The total baryon content in the Universe is a well-defined quantity, in addition to being one of the most important cosmological parameters. A variety of observations (CMB, Ly-alpha forest, Big Bang nucleosynthesis) indicate that all baryons amount to around 4% of the total matter-energy content of the Universe. However, in the local Universe the contribution of all the observed components represents around 2% of the total. Therefore, half of the baryons in the local Universe remain elusive. In this article we have presented measurements of the kinematic Sunyaev-Zel’dovich effect in Planck data towards BOSS galaxies, that are compatible with the detection of all baryons in and around these galaxies (including the missing baryons), which represents around half of the total baryons in the Universe out to z=0.12, the maximum redshift sampled by these galaxies.
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Stellar ages are key to several fields of astrophysics such as exoplanet research, galactic-archeology, and of course stellar physics. Obtaining the ages of stars is however not straightforward and requires stellar modeling. The most widely used technique only requires stellar colors or temperature and surface gravity, but the uncertainties are quite large. This technique is most efficient for stars belonging to clusters, as they were born from the same molecular cloud and share the same ages. In the last decades, based on the study of stellar acoustic waves, asteroseismology became the most
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The cosmic evolution of the barred galaxy population provides key information about the secular evolution of galaxies and the settling of rotationally dominated discs. We study the bar fraction in the SMACSJ0723.37323 (SMACS0723) cluster of galaxies at z = 0.39 using the Early Release Observations obtained with the NIRCam instrument mounted on the JWST telescope. We visually inspected all cluster member galaxies using the images from the NIRCam F200W filter. We classified the galaxies into ellipticals and discs and determine the presence of a bar. The cluster member selection was based on a
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Dark matter is an invisible substance that makes up more than eighty percent of the matter content of the universe. We know of its existence due to its gravitational influence, being a key ingredient to understand everything from the large-scale evolution of the universe to the formation of galaxies like the Milky Way, of which we are part of . However, very little is known about its nature, which constitutes one of the greatest unsolved problems in contemporary physics. The fuzzy dark matter model has recently been studied as a promising candidate. In this model , it is postulated that dark
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