Search for ultra high-energy cosmic rays from radiogalaxy Virgo A.

Active galactic nuclei (AGNs) are considered to be one of the most appropriate sources of ultra high-energy cosmic rays (UHECRs, |$E \gtrsim 10^{18}\, \mathrm{eV}$|⁠). Radiogalaxy Virgo A (M87) in the centre of a cluster of galaxies Virgo Cluster (VC) can be a prominent source of UHECRs. We investigate the possible contribution of Virgo A and the VC to the flux of events with trans-GZK energies – extremely high-energy cosmic rays (EHECRs) – from the recent Auger and Telescope Array (TA) data sets (⁠|$E \gt 52\, \mathrm{EeV}$| and |$E \gt 57\, \mathrm{EeV}$|⁠, respectively). We simulate EHECR propagation from Virgo A and the VC taking into account their deflections in galactic and extragalactic magnetic fields and show that there is no excess of EHECR arrival directions from Virgo A/VC images at different EHECR rigidities. By means of event-by-event analysis, we recover the extragalactic arrival directions of EHECR events detected by Auger and TA for the representative set of nuclei H(p), He, N, Si, Fe, and find evidences of enhanced fluxes of N–Si–Fe EHECRs from the Local Filament and hot/cold spot regions. The Local Filament with its enhanced magnetic field is an expected contributor to the UHECR flux as the closest to Earth last scattering centre, whereas hot/cold spot region is a part of a larger arc-like spot, possibly created by the diffusively spreading jet of UHECRs, accelerated in the relativistic jet of Virgo A during a prominent nuclear outburst about 10 – 12Myr ago. [ABSTRACT FROM AUTHOR]