Carmelo Evoli

The Galactic Center GeV excess from a series of leptonic cosmic-ray outbursts

It has been proposed that a recent outburst of cosmic-ray electrons could account for the excess of GeV-scale gamma rays observed from the region surrounding the Galactic Center. After studying this possibility in some detail, we identify scenarios in which a series of leptonic cosmic-ray outbursts could plausibly generate the observed excess. The morphology of the emission observed outside of

Revisiting the SN1987A gamma-ray limit on ultralight axion-like particles

sim1^{circ}-2^{circ}

Cosmic ray electrons, positrons and the synchrotron emission of the Galaxy: consistent analysis and implications

from the Galactic Center can be accommodated with two outbursts, one which took place approximately

Secondary antiprotons as a Galactic Dark Matter probe

sim10^6

The nature of dark matter from the global high-redshift H i 21 cm signal

years ago, and another (injecting only about 10% as much energy as the first) about

PAMELA and AMS-02

sim10^5

e^+

years ago. The emission observed from the innermost

and

sim1^{circ}-2^{circ}

e^-

requires one or more additional recent outbursts and/or a contribution from a centrally concentrated population of unresolved millisecond pulsars. In order to produce a spectrum that is compatible with the measured excess (whose shape is approximately uniform over the region of the excess), the electrons from the older outburst must be injected with significantly greater average energy than those injected more recently, enabling their spectra to be similar after

spectra are reproduced by three-dimensional cosmic-ray modeling

sim10^6