Search Publications
XMM-Newton observation of 4U 1820-30. Broad band spectrum and the contribution of the cold interstellar medium
Waters, L. B. F. M.; Kaastra, J. S.; Costantini, E. +6 more
We present an analysis of the bright X-ray binary 4U 1820-30, thet is based mainly on XMM-Newton-RGS data, in addition to complementary data from XMM-Newton-EPIC-pn, INTEGRAL, and Chandra-HETG, to investigate different aspects of the source. The broad band continuum is fitted well by a classical combination of black body and Comptonized emission. …
Instantaneous Starburst of the Massive Clusters Westerlund 1 and NGC 3603 YC
Henning, Thomas; Da Rio, Nicola; Gennaro, Mario +9 more
We present a new method to determine the age spread of resolved stellar populations in a starburst cluster. The method relies on a two-step process. In the first step, kinematic members of the cluster are identified based on multi-epoch astrometric monitoring. In the second step, a Bayesian analysis is carried out, comparing the observed photometr…
Herschel/HIFI Discovery of HCl+ in the Interstellar Medium
Falgarone, E.; Godard, B.; Teyssier, D. +12 more
The radical ion HCl+, a key intermediate in the chlorine chemistry of the interstellar gas, has been identified for the first time in the interstellar medium with the Herschel Space Observatory's Heterodyne Instrument for the Far-Infrared. The ground-state rotational transition of H35Cl+, 2Π3/2
Binaries among Debris Disk Stars
Zuckerman, B.; Rodriguez, David R.
We have gathered a sample of 112 main-sequence stars with known debris disks. We collected published information and performed adaptive optics observations at Lick Observatory to determine if these debris disks are associated with binary or multiple stars. We discovered a previously unknown M-star companion to HD 1051 at a projected separation of …
A study of X-ray flares - II. RS CVn-type binaries
Pandey, J. C.; Singh, K. P.
We present an analysis of seven flares detected from five RS CVn-type binaries (UZ Lib, σ Gem, λ And, V711 Tau and EI Eri) observed with XMM-Newton observatory. The quiescent state X-ray luminosities in the energy band of 0.3-10.0 keV of these stars were found to be 1030.7-30.9 erg s-1. The exponential decay time in all the s…
Optical Emission of the Ultraluminous X-Ray Source NGC 5408 X-1: Donor Star or Irradiated Accretion Disk?
Kaaret, P.; Tao, L.; Corbel, S. +3 more
We obtained three epochs of simultaneous Hubble Space Telescope (HST)/Wide Field Camera 3 and Chandra observations of the ultraluminous X-ray source (ULX) NGC 5408 X-1. The counterpart of the X-ray source is seen in all HST filters, from the UV through the near-IR (NIR), and for the first time, we resolve the optical nebula around the ULX. We iden…
Extensive surface pedogenic alteration of the Martian Noachian crust suggested by plateau phyllosilicates around Valles Marineris
Jaumann, R.; Quantin, Cathy; Le Deit, Laetitia +6 more
Thousands of phyllosilicate-rich outcrops, mainly iron or magnesium-rich are exposed on Noachian terrains in the Martian southern highlands. We analyzed 90 CRISM observations and more than a hundred HiRISE images located on the plateaus surrounding Valles Marineris. We mapped an extensive Al- and Fe/Mg-phyllosilicate-rich formation covering at lea…
Gas sloshing, cold fronts, Kelvin-Helmholtz instabilities and the merger history of the cluster of galaxies Abell 496
Ghizzardi, S.; Lovisari, L.; Brüggen, M. +4 more
We investigate the origin and nature of the multiple sloshing cold fronts in the core of Abell 496 by direct comparison between observations and dedicated hydrodynamical simulations. Our simulations model a minor merger with a 4 × 1013 M⊙ subcluster crossing A496 from the south-west to the north-north-east, passing the cluste…
Forward Cascade of Whistler Turbulence: Three-dimensional Particle-in-cell Simulations
Gary, S. Peter; Chang, Ouliang; Wang, Joseph
This manuscript describes the first ensemble of three-dimensional (3D) particle-in-cell (PIC) plasma simulations of whistler turbulence. The computational model represents a collisionless, homogeneous, magnetized plasma on which an initial spectrum of relatively long wavelength whistler fluctuations is imposed. The simulations represent a range of…
HR 5907: Discovery of the most rapidly rotating magnetic early B-type star by the MiMeS Collaboration
Rivinius, Th.; Wade, G. A.; Bohlender, D. A. +14 more
We report the discovery and analysis of a very strong magnetic field in the rapidly rotating early B-type star HR 5907, based on observations obtained as part of the Magnetism in Massive Stars (MiMeS) project. We infer a rotation period of 0.508 276+0.000 015-0.000 012 d from photometric and Hα EW measurements, making this th…