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Dark energy

The dominant and most mysterious ingredient of the current standard model, is, without doubt, the so-called dark energy, that contributes about 75% of the mass/energy density of the Universe, and causes the current accelerating expansion. The most direct evidence for this acceleration comes from the observation of "standard candles" at cosmological distances, or rather objects whose intrinsic luminosities can be calibrated a priori, so that their distance can be measured via their apparent luminosity. The so-called type Ia supernovae have been used in this way, and at the end of the '90s allowed the acceleration to be detected for the first time. Current and future research will concentrate on identifying a time dependence on the so-called "equation of state" of dark energy, to demonstrate whether dark energy is simply Einstein's cosmological constant, or if it is connected to a primordial energy field also related to the formation of elementary particles. To this end, various projects either underway or proposed for the future, are dedicated to systematic searches for type Ia supernovae, both from the ground and space. These will surely greatly increase the volume of data on distant SNe, shedding new light on the nature of cosmic acceleration. The search for and the calibration of new standard candles (such as "core-collapse" SNe and gamma-ray bursts) are also areas of research receiving growing attention.

 

Other experiments plan to cover large areas of the sky with high quality images (and so in general observed from space) to measure so-called weak lensing. This distortion, introduced in the images of "background" galaxies by the mass distribution along the path that the photons travel to reach us, depends on the gravitational growth of fluctuations, and ultimately on the cosmological parameters. The final goal of these surveys is make maps of the "shear", as the weak lensing deflection is called, in various redshift intervals and reproduce the tomographic distribution of cosmic structure at successive epochs. These "tomographic plates" directly measure the expansion and structure growth history of the Universe that depend directly on the presence of dark energy.

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Studying the birth of exoplanets with chemistry

Sep 23, 2022

Studying the birth of exoplanets with chemistry A new study led by Elenia Pacetti, PhD student at La Sapienza University and INAF, jointly uses ultra-volatile, volatile, and refractory elements in the atmospheres of giant planets to develop a unified method to shed light on how and where giant planets form. The new work, published in The Astrophysical Journal, paves the road to the exoplanetary studies of the ESA mission Ariel

Stellar evolution along the HR diagram with Gaia

Sep 21, 2022

Stellar evolution along the HR diagram with Gaia The hybrid workshop started its activities in the INAF National Auditorium “Ernesto Capocci” of the Capodimonte Astronomical Observatory in Naples

The discovery of an extremely energetic gamma-ray burst from the infant Universe

Sep 21, 2022

The discovery of an extremely energetic gamma-ray burst from the infant Universe An international effort led by INAF researcher Andrea Rossi discovered and followed up the gamma-ray burst GRB 210905A, one of the most luminous events ever recorded that exploded when our Universe was just less than 900 million years old