Search Publications
Substorm expansion triggered by a sudden impulse front propagating from the dayside magnetopause
Dandouras, I.; Nakamura, R.; Lucek, E. A. +12 more
We examine a substorm expansion on 21 June 2007, which occurred <2 min after a solar wind discontinuity accompanied by a dynamic pressure (P d ) increase impinged on the magnetopause. To investigate how the perturbation due to such P d increase propagates in the magnetosphere and what the timing analysis may imply about…
Revealing the fastest component of the DG Tauri outflow through X-rays
Günther, H. M.; Matt, S. P.; Li, Z. -Y.
Context: Some T Tauri stars show a peculiar X-ray spectrum that can be modelled by two components with different absorbing column densities.
Aims: We seek to explain the soft X-ray component in DG Tau, the best studied of these sources, with an outflow model, taking observations at other wavelengths into consideration.
Methods: We constrai…
Spitzer Observations of a Gravitationally Lensed Quasar, QSO 2237+0305
Gorjian, Varoujan; Agol, Eric; Gogarten, Stephanie M. +1 more
The four-image gravitationally lensed quasar QSO 2237+0305 is microlensed by stars in the lens galaxy. The amplitude of microlensing variability can be used to infer the relative size of the quasar as a function of wavelength; this provides a test of quasar models. Toward this end, we present Spitzer Space Telescope Infrared Spectrograph and Infra…
A spectroscopic survey of EC4, an extended cluster in Andromeda's halo
Tanvir, N.; Mackey, A. D.; Martin, N. F. +8 more
We present a spectroscopic survey of candidate red giant branch stars in the extended star cluster, EC4, discovered in the halo of M31 from our Canada-France-Hawaii Telescope/MegaCam survey, overlapping the tidal streams, Streams`Cp' and `Cr'. These observations used the DEep Imaging Multi-Object Spectrograph mounted on the Keck II telescope to ob…
Swift follow-up observations of 17 INTEGRAL sources of uncertain or unknown nature
Chaty, S.; Tomsick, J. A.; Rodriguez, J.
Context: The positional accuracy of the IBIS telescope on-board INTEGRAL, albeit unprecedented in the >20 keV range, is still not good enough to identify many hard X-ray sources discovered by INTEGRAL. This indeed prevents counterparts from being found at other wavelengths, which is the only way to unveil the true nature of these sources.
A…
Relativistic Rings due to Schwarzschild Gravitational Lensing
Bisnovatyi-Kogan, G. S.; Tsupko, O. Yu.
Long-lived auroral structures and atmospheric losses through auroral flux tubes on Mars
Barabash, S.; Lundin, R.; Woch, J. +2 more
The ASPERA-3 observations of electron and ion fluxes over the regions dominated by crustal magnetic fields show the existence of long-lived and active aurora-type magnetic flux tubes with a width of 20-150 km. The activity manifests itself by large electron energy fluxes (≥10-4 W/m2) and strong distortions in the upper (350-4…
Nonlinear Development of Shocklike Structure in the Solar Wind
Parks, G. K.; Lin, N.; Lee, E. +1 more
We report first in situ multispacecraft observations of nonlinear steepening of compressional pulses in the solar wind upstream of Earth’s bow shock. The magnetic field of a compressional pulse formed at the upstream edge of density holes is shown to suddenly break and steepen into a shocklike structure. During the early phase of development therm…
X-Ray Reflection Nebulae with Large Equivalent Widths of the Neutral Iron Kα Line in the Sagittarius C Region
Koyama, Katsuji; Nakajima, Hiroshi; Matsumoto, Hironori +5 more
This paper reports on the first results of a Suzaku observation in the Sgr C region. We detected four diffuse clumps with strong line emission at 6.4keV, Kα from neutral or low-ionized Fe. One of them, M359.38-0.00, was newly discovered with Suzaku. The X-ray spectra of the two bright clumps, M359.43-0.07 and M359.47-0.15, after subtracting the ga…
Fully 3-dimensional calculations of dust mantle formation for a model of Comet 67P/Churyumov-Gerasimenko
Rosenberg, Eric D.; Prialnik, Dina
A fully 3-dimensional implicit numerical model for comet nucleus evolution is presented, emphasizing dust mantle formation. A spherical configuration is considered with an initial composition of amorphous H 2O ice and dust, taking into account a discrete dust-grain size distribution. The model is applied to Comet 67P/Churyumov-Gerasimen…