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The arrival directions of cosmic rays detected by the Pierre AugerObservatory (Auger) with energies above 39~EeV were recently reported tocorrelate with the positions of 23 nearby starburst galaxies (SBGs): in theirbest-fit model, 9.7\% of the cosmic-ray flux originates from these objects andundergoes angular diffusion on a $12.9^\circ$~scale. On the other hand, some ofthe SBGs on their list, including the brightest one (M82), are at northerndeclinations outside the Auger field of view. Data from detectors in thenorthern hemisphere would be needed to look for cosmic-ray excesses near theseobjects. In this work, we tested the Auger best-fit model against datacollected by the Telescope Array (TA) in a 9-year period, without trying tore-optimize the model parameters for our dataset in order not to introducestatistical penalties. The resulting test statistic (double log-likelihoodratio) was $-1.00$, corresponding to $1.1\sigma$ significance amongisotropically generated random datasets, and to $-1.4\sigma$ significance amongones generated assuming the Auger best-fit model. In other words, our data isstill insufficient to conclusively rule out either hypothesis. The ongoingfourfold expansion of TA will collect northern hemisphere data with much morestatistics, improving our ability to discriminate between different fluxmodels.

Investigating an angular correlation between nearby starburst galaxies and UHECRs with the Telescope Array experiment