Galactic Center gamma-ray ``excess'' from an active past of the Galactic Centre?

Petrović, Jovana; Serpico, Pasquale Dario; Zaharijaš, Gabrijela

doi:10.1088/1475-7516/2014/10/052

Cited by 183 publications

(202 citation statements)

References 61 publications

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“…Is this excess due to presently unknown sources, e.g. as yet unknown pulsars or past activity of the GC [42,109], or are we detecting evidence of new physics at the fundamental scale? This question can be answered by observations of nearby pulsars with e-ASTROGAM.…”

Section: Antimatter and Wimp Dark Mattermentioning

confidence: 99%

The e-ASTROGAM mission

et al. 2017

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e-ASTROGAM ('enhanced ASTROGAM') is a breakthrough Observatory space mission, with a detector composed by a Silicon tracker, a calorimeter, and an anticoincidence system, dedicated to the study of the non-thermal Universe in the photon energy range from 0.3 MeV to 3 GeV -the lower energy limit can be pushed to energies as low as 150 keV, albeit with rapidly degrading angular resolution, for the tracker, and to 30 keV for calorimetric detection. The mission is based on an advanced space-proven detector technology, with unprecedented sensitivity, angular and energy resolution, combined with polarimetric capability. Thanks to its performance in the MeV-GeV domain, substantially improving its predecessors, e-ASTROGAM will open a new window on the non-thermal Universe, making pioneering observations of the most powerful Galactic and extragalactic sources, elucidating the nature of their relativistic outflows and their effects on the surroundings. With a line sensitivity in the MeV energy range one to two orders of magnitude better than previous generation instruments, e-ASTROGAM will determine the origin of key isotopes fundamental for the understanding of supernova explosion and the chemical evolution of our Galaxy. The mission will provide unique data of significant interest to a broad astronomical community, complementary to powerful observatories such as LIGO-Virgo-GEO600-KAGRA, SKA, ALMA, E-ELT, TMT, LSST, JWST, Athena, CTA, IceCube, KM3NeT, and the promise of eLISA.

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Section: Antimatter and Wimp Dark Mattermentioning

confidence: 99%

The e-ASTROGAM mission

et al. 2017

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“…However, its spectral properties are strongly dependent on the assumed IEM, making it challenging to conclusively identify its origin. As a result, it remains unclear whether this signal arises from DM annihilation rather than from a currently unknown contribution from astrophysics such as a large population of milli-second pulsars, cosmic-ray (CR) proton or electron outbursts, additional cosmic ray sources, and/or emission from a stellar over-density in the Galactic bulge [11,16,[18][19][20][21][22][23]. An interesting development is the use of statistical tools which indicate that GeV photons from the direction of the inner galaxy region show significantly more clustering than would be expected from Poisson noise from smooth components [24][25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Dark matter interpretation of the Fermi -LAT observation toward the Galactic Center

et al. 2017

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The center of the Milky Way is predicted to be the brightest region of γ-rays generated by selfannihilating dark matter particles. Excess emission about the Galactic center above predictions made for standard astrophysical processes has been observed in γ-ray data collected by the Fermi Large Area Telescope. It is well described by the square of an NFW dark matter density distribution. Although other interpretations for the excess are plausible, the possibility that it arises from annihilating dark matter is valid. In this paper, we characterize the excess emission as annihilating dark matter in the framework of an effective field theory. We consider the possibility that the annihilation process is mediated by either pseudo-scalar or vector interactions and constrain the coupling strength of these interactions by fitting to the Fermi Large Area Telescope data for energies 1-100 GeV in the 15 • × 15 • region about the Galactic center using self-consistently derived interstellar emission models and point source lists for the region. The excess persists and its spectral characteristics favor a dark matter particle with a mass in the range approximately from 50 to 190 (10 to 90) GeV and annihilation cross section approximately from 1×10 −26 to 4×10 −25 (6×10 −27 to 2×10 −25 ) cm 3 /s for pseudo-scalar (vector) interactions. We map these intervals into the corresponding WIMP-neutron scattering cross sections and find that the allowed range lies well below current and projected direct detection constraints for pseudo-scalar interactions, but are typically ruled out for vector interactions.

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“…11 -15]. Models attributing the excess to either hadronic [16] or leptonic [17,18] outbursts from the central black hole have been motivated primarily by the known variability of the GC region, and the existence of non-steady state emission sources such as the Fermi bubbles. Finally, models of pulsar emission have been posited due to the spectral similarilty of the GeV excess to the population of observed γ-ray pulsars [4,[19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Known radio pulsars do not contribute to the Galactic Center gamma-ray excess

Linden

2016

Phys. Rev. D

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Observations using the Fermi Large Area Telescope (Fermi-LAT) have found a significant γ-ray excess surrounding the center of the Milky Way (GC). One possible interpretation of this excess invokes γ-ray emission from an undiscovered population of either young or recycled pulsars densely clustered throughout the inner kiloparsec of the Milky Way. While these systems, by construction, have individual fluxes that lie below the point source sensitivity of the Fermi-LAT, they may already be observed in multiwavelength observations. Notably the Australia Telescope National Facility (ATNF) catalog of radio pulsars includes 270 sources observed in the inner 10 • around the GC. We calculate the γ-ray emission observed from these 270 sources and obtain three key results: (1) point source searches in the GC region produce a plethora of highly significant γ-ray "hotspots", compared to searches far from the Galactic plane, (2) there is no statistical correlation between the positions of these γ-ray hotspots and the locations of ATNF pulsars, and (3) the spectrum of the most statistically significant γ-ray hotspots is substantially softer than the spectrum of the GC γ-ray excess. These results place strong constraints on models where young pulsars produce the majority of the γ-ray excess, and disfavors some models where milli-second pulsars produce the γ-ray excess.

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Galactic Center gamma-ray ``excess'' from an active past of the Galactic Centre?

Cited by 183 publications

References 61 publications

The e-ASTROGAM mission

The e-ASTROGAM mission

Dark matter interpretation of the Fermi -LAT observation toward the Galactic Center

Known radio pulsars do not contribute to the Galactic Center gamma-ray excess

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