TY - JOUR A1 - Schöller, Markus A1 - Hubrig, Swetlana A1 - Fossati, L. A1 - Carroll, Thorsten Anthony A1 - Briquet, Maryline A1 - Oskinova, Lida A1 - Järvinen, S. A1 - Ilyin, Ilya A1 - Castro, N. A1 - Morel, T. A1 - Langer, N. A1 - Przybilla, N. A1 - Nieva, M. -F. A1 - Kholtygin, A. F. A1 - Sana, H. A1 - Herrero, A. A1 - Barba, R. H. A1 - de Koter, A. T1 - B fields in OB stars (BOB) BT - Concluding the FORS2 observing campaign JF - Astronomy and astrophysics : an international weekly journal N2 - Aims. The B fields in OB stars (BOB) Collaboration is based on an ESO Large Programme to study the occurrence rate, properties, and ultimately the origin of magnetic fields in massive stars. Methods. In the framework of this program, we carried out low-resolution spectropolarimetric observations of a large sample of massive stars using FORS2 installed at the ESO VLT 8m telescope. Results. We determined the magnetic field values with two completely independent reduction and analysis pipelines. Our in-depth study of the magnetic field measurements shows that differences between our two pipelines are usually well within 3 sigma errors. From the 32 observations of 28 OB stars, we were able to monitor the magnetic fields in CPD -57 degrees 3509 and HD164492C, confirm the magnetic field in HD54879, and detect a magnetic field in CPD -62 degrees 2124. We obtain a magnetic field detection rate of 6 +/- 3% for the full sample of 69 OB stars observed with FORS 2 within the BOB program. For the preselected objects with a nu sin i below 60 km s(-1), we obtain a magnetic field detection rate of 5 +/- 5%. We also discuss X-ray properties and multiplicity of the objects in our FORS2 sample with respect to the magnetic field detections. KW - polarization KW - stars: early-type KW - stars: magnetic field KW - stars: massive Y1 - 2017 U6 - https://doi.org/10.1051/0004-6361/201628905 SN - 1432-0746 VL - 599 PB - EDP Sciences CY - Les Ulis ER - TY - JOUR A1 - Hubrig, Swetlana A1 - Kholtygin, A. A1 - Ilyin, Ilya A1 - Schöller, M. A1 - Oskinova, Lida T1 - THE FIRST SPECTROPOLARIMETRIC MONITORING OF THE PECULIAR O4 Ief SUPERGIANT zeta PUPPIS JF - The astrophysical journal : an international review of spectroscopy and astronomical physics N2 - The origin of the magnetic field in massive O-type stars is still under debate. To model the physical processes responsible for the generation of O star magnetic fields, it is important to understand whether correlations between the presence of a magnetic field and stellar evolutionary state, rotation velocity, kinematical status, and surface composition can be identified. The O4 Ief supergiant zeta Pup is a fast rotator and a runaway star, which may be a product of a past binary interaction, possibly having had an encounter with the cluster Trumper 10 some 2 Myr ago. The currently available observational material suggests that certain observed phenomena in this star may be related to the presence of a magnetic field. We acquired spectropolarimetric observations of zeta Pup with FORS 2 mounted on the 8 m Antu telescope of the Very Large Telescope to investigate if a magnetic field is indeed present in this star. We show that many spectral lines are highly variable and probably vary with the recently detected period of 1.78 day. No magnetic field is detected in zeta Pup, as no magnetic field measurement has a significance level higher than 2.4 sigma. Still, we studied the probability of a single sinusoidal explaining the variation of the longitudinal magnetic field measurements. KW - stars: atmospheres KW - stars: early-type KW - stars: individual (zetaPup) KW - stars: magnetic field KW - stars: variables: general Y1 - 2016 U6 - https://doi.org/10.3847/0004-637X/822/2/104 SN - 0004-637X SN - 1538-4357 VL - 822 PB - IOP Publ. Ltd. CY - Bristol ER - TY - GEN A1 - Morel, T. A1 - Castro, Norberto A1 - Fossati, Luca A1 - Hubrig, Swetlana A1 - Langer, N. A1 - Przybilla, Norbert A1 - Schöller, Markus A1 - Carroll, Thorsten Anthony A1 - Ilyin, Ilya A1 - Irrgang, Andreas A1 - Oskinova, Lida A1 - Schneider, Fabian R. N. A1 - Simon Díaz, Sergio A1 - Briquet, Maryline A1 - González, Jean-Francois A1 - Kharchenko, Nina A1 - Nieva, M.-F. A1 - Scholz, Ralf-Dieter A1 - de Koter, Alexander A1 - Hamann, Wolf-Rainer A1 - Herrero, Artemio A1 - Maíz Apellániz, Jesus A1 - Sana, Hugues A1 - Arlt, Rainer A1 - Barbá, Rodolfo H. A1 - Dufton, Polly A1 - Kholtygin, Alexander A1 - Mathys, Gautier A1 - Piskunov, Anatoly E. A1 - Reisenegger, Andreas A1 - Spruit, H. A1 - Yoon, S.-C. T1 - The B fields in OB stars (BOB) survey T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - The B fields in OB stars (BOB) survey is an ESO large programme collecting spectropolarimetric observations for a large number of early-type stars in order to study the occurrence rate, properties, and ultimately the origin of magnetic fields in massive stars. As of July 2014, a total of 98 objects were observed over 20 nights with FORS2 and HARPSpol. Our preliminary results indicate that the fraction of magnetic OB stars with an organised, detectable field is low. This conclusion, now independently reached by two different surveys, has profound implications for any theoretical model attempting to explain the field formation in these objects. We discuss in this contribution some important issues addressed by our observations (e.g., the lower bound of the field strength) and the discovery of some remarkable objects. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 821 KW - magnetic fields KW - stars: early-type KW - stars: magnetic fields KW - stars: individual (HD 164492C, CPD –57 ◦ 3509, HD 54879, β CMa, ε CMa) Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-415238 SN - 1866-8372 IS - 821 ER -