academy of Science, invites you to an Italian Night with Five Southern Stars!

Gaia draws a new map of the galactic spirals

Jul 28, 2021

Gaia draws a new map of the galactic spirals An international team led by researchers of the the Italian National Institute for Astrophysics (INAF) has compiled the most detailed map yet of the Milky Way’s spiral structure within about 16,000 light years from the Sun, by making use of the position and brightness of around 600,000 young stars measured by Gaia, the European Space Agency’s star surveyor