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We investigate the nature of subsets of spheres which satisfy a tameness condition associated with the Bieri–Groves FPm-conjecture. We find that there is a natural polyhedrality in the case of n-tame subsets of an (n − 1)-sphere. In the case n = 3 we establish a strong polyhedrality condition for certain maximal open 3-tame sets. Many examples are included.

Active targets are perfect tools for the study of reactions induced by radioactive ion beams of very low intensity. Thus, they make possible the study of direct and compound reactions at the same time. In this talk, we will present the results obtained with the MAYA active target for low energy reactions induced by the halo nucleus 11Li. A method used to measure the mass of short-lived nuclei, applied to the 11Li case will be discussed. The experimantal angular distribution of the two halo-neutron transfer reaction 1H(11Li,9Li)t at 4.3A MeV, using the MAYA detector as a thin target, will be presented and compared to coupled reaction channel calculations including 3-body models in order to extract informations on the structure of the 11Li halo. The extraction of the 11Li+p optical potential using the data on the elastic scattering, will also be discussed. Finally, the excitation function of the resonant elastic scattering reaction, determined using the MAYA detector as a thick target, will be presented. Extraction of information on the structure of possible 12Li isobaric analog states observed in 12Be using several R-matrix calculations will be shown.

Active target MAYA, expérience TRIUMF; The mass of 11Li has been determined from Q-value measurements of the 1H(11Li, 9Li)3H reaction. The experiment was performed at TRIUMF laboratory with the GANIL active target MAYA. Energy-energy and angle-angle kinematics reconstruction give a Q value of 8.119(22) MeV for the reaction. The derived 11Li two-neutron separation energy is S2n = 363(22) keV.

The p(\nuc{11}{Li},\nuc{9}{Li})t reaction has been studied for the first time at an incident energy of 3$A$ MeV delivered by the new ISAC-2 facility at TRIUMF. An active target detector MAYA, build at GANIL, was used for the measurement. The differential cross sectionshave been determined for transitions to the \nuc{9}{Li} ground andthe first excited states in a wide range of scattering angles. Multistep transfer calculations using different \nuc{11}{Li} model wave functions, shows that wave functions with strong correlations between the halo neutrons are the most successful in reproducing the observation., Comment: 6 pages, 3 figures, submitted to Physical Review Letters

The circumgalactic medium (CGM) is one of the frontiers of galaxy formation and intimately connected to the galaxy via accretion of gas on to the galaxy and gaseous outflows from the galaxy. Here we analyse the magnetic field in the CGM of the Milky Way-like galaxies simulated as part of the \textsc{Auriga} project that constitutes a set of high resolution cosmological magnetohydrodynamical zoom simulations. We show that before $z=1$ the CGM becomes magnetised via galactic outflows that transport magnetised gas from the disk into the halo. At this time the magnetisation of the CGM closely follows its metal enrichment. We then show that at low redshift an in-situ turbulent dynamo that operates on a timescale of Gigayears further amplifies the magnetic field in the CGM and saturates before $z=0$. The magnetic field strength reaches a typical value of $0.1\,\mu G$ at the virial radius at $z=0$ and becomes mostly uniform within the virial radius. Its Faraday rotation signal is in excellent agreement with recent observations. For most of its evolution the magnetic field in the CGM is an unordered small scale field. Only strong coherent outflows at low redshift are able to order the magnetic field in parts of the CGM that are directly displaced by these outflows., Comment: 14 pages, 15 figures, accepted by MNRAS, updated Fig. 15 in proofs with errorbars