Related papers: Annihilations from the Galactic Centre
Recent observations of the 511 keV positron-electron annihilation line in the Galactic centre region by the INTEGRAL/SPI spectrometer have stirred up new speculations about the origin of the large corresponding positron injection rate.…
The gamma-ray excess observed from the Galactic Center can be interpreted as dark matter particles annihilating into Standard Model fermions with a cross section near that expected for a thermal relic. Although many particle physics models…
The rotation curves of some star forming massive galaxies at redshift two decline over the radial range of a few times the effective radius, indicating a significant deficit of dark matter (DM) mass in the galaxy centre. The DM mass deficit…
The supermassive black hole at the center of a distant galaxy can be weighed, in rare but realistic cases, when the galaxy acts as a strong gravitational lens. The central image that should be produced by the lens is either destroyed or…
Dense gas in the centre of galaxies feeds massive black holes, but can also become a source of obscuration and limit our ability to find faint Active Galactic Nuclei (AGN). We use a high resolution cosmological radiative hydrodynamics…
Cosmological simulations of the $\Lambda$CDM model suggest that the dark matter halos of dwarf galaxies are denser in their center than what observational data of such galaxies imply. In this letter, we propose a novel solution to this…
Recently, an analysis of data from the Fermi Gamma Ray Space Telescope has revealed a flux of gamma rays concentrated around the inner ~0.5 degrees of the Milky Way, with a spectrum that is sharply peaked at 2-4 GeV. If interpreted as the…
Recent observations from PAMELA, FERMI, and ATIC point to a new source of high energy cosmic rays. If these signals are due to annihilating dark matter, then the annihilation cross section in the present day must be substantially larger…
Supermassive black holes inhabit galactic nuclei, and their presence influences in crucial ways the evolution of the stellar distribution. The low-density cores observed in bright galaxies are probably a result of black hole infall, while…
Excess Fermi GeV emission around the Galactic Centre has been interpreted as a possible signature of annihilating dark matter. Here we analyse three aspects of this claim: its spectral cutoff, the correlation between the spectral shape of…
Recently, data of taken with the OSSE experiment have been combined with scanning observations by TGRS and SMM to produce maps of the narrow Galactic 511 keV line emission (Purcell et al. 1997). A modelling of the combined data give…
We investigate the inspiral of a high mass-ratio black hole binary located in the nucleus of a galaxy, where the primary central black hole is surrounded by a dense dark matter spike formed through accretion during the black hole growth…
More than 10^43 positrons annihilate every second in the centre of our Galaxy yet, despite four decades of observations, their origin is still unknown. Many candidates have been proposed, such as supernovae and low mass X-ray binaries.…
The recombination history of the Universe provides a useful tool for constraining the annihilation of dark matter particles. Even a small fraction of dark matter particles annihilated during the cosmic dark age can provide sufficient energy…
It is argued that supermassive black holes in the nuclei of galaxies most likely have grown coevally with their host dark matter halos. A calculation based on Press-Schechter within this framework shows that the mean rate of accretion of…
Most supermassive black holes (SMBHs) are accreting at very low levels and are difficult to distinguish from the galaxy centers where they reside. Our own Galaxy's SMBH provides a uniquely instructive exception, and we present a close-up…
In the past few decades, observations indicated that an unexplained high production rate of positrons (the strong 511 keV line) exists in the Milky Way center. By using the fact that a large amount of high density gas used to exist near the…
The connection between dark matter and giant black holes in the galactic nuclei is investigated. The joint evolution of dark and luminous matter in averaged self-consistent gravitational potential is considered. It is shown that the…
The massive black hole (MBH) in the Galactic Center and the stars around it form a unique stellar dynamics laboratory for studying how relaxation processes affect the distribution of stars and compact remnants and lead to close interactions…
We consider the possibility that the dark matter is coupled through its mass to a scalar field associated with the dark energy of the Universe. In order for such a field to play a role at the present cosmological distances, it must be…