Cross-correlation of weak lensing and gamma rays: implications for the nature of dark matter

Abstract

We measure the cross-correlation between Fermi-LAT gamma-ray photons and over 1000 deg 2 of weak lensing data from the Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS), the Red Cluster Sequence Lensing Survey (RCSLenS), and the Kilo Degree Survey (KiDS). We present the first measurement of tomographic weak lensing cross-correlations and the first application of spectral binning to cross-correlations between gamma rays and weak lensing. The measurements are performed using an angular power spectrum estimator while the covariance is estimated using an analytical prescription. We verify the accuracy of our covariance estimate by comparing it to two internal covariance estimators. Based on the non-detection of a cross-correlation signal, we derive constraints on weakly interacting massive particle (WIMP) dark matter. We compute exclusion limits on the dark matter annihilation cross-section σ ann v , decay rate Γ dec , and particle mass m DM . We find that in the absence of a cross-correlation signal, tomography does not significantly improve the constraining power of the analysis. Assuming a strong contribution to the gamma-ray flux due to small-scale clustering of dark matter and accounting for known astrophysical sources of gamma rays, we exclude the thermal relic cross-section for particle masses of m DM < ∼ 20 GeV.

Tomographic Imaging of the Fermi-LAT γ-Ray Sky through Cross-correlations: A Wider and Deeper Look

“…Indeed, in X15, we did show that, even without foreground removal, the recovered cross-correlations were unbiased, while the main impact of foreground removal was to suppress the background and thus to reduce the size of the random errors. Similar conclusions were reached in the recent cross-correlation analysis of weak lensing catalogs with Fermi-LAT performed by Tröster et al (2017). Analogous considerations apply to the point sources.…”

“…Among these we can list anisotropy analyses (Ando & Komatsu 2006Ando 2009;Ackermann et al 2012c;Cuoco et al 2012;Harding & Abazajian 2012;Fornasa et al 2013Fornasa et al , 2016Di Mauro et al 2014b;, pixel statistic analyses (Dodelson et al 2009;Malyshev & Hogg 2011;Feyereisen et al 2015;Lisanti et al 2016;Zechlin et al 2016aZechlin et al , 2016b, and cross-correlations with tracers of the large-scale structure of the universe (Ando 2014;Ando et al 2014;Fornengo & Regis 2014;Shirasaki et al 2014;Camera et al 2015;Cuoco et al 2015;Fornengo et al 2015;Regis et al 2015;Xia et al 2015;Feng et al 2017;Shirasaki et al 2016;Tröster et al 2017), which we will investigate in the following.…”

Correlation of extragalactic γ rays with cosmic matter density distributions from weak gravitational lensing

“…Since our measurements in the HSCS16A cover a smaller sky area than Ref. [24], our constraints are found to be weaker. Also it is unlikely for us to be able to place constraint on DM annihilation at a similar level as the local measurements [60], even if we use the HSC final data release, because the increased sky coverage can improve the statistical uncertainty only by a factor of ∼ 3 − 4.…”

Fundamental physics with the Square Kilometre Array

“…For details concerning data and models see, Xia et al (2015) and Cuoco et al (2015), respectively. emission peaking at low redshift and the unresolved astrophysical production of the same observables more pronounced towards intermediate redshift (e.g., Camera et al 2013bCamera et al , 2015dFornengo et al 2015;Xia et al 2015;Branchini et al 2017;Tröster et al 2017). Specifically, we discuss here the impact of the catalogue of HI galaxies that will be obtained by the SKA on the cross-correlation with Fermi Large Area Telescope (LAT) γ -ray maps.…”