On the separation between baryonic and dark matter: evidence for phantom dark matter?

Abstract

The recent years have seen combined measurements of X-ray and (weak) lensing contours for colliding galaxy clusters such as, for instance, the famous "Bullet" cluster. These observations have revealed offsets in the peaks of the baryonic and (dominant) gravitational matter component of order ~(100-200) kpc. Such discrepancies are difficult to explain using modified theories for gravity other than dark matter. Or are they not? Here we use the concept of "phantom dark matter" that is based upon a Newtonian interpretation of the MONDian gravitational potential. We show that this idea is in fact capable of producing substantial offsets in idealistic density configurations, involving a uniform external field. However, when analysed in a MONDian cosmological framework we deduce that the size (and probablity) of the effect is too small to explain the observed offsets found in the most recent observations, at least in the simplest incarnation of phantom dark matter as discussed here. The lensing centers in merging galaxy clusters are likely very close to the centers of true mass even in a MONDian cosmology. This gives the support to the idea that neutrino-like non-collisional matter might be responsible for the observed offsets of lensing and X-ray peaks.

6 pages, 5 figures, accepted for publication in ApJ

References in corpus (28)

• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• A direct empirical proof of the existence of dark matter
• Revealing the properties of dark matter in the merging cluster MACSJ0025.4-1222
• The speed of the `bullet' in the merging galaxy cluster 1E0657-56
• On the Proof of Dark Matter, the Law of Gravity and the Mass of Neutrinos
• The Tensor-Vector-Scalar theory and its cosmology
• The Bullet Cluster 1E0657-558 evidence shows Modified Gravity in the absence of Dark Matter
• Tidal dwarf galaxies as a test of fundamental physics
• Confrontation of MOND with the rotation curves of early-type disc galaxies
• Generalizing TeVeS Cosmology
• Are sterile neutrinos consistent with clusters, the CMB and MOND?
• Dwarf Spheroidals in MOND
• Milky Way potentials in CDM and MOND. Is the Large Magellanic Cloud on a bound orbit?
• Cosmological Structure Formation under MOND: a new numerical solver for Poisson's equation
• How Rare is the Bullet Cluster?
• Coincidences of Dark Energy with Dark Matter -- Clues for a Simple Alternative?
• Loss of mass and stability of galaxies in MOND
• The Dynamics of Subhalos in Warm Dark Matter Models
• MOND and the mass discrepancies in tidal dwarf galaxies
• The collision velocity of the bullet cluster in conventional and modified dynamics
• MOND plus classical neutrinos not enough for cluster lensing
• Strong lensing probability for testing TeVeS theory
• Forming Galaxies with MOND
• Galactic kinematics with modified Newtonian dynamics
• MOND rotation curves of very low mass spiral galaxies
• An analytic model for non-spherical lenses in covariant MOdified Newtonian Dynamics
• Testing Alternative Theories of Dark Matter with the CMB
• Galaxy Bulges As Tests of CDM vs MOND in Strong Gravity

Cited by in corpus (8)

• Modified Newtonian Dynamics (MOND): Observational Phenomenology and Relativistic Extensions
• The dark matter of gravitational lensing
• From galactic bars to the Hubble tension: weighing up the astrophysical evidence for Milgromian gravity
• Releasing scalar fields: cosmological simulations of scalar-tensor theories for gravity beyond the static approximation
• Galaxy Cluster Bulk Flows and Collision Velocities in QUMOND
• Lopsidedness of cluster galaxies in modified gravity
• Offset between dark matter and ordinary matter: evidence from a sample of 38 lensing clusters of galaxies
• Distribution of Phantom Dark Matter in Dwarf Spheroidals