Search Publications
Geological evolution of Ares Vallis on Mars: Formation by multiple events of catastrophic flooding, glacial and periglacial processes
Komatsu, Goro; Pondrelli, Monica; Pacifici, Andrea
Ares Vallis is one of the greatest outflow channels of Mars. Using high-resolution images of recent missions to Mars (MGS, 2001 Odyssey, and Mars Express), we investigated Ares Vallis and its valley arms, taking advantage of 3-dimensional analysis performed using the high-resolution stereo capability of the Mars Express High Resolution Stereo Came…
Cluster and Double Star multipoint observations of a plasma bubble
Zhang, T. L.; Dandouras, I.; Lucek, E. +14 more
Depleted flux tubes, or plasma bubbles, are one possible explanation of bursty bulk flows, which are transient high speed flows thought to be responsible for a large proportion of flux transport in the magnetotail. Here we report observations of one such plasma bubble, made by the four Cluster spacecraft and Double Star TC-2 around 14:00 UT on 21 …
Dust Production and Mass Loss in the Galactic Globular Cluster NGC 362
Gordon, Karl D.; Boyer, Martha L.; Meixner, Margaret +14 more
We investigate dust production and stellar mass loss in the Galactic globular cluster NGC 362. Due to its close proximity to the Small Magellanic Cloud (SMC), NGC 362 was imaged with the Infrared Array Camera and Multiband Imaging Photometer cameras onboard the Spitzer Space Telescope as part of the Surveying the Agents of Galaxy Evolution (SAGE-S…
Ocean tides heat Enceladus
Tyler, R. H.
With a young, highly reflective surface and vigorous geological activity, Saturn's tiny moon Enceladus has been one of the most mysterious planetary bodies in the solar system. Recent observations from the Cassini spacecraft show vast plumes of vapor erupting from geysers near the south pole, and inferred heat fluxes of about 100 mW/m2 for the sam…
Discovery of the orbital period in the supergiant fast X-ray transient IGR J17544-2619
Hill, A. B.; Bird, A. J.; Scaringi, S. +3 more
The supergiant fast X-ray transient (SFXT) system IGR J17544-2619 has displayed many large outbursts in the past and is considered an archetypal example of SFXTs. A search of the INTEGRAL/ISGRI data archive from MJD 52698-54354 has revealed 11 outbursts and timing analysis of the light curve identifies a period of 4.926 +/- 0.001d which we interpr…
A Universal Luminosity Function for Radio Supernova Remnants
Chomiuk, Laura; Wilcots, Eric M.
We compile radio supernova remnant (SNR) samples from the literature for 19 nearby galaxies ranging from the SMC to Arp 220, and use this data to constrain the SNR luminosity function (LF) at 20 cm. We find that radio SNR populations are strikingly similar across galaxies. The LF can be described as a power law with constant index and scaling prop…
Metal abundances in the cool cores of galaxy clusters
Molendi, S.; de Grandi, S.
We use XMM-Newton data to carry out a detailed study of the Si, Fe and Ni abundances in the cool cores of a representative sample of 26 local clusters. We performed a careful evaluation of the systematic uncertainties related to the instruments, the plasma codes and the spectral modeling, finding that the major source of uncertainty is the plasma …
Three-Dimensional Magnetohydrodynamic Models of Twisted Multithreaded Coronal Loop Oscillations
Ofman, L.
The multithreaded structure of active region coronal loops was deduced from past spectroscopic observations. Recent high-resolution observations by Transition Region and Coronal Explorer and Hinode satellites provided direct evidence that active region loops consist of multiple magnetic threads filled with plasma with higher density than neighbori…
The blazar S5 0014+813: a real or apparent monster?
Ghirlanda, G.; Ghisellini, G.; Tavecchio, F. +4 more
A strong hard X-ray luminosity from a blazar flags the presence of a very powerful jet. If the jet power is in turn related to the mass accretion rate, the most luminous, hard X-ray blazars should pinpoint the largest accretion rates, and thus the largest black hole masses. These ideas are confirmed by the Swift satellite observations of the blaza…
Statistical equilibrium of silicon in the atmospheres of metal-poor stars
Zhao, G.; Mashonkina, L.; Shi, J. R. +1 more
Aims: The statistical equilibrium of neutral and ionized silicon in the atmospheres of metal-poor stars is discussed. Non-local thermodynamic equilibrium effects (NLTE) are investigated and the silicon abundances in metal-poor stars determined.
Methods: We have used high resolution, high signal to noise ratio spectra from the UVES spectragraph…