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Full-Text Articles in Physical Sciences and Mathematics
Magnetic Ob[A] Stars With Tess: Probing Their Evolutionary And Rotational Properties (Mobster) – I. First-Light Observations Of Known Magnetic B And A Stars, A. David-Uraz, C. Neiner, J. Sikora, D. M. Bowman, V. Petit, S. Chowdhury, G. Handler, M. Pergeorelis, M. Cantiello, David H. Cohen, C. Erba, Z. Keszthelyi, V. Khalack, O. Kobzar, O. Kochukhov, J. Labadie-Bartz, C. C. Lovekin, R. Macinnis, S. P. Owocki, H. Pablo, M. E. Shultz, A. Ud-Doula, G. A. Wade, Mobster Collaboration
Magnetic Ob[A] Stars With Tess: Probing Their Evolutionary And Rotational Properties (Mobster) – I. First-Light Observations Of Known Magnetic B And A Stars, A. David-Uraz, C. Neiner, J. Sikora, D. M. Bowman, V. Petit, S. Chowdhury, G. Handler, M. Pergeorelis, M. Cantiello, David H. Cohen, C. Erba, Z. Keszthelyi, V. Khalack, O. Kobzar, O. Kochukhov, J. Labadie-Bartz, C. C. Lovekin, R. Macinnis, S. P. Owocki, H. Pablo, M. E. Shultz, A. Ud-Doula, G. A. Wade, Mobster Collaboration
Physics & Astronomy Faculty Works
In this paper we introduce the MOBSTER collaboration and lay out its scientific goals. We present first results based on the analysis of 19 previously known magnetic O, B, and A stars observed in 2-min cadence in sectors 1 and 2 of the Transiting Exoplanet Survey Satellite (TESS) mission. We derive precise rotational periods from the newly obtained light curves and compare them to previously published values. We also discuss the overall photometric phenomenology of the known magnetic massive and intermediate-mass stars and propose an observational strategy to augment this population by taking advantage of the high-quality observations produced by …
Extreme Resonance Line Profile Variations In The Ultraviolet Spectra Of Ngc 1624-2: Probing The Giant Magnetosphere Of The Most Strongly Magnetized Known O-Type Star, A. David-Uraz, C. Erba, V. Petit, A. W. Fullerton, F. Martins, N. R. Walborn, R. Macinnis, R. H. Barbá, David H. Cohen, J. Maíz Apellániz, Y. Nazé, S. P. Owocki, J. O. Sundqvist, A Ud-Doula, G. A. Wade
Extreme Resonance Line Profile Variations In The Ultraviolet Spectra Of Ngc 1624-2: Probing The Giant Magnetosphere Of The Most Strongly Magnetized Known O-Type Star, A. David-Uraz, C. Erba, V. Petit, A. W. Fullerton, F. Martins, N. R. Walborn, R. Macinnis, R. H. Barbá, David H. Cohen, J. Maíz Apellániz, Y. Nazé, S. P. Owocki, J. O. Sundqvist, A Ud-Doula, G. A. Wade
Physics & Astronomy Faculty Works
In this paper, we present high-resolution HST/COS observations of the extreme magnetic O star NGC 1624-2. These represent the first ultraviolet spectra of this archetypal object. We examine the variability of its wind-sensitive resonance lines, comparing it to that of other known magnetic O stars. In particular, the observed variations in the profiles of the C iv and Si iv doublets between low state and high state are the largest observed in any magnetic O-type star, consistent with the expected properties of NGC 1624-2’s magnetosphere. We also observe a redshifted absorption component in the low state, a feature not seen …
Magnetic Massive Stars As Progenitors Of ‘Heavy’ Stellar-Mass Black Holes, V. Petit, Z. Keszthelyi, R. Macinnis, David H. Cohen, R. H. D. Townsend, G. A. Wade, S. L. Thomas, S. P. Owocki, J. Puls, A. Ud-Doula
Magnetic Massive Stars As Progenitors Of ‘Heavy’ Stellar-Mass Black Holes, V. Petit, Z. Keszthelyi, R. Macinnis, David H. Cohen, R. H. D. Townsend, G. A. Wade, S. L. Thomas, S. P. Owocki, J. Puls, A. Ud-Doula
Physics & Astronomy Faculty Works
The groundbreaking detection of gravitational waves produced by the inspiralling and coalescence of the black hole (BH) binary GW150914 confirms the existence of ‘heavy’ stellar-mass BHs with masses >25 M⊙. Initial characterization of the system by Abbott et al. supposes that the formation of BHs with such large masses from the evolution of single massive stars is only feasible if the wind mass-loss rates of the progenitors were greatly reduced relative to the mass-loss rates of massive stars in the Galaxy, concluding that heavy BHs must form in low-metallicity (Z ≲ 0.25-0.5 Z⊙) environments. However, strong surface magnetic fields also …
A Jvla Survey Of The High-Frequency Radio Emission Of The Massive Magnetic B- And O-Type Stars, S. Kurapati, P. Chandra, G. Wade, David H. Cohen, A. David-Uraz, M. Gagne, J. Grunhut, M. E. Oksala, V. Petit, M. Shultz, J. Sundqvist, R. H. D. Townsend, A. Ud-Doula
A Jvla Survey Of The High-Frequency Radio Emission Of The Massive Magnetic B- And O-Type Stars, S. Kurapati, P. Chandra, G. Wade, David H. Cohen, A. David-Uraz, M. Gagne, J. Grunhut, M. E. Oksala, V. Petit, M. Shultz, J. Sundqvist, R. H. D. Townsend, A. Ud-Doula
Physics & Astronomy Faculty Works
We conducted a survey of seven magnetic O-type stars and eleven B-type stars with masses above 8 M⊙ using the Very Large Array in the 1, 3 and 13 cm bands. The survey resulted in a detection of two O- and two B-type stars. While the detected O-type stars – HD 37742 and HD 47129 – are in binary systems, the detected B-type stars, HD 156424 and ALS 9522, are not known to be in binaries. All four stars were detected at 3 cm, whereas three were detected at 1 cm and only one star was detected at 13 cm. …
The Mimes Survey Of Magnetism In Massive Stars: Introduction And Overview, G. A. Wade, C. Neiner, E. Alecian, J. H. Grunhut, V. Petit, B. De Batz, D. A. Bohlender, David H. Cohen, H. F. Heinrichs, O. Kochukhov, J. D. Landstreet, N. Manset, F. Martins, S. Mathis, M. E. Oksala, S. P. Owocki, T. Rivinius, M. E. Shultz, J. O. Sundqvist, R. H. D. Townsend, A. Ud-Doula, J.-C. Bouret, J. Braithwaite, M. Briquet, A. C. Carciofi, A. David-Uraz, C. P. Folsom, A. W. Fullerton, B. Leroy, W. L. F. Marcolino, A. F. J. Moffat, Y. Nazé, N. St Louis, M. Aurière, S. Bagnulo, J. D. Bailey, R. H. Barbá, A. Blazère, T. Böhm, C. Catala, J.-F. Donati, L. Ferrario, D. Harrington, I. D. Howarth, R. Ignace, L. Kaper, T. Lüftinger, R. Prinja, J. S. Vink, W. W. Weiss, I. Yakunin
The Mimes Survey Of Magnetism In Massive Stars: Introduction And Overview, G. A. Wade, C. Neiner, E. Alecian, J. H. Grunhut, V. Petit, B. De Batz, D. A. Bohlender, David H. Cohen, H. F. Heinrichs, O. Kochukhov, J. D. Landstreet, N. Manset, F. Martins, S. Mathis, M. E. Oksala, S. P. Owocki, T. Rivinius, M. E. Shultz, J. O. Sundqvist, R. H. D. Townsend, A. Ud-Doula, J.-C. Bouret, J. Braithwaite, M. Briquet, A. C. Carciofi, A. David-Uraz, C. P. Folsom, A. W. Fullerton, B. Leroy, W. L. F. Marcolino, A. F. J. Moffat, Y. Nazé, N. St Louis, M. Aurière, S. Bagnulo, J. D. Bailey, R. H. Barbá, A. Blazère, T. Böhm, C. Catala, J.-F. Donati, L. Ferrario, D. Harrington, I. D. Howarth, R. Ignace, L. Kaper, T. Lüftinger, R. Prinja, J. S. Vink, W. W. Weiss, I. Yakunin
Physics & Astronomy Faculty Works
The MiMeS (Magnetism in Massive Stars) project is a large-scale, high-resolution, sensitive spectropolarimetric investigation of the magnetic properties of O- and early B-type stars. Initiated in 2008 and completed in 2013, the project was supported by three Large Program allocations, as well as various programmes initiated by independent principal investigators, and archival resources. Ultimately, over 4800 circularly polarized spectra of 560 O and B stars were collected with the instruments ESPaDOnS (Echelle SpectroPolarimetric Device for the Observation of Stars) at the Canada–France–Hawaii Telescope, Narval at the Télescope Bernard Lyot and HARPSpol at the European Southern Observatory La Silla 3.6 m …
X-Ray Emission From The Giant Magnetosphere Of The Magnetic O-Type Star Ngc 1624-2, V. Petit, David H. Cohen, G. A. Wade, Y. Nazé, S. P. Owocki, J. O. Sundqvist, A. Ud-Doula, A. Fullerton, M. Leutenegger, M. Gagné
X-Ray Emission From The Giant Magnetosphere Of The Magnetic O-Type Star Ngc 1624-2, V. Petit, David H. Cohen, G. A. Wade, Y. Nazé, S. P. Owocki, J. O. Sundqvist, A. Ud-Doula, A. Fullerton, M. Leutenegger, M. Gagné
Physics & Astronomy Faculty Works
We observed NGC 1624-2, the O-type star with the largest known magnetic field (Bp ∼ 20 kG), in X-rays with the Advanced CCD Imaging Spectrometer (ACIS-S) camera on-board the Chandra X-ray Observatory. Our two observations were obtained at the minimum and maximum of the periodic Hα emission cycle, corresponding to the rotational phases where the magnetic field is the closest to equator-on and pole-on, respectively. With these observations, we aim to characterize the star's magnetosphere via the X-ray emission produced by magnetically confined wind shocks. Our main findings are as follows. (i) The observed spectrum of NGC 1624-2 is hard, …
Detection Of 610-Mhz Radio Emission From Hot Magnetic Stars, P. Chandra, G. A. Wade, J. O. Sundqvist, D. Oberoi, J. H. Grunhut, A. Ud-Doula, V. Petit, David H. Cohen, M. E. Oksala, A. David-Uraz
Detection Of 610-Mhz Radio Emission From Hot Magnetic Stars, P. Chandra, G. A. Wade, J. O. Sundqvist, D. Oberoi, J. H. Grunhut, A. Ud-Doula, V. Petit, David H. Cohen, M. E. Oksala, A. David-Uraz
Physics & Astronomy Faculty Works
We have carried out a study of radio emission from a small sample of magnetic O- and B-type stars using the Giant Metrewave Radio Telescope, with the goal of investigating their magnetospheres at low frequencies. These are the lowest frequency radio measurements ever obtained of hot magnetic stars. The observations were taken at random rotational phases in the 1390 and the 610 MHz bands. Out of the eight stars, we detect five B-type stars in both the 1390 and the 610 MHz bands. The three O-type stars were observed only in the 1390 MHz band, and no detections were obtained. …
Confirming Hd 23478 As A New Magnetic B Star Hosting An Hα-Bright Centrifugal Magnetosphere, J. Sikora, G. A. Wade, D. A. Bohlender, C. Neiner, M. E. Oksala, M. Shultz, David H. Cohen, A. Ud-Doula, J. Grunhut, D. Monin, S. Owocki, V. Petit, T. Rivinus, R. H. D. Townsend
Confirming Hd 23478 As A New Magnetic B Star Hosting An Hα-Bright Centrifugal Magnetosphere, J. Sikora, G. A. Wade, D. A. Bohlender, C. Neiner, M. E. Oksala, M. Shultz, David H. Cohen, A. Ud-Doula, J. Grunhut, D. Monin, S. Owocki, V. Petit, T. Rivinus, R. H. D. Townsend
Physics & Astronomy Faculty Works
In this paper, we report 23 magnetic field measurements of the B3IV star HD 23478: 12 obtained from high-resolution Stokes V spectra using the ESPaDOnS (Canada–France–Hawaii Telescope) and Narval (Télescope Bernard Lyot) spectropolarimeters, and 11 from medium-resolution Stokes V spectra obtained with the DimaPol spectropolarimeter (Dominion Astronomical Observatory). HD 23478 was one of two rapidly rotating stars identified as potential ‘centrifugal magnetosphere’ hosts based on IR observations from the Apache Point Observatory Galactic Evolution Experiment survey. We derive basic physical properties of this star including its mass (M=6.1+0.8−0.7M⊙), effective temperature (Teff = 20 ± 2 kK), radius (R=2.7+1.6−0.9R⊙), and age …