Collisionally regenerated dark matter structures in galactic nuclei

Merritt, David; Harfst, Stefan; Bertone, Gianfranco

doi:10.1103/physrevd.75.043517

Cited by 61 publications

(74 citation statements)

References 86 publications

(137 reference statements)

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“…If other models for the DM distributions are considered (see, for instance [35] and references therein) the qualitative aspects of the problem are preserved although, of course, quantitative results on apoastron shifts may be different. The top-left panel shows the central black hole contribution to the S2 shift that amounts to about 580 arcsec.…”

Section: Discussionmentioning

confidence: 99%

Apoastron shift constraints on dark matter distribution at the Galactic Center

et al. 2007

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The existence of dark matter (DM) at scales of few pc down to ≃ 10 −5 pc around the centers of galaxies and in particular in the Galactic Center region has been considered in the literature.Under the assumption that such a DM clump, principally constituted by non-baryonic matter (like WIMPs) does exist at the center of our galaxy, the study of the γ-ray emission from the Galactic Center region allows us to constrain both the mass and the size of this DM sphere.Further constraints on the DM distribution parameters may be derived by observations of bright infrared stars around the Galactic Center. Hall and Gondolo [1] used estimates of the enclosed mass obtained in various ways and tabulated by Ghez et al. [2,3]. Moreover, if a DM cusp does exist around the Galactic Center it could modify the trajectories of stars moving around it in a sensible way depending on the DM mass distribution. Here, we discuss the constraints that can be obtained with the orbit analysis of stars (as S2 and S16) moving inside the DM concentration with present and next generations of large telescopes. In particular, consideration of the S2 star apoastron shift may allow improving limits on the DM mass and size.

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Section: Discussionmentioning

confidence: 99%

Apoastron shift constraints on dark matter distribution at the Galactic Center

et al. 2007

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“…These maps represent a powerful tool to rapidly, and efficiently, investigate the detectability of any population of point sources of DM annihilation, such as small scale clumps [62,63,64,65,66,67], compact DM structures like Spikes [39,40,41,42,68] or Crests [45], and DM mini-spikes [34,47]. All these objects would appear as pointlike sources with GLAST, if their angular size is smaller than the angular resolution of the instrument, i.e.…”

Section: Discussionmentioning

confidence: 99%

“…Collisional generation of these DM "crests" (Collisionally REgenerated STtructures) was demonstrated even in the extreme case where the DM density was lowered by slingshot ejection from a binary super-massive black hole. However, the enhancement of the annihilation signal from a DM crest is typically much smaller than for adiabatic spikes [45].…”

Section: A the Mini-spikes Scenariomentioning

confidence: 99%

“…We limit ourselves here to note that adiabatic spikes are rather fragile structures, that require fine-tuned conditions to form at the center of galactic halos [42], and that can be easily destroyed by dynamical processes such as major mergers [43] and gravitational scattering off stars [40,44]. It was recently shown that a ρ ∝ r −3/2 DM overdensity can be predicted in any halo at the center of any galaxy old enough to have grown a power-law density cusp in the stars via the Bahcall-Wolf mechanism [45]. Collisional generation of these DM "crests" (Collisionally REgenerated STtructures) was demonstrated even in the extreme case where the DM density was lowered by slingshot ejection from a binary super-massive black hole.…”

Section: A the Mini-spikes Scenariomentioning

confidence: 99%

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GLAST Sensitivity to Point Sources of Dark Matter Annihilation

Morselli¹,

Bertone²,

Busetto³

et al. 2007

AIP Conference Proceedings

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We study the prospects for detecting gamma-rays from point sources of Dark Matter annihilation with the space satellite GLAST. We simulate the instrument response to the gamma-ray spectrum arising from the annihilation of common Dark Matter candidates, and derive full-sky sensitivity maps for the detection of point sources and for the identification of the Dark Matter (as opposed to astrophysical) origin of the gamma-ray emission. These maps represent a powerful tool to assess the detectability of point sources, i.e. sources with angular size smaller than the angular resolution of GLAST, ∆θ ∼ 0.1 • , in any DM scenario. As an example, we apply the obtained results to the so-called mini-spikes scenario, where the annihilation signal originates from large Dark Matter overdensities around Intermediate Mass Black Holes. We find that if these objects exist in the Galaxy, not only GLAST should be able to detect them over a timescale as short as 2 months, but in many cases it should be possible to determine with good accuracy the mass of the annihilating Dark Matter particles, while null searches would place stringent constraints on this scenario.

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“…In [21] it was shown that the adiabatic growth of the BH at the center of the halo causes a steepening, called spike, of the initial halo profile toward the GC. Successive studies [14,15,[22][23][24][25][26][27][28] showed that considering physical effects such as scattering of DM particles off stars, capture by the BH, selfannihilation and capture within stars during the evolution of the DM distribution, results in a shallower profile, ρ sp (r) ∝ r −3/2 . For the SUSY models A-D, and generally for all theτ CR parameter space, the spin independent and spin dependent elastic neutralino-nucleon cross sections are in the range 10 −11 -10 −9 pb and 10 −8 -10…”

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confidence: 99%

New gamma ray signal from gravitationally boosted neutralinos at the Galactic Center

et al. 2012

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We discuss on the possibility that colliding dark matter particles in the form of neutralinos may be gravitationally boosted near the super-massive black hole at the galactic center so that they can have enough collision energy to annihilate into a stau pair. Since in some phenomenologically favored supersymmetric models the mass splitting between the neutralino and the lightest stau, one of the two scalar superpartners of the tau lepton, is a few GeVs, this channel may be allowed. In addition, staus can only decay into a tau lepton and another neutralino. We calculate the gamma-ray spectrum and flux generated by the tau pair discussing the observability of the obtained features.PACS numbers: 95.35.+d, 12.60.Jv, 98.35.Gi Dark matter (DM) accounts for more than 80% of the mass of the Universe but its nature is still one of the open problems in Physics. In a widely accepted theoretical scenario, DM is formed by a weakly interacting massive particle (WIMP) that has been in thermal equilibrium with Standard Model (SM) matter in the early Universe, leaving, after decoupling, the DM relic density as inferred by WMAP [1]. In this light, supersymmetric (SUSY) extensions of the SM provide a natural WIMP candidate. In the minimal supersymmetric standard model (MSSM), R-parity conservation assures that if the lightest supersymmetric particle is the lightest of the four neutralino states-indicated as χ in the following-, this particle is absolutely stable. In a phenomenologically favored scenario of the constrained MSSM (CMSSM), the stau coannihilation region (τ CR ) [2], the lightest stau,τ 1 , one of the scalar super-partners of the tau lepton, is close in mass to the neutralino. In theτ CR parameter space the cross section for non-relativistic annihilation into fermions of the SM, χχ → ff , is typically small and results in a too large relic density. However, including the so-called coannihilation processes [3], as for example χτ 1 ,τ 1τ1 collisions, when the mass splittings of the involved particles are small, one can efficiently enhance the thermally averaged cross section σv , and, consequently, diminish the relic density to the measured value.The standard cosmological model predict that nonrelativistic cold DM particles (v/c ∼ 10 −3 ) cluster into halos [4] that contain baryonic matter. Since DM in the halo follows a certain mass distribution, the two-body annihilation processes can happen at a rate that is proportional to the DM mass density squared. Therefore, the highest chances to detect an observable indirect signal of their existence are attained in a region with high DM density, in particular, in the galactic center (GC). Among * mirco.cannoni@dfa.uhu.es † mario.gomez@dfa.uhu.es ‡ mperezga@usal.es § vergados@uoi.gr the various signatures from DM annihilation, gamma-ray signals have received much attention. A continuum spectrum of secondary photons may arise from hadronization and decay of the annihilation products [5] and from radiation from final state charged particles [6]. Direct annihilation into photon...

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Collisionally regenerated dark matter structures in galactic nuclei

Cited by 61 publications

References 86 publications

Apoastron shift constraints on dark matter distribution at the Galactic Center

Apoastron shift constraints on dark matter distribution at the Galactic Center

GLAST Sensitivity to Point Sources of Dark Matter Annihilation

New gamma ray signal from gravitationally boosted neutralinos at the Galactic Center

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