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Implications of strong intergalactic magnetic fields for ultrahigh-energy cosmic-ray astronomy
Alves Batista, Rafael,Shin, Min-Su,Devriendt, Julien,Semikoz, Dmitri,Sigl, Guenter American Physical Society 2017 Physical review. D Vol.96 No.2
<P>We study the propagation of ultrahigh-energy cosmic rays in the magnetized cosmic web. We focus on the particular case of highly magnetized voids (B similar to nG), using the upper bounds from the Planck satellite. The cosmic web was obtained from purely magnetohydrodynamical cosmological simulations of structure formation considering different power spectra for the seed magnetic field in order to account for theoretical uncertainties. We investigate the impact of these uncertainties on the propagation of cosmic rays, showing that they can affect the measured spectrum and composition by up to. similar or equal to 80% and. similar or equal to 5%, respectively. In our scenarios, even if magnetic fields in voids are strong, deflections of 50 EeV protons from sources closer than similar to 50 Mpc are less than 15 degrees in approximately 10-50% of the sky, depending on the distribution of sources and magnetic power spectrum. Therefore, UHECR astronomy might be possible in a significant portion of the sky depending on the primordial magnetic power spectrum, provided that protons constitute a sizeable fraction of the observed UHECR flux.</P>
Early-type Galaxy Spin Evolution in the Horizon-AGN Simulation
Choi, Hoseung,Yi, Sukyoung K.,Dubois, Yohan,Kimm, Taysun,Devriendt, Julien. E. G.,Pichon, Christophe American Astronomical Society 2018 The Astrophysical journal Vol.856 No.2
<P>Using the Horizon-AGN simulation data, we study the relative role of mergers and environmental effects in shaping the spin of early-type galaxies (ETGs) after z similar or equal to 1. We follow the spin evolution of 10,037 color-selected ETGs more massive than 10(10) M-circle dot that are divided into four groups: cluster centrals (3%), cluster satellites (33%), group centrals (5%), and field ETGs (59%). We find a strong mass dependence of the slow rotator fraction, f(SR), and the mean spin of massive ETGs. Although we do not find a clear environmental dependence of f(SR), a weak trend is seen in the mean value of the spin parameter driven by the satellite ETGs as they gradually lose their spin as their environment becomes denser. Galaxy mergers appear to be the main cause of total spin changes in 94% of the central ETGs of halos with M-vir > 10(12.5) M-circle dot, but only 22% of satellite and field ETGs. We find that non-mergerinduced tidal perturbations better correlate with the galaxy spin down in satellite ETGs than in mergers. Given that the majority of ETGs are not central in dense environments, we conclude that non-merger tidal perturbation effects played a key role in the spin evolution of ETGs observed in the local (z < 1) universe.</P>
Gas flows in the circumgalactic medium around simulated high-redshift galaxies
Mitchell, Peter D,Blaizot, Jé,ré,my,Devriendt, Julien,Kimm, Taysun,Michel-Dansac, Lé,o,Rosdahl, Joakim,Slyz, Adrianne Blackwell Publishing Ltd 2018 MONTHLY NOTICES- ROYAL ASTRONOMICAL SOCIETY Vol.474 No.4
The Horizon-AGN simulation: morphological diversity of galaxies promoted by AGN feedback
Dubois, Yohan,Peirani, Sé,bastien,Pichon, Christophe,Devriendt, Julien,Gavazzi, Raphaë,l,Welker, Charlotte,Volonteri, Marta Oxford University Press 2016 MONTHLY NOTICES- ROYAL ASTRONOMICAL SOCIETY Vol.463 No.4