Dark matter is currently one of the main mysteries of the Universe. There is much strong indirect evidence that supports its existence, but there is yet no sign of a direct detection(1-3). Moreover, at the scale of galaxies, there is tension between the theoretically expected dark matter distribution and its indirectly observed distribution(4-7). Therefore, phenomena associated with dark matter have a chance of serving as a window towards new physics. The radial acceleration relation(8,9) confirms that a non-trivial acceleration scale a(0) can be found from the internal dynamics of several galaxies. The existence of such a scale is not obvious as far as the standard cosmological model is concerned(10,11), and it has been interpreted as a possible sign of modified gravity(12,13). Here, we consider 193 high-quality disk galaxies and, using Bayesian inference, show that the probability of existence of a fundamental acceleration is essentially O: the null hypothesis is rejected at more than 10 sigma. We conclude that a(0) is of emergent nature. In particular, the modified Newtonian dynamics theory(14-17)-a well-known alternative to dark matter based on the existence of a fundamental acceleration scale-or any other theory that behaves like it at galactic scales, is ruled out as a fundamental theory for galaxies at more than 10 sigma.

Absence of a fundamental acceleration scale in galaxies

del Popolo, Antonino;
2018-01-01

Abstract

Dark matter is currently one of the main mysteries of the Universe. There is much strong indirect evidence that supports its existence, but there is yet no sign of a direct detection(1-3). Moreover, at the scale of galaxies, there is tension between the theoretically expected dark matter distribution and its indirectly observed distribution(4-7). Therefore, phenomena associated with dark matter have a chance of serving as a window towards new physics. The radial acceleration relation(8,9) confirms that a non-trivial acceleration scale a(0) can be found from the internal dynamics of several galaxies. The existence of such a scale is not obvious as far as the standard cosmological model is concerned(10,11), and it has been interpreted as a possible sign of modified gravity(12,13). Here, we consider 193 high-quality disk galaxies and, using Bayesian inference, show that the probability of existence of a fundamental acceleration is essentially O: the null hypothesis is rejected at more than 10 sigma. We conclude that a(0) is of emergent nature. In particular, the modified Newtonian dynamics theory(14-17)-a well-known alternative to dark matter based on the existence of a fundamental acceleration scale-or any other theory that behaves like it at galactic scales, is ruled out as a fundamental theory for galaxies at more than 10 sigma.
MODIFIED NEWTONIAN DYNAMICS, MASS MODELS, CLUSTERS.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11769/358702
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