ALBERT

Description: Cosmic ray transport and anisotropies to high energies P. L. Biermann, L. I. Caramete, A. Meli, B. N. Nath, E.-S. Seo, V. de Souza, and J. Becker Tjus ASTRA Proc., 2, 39-44, https://doi.org/10.5194/ap-2-39-2015, 2015 Using the data from the Interstellar Medium (ISM) we propose a physical model for the spectrum of the magnetic irregularities in the ISM. With this model we discuss the Galactic Cosmic Ray (GCR) spectrum, as well as the extragalactic Ultra High Energy Cosmic Rays (UHECRs), their chemical abundances and anisotropies. UHECRs may include a proton component from many radio galaxies integrated over vast distances, visible already below 3 EeV.

Description: Gamma-ray emitting supernova remnants as the origin of Galactic cosmic rays M. Kroll, J. Becker Tjus, B. Eichmann, and N. Nierstenhöfer ASTRA Proc., 2, 57-62, https://doi.org/10.5194/ap-2-57-2015, 2015 It is generally believed that the cosmic ray spectrum below the knee is of Galactic origin, although the exact sources making up the entire cosmic ray energy budget are still unknown. Including effects of magnetic amplification, Supernova Remnants (SNR) could be capable of accelerating cosmic rays up to a few PeV and they represent the only source class with a sufficient non-thermal energy budget to explain the cosmic ray spectrum up to the knee. Now, gamma-ray measurements of SNRs for the first time allow to derive the cosmic ray spectrum at the source, giving us a first idea of the concrete, possible individual contributions to the total cosmic ray spectrum. In this contribution, we use these features as input parameters for propagating cosmic rays from its origin to Earth using GALPROP in order to investigate if these supernova remnants reproduce the cosmic ray spectrum and if supernova remnants in general can be responsible for the observed energy budget.

Description: A Consistent Scenario for the IBEX Ribbon, Anisotropies in TeV Cosmic Rays, and the Local Interstellar Medium N. A. Schwadron, P. Frisch, F. C. Adams, E. R. Christian, P. Desiati, H. O. Funsten, J. R. Jokipii, D. J. McComas, E. Moebius, and G. Zank ASTRA Proc., 2, 9-16, https://doi.org/10.5194/ap-2-9-2015, 2015 We develop a simple diffusive model of the propagation of cosmic rays and the associated cosmic ray anisotropy due to cosmic ray streaming against the local interstellar flow. We show that the local plasma and field conditions sampled by IBEX provide characteristics that consistently explain TeV cosmic ray anisotropies. These results support models that place the interstellar magnetic field direction near the center of the IBEX ribbon.

Description: MHD flows at astropauses and in astrotails D. H. Nickeler, T. Wiegelmann, M. Karlický, and M. Kraus ASTRA Proc., 1, 51-60, https://doi.org/10.5194/ap-1-51-2014, 2014 The geometrical shapes and the physical properties of stellar wind – interstellar medium interaction regions form an important stage for studying stellar winds and their embedded magnetic fields as well as cosmic ray modulation. Our goal is to provide a proper representation and classification of counter-flow configurations and counter-flow interfaces in the frame of fluid theory. In addition we calculate flows and large-scale electromagnetic fields based on which the large-scale dynamics and its role as possible background for particle acceleration, e.g., in the form of anomalous cosmic rays, can be studied. We find that for the definition of the boundaries, which are determining the astropause shape, the number and location of magnetic null points and stagnation points is essential. Multiple separatrices can exist, forming a highly complex environment for the interstellar and stellar plasma. Furthermore, the formation of extended tail structures occur naturally, and their stretched field and streamlines provide surroundings and mechanisms for the acceleration of particles by field-aligned electric fields.

Description: Observations of the anisotropy of cosmic rays at TeV–PeV S. BenZvi ASTRA Proc., 1, 33-37, https://doi.org/10.5194/ap-1-33-2014, 2014 During the past decade, multiple observatories have reported significant observations of the anisotropy of cosmic rays in the TeV energy band. The anisotropy has been observed at large scales and small scales in both the Northern and Southern Hemispheres. The source of the anisotropy is not well-understood, though both a galactic and a heliospheric origin have been suggested. We discuss recent observations of the shape and energy dependence of the anisotropy, with particular attention to measurements by the IceCube Neutrino Observatory in the Southern Hemisphere and the Milagro and High-Altitude Water Cherenkov (HAWC) observatories in the Northern Hemisphere.

Description: Cosmic rays as regulators of molecular cloud properties M. Padovani, P. Hennebelle, and D. Galli ASTRA Proc., 1, 23-27, https://doi.org/10.5194/ap-1-23-2014, 2014 Cosmic rays are the main agents in controlling the chemical evolution and setting the ambipolar diffusion time of a molecular cloud. We summarise the processes causing the energy degradation of cosmic rays due to their interaction with molecular hydrogen, focusing on the magnetic effects that influence their propagation. Making use of magnetic field configurations generated by numerical simulations, we show that the increase of the field line density in the collapse region results in a reduction of the cosmic-ray ionisation rate. As a consequence the ionisation fraction decreases, facilitating the decoupling between the gas and the magnetic field.

Description: Cosmic ray particles from exploding massive stars with winds P. L. Biermann ASTRA Proc., 1, 29-31, https://doi.org/10.5194/ap-1-29-2014, 2014 The origin of cosmic rays is still unsettled. Many sources have been proposed over the years, and exploding stars still provide the most promising candidates. Here we examine one of these scenarios, and compare the resulting predictions with data: Massive stars have winds, and when these stars explode, the resulting shock runs through the wind. The observable phenomenon is called radio-supernova, and many have been observed in non-thermal radio emission. This emission allows to determine the magnetic field in the wind as a function of radius, and so allows to check, whether such explosions can achieve the high energies required and also explain the flux and the spectra of cosmic rays. The observations show this to be the case, and so we conclude that radio supernovae can explain the high-energy Galactic cosmic rays over the entire energy range, and that the spectral predictions are compatible with observations.

Description: Observation of the Cosmic-Ray Shadow of the Moon and Sun with IceCube F. Bos, F. Tenholt, J. Becker Tjus, and S. Westerhoff ASTRA Proc., 2, 5-8, https://doi.org/10.5194/ap-2-5-2015, 2015 Moon shadow analyses are standard methods to calibrate cosmic-ray detectors. We report on a three-year observation of cosmic-ray Moon and Sun shadows in different detector configurations. The cosmic-ray Moon shadow was observed with high statistical significance (〉 6σ) in previous analyses when the IceCube detector operated in a smaller configuration before it was completed in December 2010. This work shows first analyses of the cosmic-ray Sun shadow in IceCube. A binned analysis in one-dimension is used to measure the Moon and Sun shadow with high statistical significance greater than 12σ.

Description: The large-scale anisotropy with the PAMELA calorimeter A. Karelin, O. Adriani, G. Barbarino, G. Bazilevskaya, R. Bellotti, M. Boezio, E. Bogomolov, M. Bongi, V. Bonvicini, S. Bottai, A. Bruno, F. Cafagna, D. Campana, R. Carbone, P. Carlson, M. Casolino, G. Castellini, C. De Donato, C. De Santis, N. De Simone, V. Di Felice, V. Formato, A. Galper, S. Koldashov, S. Koldobskiy, S. Krut'kov, A. Kvashnin, A. Leonov, V. Malakhov, L. Marcelli, M. Martucci, A. Mayorov, W. Menn, M. Mergé, V. Mikhailov, E. Mocchiutti, A. Monaco, N. Mori, R. Munini, G. Osteria, F. Palma, B. Panico, P. Papini, M. Pearce, P. Picozza, M. Ricci, S. Ricciarini, R. Sarkar, M. Simon, V. Scotti, R. Sparvoli, P. Spillantini, Y. Stozhkov, A. Vacchi, E. Vannuccini, G. Vasilyev, S. Voronov, Y. Yurkin, G. Zampa, and N. Zampa ASTRA Proc., 2, 35-37, https://doi.org/10.5194/ap-2-35-2015, 2015 The large-scale anisotropy (or the so-called star-diurnal wave) has been studied using the calorimeter of the space-born experiment PAMELA. The cosmic ray anisotropy has been obtained for the Southern and Northern hemispheres simultaneously in the equatorial coordinate system for the time period 2006–2014. The dipole amplitude and phase have been measured for energies 1–20 TeV n -1 .

Description: Diffuse synchrotron emission from galactic cosmic ray electrons G. Di Bernardo, D. Grasso, C. Evoli, and D. Gaggero ASTRA Proc., 2, 21-26, https://doi.org/10.5194/ap-2-21-2015, 2015 Magnetic fields permeate the interstellar medium (ISM), extending far beyond the Galactic disc. The non-thermal phenomena, like e.g. the Galactic radio emission is doubtless a viable method of observation to clearly delineate the magnetic structure of our Galaxy. In this regard, the aim addressed in this contribution is to simulate the polarized Galactic synchrotron emission, due to the diffuse radiation by charged relativistic particles, at all relevant frequencies, 10 MHz up to 100 GHz.