Search Publications
Coronal magnetic field measurement using loop oscillations observed by Hinode/EIS
Young, P. R.; Nakariakov, V. M.; Verwichte, E. +1 more
We report the first spectroscopic detection of a kink MHD oscillation of a solar coronal structure by the Extreme-Ultraviolet Imaging Spectrometer (EIS) on the Japanese Hinode satellite. The detected oscillation has an amplitude of 1 km s-1 in the Doppler shift of the FeXII 195 Å spectral line (1.3~MK), and a period of 296~s. The unique…
Non-LTE line formation for heavy elements in four very metal-poor stars
Zhao, G.; Mashonkina, L.; Aoki, W. +6 more
Aims:Stellar parameters and abundances of Na, Mg, Al, K, Ca, Sr, Ba, and Eu are determined for four very metal-poor (VMP) stars (-2.15 ≥ [Fe/H] ≥ -2.66). For two of them, HD 84937 and HD 122563, the fraction of the odd isotopes of Ba derived for the first time.
Methods: Determination of an effective temperature, surface gravity, and element ab…
A new activity phase of the blazar 3C 454.3 . Multifrequency observations by the WEBT and XMM-Newton in 2007-2008
Lee, C. -U.; Pian, E.; Lähteenmäki, A. +72 more
Aims: The Whole Earth Blazar Telescope (WEBT) consortium has been monitoring the blazar
Methods: We present and analyse the multifrequency results of the 2007-2008 observing season, including XMM-Newton observations and near…
The cosmological properties of AGN in the XMM-Newton Hard Bright Survey
Page, M. J.; Carrera, F. J.; Caccianiga, A. +7 more
Aims: We investigate here the X-ray luminosity function (XLF) of absorbed (NH between 4 × 1021 and 1024 cm-2) and unabsorbed (NH < 4 × 1021 cm-2) AGN, the fraction of absorbed AGN as a function of LX (and z), the intrinsic NH distribution of the A…
Near-infrared mapping and physical properties of the dwarf-planet Ceres
Berthier, J.; Carry, B.; Hestroffer, D. +5 more
Aims:We study the physical characteristics (shape, dimensions, spin axis direction, albedo maps, mineralogy) of the dwarf-planet Ceres based on high angular-resolution near-infrared observations.
Methods: We analyze adaptive optics J/H/K imaging observations of Ceres performed at Keck II Observatory in September 2002 with an equivalent spatial…
Detailed high-energy characteristics of AXP 4U 0142+61. Multi-year observations with INTEGRAL, RXTE, XMM-Newton, and ASCA
Knödlseder, J.; Kuiper, L.; Hermsen, W. +4 more
4U 0142+61 is one of the Anomalous X-ray Pulsars exhibiting hard X-ray emission above 10 keV discovered with INTEGRAL. In this paper we present detailed spectral and temporal characteristics both in the hard X-ray (>10 keV) and soft X-ray (<10 keV) domains obtained using data from INTEGRAL, XMM-Newton, ASCA and RXTE. Accumulating data collec…
Cosmological parameters from strong gravitational lensing and stellar dynamics in elliptical galaxies
Grillo, C.; Lombardi, M.; Bertin, G.
Context: Observations of the cosmic microwave background, light element abundances, large-scale distribution of galaxies, and distant supernovae are the primary tools for determining the cosmological parameters that define the global structure of the Universe.
Aims: Here we illustrate how the combination of observations related to strong gravi…
A synchrotron self-Compton scenario for the very high energy γ-ray emission of the radiogalaxy M 87. Unifying the TeV emission of blazars and other AGNs?
Boisson, C.; Sol, H.; Katarzyński, K. +1 more
Context: M 87 is the first extragalactic source detected in the TeV range that is not a blazar. With the increasing performances of ground-based Čerenkov telescopes, we can now probe the variability in the γ-ray flux on small timescales, thus putting strong constraints on the size of the emitting zone. The large scale jet of M 87 is misaligned wit…
Hinode EUV spectroscopic observations of coronal oscillations
Erdélyi, R.; Taroyan, Y.
Context: Waves offer a unique opportunity to understand and diagnose the properties of the solar coronal plasma.
Aims: Hinode/EIS observations are analysed to detect wave and oscillatory motions in the solar corona.
Methods: The EIS observations were carried out using a selection of EUV lines. Hinode/XRT images are taken concurrently.
…
Discovery of a bipolar X-ray jet from the T Tauri star DG Tauri
Audard, M.; Güdel, M.; Briggs, K. R. +2 more
Aims:We have obtained and analyzed Chandra ACIS-S observations of the strongly accreting classical T Tauri star DG Tau. Our principal goals are to map the immediate environment of the star to characterize possible extended X-rays formed in the jet, and to re-visit the anomalous, doubly absorbed X-ray spectrum of DG Tau itself.
Methods: We comb…