From Dawn till Dusk

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Created: Wednesday, 01 December 2021 07:06

About 90% of visible (baryonic) matter in the Universe is made of cosmic gas. This is the main driver of star formation and galaxy growth through cooling and condensation, from the early cosmic phases, the cosmic dawn, till reionization and later cosmological epochs. Gas fragments in low-temperature sites having a chemical composition dominated by neutral hydrogen, HI, and molecular hydrogen, H2, the most abundant molecule in the Cosmos. Therefore, investigating cold-gas evolution and the origin of its (atomic and molecular) components is one of the most challenging goals from both a theoretical and an observational point of view.

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FORS 1 arrived at INAF-OATs

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Created: Tuesday, 10 August 2021 07:06

​FORS 1 (FOcal Reducer and low dispersion Spectrograph), spectrograph / imager operating in the visible range (between 330 and 1100 nm), will be upgraded, in particular concerning the electronics and software system, by the Observatory control system team.
The instrument allows different observational modes: imaging, polarimetry, long slit and multi-object spectroscopy. Currently the section of polarimetric filters and camera focusing has been delivered. Subsequently, the collimator section and the top section containing the long slits for spectroscopy will be shipped. The instrument will be temporarily installed in the integration room, in the Basovizza site of the Trieste Astronomical Observatory, to carry out the refurbishment of the motorized stages and control electronics parts as well as for testing the instrument control software.

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The myth of Icarus in groups of galaxies

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Created: Tuesday, 27 July 2021 07:06

Just as planets and comets in the solar system orbit the center of mass where the Sun is located, so do galaxies in groups of galaxies, orbiting around the center of mass of their group, where a giant galaxy is often found. A study carried out by an international team calculated the orbital characteristics of a sample of over 5,000 galaxies in about a hundred groups of galaxies.

The study found that when the giant galaxy in the center of the group is very dominant - that is, much brighter than any other galaxy in the group - the orbits of the other galaxies are very radial, similar to the orbits of comets in the solar system. Their orbital pericenter is therefore very close to the dominant galaxy. The orbits of galaxies in groups characterized by less dominant central galaxies are instead more isotropic, neither too circular, nor too radial.

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The A3391/95 system observed by eROSITA at a giant crossroad

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Created: Wednesday, 30 June 2021 07:06