A NOVEL APPROACH IN THE WEAKLY INTERACTING MASSIVE PARTICLE QUEST: CROSS-CORRELATION OF GAMMA-RAY ANISOTROPIES AND COSMIC SHEAR
- CENTRA, Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Lisboa (Portugal)
- School of Physics and Astronomy, University of Nottingham, Nottingham (United Kingdom)
- Dipartimento di Fisica, Universita di Torino and INFN, Torino (Italy)
Both cosmic shear and cosmological gamma-ray emission stem from the presence of dark matter (DM) in the universe: DM structures are responsible for the bending of light in the weak-lensing regime and those same objects can emit gamma rays, either because they host astrophysical sources (active galactic nuclei or star-forming galaxies) or directly by DM annihilations (or decays, depending on the properties of the DM particle). Such gamma rays should therefore exhibit strong correlation with the cosmic shear signal. In this Letter, we compute the cross-correlation angular power spectrum of cosmic shear and gamma rays produced by the annihilation/decay of weakly interacting massive particle DM, as well as by astrophysical sources. We show that this observable provides novel information on the composition of the extragalactic gamma-ray background (EGB), since the amplitude and shape of the cross-correlation signal strongly depend on which class of sources is responsible for the gamma-ray emission. If the DM contribution to the EGB is significant (at least in a definite energy range), although compatible with current observational bounds, its strong correlation with the cosmic shear makes such signal potentially detectable by combining Fermi Large Area Telescope data with forthcoming galaxy surveys, like the Dark Energy Survey and Euclid. At the same time, the same signal would demonstrate that the weak-lensing observables are indeed due to particle DM matter and not to possible modifications of general relativity.
- OSTI ID:
- 22118734
- Journal Information:
- Astrophysical Journal Letters, Vol. 771, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COSMOLOGY AND ASTRONOMY
ANISOTROPY
ANNIHILATION
ASTROPHYSICS
CORRELATIONS
EMISSION SPECTRA
GALAXIES
GALAXY NUCLEI
GAMMA ASTRONOMY
GAMMA DETECTION
GAMMA SPECTRA
GENERAL RELATIVITY THEORY
GRAVITATIONAL LENSES
NONLUMINOUS MATTER
PARTICLE IDENTIFICATION
PHOTON EMISSION
POSTULATED PARTICLES
SHEAR
TELESCOPE COUNTERS
UNIVERSE
WEAK INTERACTIONS