TY - JOUR A1 - Georgy, C. A1 - Ekström, S. A1 - Hirschi, R. A1 - Meynet, G. A1 - Groh, J. H. A1 - Eggenberger, P. T1 - Wolf-Rayet stars as an evolved stage of stellar life JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - Wolf-Rayet (WR) stars, as they are advanced stages of the life of massive stars, provide a good test for various physical processes involved in the modelling of massive stars, such as rotation and mass loss. In this paper, we show the outputs of the latest grids of single massive stars computed with the Geneva stellar evolution code, and compare them with some observations. We present a short discussion on the shortcomings of single stars models and we also briefly discuss the impact of binarity on the WR populations. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-88097 SP - 229 EP - 232 ER - TY - JOUR A1 - Munoz, M. A1 - Moffat, Anthony F. J. A1 - Hill, G. M. A1 - Richardson, N. D. A1 - Pablo, H. T1 - The missing Wolf-Rayet X-ray binary systems JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - We investigate the rarity of the Wolf-Rayet X-ray binaries (WRXRBs) in contrast to their predecessors, the high mass X-ray binaries (HMXRBs). Recent studies suggest that common envelope (CE) mergers during the evolution of a HMXRBs may be responsible (Linden et al. 2012). We conduct a binary population synthesis to generate a population of HMXRBs mimicking the Galactic sample and vary the efficiency parameter during the CE phase to match the current WRXRB to HMXRB ratio. We find that ∼50% of systems must merge to match observational constraints. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-88082 SP - 225 EP - 228 ER - TY - JOUR A1 - Vanbeveren, D. A1 - Mennekens, N. T1 - Massive star population synthesis with binaries JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - We first give a short historical overview with some key facts of massive star population synthesis with binaries. We then discuss binary population codes and focus on two ingredients which are important for massive star population synthesis and which may be different in different codes. Population simulations with binaries is the third part where we consider the initial massive binary frequency, the RSG/WR and WC/WN and SNII/SNIbc number ratio's, the probable initial rotational velocity distribution of massive stars. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-88071 SP - 217 EP - 224 ER - TY - JOUR A1 - Sanyal, D. A1 - Moriya, T. J. A1 - Langer, N. T1 - Envelope inflation in Wolf-Rayet stars and extended supernova shock breakout signals JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - Massive, luminous stars reaching the Eddington limit in their interiors develop very dilute, extended envelopes. This effect is called envelope inflation. If the progenitors of Type Ib/c supernovae, which are believed to be Wolf-Rayet (WR) stars, have inflated envelopes then the shock breakout signals diffuse in them and can extend their rise times significantly. We show that our inflated, hydrogen-free, WR stellar models with a radius of ∼R⊙ can have shock breakout signals longer than ∼ 60 s. The puzzlingly long shock breakout signal observed in the Type Ib SN 2008D can be explained by an inflated progenitor envelope, and more such events might argue in favour of existence of inflated envelopes in general. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-88062 SP - 213 EP - 216 ER - TY - JOUR A1 - Shacham, T. A1 - Idan, I. A1 - Shaviv, N. J. T1 - A new mechanism for long long-term pulsations of hot stars? JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - We suggest several ideas which when combined could lead to a new mechanism for long-term pulsations of very hot and luminous stars. These involve the interplay between convection, radiation, atmospheric clumping and winds, which collectively feed back to stellar expansion and contraction. We discuss these ideas and point out the future work required in order to fill in the blanks. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-88058 SP - 209 EP - 212 ER - TY - JOUR A1 - Pablo, H. A1 - Moffat, Anthony F. J. T1 - WR Time Series Photometry BT - A Forest of Possibilities JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - We take a comprehensive look at Wolf Rayet photometric variability using the MOST satellite. This sample, consisting of 6 WR stars and 6 WC stars defies all typical photometric analysis. We do, however, confirm the presence of unusual periodic signals resembling sawtooth waves which are present in 11 out of 12 stars in this sample. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-88031 SP - 205 EP - 208 ER - TY - JOUR A1 - Grassitelli, L. A1 - Langer, N. A1 - Sanyal, D. A1 - Fossati, Luca A1 - Bestenlehner, J. M. T1 - Instabilities in the envelope of Wolf-Rayet stars JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - Wolf-Rayet stars are very hot stars close to the Eddington limit. In the conditions encountered in their radiation pressure dominated outer layers several instabilities are expected to arise. These instabilities could influence both the dynamic of their optically thick winds and the observed spectral lines introducing small and large scale variability. We investigate the conditions in the convective envelopes of our helium star models and relate them to the appearance of a high number of stochastic density inhomogeneities, i.e. clumping in the optically thick wind. We also investigate the pulsational stability of these envelope, considering the effect of the high stellar wind mass loss rates. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-88024 SP - 201 EP - 204 ER - TY - JOUR A1 - McClelland, L. A. S. A1 - Eldridge, J. J. T1 - Helium stars BT - Towards an understanding of Wolf–Rayet evolution JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - There are outstanding problems in trying to reproduce the observed nature of Wolf–Rayet stars from theoretical stellar models. We have investigated the effects of uncertainties, such as composition and mass-loss rate, on the evolution and structure of Wolf–Rayet stars and their lower mass brethren. We find that the normal Conti scenario needs to be altered, with different WR types being due to different initial masses as well as different stages of evolution. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-88010 SP - 197 EP - 200 ER - TY - JOUR A1 - Szécsi, D. A1 - Langer, N. A1 - Sanyal, D. A1 - Evans, C. J. A1 - Bestenlehner, J. M. A1 - Raucq, F. T1 - Do rapidly-rotating massive stars at low metallicity form Wolf–Rayet stars? JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - The evolution of massive stars is strongly influenced by their initial chemical composition. We have computed rapidly-rotating massive star models with low metallicity (∼1/50 Z⊙) that evolve chemically homogeneously and have optically-thin winds during the main sequence evolution. These luminous and hot stars are predicted to emit intense mid- and far-UV radiation, but without the broad emission lines that characterize WR stars with optically-thick winds. We show that such Transparent Wind UV-Intense (TWUIN) stars may be responsible for the high number of He ii ionizing photons observed in metal-poor dwarf galaxies, such as IZw 18. We find that these TWUIN stars are possible long-duration gamma-ray burst progenitors. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87997 SP - 189 EP - 192 ER - TY - JOUR A1 - Meynet, G. A1 - Georgy, C. A1 - Maeder, A. A1 - Ekström, S. A1 - Groh, J. H. A1 - Barblan, F. A1 - Song, H. F. A1 - Eggenberger, P. T1 - Physics of massive stars relevant for the modeling of Wolf-Rayet populations JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - Key physical ingredients governing the evolution of massive stars are mass losses, convection and mixing in radiative zones. These effects are important both in the frame of single and close binary evolution. The present paper addresses two points: 1) the differences between two families of rotating models, i.e. the family of models computed with and without an efficient transport of angular momentum in radiative zones; 2) The impact of the mass losses in single and in close binary models. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87971 SP - 183 EP - 188 ER - TY - JOUR A1 - Eldridge, J. J. A1 - McClelland, L. A. S. A1 - Xiao, L. A1 - Stanway, E. R. A1 - Bray, J. T1 - The importance of getting single-star and binary physics correct JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - We discuss the uncertainties that need to be considered when creating numerical models of WR stars. We pay close attention to inflation and duplicity of the stellar models, highlighting several observational tests that show these are key to understanding WR stellar populations. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87966 SP - 177 EP - 182 ER - TY - JOUR A1 - Koenigsberger, C. T1 - HD5980 BT - wind collisions and binary star evolution JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - HD5980 is a multiple system containing at least 3 very massive and luminous stars. Located in the Small Magellanic Cloud, it is an ideal system for studying the massive star structure and evolutionary processes in low-metallicity environments. Intensely observed over the past few decades, HD5980 is a treasure trove of information on stellar wind structure, on wind-wind collisions and on the formation of wind-blown circumstellar structures. In addition, its characteristics suggest that the eclipsing WR+LBV stars of the system are the product of quasihomogeneous chemical evolution, thus making them candidate pair production supernovae or GRB progenitors. This paper summarizes some of the outstanding results derived from half a century of observations and recent theoretical studies. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87954 SP - 171 EP - 174 ER - TY - JOUR A1 - Weis, K. T1 - Family ties of WR to LBV nebulae yielding clues for stellar evolution JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - Luminous Blue Variables (LBVs) are stars is a transitional phase massive stars may enter while evolving from main-sequence to Wolf-Rayet stars. The to LBVs intrinsic photometric variability is based on the modulation of the stellar spectrum. Within a few years the spectrum shifts from OB to AF type and back. During their cool phase LBVs are close to the Humphreys-Davidson (equivalent to Eddington/Omega-Gamma) limit. LBVs have a rather high mass loss rate, with stellar winds that are fast in the hot and slower in the cool phase of an LBV. These alternating wind velocities lead to the formation of LBV nebulae by wind-wind interactions. A nebula can also be formed in a spontaneous giant eruption in which larger amounts of mass are ejected. LBV nebulae are generally small (< 5 pc) mainly gaseous circumstellar nebulae, with a rather large fraction of LBV nebulae being bipolar. After the LBV phase the star will turn into a Wolf-Rayet star, but note that not all WR stars need to have passed the LBV phase. Some follow from the RSG and the most massive directly from the MS phase. In general WRs have a large mass loss and really fast stellar winds. The WR wind may interact with winds of earlier phases (MS, RSG) to form WR nebulae. As for WR with LBV progenitors the scenario might be different, here no older wind is present but an LBV nebula! The nature of WR nebulae are therefore manifold and in particular the connection (or family ties) of WR to LBV nebulae is important to understand the transition between these two phases, the evolution of massive stars, their winds, wind-wind and wind-nebula interactions. Looking at the similarities and differences of LBV and WR nebula, figuring what is a genuine LBV and WR nebula are the basic question addressed in the analysis presented here. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87949 SP - 167 EP - 170 ER - TY - JOUR A1 - Madura, T. I. A1 - Clementel, N. A1 - Gull, T. R. A1 - Kruip, C. J. H. A1 - Paardekooper, J.-P. A1 - Icke, V. T1 - 3D hydrodynamical and radiative transfer modeling of η Carinae's colliding winds JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - We present results of full 3D hydrodynamical and radiative transfer simulations of the colliding stellar winds in the massive binary system η Carinae. We accomplish this by applying the SimpleX algorithm for 3D radiative transfer on an unstructured Voronoi-Delaunay grid to recent 3D smoothed particle hydrodynamics (SPH) simulations of the binary colliding winds. We use SimpleX to obtain detailed ionization fractions of hydrogen and helium, in 3D, at the resolution of the original SPH simulations. We investigate several computational domain sizes and Luminous Blue Variable primary star mass-loss rates. We furthermore present new methods of visualizing and interacting with output from complex 3D numerical simulations, including 3D interactive graphics and 3D printing. While we initially focus on η Car, the methods employed can be applied to numerous other colliding wind (WR 140, WR 137, WR 19) and dusty `pinwheel' (WR 104, WR 98a) binary systems. Coupled with 3D hydrodynamical simulations, SimpleX simulations have the potential to help determine the regions where various observed time-variable emission and absorption lines form in these unique objects. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87930 SP - 163 EP - 166 ER - TY - JOUR A1 - Hamaguchi, K. A1 - Corcoran, M. F. T1 - Extremely Hard X-ray Emission from η Car Observed with XMM-Newton and NuSTAR around Periastron in 2014.6 JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - The super massive binary system, η Car, experienced periastron passage in the summer of 2014. We observed the star twice around the maximum (forb =0.97, 2014 June 6) and just before the minimum (ϕorb =0.99, 2014 July 28) of its wind-wind colliding (WWC) X-ray emis-sion using the XMM-Newton and NuSTAR observatories, the latter of which is equipped with extremely hard X-ray (>10 keV) focusing mirrors. In both observations, NuSTAR detected the thermal X-ray tail up to 40-50 keV. The hard slope is consistent with an electron tem- perature of ∼6 keV, which is significantly higher than the ionization temperature (kT ∼4 keV) measured from the Fe K emission lines, assuming collisional equilibrium plasma. The spectrum did not show a hard power-law component above this energy range, unlike earlier detections with INTEGRAL and Suzaku. In the second NuSTAR observation, the X-ray flux above 5 keV declined gradually in ∼1 day. This result suggests that the WWC apex was gradually hidden behind the optically thick primary wind around conjunction. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87926 SP - 159 EP - 162 ER - TY - JOUR A1 - Morris, P. W. T1 - Measuring η Carinae's High Mass Ejecta in the Infrared and Sub-millimeter JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - I address uncertainties on the spatial distribution and mass of the dust formed in η Carinae's Homunculus nebula with data being combined from several space- and ground-based facilities spanning near-infrared to sub-mm wavelengths, in terms of observational constraints and modeling. Until these aspects are better understood, the mass loss history and mechanisms responsible for η Car's enormous eruption(s) remain poorly constrained. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87895 SP - 155 EP - 158 ER - TY - JOUR A1 - Gull, T. R. T1 - Eta Carinae BT - Many Advances .... Even More Puzzles JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - Since Augusto Damineli's demonstration in 1996 that Eta Carinae is a binary with a 5.52 year period, many innovative observations and increasingly advanced three-dimensional models have led to considerable insight on this massive system that ejected at least ten, possibly forty, solar masses in the nineteenth century. Here we present a review of our current understanding of this complex system and point out continuing puzzles. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87876 SP - 149 EP - 154 ER - TY - JOUR A1 - Küker, Manfred T1 - Magnetospheres of massive stars JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - We study the interaction of line-driven winds from massive stars with the magnetic field rooted in these stars by carrying out numerical simulations using the Nirvana MHD code in 2D in spherical polar coordinates. The code's adaptive mesh refinement feature allows high spatial resolution across the whole simulation box. We study both O and Wolf-Rayet stars for a range of magnetic field strengths from weak to strong as measured by the confinement parameter. For weak fields our simulations show that the initially dipolar field opens up far away from the star and a thin disk-like structure forms in the equatorial plane of the magnetic field. For stronger fields the disk is disrupted close to the stellar surface and closed field lines persist at low latitudes. For very strong fields a pronounced magnetosphere forms where the gas is forced to move along the field lines and eventually falls back to the stellar surface. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87864 SP - 143 EP - 146 ER - TY - JOUR A1 - Vink, J. S. T1 - The True origin of Wolf-Rayet stars JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - The Wolf-Rayet (WR) phenomenon is widespread in astronomy. It involves classical WRs, very massive stars (VMS), WR central stars of planetary nebula CSPN [WRs], and supernovae (SNe). But what is the root cause for a certain type of object to turn into an emission-line star? In this contribution, I discuss the basic aspects of radiation-driven winds that might reveal the ultimate difference between WR stars and canonical O-type stars. I discuss the aspects of (i) self-enrichment via CNO elements, (ii) high effective temperatures (Tₑff), (iii) an increase in the helium abundance (Y ), and finally (iv) the Eddington factor Γₑ. Over the last couple of years, we have made a breakthrough in our understanding of Γₑ -dependent mass loss, which will have far-reaching consequences for the evolution and fate of the most massive stars in the Universe. Finally, I discuss the prospects for studies of the WR phenomenon in the highest redshift Lyα and He ii emitting galaxies. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87848 SP - 133 EP - 138 ER - TY - JOUR A1 - Liermann, A. T1 - Evolution of Wolf-Rayet spectra JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - Wolf-Rayet stars are important sources for the enrichment of the ISM with nuclear processed elements, UV photons and momentum. They are descendants of high-mass stars for which short lifetimes and transition times can hamper the spectral classification of the stars in their different evolutionary phases. The expanded stellar atmospheres of Wolf-Rayet stars can show spectra which seem inconsistent with the anticipated underlying evolution phase, for example in late hydrogen-burning WN stars and Of/WN transition stars. We present a sequence of synthetic spectra of the Potsdam Wolf-Rayet models based on the latest Geneva stellar evolution models. This will visualize the changes in stellar spectra over a full stellar lifetime. Direct comparison with observed stellar spectra, as well as the evolution of diagnostic line ratios will improve the connection of spectral classification and evolution phase. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87830 SP - 129 EP - 132 ER - TY - JOUR A1 - Kourniotis, M. A1 - Bonanos, A. A1 - Najarro, F. T1 - Accurate parameters of massive binaries in the Danks clusters JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - We present results from our near-infrared spectroscopy with VLT/ISAAC of four, massive eclipsing binary systems in the young, heavily reddened, massive Danks clusters. We derive accurate fundamental parameters and the distance to these massive systems, which comprise of OIf+, WR and O-type stars. Our goal is to increase the sample of well-studied WR stars and constrain their physics by comparison with evolutionary models. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87819 SP - 121 EP - 124 ER - TY - JOUR A1 - Najarro, F. A1 - de la Fuente, D. A1 - Geballe, T. R. A1 - Figer, D. F. A1 - Hillier, D. J. T1 - The WR population in the Galactic Center JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - The Galactic Center (GC) hosts three of the most massive WR rich, resolved young clusters in the Local Group as well as a large number of apparently isolated massive stars. Therefore, it constitutes a test bed to study the star formation history of the region, to probe a possible top-heavy scenario and to address massive star formation (clusters vs isolation) in such a dense and harsh environment. We present results from our ongoing infrared spectroscopic studies of WRs and other massive stars at the Center of the Milky Way. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87794 SP - 113 EP - 116 ER - TY - JOUR A1 - Tramper, F. A1 - Straal, S. M. A1 - Sanyal, D. A1 - Sana, Hugues A1 - de Koter, A. A1 - Gräfener, G. A1 - Langer, N. A1 - Vink, J. S. A1 - de Mink, S. E. A1 - Kaper, L. T1 - Massive Wolf-Rayet stars on the verge to explode BT - the properties of the WO stars JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - The enigmatic oxygen-sequence Wolf-Rayet stars represent a rare stage in the evolution of massive stars. Their properties can provide unique constraints on the pre-supernova evolution of massive stars. This work presents the results of a quantitative spectroscopic analysis of the known single WO stars, with the aim to obtain the key stellar parameters and deduce their evolutionary state.X-Shooter spectra of the WO stars are modeled using the line-blanketed non-local thermal equilibrium atmosphere code cmfgen. The obtained stellar parameters show that the WO stars are very hot, with temperatures ranging from 150 kK to 210 kK. Their chemical composition is dominated by carbon (>50%), while the helium mass fraction is very low (down to 14%). Oxygen mass fractions reach as high as 25%. These properties can be reproduced with dedicated evolutionary models for helium stars, which show that the stars are post core-helium burning and very close to their eventual supernova explosion. The helium-star masses indicate initial masses or approximately 40 - 60M⊙.Thus, WO stars represent the final evolutionary stage of stars with estimated initial masses of 40 - 60M⊙. They are post core-helium burning and may explode as type Ic supernovae within a few thousand years. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87786 SP - 109 EP - 112 ER - TY - JOUR A1 - Rosslowe, C. K. A1 - Crowther, P. A. A1 - Clark, J. S. A1 - Negueruela, I. T1 - Physical properties of the WR stars in Westerlund 1 JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - The Westerlund 1 (Wd1) cluster hosts a rich and varied collection of massive stars. Its dynamical youth and the absence of ongoing star formation indicate a coeval population. As such, the simultaneous presence of both late-type supergiants and Wolf-Rayet stars has defied explanation in the context of single-star evolution. Observational evidence points to a high binary fraction, hence this stellar population offers a robust test for stellar models accounting for both single-star and binary evolution. We present an optical to near-IR (VLT & NTT) spectroscopic analysis of 22 WR stars in Wd 1, delivering physical properties for the WR stars. We discuss how these differ from the Galactic field population, and how they may be reconciled with the predictions of single and binary evolutionary models. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87779 SP - 105 EP - 108 ER - TY - JOUR A1 - Neugent, K. F. A1 - Massey, P. A1 - Hillier, D. J. A1 - Morrell, N. I. T1 - The Discovery and Physical Parameterization of a New Type of Wolf-Rayet Star JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - As part of our ongoing Wolf-Rayet (WR) Magellanic Cloud survey, we have discovered 13 new WRs. However, the most exciting outcome of our survey is not the number of new WRs, but their unique characteristics. Eight of our discoveries appear to belong to an entirely new class of WRs. While one might naively classify these stars as WN3+O3V binaries, such a pairing is unlikely. Preliminary CMFGN modeling suggests physical parameters similar to early-type WNs in the Large Magellanic Cloud except with mass-loss rates three to five times lower and slightly higher temperatures. The evolution status of these stars remains an open question. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87766 SP - 101 EP - 104 ER - TY - JOUR A1 - Chené, A.-N. A1 - Wyrick, D. A1 - Borissova, J. A1 - Kuhn, M. A1 - Hervé, A. A1 - Ramírez Alegría, S. A1 - Bonatto, C. A1 - Bouret, J.-C. A1 - Kurtev, R. T1 - Improving distances to Galactic Wolf-Rayet stars JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - Before GAIA improves the HIPPARCOS survey, direct determination of the distance via parallax is only possible for γ Vel, but the analysis of the cluster or association to which WR stars are associated can give distances with a 50% to a 10% accuracy. The list of Galactic clusters, associations and clusters/association candidates has grown significantly in the last decade with the numerous deep, high resolution surveys of the Milky Way. In this work, we revisit the fundamental parameters of known clusters with WR stars, and we present the search for new ones. All our work is based on the catalogs from the VVV (from the VISTA telescope) and the UKIDS (from the UKIRT telescope) near infrared surveys. Finally, the relations between the fundamental parameters of clusters with WR stars are explored. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87759 SP - 97 EP - 100 ER - TY - JOUR A1 - Hoffman, J. L. A1 - Lomax, J. R. T1 - Structure and fate of binary WR stars BT - Clues from spectropolarimetry JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - Because most massive stars have been or will be affected by a companion during the course of their evolution, we cannot afford to neglect binaries when discussing the progenitors of supernovae and GRBs. Analyzing linear polarization in the emission lines of close binary systems allows us to probe the structures of these systems' winds and mass flows, making it possible to map the complex morphologies of the mass loss and mass transfer structures that shape their subsequent evolution. In Wolf-Rayet (WR) binaries, line polarization variations with orbital phase distinguish polarimetric signatures arising from lines that scatter near the stars from those that scatter far from the orbital plane. These far-scattering lines may form the basis for a "binary line-effect method" of identifying rapidly rotating WR stars (and hence GRB progenitor candidates) in binary systems. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87737 SP - 85 EP - 88 ER - TY - JOUR A1 - St-Louis, N. T1 - Studying Large and Small Scale Wind Asymmetries with Spectroscopy and Polarimetry JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - In this paper, I review observational evidence from spectroscopy and polarimetry for the presence of small and large scale structure in the winds of Wolf-Rayet (WR) stars. Clumping is known to be ubiquitous in the winds of these stars and many of its characteristics can be deduced from spectroscopic time-series and polarisation lightcurves. Conversely, a much smaller fraction of WR stars have been shown to harbour larger scale structures in their wind (∼ 1/5) while they are thought to be present is the winds of most of their O-star ancestors. The reason for this difference is still unknown. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87726 SP - 79 EP - 84 ER - TY - JOUR A1 - Aldoretta, E. J. A1 - St-Louis, N. A1 - Richardson, N. D. A1 - Moffat, Anthony F. J. A1 - Eversberg, T. A1 - Hill, G. M. T1 - The Results of the 2013 Pro-Am Wolf-Rayet Campaign JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - Professional and amateur astronomers around the world contributed to a 4-month long campaign in 2013, mainly in spectroscopy but also in photometry, interferometry and polarimetry, to observe the first 3 Wolf-Rayet stars discovered: WR 134 (WN6b), WR 135 (WC8) and WR 137 (WC7pd+O9). Each of these stars are interesting in their own way, showing a variety of stellar wind structures. The spectroscopic data from this campaign were reduced and analyzed for WR 134 in order to better understand its behavior and long-term periodicity in the context of CIRs in the wind. We will be presenting the results of these spectroscopic data, which include the confirmation of the CIR variability and a time-coherency of ∼ 40 days (half-life of ∼ 20 days). Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87713 SP - 75 EP - 78 ER - TY - JOUR A1 - Eversberg, T. A1 - Aldoretta, E. J. A1 - Knapen, J. H. A1 - Moffat, Anthony F. J. A1 - Morel, T. A1 - Ramiaramanantsoa, T. A1 - Rauw, G. A1 - Richardson, N. D. A1 - St-Louis, N. A1 - Teodoro, M. T1 - World-wide amateur observations BT - A viable future of massive star research JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - For some years now, spectroscopic measurements of massive stars in the amateur domain have been fulfilling professional requirements. Various groups in the northern and southern hemispheres have been established, running successful professional-amateur (ProAm) collaborative campaigns, e.g., on WR, O and B type stars. Today high quality data (echelle and long-slit) are regularly delivered and corresponding results published. Night-to-night long-term observations over months to years open a new opportunity for massive-star research. We introduce recent and ongoing sample campaigns (e.g. ∊ Aur, WR 134, ζ Pup), show respective results and highlight the vast amount of data collected in various data bases. Ultimately it is in the time-dependent domain where amateurs can shine most. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87705 SP - 71 EP - 74 ER - TY - JOUR A1 - Hillier, D. J. T1 - Spectrum formation in Wolf-Rayet stars JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - We highlight the basic physics that allows fundamental parameters, such as the effective temperature, luminosity, abundances, and mass-loss rate, of Wolf-Rayet (W-R) stars to be determined. Since the temperature deduced from the spectrum of a W-R star is an ionization temperature, a detailed discussion of the ionization structure of W-R winds, and how it is set, is given. We also provide an overview of line and continuum formation in W-R stars. Mechanisms that contribute to the strength of different emission lines, such as collisional excitation, radiative recombination, dielectronic recombination, and continuum uorescence, are discussed. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87669 SP - 65 EP - 70 ER - TY - JOUR A1 - Srivastava, S. A1 - Kehrig, C. A1 - Kantharia, N. G. A1 - Pérez-Montero, E. A1 - Vílchez, J. M. A1 - Iglesias-Páramo, J. A1 - Janardhan, P. T1 - A 2D view of Wolf-Rayet Galaxies JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - The main objective of this work is to investigate the evolution of massive stars, and the interplay between them and the ionized gas for a sample of local metal-poor Wolf-Rayet galaxies. Optical integral field spectrocopy was used in combination with multi-wavelength radio data. Combining optical and radio data, we locate Wolf-Rayet stars and supernova remnants across the Wolf-Rayet galaxies to study the spatial correlation between them. This study will shed light on the massive star formation and its feedback, and will help us to better understand distant star-forming galaxies. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87650 SP - 59 EP - 62 ER - TY - JOUR A1 - Kehrig, C. A1 - Vílchez, J. M. A1 - Pérez-Montero, E. A1 - Iglesias-Páramo, J. A1 - Brinchmann, Jarle A1 - Crowther, P. A. A1 - Durret, F. A1 - Kunth, D. T1 - PopIII-star siblings in IZw18 and metal-poor WR galaxies unveiled from integral field spectroscopy JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - Here, we highlight our recent results from the IFS study of Mrk178, the closest metal-poor WR galaxy, and of IZw18, the most metal-poor star-forming galaxy known in the local Universe. The IFS data of Mrk178 show the importance of aperture effects on the search for WR features, and the extent to which physical variations in the ISM properties can be detected. Our IFS data of IZw18 reveal its entire nebular HeIIλ4686-emitting region, and indicate for the very first time that peculiar, hot (nearly) metal-free ionizing stars (called here PopIII-star siblings) might hold the key to the HeII-ionization in IZw18. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87648 SP - 55 EP - 58 ER - TY - JOUR A1 - Bomans, Dominik J. A1 - Becker, Andrew C. A1 - Kleemann, B. A1 - Weis, K. A1 - Pasquali, A. T1 - Luminous Wolf-Rayet stars at low metallicity JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - The evolution of massive stars in very low metallicity galaxies is less well observationally constrained than in environments more similar to the Milky Way, M33, or the LMC. We discuss in this contribution the current state of our program to search for and characterize Wolf-Rayet stars (and other massive emission line stars) in low metallicity galaxies in the Local Volume. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87635 SP - 51 EP - 54 ER - TY - JOUR A1 - Becker, Andrew C. A1 - Bomans, Dominik J. A1 - Weis, K. T1 - Finding new Wolf-Rayet stars in the Magellanic Clouds JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - Obtaining a complete census of massive, evolved stars in a galaxy would be a key ingredient for testing stellar evolution models. However, as the evolution of stars is also strongly dependent on their metallicity, it is inevitable to have this kind of data for a variety of galaxies with different metallicities. Between 2009 and 2011, we conducted the Magellanic Clouds Massive Stars and Feedback Survey (MSCF); a spatially complete, multi-epoch, broad- and narrow-band optical imaging survey of the Large and Small Magellanic Clouds. With the inclusion of shallow images, we are able to give a complete photometric catalog of stars between B ≈ 18 and B ≈ 19 mag. These observations were augmented with additional photometric data of similar spatial res- olution from UV to IR (e.g. from GALEX, 2MASS and Spitzer) in order to sample a large portion of the spectral energy distribution of the brightest stars (B < 16 mag) in the Magel- lanic Clouds. Using these data, were are able to train a machine learning algorithm that gives us a good estimate of the spectral type of tens of thousands of stars. This method can be applied to the search for Wolf-Rayet-Stars to obtain a sample of candi- dates for follow-up observations. As this approach can, in principle, be adopted for any resolved galaxy as long as sufficient photometric data is available, it can form an effective alternative method to the classical strategies (e.g. He II filter imaging). Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87618 SP - 47 EP - 50 ER - TY - JOUR A1 - Gómez-González, Víctor Mauricio Alfonso A1 - Mayya, Yalia Divakara A1 - Rosa-González, D. T1 - Detection and Characterization of Wolf-Rayet stars in M81 with GTC/OSIRIS spectra and HST images JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - Here we investigate a sample of young star clusters (YSCs) and other regions of recent star formation with Wolf-Rayet (W-R) features detected in the relatively nearby spiral galaxy M81 by analysing long-slit (LS) and Multi-Object Spectroscopy (MOS) spectra obtained with the OSIRIS instrument at the 10.4-m Gran Telescopio Canarias (GTC). We take advantage of the synergy between GTC spectra and Hubble Space Telescope (HST) images to also reveal their spatial localization and the environments hosting these stars. We finally discuss and comment on the next steps of our study. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87604 SP - 43 EP - 46 ER - TY - JOUR A1 - Massey, P. A1 - Neugent, K. F. A1 - Morrell, N. I. T1 - Finding Wolf-Rayet Stars in the Local Group JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - We summarize past and current surveys for WRs among the Local Group galaxies, empha- sizing both the why and how. Such studies are invaluable for helping us learn about massive star evolution, and for providing sensitive tests of the stellar evolution models. But for such surveys to be useful, the completeness limits must be well understood. We illustrate that point by following the “evolution” of the observed WC/WN ratio in nearby galaxies. We end by examining our new survey for WR stars in the Magellanic Clouds, which has revealed a new type of WN star, never before seen. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87592 SP - 35 EP - 42 ER - TY - JOUR A1 - Roman-Lopes, A. A1 - Franco, G. A. P. A1 - Sanmartin, D. T1 - SOAR Near-Infrared and Optical Survey of OIf* and OIf*/WN Stars in the Periphery of Galactic Massive Star Forming Regions JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - In this contribution we present some preliminary results obtained from a SOAR-Goodman optical spectroscopic survey aimed to confirm the OIf* - OIf*/WN nature of a sample of Galactic candidates that were previously confirmed as massive stars based on near-infrared spectra taken with OSIRIS at SOAR. With only a few of such stars known in the Galaxy to date, our study significantly contributes to improve the number of known Galactic O2If* stars, as well as almost doubling the number of known members of the galactic sample of the rare type OIf*/WN. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87585 SP - 31 EP - 34 ER - TY - JOUR A1 - Marston, A. P. A1 - Mauerhan, J. A1 - Morris, P. W. A1 - Van Dyk, S. T1 - Finding Wolf-Rayet Stars in the Milky Way BT - Inputs to Star Formation and Stellar Evolution JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - The total population of Wolf-Rayet (WR) stars in the Galaxy is predicted by models to be as many as ~6000 stars, and yet the number of catalogued WR stars as a result of optical surveys was far lower than this (~200) at the turn of this century. When beginning our WR searches using infrared techniques it was not clear whether WR number predictions were too optimistic or whether there was more hidden behind interstellar and circumstellar extinction. During the last decade we pioneered a technique of exploiting the near- and mid-infrared continuum colours for individual point sources provided by large-format surveys of the Galaxy, including 2MASS and Spitzer/GLIMPSE, to pierce through the dust and reveal newly discovered WR stars throughout the Galactic Plane. The key item to the colour discrimination is via the characteristic infrared spectral index produced by the strong winds of the WR stars, combined with dust extinction, which place WR stars in a relatively depopulated area of infrared colour-colour diagrams. The use of the Spitzer/GLIMPSE 8µm and, more recently, WISE 22µm fluxes together with cross-referencing with X-ray measurements in selected Galactic regions have enabled improved candidate lists that increased our confirmation success rate, achieved via follow-up infrared and optical spectroscopy. To date a total of 102 new WR stars have been found with many more candidates still available for follow-up. This constitutes an addition of ~16% to the current inventory of 642 Galactic WR stars. In this talk we review our methods and provide some new results and a preliminary review of their stellar and interstellar medium environments. We provide a roadmap for the future of this search, including statistical modeling, and what we can add to star formation and high mass star evolution studies. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87577 SP - 27 EP - 30 ER - TY - JOUR A1 - Moffat, Anthony F. J. T1 - General overview of Wolf-Rayet stars JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - Although we all use the name Wolf-Rayet to refer to specific groups of stars, “Wolf-Rayet” per se is really an astrophysical phenomenon of fast-moving, hot plasma, normally expanding around a hot star. However, expediency demands that we follow established traditions by referring to three specific kinds of WR stars: (1) cWR, “classical” He-burning descendants of massive, O-type stars, presumably all of which pass through a WR stage; (2) WNh, the most massive and luminous hydrogen-rich main-sequence stars with strong winds; and (3) [WR], the central stars of some 15 % of Planetary Nebulae. Wolf-Rayet stars are the epitome of relatively stable stars with the highest mass-loss rates for their kind. It behooves us to understand the what, how and why of this circumstance, along with its manyfold and fascinating consequences. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87552 SP - 13 EP - 18 ER - TY - JOUR A1 - Crowther, P. A. T1 - Wolf-Rayet content of the Milky Way JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - An overview of the known Wolf-Rayet (WR) population of the Milky Way is presented, including a brief overview of historical catalogues and recent advances based on infrared photometric and spectroscopic observations resulting in the current census of 642 (vl.13 online catalogue). The observed distribution of WR stars is considered with respect to known star clusters, given that ≤20% of WR stars in the disk are located in clusters. WN stars outnumber WC stars at all galactocentric radii, while early-type WC stars are strongly biased against the inner Milky Way. Finally, recent estimates of the global WR population in the Milky Way are reassessed, with 1,200±100 estimated, such that the current census may be 50% complete. A characteristic WR lifetime of 0.25 Myr is inferred for an initial mass threshold of 25 M⊙. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87562 SP - 21 EP - 26 ER - TY - JOUR ED - Ette, Ottmar ED - Knobloch, Eberhard T1 - Über die Autoren T1 - Concerning the authors T1 - Sobre los autores T1 - Sur les auteurs JF - HiN : Alexander von Humboldt im Netz ; International Review for Humboldtian Studies Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-86985 SN - 1617-5239 SN - 2568-3543 VL - XVI IS - 30 SP - 99 EP - 101 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Werner, Petra T1 - In der Naturgeschichte „etwas Höheres suchen“ BT - zu Humboldts Konzept der Pflanzengeographie JF - HiN : Alexander von Humboldt im Netz ; International Review for Humboldtian Studies N2 - Der Erwerb der südamerikanischen Reisetagebücher Alexander von Humboldts durch die Staatsbibliothek Preußischer Kulturbesitz war 2014 ein bedeutendes Ereignis. In einem ersten Schritt wertet der Artikel unveröffentlichte Teile der Tagebücher und Dokumente aus dem Nachlass aus, um den „Kosmos Humboldt´scher Interessen“ zum Thema Pflanzengeographie zu umreißen, darunter auch seine Überlegungen zum Einfluss von Mensch und Tier auf die Ausbreitung von Pflanzen und die Veränderung von Vegetation. Die Einsichten des Gelehrten zur Abhängigkeit Europas von der sogenannten „Neuen Welt“ hinsichtlich der Nahrungsmittel werden ebenso behandelt. So vertrat Humboldt in seinen Ausführungen zum Thema „Was sind Barbaren?“ die These, dass Isolierung von Menschen aus der Gemeinschaft, Elend, Nahrungsmangel, klimatische Ursachen usw. „die Spuren von Zivilisation vertilgen“. Er betonte, dass es nötig sein, in einem weltweiten Wettstreit intellektueller Kräfte die Ressourcenknappheit zu überwinden. N2 - The acquisition of the “American travel diaries” of Alexander von Humboldt in 2014 by the German State Library in Berlin was a major event for the scientific world. As a first step in the scientific evaluation of the recorded observations, measurements and ideas about the geography of plants in Humboldt´s diary, the article outlines the so-called “Cosmos of Humboldt´s interests”. This includes his ideas about the variations of plant species caused by the activities of mankind and also animals. In the article “What are barbarians?”, published in 1826, von Humboldt argued that in order to overcome isolation, human misery, lack of food, climate changes – all forces threatening the decline of civilization – it was necessary to propel a worldwide intellectual contest to overcome the shortage of the planet’s resources. KW - Amerikanische Reisetagebücher KW - Naturgeschichte KW - Pflanzengeographie Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-86975 SN - 1617-5239 SN - 2568-3543 VL - XVI IS - 30 SP - 84 EP - 98 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Lundberg, Karin T1 - Networking knowledge BT - considering Alexander von Humboldt‘s legacy in a new shared space in education JF - HiN : Alexander von Humboldt im Netz ; International Review for Humboldtian Studies N2 - Global citizenship and diversity are well-represented concepts in today’s higher education. Learning outcomes and competencies are designed to sensitize students to the many cultural backgrounds of U.S. learning institutions. Nevertheless, true globality, as represented through diverse discourses and perspectives of the world, still seems neglected in curricula and course assignments. This article explores the possibilities offered through a new shared space in education where different forms of networked knowledge and multifaceted perspectives can build a global platform of exchange in a diverse student population. The universal science concept described by Alexander von Humboldt at the beginning of the 19th Century illuminates this intertwined approach to knowledge of the world, which has the potential to positively impact contemporary curricula and course design. Von Humboldt’s writings emphasize inclusion and interplay among cultures and natural phenomena. By inviting our students to be active representatives of diverse discourses, these interconnecting links will become more transparent. In turn, productive forms of knowing about the world may enrich current learning objectives and thereby reflect a true global citizenship as it evolves in a new shared space of education. Keywords: global citizenship, plurality, diverse discourses, multicultural education. N2 - Weltbürgerschaft und kulturelle Vielfalt sind überall gegenwärtige Konzepte im heutigen Bildungswesen. In den Vereinigten Staaten werden Lernziele und Kompetenzen geformt, um die Studenten gegenüber den vielen kulturellen Hintergründen, die in den Bildungsinstitutionen vorzutreffen sind, zu sensibilisieren.Trotzdem wird wahre Globalität, wie sie heute in den vielfältigen Diskursen und Perspektiven der Welt repräsentiert ist, immer noch in Lehrplänen und Studienarbeiten vernachlässigt. Dieser Artikel untersucht die Möglichkeiten, die sich heute im Bildungswesen durch den neuen, gemeinsam geteilten, globalen Bildungsraum anbieten, in dem die multikulturelle Studentenbevölkerung verschiedene Formen vernetzten Wissens und facettenreiche Perspektiven der Welt eine globale Plattform des Austausches bildet. Das von Alexander von Humboldt am Anfang des neunzehnten Jahrhunderts beschriebene universale Wissenschaftskonzept, beleuchtet solch einen vernetzten Ansatz an ein Wissen um die Welt, der auf heutige Bildungskonzepte und Kursdesigns einen positiven Einfluss nehmen könnte. Humboldts Schriften unterstreichen die Bedeutung der Inklusivität und des Wechselspiels zwischen Kulturen und Naturphänomenen. Indem wir Studenten mit unterschiedlichem kulturellen Hintergrundwissen dazu einladen, ihre jeweiligen Diskurse des Wissens aktiv zu repräsentieren, werden diese gegenseitig mit einander verknüpten Beziehungen des Wissens transparenter. Auf diese Weise, entsteht die Möglichkeit, heutige Lernziele mit neuen, produktiven Formen des Weltwissens zu berreichern, worin sich ein wahres Weltbürgertum, wie es sich in diesem neuen Bildungsraum des globalen Austausches hervortut, wiederspiegeln würde. N2 - La citoyenneté mondiale et la diversité figurent aujourd’hui parmi les concepts les plus représentés dans les études supérieures. Les résultats de l’apprentissage et les compétences sont conçus pour rendre les étudiants sensibles aux nombreuses origines culturelles des établissements d’instruction des États-Unis. Néanmoins, la vraie globalité, représentée à travers des perspectives et des discours divers, semble être toujours négligée dans les programmes scolaires et les attributions de cours. Dans cet article l’auteur explore les possibilités offertes par un nouvel espace partagé dans le domaine de l’éducation -- une éducation caractérisée d’ailleurs par des formes variées de connaissances atteintes dans des réseaux différents et en des perspectives multiples qui peuvent contribuer à construire une plate-forme globale d’échange dans une population d’étudiants hétérogène. Le concept de la science universelle décrit par Alexander von Humboldt au début du dix-neuvième siècle éclaire cette approche étroitement liée aux connaissances du monde qui a le potentiel d’avoir un impact positif sur les programmes scolaires contemporains et les conceptions des cours. En effet, dans son oeuvre Von Humboldt met l’emphase sur l’importance de l’inclusion et de l’interaction entre les cultures et les phénomènes naturels. En invitant nos étudiants à être des représentants actifs de discours divers, ces liens d’interconnexion leur seront de plus en plus évidents. Par conséquent, il se peut que les objectifs du savoir puissent être enrichis par ces façons différentes de connaître le monde tandis qu’ils réflèteront de plus en plus une véritable citoyenneté mondiale qui évoluera en même temps en réponse à ce nouvel espace partagé dans l’éducation contemporaine. Mots-clés: la citoyenneté mondiale, la pluralité, les discours divers, l’éducation multiculturelle. KW - Erziehung KW - Netzwerke des Wissens Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-86968 SN - 1617-5239 SN - 2568-3543 VL - XVI IS - 30 SP - 78 EP - 83 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Heyd, Thomas T1 - Ascensión al Teide de Alexander von Humboldt JF - HiN : Alexander von Humboldt im Netz ; International Review for Humboldtian Studies N2 - En este breve ensayo propongo que en la ascensión al Teide Alexander von Humboldt pudo adquirir una perspectiva integral, que le sirvió como marco de comunicación científica para aunar la multitud de datos que se había dispuesto a recoger en su breve estancia en la isla. Más aun, de ahí en adelante este marco además le serviría para darle sentido de conjunto a las incontables y diversas informaciones que recogería en los restantes cinco años de viaje. Para poner en evidencia el enfoque de la visita a Tenerife de Humboldt, analizo su relato de la ascensión al Teide suponiendo que está estructurado según los relatos de viajes épicos y peregrinaciones. N2 - In dieser kurzen Abhandlung wird dargelegt, dass Alexander von Humboldt durch die Besteigung des Teide eine integrierende Perspektive erwerben konnte, die ihm als Rahmen wissenschaftlicher Kommunikation dienen würde um die Vielzahl der Daten, welche er sich vorgenommen hatte auf der Insel zu sammeln, zu vereinen. Darüber hinaus wird ihm dieser Rahmen von hier an auch dazu dienen, um den unzähligen und verschiedenartigen Informationen, die er in den verbleibenden fünf Reisejahren sammeln würde, einen einheitlichen Sinn zu geben. Um die Blickrichtung von Humboldts Besuch auf Teneriffa darzulegen, untersuche ich seinen Bericht über die Besteigung des Teide unter der Annahme, dass er den Aufbau epischer Reisen und Pilgerfahrten hat. N2 - In this brief essay I propose that, with the ascent of the Teide, Alexander von Humboldt was able to acquire an integrating perspective that served him as a framework for scientific communication to unify the multitude of data that he had set out to collect during his brief stay on the island. Moreover, thereafter this framework would also serve him to give a unified sense to the countless and diverse kinds of information that he could collect during the remaining five years of travel. To bring out the focus of Humboldt’s visit to Tenerife, I analyse his account of the ascent of the Teide by assuming that it is structured in the manner of the stories of epic journeys and pilgrimages. KW - Bergbesteigung KW - Tenerife KW - Teneriffa KW - Vulkanlandschaften Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-86956 SN - 1617-5239 SN - 2568-3543 VL - XVI IS - 30 SP - 68 EP - 77 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Garrido, Elisa T1 - Arte, ciencia y cultura visual en el atlas pintoresco BT - vista de la Plaza Mayor de Mexico JF - HiN : Alexander von Humboldt im Netz ; International Review for Humboldtian Studies N2 - Lo pintoresco se puede definir como un sentimiento que invita al espectador de una escena particular a reproducirla en un cuadro, algo que permitió a los viajeros del siglo XIX transportar las imágenes como posesiones, especialmente a través de la publicación de un Atlas Pittoresque. Cada una de esas imágenes es un testimonio de los viajes y sus historias cruzadas. Este es el caso de la lámina III, Vista de la Plaza Mayor de México, que forma parte de la obra Vues des Cordillères et Monuments des Peuples Indigènes de l’Amérique, una imagen que ilustra las redes de intercambio que se sucedían entre artistas y científicos a través de los viajes y expediciones. N2 - The picturesque can be explained as a feeling that invites the viewer of a particular scene to be reproduced in a frame, which allowed the travellers to move images as possessions, especially through the publication of the Atlas Pittoresque. Each of these images is a testimony of interlinked travelogues. This is the case of the Plate III, Vue de la Grande Place de Mexico in Vues des Cordillères et Monuments des Peuples Indigènes de l’Amérique, an image illustrating the exchange networks that were happening between artists and scientists through the travels and expeditions. N2 - On peut définir le pittoresque comme un sentiment invitant le spectateur d’une scène particulière à la reproduire dans un tableau, et qui a permis aux voyageurs de transporter les images comme des possessions, particulièrement vers la publication d’un Atlas Pittoresque. Chacune de ces images est un témoignage des voyages et ses histoires croisées. C‘est le cas de la Planche III, Vue de la Grande Place de Mexico, qu’appartiennent aux Vues des Cordillères et Monuments des Peuples Indigènes de l’Amérique, une image représentant des réseaux d‘échanges entre les artistes et les scientifiques vers les voyages et les expéditions. KW - Bildtafeln KW - México KW - Plaza Mayor KW - Reiterstandbild KW - Vues des Cordilleres Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-86949 SN - 1617-5239 SN - 2568-3543 VL - XVI IS - 30 SP - 54 EP - 67 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Buffon, Giuseppe T1 - The Franciscans in Cathay BT - memory of men and places. A Contribution for the genealogy of geographical knowledge of Alexander von Humboldt JF - HiN : Alexander von Humboldt im Netz ; International Review for Humboldtian Studies N2 - The study analyzes the process that leads to the elaboration of the thesis of a continuity between the Medieval Asia mission and the New World mission. This effort, undertaken by the Catholic historiography of the mission during the XIX century, is the result of the impulse provided by Alexander von Humboldt’s studies about the discovery of America (Examen critique). The data about the geography of Asia collected by the missionaries-travelers working in the territory between Karakorum and Khanbalik during the XIII e XIV century reaches Christopher Colombus with the mediation of Roger Bacon, whom Humboldt himself esteems as a true cultural mediator. The conclusion of the article tries to identify reasons and modalities of the secularization of the missionary concept, i.e. the shift from the ideal of the propagation of the Christian message to a prevailing interest for cartography and topography, transformations arranged by a late medieval historiography that introduces into martyrolagia the loca toponomastica. N2 - Lo studio analizza il processo che conduce all’elaborazione della tesi di una continuità tra missione asiatica medievale e missione nel Nuovo Mondo. L’impegno, assunto dalla storiografia missionaria cattolica lungo il corso del XIX secolo, costituisce l’esito dell’impulso proveniente dagli studi svolti da Alexander von Humboldt intorno all’esplorazione delle Americhe (Examen critique). Le informazioni sullo spazio asiatico trasmesse dai missionari operanti durante il XIII e il XIV secolo tra Karakorum e Khanbaliq pervengono a Cristoforo Colombo mediante Ruggero Bacone (Opus majus), che Humlbodt stesso stima mediatore culturale per antonomasia. La parte conclusiva della ricerca si occupa di stabilire modalità e ragioni della secolarizzazione del concetto di missione, cioè del trasferimento all’interesse cartografico dell’anelito alla propagazione del messaggio cristiano fino agli estremi confini della terra, trasformazione predisposta dalla storiografia medievale che nei martirologia inserisce appunto i loca toponomastici. N2 - El estudio analiza el proceso que conduce a la elaboración de la tesis sobre una posible continuidad entre la misión asiática medieval y la misión en el Nuevo Mundo. El empeño, asumido por parte de la historiografía misionera católica a lo largo del siglo XIX, constituye el resultado del impulso proveniente de los estudios desarrollados por Alexander von Humboldt en torno a la exploración de las Américas (Examen critique). Las informaciones sobre el espacio asiático transmitidas por los misioneros que operaron durante los siglos XIII y XIV entre Karakorum y Khanbaliq llegan a Cristobal Colón a través de Roger Bacon (Opus majus), que el mismo Humboldt considera como un mediador cultural por antonomasia. La parte conclusiva de la investigación se dedica a establecer las modalidades y regiones de la secularización del concepto de misión, es decir, de la transferencia al interés cartográfico del anhelo por la propagación del mensaje cristiano hasta los extremos confines de la tierra, una transformación que fue predispuesta por la historiografía medieval que en los martirologios insertaba los lugares toponímicos. KW - examen critique KW - Franziskaner KW - Kolonialgeschichte KW - Kolonialismus KW - Kolumbus KW - Ordensgeschichte Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-86920 SN - 1617-5239 SN - 2568-3543 VL - XVI IS - 30 SP - 13 EP - 28 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Schwarz, Ingo T1 - „Uebrigens verbleibe ich mit besonderer Werthschätzung Euer gnädiger König“ BT - zum Briefwechsel Alexander von Humboldts mit Friedrich Wilhelm III. im September 1804 JF - HiN : Alexander von Humboldt im Netz ; International Review for Humboldtian Studies KW - Briefedition und -korrespondenz KW - Briefwechsel KW - Friedrich Wilhelm III. KW - Paris Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-86913 SN - 1617-5239 SN - 2568-3543 VL - XVI IS - 30 SP - 7 EP - 12 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Grözinger, Elvira T1 - Benjamin M. Grilj (Hrsg.): Schwarze Milch. Zurückgehaltene Briefe aus den Todeslagern Transnistriens / rezensiert von Elvira Grözinger JF - PaRDeS : Zeitschrift der Vereinigung für Jüdische Studien [21 (2015)] = Jesus in den Jüdischen Kulturen des 19. und 20. Jahrhunderts JF - PaRDeS : Journal of the Association of Jewish Studies [21 (2015)] = Jesus in the Jewish cultures of the 19th and 20th century N2 - Rezensiertes Werk: Benjamin M. Grilj (Hrsg.): Schwarze Milch. Zurückgehaltene Briefe aus den Todeslagern Transnistriens. In Kooperation mit Serhij Osatschuk und Dmytro Zhmundyljak. Innsbruck – Wien – Bozen: Studien Verlag 2013. 1077 S. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-86360 SN - 978-3-86956-331-2 SN - 1614-6492 SN - 1862-7684 VL - 21 SP - 262 EP - 265 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Grözinger, Elvira T1 - Die Verfolgung und Ermordung der europäischen Juden durch das nationalsozialistische Deutschland 1933–1945. Bd. 9: Polen. Generalgouvernement August 1941–1945 / rezensiert von Elvira Grözinger JF - PaRDeS : Zeitschrift der Vereinigung für Jüdische Studien [21 (2015)] = Jesus in den Jüdischen Kulturen des 19. und 20. Jahrhunderts JF - PaRDeS : Journal of the Association of Jewish Studies [21 (2015)] = Jesus in the Jewish cultures of the 19th and 20th century N2 - Rezensiertes Werk: Die Verfolgung und Ermordung der europäischen Juden durch das nationalsozialistische Deutschland 1933–1945. Bd. 9: Polen. Generalgouvernement August 1941–1945. Bearbeitet von Klaus-Peter Friedrich. München: Oldenbourg 2014. 878 S. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-86334 SN - 978-3-86956-331-2 SN - 1614-6492 SN - 1862-7684 VL - 21 SP - 259 EP - 262 PB - Universitätsverlag Potsdam CY - Potsdam ER -