In a fascinating, as it is mysterious, dark matter with a & # 39 is one of the great mysteries of astrophysics and cosmology. It is believed 90 per cent of the matter in the universe, but its existence has been demonstrated only indirectly, and has recently been called into question. A new study by SISSA removes the last doubts about the presence of dark matter in galaxies, denying empirical relationships in support of alternative theories. In the published study, in Astrophysical JournalAnd also offers new insights into understanding the nature of dark matter and its relationship with ordinary matter.
From the expansion of the universe to the movement of the stars in the galaxies, there are a lot of & # 39; families that can not be explained only by the presence of baryonic matter. Attractive force generated by the matter is not sufficient to explain the observed gravitational effects. This led to the theory of the existence of invisible dark matter and ideas that galaxies embedded in it a spherical halo.
"Three years ago, a few colleagues in the Case Western Reserve University strongly challenged our understanding of the universe and in-depth work of many researchers, casts doubt on the existence of dark matter in galaxies," says K & # 39; ravines Di Paola, a doctoral student in astrophysics at SISSA. "Analyzing the rotation curves of galaxies 153, mostly" classic "spiral type, they received an empirical relationship between the total gravitational acceleration star (observed) and components that we observe in the presence of only ordinary matter in the classical Newtonian theory. This empirical relationship, which seemed to be really in all the galaxies they analyzed with any radius of the galaxy, reasoned explanation of the gravitational acceleration does not necessarily call into question the dark matter, but with the participation of, for example, the theory of modified gravity, such as modified Newtonian dynamics (MOND) ".
Di Paola and her team wanted to test this relationship by analyzing the rotation curves of spiral non-classic Kind-72 galaxies with low surface brightness (LSB) and 34 dwarf galaxies disk galaxies. They made a more advanced results, finding a relationship that, in addition to general gravitational acceleration and its normal component, as well as include the galactic radius and morphology of galaxies.
"We have studied the relationship between the total acceleration and a common component in 106 galaxies to obtain results that are different from those that have been previously observed," explains Paolo Salucci, a professor of astrophysics at SISSA and one of the research authors. "This not only demonstrates the inaccuracy empirical relationship described above, but removes doubts about the existence of dark matter in galaxies. in addition, a new relationship found may provide important information for understanding the nature of an indefinite component. "
Test galactic clarify the existence of dark matter
S. Di Paola et al. Acceleration relationship Radial (RAR): Critical Cases dwarf galaxies drives and low surface brightness, Astrophysical Journal (2019). DOI: 10,3847 / 1538-4357 / aaffd6
Dark matter exists: Observations refute alternative explanations (2019, April 30)
received April 30, 2019
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