@article{EvansSmarttLeeetal.2005, author = {Evans, C. J. and Smartt, S. J. and Lee, J. K. and Lennon, D. J. and Kaufer, A. and Dufton, P. L. and Trundle, C. and Herrero, A. and Simon D{\´i}az, Sergio and de Koter, A. and Hamann, Wolf-Rainer and Hendry, M. A. and Hunter, I. and Irwin, M. J. and Korn, A. J. and Kudritzki, R. P. and Langer, Norbert and Mokiem, M. R. and Najarro, F. and Pauldrach, A. W. A. and Przybilla, Norbert and Puls, J. and Ryans, R. S. I. and Urbaneja, M. A. and Venn, K. A. and Villamariz, M. R.}, title = {The VLT-FLAMES survey of massive stars : Observations in the Galactic clusters NGC3293, NGC4755 and NGC6611}, year = {2005}, abstract = {We introduce a new survey of massive stars in the Galaxy and the Magellanic Clouds using the Fibre Large Array Multi- Element Spectrograph ( FLAMES) instrument at the Very Large Telescope ( VLT). Here we present observations of 269 Galactic stars with the FLAMES- Giraffe Spectrograph ( R similar or equal to 25 000), in fields centered on the open clusters NGC3293, NGC4755 and NGC6611. These data are supplemented by a further 50 targets observed with the Fibre- Fed Extended Range Optical Spectrograph ( FEROS, R = 48 000). Following a description of our scientific motivations and target selection criteria, the data reduction methods are described; of critical importance the FLAMES reduction pipeline is found to yield spectra that are in excellent agreement with less automated methods. Spectral classifications and radial velocity measurements are presented for each star, with particular attention paid to morphological peculiarities and evidence of binarity. These observations represent a significant increase in the known spectral content of NGC3293 and NGC4755, and will serve as standards against which our subsequent FLAMES observations in the Magellanic Clouds will be compared}, language = {en} } @article{DenglerWagnerDembiczetal.2018, author = {Dengler, J{\"u}rgen and Wagner, Viktoria and Dembicz, Iwona and Garcia-Mijangos, Itziar and Naqinezhad, Alireza and Boch, Steffen and Chiarucci, Alessandro and Conradi, Timo and Filibeck, Goffredo and Guarino, Riccardo and Janisova, Monika and Steinbauer, Manuel J. and Acic, Svetlana and Acosta, Alicia T. R. and Akasaka, Munemitsu and Allers, Marc-Andre and Apostolova, Iva and Axmanova, Irena and Bakan, Branko and Baranova, Alina and Bardy-Durchhalter, Manfred and Bartha, Sandor and Baumann, Esther and Becker, Thomas and Becker, Ute and Belonovskaya, Elena and Bengtsson, Karin and Benito Alonso, Jose Luis and Berastegi, Asun and Bergamini, Ariel and Bonini, Ilaria and Bruun, Hans Henrik and Budzhak, Vasyl and Bueno, Alvaro and Antonio Campos, Juan and Cancellieri, Laura and Carboni, Marta and Chocarro, Cristina and Conti, Luisa and Czarniecka-Wiera, Marta and De Frenne, Pieter and Deak, Balazs and Didukh, Yakiv P. and Diekmann, Martin and Dolnik, Christian and Dupre, Cecilia and Ecker, Klaus and Ermakov, Nikolai and Erschbamer, Brigitta and Escudero, Adrian and Etayo, Javier and Fajmonova, Zuzana and Felde, Vivian A. and Fernandez Calzado, Maria Rosa and Finckh, Manfred and Fotiadis, Georgios and Fracchiolla, Mariano and Ganeva, Anna and Garcia-Magro, Daniel and Gavilan, Rosario G. and Germany, Markus and Giladi, Itamar and Gillet, Francois and Giusso del Galdo, Gian Pietro and Gonzalez, Jose M. and Grytnes, John-Arvid and Hajek, Michal and Hajkova, Petra and Helm, Aveliina and Herrera, Mercedes and Hettenbergerova, Eva and Hobohm, Carsten and Huellbusch, Elisabeth M. and Ingerpuu, Nele and Jandt, Ute and Jeltsch, Florian and Jensen, Kai and Jentsch, Anke and Jeschke, Michael and Jimenez-Alfaro, Borja and Kacki, Zygmunt and Kakinuma, Kaoru and Kapfer, Jutta and Kavgaci, Ali and Kelemen, Andras and Kiehl, Kathrin and Koyama, Asuka and Koyanagi, Tomoyo F. and Kozub, Lukasz and Kuzemko, Anna and Kyrkjeeide, Magni Olsen and Landi, Sara and Langer, Nancy and Lastrucci, Lorenzo and Lazzaro, Lorenzo and Lelli, Chiara and Leps, Jan and Loebel, Swantje and Luzuriaga, Arantzazu L. and Maccherini, Simona and Magnes, Martin and Malicki, Marek and Marceno, Corrado and Mardari, Constantin and Mauchamp, Leslie and May, Felix and Michelsen, Ottar and Mesa, Joaquin Molero and Molnar, Zsolt and Moysiyenko, Ivan Y. and Nakaga, Yuko K. and Natcheva, Rayna and Noroozi, Jalil and Pakeman, Robin J. and Palpurina, Salza and Partel, Meelis and Paetsch, Ricarda and Pauli, Harald and Pedashenko, Hristo and Peet, Robert K. and Pielech, Remigiusz and Pipenbaher, Natasa and Pirini, Chrisoula and Pleskova, Zuzana and Polyakova, Mariya A. and Prentice, Honor C. and Reinecke, Jennifer and Reitalu, Triin and Pilar Rodriguez-Rojo, Maria and Rolecek, Jan and Ronkin, Vladimir and Rosati, Leonardo and Rosen, Ejvind and Ruprecht, Eszter and Rusina, Solvita and Sabovljevic, Marko and Maria Sanchez, Ana and Savchenko, Galina and Schuhmacher, Oliver and Skornik, Sonja and Sperandii, Marta Gaia and Staniaszek-Kik, Monika and Stevanovic-Dajic, Zora and Stock, Marin and Suchrow, Sigrid and Sutcliffe, Laura M. E. and Swacha, Grzegorz and Sykes, Martin and Szabo, Anna and Talebi, Amir and Tanase, Catalin and Terzi, Massimo and Tolgyesi, Csaba and Torca, Marta and Torok, Peter and Tothmeresz, Bela and Tsarevskaya, Nadezda and Tsiripidis, Ioannis and Tzonev, Rossen and Ushimaru, Atushi and Valko, Orsolya and van der Maarel, Eddy and Vanneste, Thomas and Vashenyak, Iuliia and Vassilev, Kiril and Viciani, Daniele and Villar, Luis and Virtanen, Risto and Kosic, Ivana Vitasovic and Wang, Yun and Weiser, Frank and Went, Julia and Wesche, Karsten and White, Hannah and Winkler, Manuela and Zaniewski, Piotr T. and Zhang, Hui and Ziv, Yaron and Znamenskiy, Sergey and Biurrun, Idoia}, title = {GrassPlot - a database of multi-scale plant diversity in Palaearctic grasslands}, series = {Phytocoenologia}, volume = {48}, journal = {Phytocoenologia}, number = {3}, publisher = {Cramer}, address = {Stuttgart}, issn = {0340-269X}, doi = {10.1127/phyto/2018/0267}, pages = {331 -- 347}, year = {2018}, abstract = {GrassPlot is a collaborative vegetation-plot database organised by the Eurasian Dry Grassland Group (EDGG) and listed in the Global Index of Vegetation-Plot Databases (GIVD ID EU-00-003). GrassPlot collects plot records (releves) from grasslands and other open habitats of the Palaearctic biogeographic realm. It focuses on precisely delimited plots of eight standard grain sizes (0.0001; 0.001;... 1,000 m(2)) and on nested-plot series with at least four different grain sizes. The usage of GrassPlot is regulated through Bylaws that intend to balance the interests of data contributors and data users. The current version (v. 1.00) contains data for approximately 170,000 plots of different sizes and 2,800 nested-plot series. The key components are richness data and metadata. However, most included datasets also encompass compositional data. About 14,000 plots have near-complete records of terricolous bryophytes and lichens in addition to vascular plants. At present, GrassPlot contains data from 36 countries throughout the Palaearctic, spread across elevational gradients and major grassland types. GrassPlot with its multi-scale and multi-taxon focus complements the larger international vegetationplot databases, such as the European Vegetation Archive (EVA) and the global database " sPlot". Its main aim is to facilitate studies on the scale-and taxon-dependency of biodiversity patterns and drivers along macroecological gradients. GrassPlot is a dynamic database and will expand through new data collection coordinated by the elected Governing Board. We invite researchers with suitable data to join GrassPlot. Researchers with project ideas addressable with GrassPlot data are welcome to submit proposals to the Governing Board.}, language = {en} } @misc{GvaramadzeKniazevMiroshnichenkoetal.2012, author = {Gvaramadze, V. V. and Kniazev, A. Y. and Miroshnichenko, A. S. and Berdnikov, Leonid N. and Langer, N. and Stringfellow, G. S. and Todt, Helge Tobias and Hamann, Wolf-Rainer and Grebel, E. K. and Buckley, D. and Crause, L. and Crawford, S. and Gulbis, A. and Hettlage, C. and Hooper, E. and Husser, T. -O. and Kotze, P. and Loaring, N. and Nordsieck, K. H. and O'Donoghue, D. and Pickering, T. and Potter, S. and Colmenero, E. Romero and Vaisanen, P. and Williams, T. and Wolf, M. and Reichart, D. E. and Ivarsen, K. M. and Haislip, J. B. and Nysewander, M. C. and LaCluyze, A. P.}, title = {Discovery of two new Galactic candidate luminous blue variables with Wide-field Infrared Survey Explorer}, series = {Monthly notices of the Royal Astronomical Society}, volume = {421}, journal = {Monthly notices of the Royal Astronomical Society}, number = {4}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {0035-8711}, doi = {10.1111/j.1365-2966.2012.20556.x}, pages = {3325 -- 3337}, year = {2012}, abstract = {We report the discovery of two new Galactic candidate luminous blue variable (LBV) stars via detection of circular shells (typical of confirmed and candidate LBVs) and follow-up spectroscopy of their central stars. The shells were detected at 22 mu m in the archival data of the Mid-Infrared All Sky Survey carried out with the Wide-field Infrared Survey Explorer (WISE). Follow-up optical spectroscopy of the central stars of the shells conducted with the renewed Southern African Large Telescope (SALT) showed that their spectra are very similar to those of the well-known LBVs P Cygni and AG Car, and the recently discovered candidate LBV MN112, which implies the LBV classification for these stars as well. The LBV classification of both stars is supported by detection of their significant photometric variability: one of them brightened in the R and I bands by 0.68 +/- 0.10 and 0.61 +/- 0.04 mag, respectively, during the last 1318 years, while the second one (known as Hen 3-1383) varies its B, V, R, I and Ks brightnesses by similar or equal to 0.50.9 mag on time-scales from 10 d to decades. We also found significant changes in the spectrum of Hen 3-1383 on a time-scale of similar or equal to 3 months, which provides additional support for the LBV classification of this star. Further spectrophotometric monitoring of both stars is required to firmly prove their LBV status. We discuss a connection between the location of massive stars in the field and their fast rotation, and suggest that the LBV activity of the newly discovered candidate LBVs might be directly related to their possible runaway status.}, language = {en} } @article{HubrigFossatiCarrolletal.2014, author = {Hubrig, Swetlana and Fossati, Luca and Carroll, Thorsten Anthony and Castro, Norberto and Gonzalez, J. F. and Ilyin, Ilya and Przybilla, Norbert and Schoeller, M. and Oskinova, Lida and Morel, T. and Langer, N. and Scholz, Ralf-Dieter and Kharchenko, N. V. and Nieva, M. -F.}, title = {B fields in OB stars (BOB): The discovery of a magnetic field in a multiple system in the Trifid nebula, one of the youngest star forming regions}, series = {Astronomy and astrophysics : an international weekly journal}, volume = {564}, journal = {Astronomy and astrophysics : an international weekly journal}, publisher = {EDP Sciences}, address = {Les Ulis}, organization = {BOB Collaboration}, issn = {0004-6361}, doi = {10.1051/0004-6361/201423490}, pages = {5}, year = {2014}, abstract = {Aims. Recent magnetic field surveys in O- and B-type stars revealed that about 10\% of the core-hydrogen-burning massive stars host large-scale magnetic fields. The physical origin of these fields is highly debated. To identify and model the physical processes responsible for the generation of magnetic fields in massive stars, it is important to establish whether magnetic massive stars are found in very young star-forming regions or whether they are formed in close interacting binary systems. Methods. In the framework of our ESO Large Program, we carried out low-resolution spectropolarimetric observations with FORS 2 in 2013 April of the three most massive central stars in the Trifid nebula, HD 164492A, HD 164492C, and HD 164492D. These observations indicated a strong longitudinal magnetic field of about 500-600 G in the poorly studied component HD 164492C. To confirm this detection, we used HARPS in spectropolarimetric mode on two consecutive nights in 2013 June. Results. Our HARPS observations confirmed the longitudinal magnetic field in HD 164492C. Furthermore, the HARPS observations revealed that HD 164492C cannot be considered as a single star as it possesses one or two companions. The spectral appearance indicates that the primary is most likely of spectral type B1-B1.5 V. Since in both observing nights most spectral lines appear blended, it is currently unclear which components are magnetic. Long-term monitoring using high-resolution spectropolarimetry is necessary to separate the contribution of each component to the magnetic signal. Given the location of the system HD 164492C in one of the youngest star formation regions, this system can be considered as a Rosetta Stone for our understanding of the origin of magnetic fields in massive stars.}, language = {en} } @article{PrzybillaFossatiHubrigetal.2016, author = {Przybilla, Norbert and Fossati, Luca and Hubrig, Swetlana and Nieva, M. -F. and Jaervinen, S. P. and Castro, Norberto and Schoeller, M. and Ilyin, Ilya and Butler, Keith and Schneider, F. R. N. and Oskinova, Lida and Morel, T. and Langer, N. and de Koter, A.}, title = {B fields in OB stars (BOB): Detection of a magnetic field in the He-strong star CPD-57 degrees 3509}, series = {Organic letters}, volume = {587}, journal = {Organic letters}, publisher = {EDP Sciences}, address = {Les Ulis}, organization = {BOB Collaboratio}, issn = {1432-0746}, doi = {10.1051/0004-6361/201527646}, pages = {15}, year = {2016}, abstract = {Methods. Spectropolarimetric observations with FORS2 and HARPSpol are analysed using two independent approaches to quantify the magnetic field strength. A high-S/N FLAMES/GIRAFFE spectrum is analysed using a hybrid non-LTE model atmosphere technique. Comparison with stellar evolution models constrains the fundamental parameters of the star. Results. We obtain a firm detection of a surface averaged longitudinal magnetic field with a maximum amplitude of about 1 kG. Assuming a dipolar configuration of the magnetic field, this implies a dipolar field strength larger than 3.3 kG. Moreover, the large amplitude and fast variation (within about 1 day) of the longitudinal magnetic field implies that CPD-57 degrees 3509 is spinning very fast despite its apparently slow projected rotational velocity. The star should be able to support a centrifugal magnetosphere, yet the spectrum shows no sign of magnetically confined material; in particular, emission in H alpha is not observed. Apparently, the wind is either not strong enough for enough material to accumulate in the magnetosphere to become observable or, alternatively, some leakage process leads to loss of material from the magnetosphere. The quantitative spectroscopic analysis of the star yields an effective temperature and a logarithmic surface gravity of 23 750 +/- 250 K and 4.05 +/- 0.10, respectively, and a surface helium fraction of 0.28 +/- 0.02 by number. The surface abundances of C, N, O, Ne, S, and Ar are compatible with the cosmic abundance standard, whereas Mg, Al, Si, and Fe are depleted by about a factor of 2. This abundance pattern can be understood as the consequence of a fractionated stellar wind. CPD-57 degrees 3509 is one of the most evolved He-strong stars known with an independent age constraint due to its cluster membership.}, language = {en} } @article{HartmannWaiHuetal.2016, author = {Hartmann, Bianca and Wai, Timothy and Hu, Hao and MacVicar, Thomas and Musante, Luciana and Fischer-Zirnsak, Bj{\"o}rn and Stenzel, Werner and Gr{\"a}f, Ralph and van den Heuvel, Lambert and Ropers, Hans-Hilger and Wienker, Thomas F. and H{\"u}bner, Christoph and Langer, Thomas and Kaindl, Angela M.}, title = {Homozygous YME1L1 Mutation Causes Mitochondriopathy with Optic Atrophy and Mitochondrial Network Fragmentation}, series = {eLife}, volume = {5}, journal = {eLife}, publisher = {eLife Sciences Publications}, address = {Cambridge}, issn = {2050-084X}, doi = {10.7554/eLife.16078}, pages = {1156 -- 1165}, year = {2016}, abstract = {Mitochondriopathies often present clinically as multisystemic disorders of primarily high-energy consuming organs. Assembly, turnover, and surveillance of mitochondrial proteins are essential for mitochondrial function and a key task of AAA family members of metalloproteases. We identified a homozygous mutation in the nuclear encoded mitochondrial escape 1-like 1 gene YME1L1, member of the AAA protease family, as a cause of a novel mitochondriopathy in a consanguineous pedigree of Saudi Arabian descent. The homozygous missense mutation, located in a highly conserved region in the mitochondrial pre-sequence, inhibits cleavage of YME1L1 by the mitochondrial processing peptidase, which culminates in the rapid degradation of YME1L1 precursor protein. Impaired YME1L1 function causes a proliferation defect and mitochondrial network fragmentation due to abnormal processing of OPA1. Our results identify mutations in YME1L1 as a cause of a mitochondriopathy with optic nerve atrophy highlighting the importance of YME1L1 for mitochondrial functionality in humans.}, language = {en} } @article{MusterRileyRothetal.2019, author = {Muster, Sina and Riley, William J. and Roth, Kurt and Langer, Moritz and Aleina, Fabio Cresto and Koven, Charles D. and Lange, Stephan and Bartsch, Annett and Grosse, Guido and Wilson, Cathy J. and Jones, Benjamin M. and Boike, Julia}, title = {Size distributions of arctic waterbodies reveal consistent relations in their statistical moments in space and time}, series = {Frontiers in Earth Science}, volume = {7}, journal = {Frontiers in Earth Science}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, issn = {2296-6463}, doi = {10.3389/feart.2019.00005}, pages = {15}, year = {2019}, abstract = {Arctic lowlands are characterized by large numbers of small waterbodies, which are known to affect surface energy budgets and the global carbon cycle. Statistical analysis of their size distributions has been hindered by the shortage of observations at sufficiently high spatial resolutions. This situation has now changed with the high-resolution (<5 m) circum-Arctic Permafrost Region Pond and Lake (PeRL) database recently becoming available. We have used this database to make the first consistent, high-resolution estimation of Arctic waterbody size distributions, with surface areas ranging from 0.0001 km(2) (100 m(2)) to 1 km(2). We found that the size distributions varied greatly across the thirty study regions investigated and that there was no single universal size distribution function (including power-law distribution functions) appropriate across all of the study regions. We did, however, find close relationships between the statistical moments (mean, variance, and skewness) of the waterbody size distributions from different study regions. Specifically, we found that the spatial variance increased linearly with mean waterbody size (R-2 = 0.97, p < 2.2e-16) and that the skewness decreased approximately hyperbolically. We have demonstrated that these relationships (1) hold across the 30 Arctic study regions covering a variety of (bio)climatic and permafrost zones, (2) hold over time in two of these study regions for which multi-decadal satellite imagery is available, and (3) can be reproduced by simulating rising water levels in a high-resolution digital elevation model. The consistent spatial and temporal relationships between the statistical moments of the waterbody size distributions underscore the dominance of topographic controls in lowland permafrost areas. These results provide motivation for further analyses of the factors involved in waterbody development and spatial distribution and for investigations into the possibility of using statistical moments to predict future hydrologic dynamics in the Arctic.}, language = {en} } @article{FigerNajarroMorisetal.1998, author = {Figer, Donald F. and Najarro, F. and Moris, Mark and Mclean, Ian S. and Geballe, T. R. and Ghez, A. M. and Langer, Norbert}, title = {The Pistol star}, year = {1998}, language = {en} } @article{GarciaSeguraLangerRozyczkaetal.1998, author = {Garcia-Segura, Guillermo and Langer, Norbert and Rozyczka, M. and MacLow, Mordecai-Mark}, title = {The effects of rotation and stellar magnetic fields on the nebular shapes : LBV nebulae and PNe}, year = {1998}, language = {en} } @article{WittkowskiLangerWeigelt1998, author = {Wittkowski, M. and Langer, Norbert and Weigelt, G.}, title = {Diffraction-limited Speckle-Masking interferometry of the red supergiant VY CMa*}, year = {1998}, language = {en} }