Chloe Pugh, Valery Nakariakov

Quasi-periodic pulsations (QPPs) are a common feature of solar flares that are observed in many different wavelengths. Although QPPs appear not to be as abundant in white light Kepler flare light curves as they are in solar flares, albeit in different wavelengths the structure of the pulsations are strikingly similar, hinting that the same underlying processes govern both solar and stellar flares. Here we consider a special case, observed on KIC9655129, which shows evidence of multiple periodicities. We speculate that the presence of multiple periodicities is a good indication that the QPPs were caused by magnetohydrodynamic oscillations, further strengthening the case that the physical processes in operation during stellar flares are at least analogous to those in solar flares.

Michael Leguèbe, Damien Fournier, Aaron C. Birch, Laurent Gizon in Collaboration with Inria team Magique3D

We compute acoustic Green’s functions in an axisymmetric solar background model, which may include a meridional flow and differential rotation. The wave equation is solved in the frequency domain using a finite element solver. A transparent boundary condition for the waves is implemented in the chromosphere, which represents a great improvement in computational efficiency compared to implementations based on ’sponge layers’. We perform various convergence studies that demonstrate that wave travel times can be computed with an accuracy of 0.001 s. This high level of numerical accuracy is required to interpret travel times in the deep interior, and is achieved thanks to a refined mesh in the near surface layers and around the source of excitation. The wave solver presented here lays the ground for future iterative inversion methods for flows in the deep solar interior.

One of the outstanding and unforeseen results from the Kepler mission is our new insight and understanding of red giant stars. These highly evolved stars, which are in the last stages of their life, provide extremely useful information when trying to develop stellar evolutionary models. Furthermore, they show stochastically excited oscillations thus allowing to use asteroseismic techniques to derive conditions of the most internal layers. Bright giants stars are well suited to be studied with the 1m telescopes in the Stellar Observations Network Group project (SONG) using a high resolution echelle spectrograph performing high precision measurements of their the radial velocity. The prototype node- the Hertzsprung SONG telescope- was inaugurated in October 2014 and is located at the Teide Observatory on Tenerife and providing continuous and high quality observations since then, When selecting the best targets for SONG, a precision of 1-2 m/s per point is reachable using the iodine method and a number of red giants have been observed with the SONG telescope since scientific operation started. In this talk we present the first results of these specific campaigns for a few red giants in which eigenmodes have been identified and their global seismic parameters derived.

I. Arregui

Damping of transverse waves in different solar coronal structures is a commonly observed property and a source of information about coronal conditions. Although resonant damping seems to be the most accepted mechanism for damping of transverse waves, there are other possible mechanisms. We have carried out a Bayesian analysis comparing three different models which could explain the damping in coronal loops. Our results indicate that resonant absorption is the most probable mechanism for low ratios between damping time and wave period, while the wave leakage mechanism is the best candidate for high ratios. Nonetheless, the evidence for one model against another shows a strong dependence on the data errors.

Gavin Rowell, Matthieu Renaud, Phoebe de Wilt, Fabien Voisin, Yasuo Fukui, Michael Burton, Andrew Walsh, Akiko Kawamura, Andrew Walsh, Akiko Kawamura, Felix Aharonian

We present the results of molecular spectral line observations towards Supernova Remnants such as W28, RX J1713.7-3946 and HESS J1731-347. These remnants exhibit TeV gamma-ray emission, beacons for the presence of enhanced populations of high energy particles. It follows that these objects may accelerate Galactic cosmic-ray protons via the diffusive shock mechanism, but knowledge of the environment local to such remnants is required to constrain such scenarios. The Mopra radio telescope is ideal for probing the interstellar environments of HESS gamma-ray sources through large-scale molecular line surveys. Mopra can be employed to hunt for dense gas-tracing CS and NH3 transitions to identify potential cosmic-ray target material, while simultaneously searching for shock-tracing SiO emission lines which can directly highlight shock-disrupted gas. Furthermore, spectral line width gives an insight into gas dynamics and Mopra is capable of measuring this at a ~1' resolution over degree-scale regions. We present results from recent 7 and 12mm surveys towards the above-mentioned TeV-emitting Supernova Remnants and discuss the implications for distance, the diffusion of cosmic-rays and the high energy gamma-ray spectrum.

Kai Finster, Meilee Ling, Maher Sahyoun, Morten Dreyer, Stine Holm, Martin Rasmussen, Stephanie Pilgaard

The presentation deals with activity of airborne microbial cells and how this is important for expanding our understanding of habitability and biosignatures.

G. Hornig, M.H. Page

What if there were a way to identify **where** the magnetic helicity is concentrated within a three- dimensional magnetic field? At first sight this question appears meaningless, since magnetic helicity is an integral over the whole volume of the magnetic field. But, in fact, it is possible to decompose this total helicity as an integral over individual "field line helicities" for each magnetic field line in the domain. All of these are ideal-invariant, topological quantities, and they allow us to quantify in a meaningful way how magnetic helicity is distributed within the domain. In this talk, I will show how this idea can be practically applied to typical extrapolations of the Sun's coronal magnetic field that are used in solar physics.

The solar electromagnetic and corpuscular emissions are strongly modulated by the evolution of the magnetic structure of the solar atmosphere, which is imprinted in the solar surface. The evolution of the magnetic structure leads to gradual changes in the solar activity (space climate) as well as violent events (space weather) that affect the whole Heliosphere. In particular, the solar output affects the ionized and neutral components of the Earth’s atmosphere that have a direct impact on human activities from agriculture to high-technological systems. The solar magnetism is driven by the energy transport from the inner layers to the solar atmosphere. Although systematic observations have revealed several features related to the evolution of solar activity, there is not a complete explanation of the physical processes that lead to solar activity cyclic variability and its long-term changes. Here we present a brief description of the development of a magnetograph and visible-light imager instrument to study the solar dynamo processes through observations of the solar surface magnetic field distribution. The instrument will provide measurements of the vector magnetic field and the line-of-sight velocity in the solar photosphere. As the magnetic field anchored at the solar surface produces most of the structures and energetic events in the upper solar atmosphere and significantly influences the Heliosphere, the development of this instrument plays an essential role in reaching the scientific goals of The Atmospheric and Space Science Coordination (CEA) at the Brazilian National Institute for Space Research (INPE). In particular, the INPE’s Space Weather program will benefit most from the development of this technology. Additionally, we expect that this project will be the starting point to establish a robust research program on Solar System Research at INPE. The proposed instrument has been designed to operate on the ground, but with a conceptual design flexible enough to be adapted to work on a balloon and space-based platforms. In this way, our main aim is acquiring know-how progressively to build state-of-art solar vector magnetograph and visible-light imagers for space-based platforms to contribute to the efforts of the solar-terrestrial physics community to address the main unanswered questions on how our nearby Star works.

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Community paper as part of the Denkschrift 2017 - Perspektiven der Astrophysik in Deutschland 2017 - 2030

Short How-To about how to call the MLT_ 4 recognition code.

Here you can download the EST Brochure.

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Ariane Schad

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R. J. Campbell , S. Shelyag, C. Quintero Noda, M. Mathioudakis, P. H. Keys, and A. Reid

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Dirk Soltau (first author)

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Freiburg, Germany

Kiepenheuer-Institut für Sonnenphysik, Freiburg, Germany

School of Physics, UNSW, Sydney, Australia

Coimbra (Portugal)

Angra do Heroísmo, Terceira-Açores, Portugal

Osnabrück, Germany

Aarhus, Denmark

Berne, Switzerland