TY  - JOUR
A1  - Sugawara, Y.
A1  - Tsuboi, Y.
A1  - Maeda, Y.
A1  - Pollock, A. M. T.
A1  - Williams, P. M.
T1  - The Swift monitoring of the colliding wind binary WR 21a
JF  - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015
N2  - The X-ray observations of the colliding wind binary WR 21a is reported. The first monitoring performed by Swift/XRT in order to reveal the phase-locked variation. Our observations cover 201 different epochs from 2013 October 1 to 2015 January 30 for a total exposure of about 306 ks. It is found for the first time that the luminosity varies roughly in inverse proportion to the separation of the two stars before the X-ray maximum but later drops rapidly toward periastron.
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-88517
SP  - 366
ER  - 
TY  - JOUR
A1  - Russell, C. M. P.
A1  - Corcoran, M. F.
A1  - Cuadra, J.
A1  - Owocki, S. P.
A1  - Wang, Q. D.
A1  - Hamaguchi, K.
A1  - Sugawara, Y.
A1  - Pollock, A. M. T.
A1  - Kallman, T. R.
T1  - Hydrodynamic and radiative transfer modeling of X-ray emission from colliding WR winds
BT  - WR 140 & the Galactic center
JF  - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015
N2  - Colliding Wolf-Rayet (WR) winds produce thermal X-ray emission widely observed by X-ray telescopes. In wide WR+O binaries, such as WR 140, the X-ray flux is tied to the orbital phase, and is a direct probe of the winds’ properties. In the Galactic center, ~30 WRs orbit the super massive black hole (SMBH) within ~10”, leading to a smorgasbord of wind-wind collisions. To model the X-ray emission of WR 140 and the Galactic center, we perform 3D hydrodynamic simulations to trace the complex gaseous flows, and then carry out 3D radiative transfer calculations to compute the variable X-ray spectra. The model WR 140 RXTE light curve matches the data well for all phases except the X-ray minimum associated with periastron, while the model spectra agree with the RXTE hardness ratio and the shape of the Suzaku observations throughout the orbit. The Galactic center model of the Chandra flux and spectral shape match well in the region r ≤ 3”, but the model flux falls off too rapidly beyond this radius.
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-88255
SP  - 309
EP  - 312
ER  - 
TY  - GEN
A1  - Vink, Jorick Sandor
A1  - Heger, Alexander
A1  - Krumholz, Mark R.
A1  - Puls, Joachim
A1  - Banerjee, Shiladitya
A1  - Castro, Norberto
A1  - Chen, K.-J.
A1  - Chenè, A.-N.
A1  - Crowther, P. A.
A1  - Daminelli, A.
A1  - Gräfener, G.
A1  - Groh, J. H.
A1  - Hamann, Wolf-Rainer
A1  - Heap, S.
A1  - Herrero, A.
A1  - Kaper, L.
A1  - Najarro, F.
A1  - Oskinova, Lidia M.
A1  - Roman-Lopes, A.
A1  - Rosen, A.
A1  - Sander, A.
A1  - Shirazi, M.
A1  - Sugawara, Y.
A1  - Tramper, F.
A1  - Vanbeveren, D.
A1  - Voss, R.
A1  - Wofford, A.
A1  - Zhang, Y.
T1  - Very massive stars in the local universe
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - Recent studies have claimed the existence of very massive stars (VMS) up to 300 M⊙ in the local Universe. As this finding may represent a paradigm shift for the canonical stellar upper-mass limit of 150 M⊙, it is timely to discuss the status of the data, as well as the far-reaching implications of such objects. We held a Joint Discussion at the General Assembly in Beijing to discuss (i) the determination of the current masses of the most massive stars, (ii) the formation of VMS, (iii) their mass loss, and (iv) their evolution and final fate. The prime aim was to reach broad consensus between observers and theorists on how to identify and quantify the dominant physical processes.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 601 
KW  - stars: massive stars
KW  - stars: mass-loss
KW  - stars: stellar evolution
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-415220
SN  - 1866-8372
IS  - 601
ER  -