2010, Hoeft, M., Gottlber, S.

Galaxy surveys have shown that luminous galaxies are mainly distributed in large filaments and galaxy clusters. The remaining large volumes are virtually devoid of luminous galaxies. This is in concordance with the formation of the large-scale structure in the universe as derived from cosmological simulations. However, the numerical results indicate that cosmological voids are abundantly populated with dark matter haloes which may in principle host dwarf galaxies. Observational efforts have in contrast revealed that voids are apparently devoid of dwarf galaxies. We investigate the formation of dwarf galaxies in voids by hydrodynamical cosmological simulations. Due to the cosmic ultraviolet background radiation low-mass haloes show generally a reduced baryon fraction. We determine the characteristic mass below which dwarf galaxies are baryon deficient. We show that the circular velocity below which the accretion of baryons is suppressed is approximately 40km s-1. The suppressed baryon accretion is caused by the photo-heating due to the UV background. We set up a spherical halo model and show that the effective equation of the state of the gas in the periphery of dwarf galaxies determines the characteristic mass. This implies that any process which heats the gas around dwarf galaxies increases the characteristic mass and thus reduces the number of observable dwarf galaxies. Copyright © 2010 M. Hoeft and S. Gottlöber.

2020, Bertoldo, E., Abdelhameed, A.H., Angloher, G., Bauer, P., Bento, A., Breier, R., Bucci, C., Canonica, L., D’Addabbo, A., Di Lorenzo, S., Erb, A., Feilitzsch, F.V., Ferreiro Iachellini, N., Fichtinger, S., Fuchs, D., Fuss, A., Gorla, P., Hauff, D., Ješkovský, M., Jochum, J., Kaizer, J., Kinast, A., Kluck, H., Kraus, H., Langenkämper, A., Mancuso, M., Mokina, V., Mondragon, E., Olmi, M., Ortmann, T., Pagliarone, C., Palušová, V., Pattavina, L., Petricca, F., Potzel, W., Povinec, P., Pröbst, F., Reindl, F., Rothe, J., Schäffner, K., Schieck, J., Schipperges, V., Schmiedmayer, D., Schönert, S., Schwertner, C., Stahlberg, M., Stodolsky, L., Strandhagen, C., Strauss, R., Usherov, I., Willers, M., Zema, V., Zeman, J., Brützam, M., Ganschow, S.

In the current direct dark matter search landscape, the leading experiments in the sub-GeV mass region mostly rely on cryogenic techniques which employ crystalline targets. One attractive type of crystals for these experiments is those containing lithium, due to the fact that 7Li is an ideal candidate to study spin-dependent dark matter interactions in the low mass region. Furthermore, 6Li can absorb neutrons, a challenging background for dark matter experiments, through a distinctive signature which allows the monitoring of the neutron flux directly on site. In this work, we show the results obtained with three different detectors based on LiAlO2, a target crystal never used before in cryogenic experiments.