Search Publications
About the p-mode frequency shifts in HD 49933
García, R. A.; Mathur, S.; Ballot, J. +2 more
We study the frequency dependence of the frequency shifts of the low-degree p modes measured in the F5V star HD 49933, by analyzing the second run of observations collected by the CoRoT satellite. The 137-day light curve is divided into two subseries corresponding to periods of low and high stellar activity. The activity-frequency relationship is …
1ES 0229+200: an extreme blazar with a very high minimum Lorentz factor
Tibolla, O.; Hauser, M.; Wagner, S. J. +1 more
The blazar 1ES 0229+200 is a high-frequency-peaked BL Lac object with a hard TeV spectrum extending to 10TeV. Its unusual spectral characteristics make it a frequently used probe for intergalactic radiation and magnetic fields. With new, simultaneous observations in the optical, ultraviolet (UV), and X-rays, the synchrotron emission is probed in g…
Plasma Diagnostics of an EIT Wave Observed by Hinode/EIS and SDO/AIA
Temmer, M.; Veronig, A. M.; Vršnak, B. +4 more
We present plasma diagnostics of an Extreme-Ultraviolet Imaging Telescope (EIT) wave observed with high cadence in Hinode/Extreme-Ultraviolet Imaging Spectrometer (EIS) sit-and-stare spectroscopy and Solar Dynamics Observatory/Atmospheric Imaging Assembly imagery obtained during the HOP-180 observing campaign on 2011 February 16. At the propagatin…
Far-infrared to millimeter astrophysical dust emission. II. Comparison of the two-level systems (TLS) model with astronomical data
Bernard, J. -P.; Paradis, D.; Mény, C. +1 more
Aims: In a previous paper we proposed a new model for the emission by amorphous astronomical dust grains, based on solid-state physics. The model uses a description of the disordered charge distribution (DCD) combined with the presence of two-level systems (TLS) defects in the amorphous solid composing the grains. The goal of this paper is to…
Weak- and strong-lensing analyses of the triaxial matter distribution of Abell 1689
Umetsu, Keiichi; Sereno, Mauro
Haloes formed in the standard Λ cold dark matter framework should follow a universal mass density profile and fit a well-defined mass-concentration relation. Lensing analyses of clusters with a large Einstein radius seem to contradict this scenario, with the massive cluster Abell 1689 being often claimed as a notable example of a highly over-conce…
A New Census of the Variable Star Population in the Globular Cluster NGC 2419
Di Criscienzo, M.; Clementini, G.; Ripepi, V. +6 more
We present B, V, and I CCD light curves for 101 variable stars belonging to the globular cluster NGC 2419, 60 of which are new discoveries, based on data sets obtained at the Telescopio Nazionale Galileo, the Subaru telescope, and the Hubble Space Telescope. The sample includes 75 RR Lyrae stars (38 RRab, 36 RRc, and one RRd), one Population II Ce…
Spatially and Spectrally Resolved Observations of a Zebra Pattern in a Solar Decimetric Radio Burst
Chen, Bin; Jing, Ju; Gary, D. E. +1 more
We present the first interferometric observation of a zebra-pattern radio burst with simultaneous high spectral (≈1 MHz) and high time (20 ms) resolution. The Frequency-Agile Solar Radiotelescope Subsystem Testbed (FST) and the Owens Valley Solar Array (OVSA) were used in parallel to observe the X1.5 flare on 2006 December 14. By using OVSA to cal…
The broad iron Kα line of Cygnus X-1 as seen by XMM-Newton in the EPIC-pn modified timing mode
Reynolds, C. S.; Nowak, M. A.; Dauser, T. +7 more
We present the analysis of the broadened, flourescent iron Kα line in simultaneous XMM-Newton and RXTE data from the black hole Cygnus X-1. The XMM-Newton data were taken in a modified version of the timing mode of the EPIC-pn camera. In this mode the lower energy threshold of the instrument is increased to 2.8 keV to avoid telemetry drop outs due…
ARTEMIS Science Objectives
Russell, C. T.; Khurana, K. K.; Eastwood, J. P. +17 more
NASA's two spacecraft ARTEMIS mission will address both heliospheric and planetary research questions, first while in orbit about the Earth with the Moon and subsequently while in orbit about the Moon. Heliospheric topics include the structure of the Earth's magnetotail; reconnection, particle acceleration, and turbulence in the Earth's magnetosph…
Back and forth from cool core to non-cool core: clues from radio halos
Rossetti, M.; Molendi, S.; Gastaldello, F. +3 more
X-ray astronomers often divide galaxy clusters into two classes: "cool core" (CC) and "non-cool core" (NCC) objects. The origin of this dichotomy has been the subject of debate in recent years, between "evolutionary" models (where clusters can evolve from CC to NCC, mainly through mergers) and "primordial" models (where the state of the cluster is…