Search Publications

Separating inner and outer contributions in gravitational lenses with the perturbative method

Alard, C.

Context. This paper presents a reconstruction of the gravitational lens SL2S02176-0513 with the singular perturbative method presented in Alard (2007, MNRAS, 382, L58) and Alard (2008, MNRAS, 388, 375).
Aims: The ability of the perturbative method to separate the inner and outer contributions of the potential in gravitational lenses is tested…

A series of plasma flow vortices in the tail plasma sheet associated with solar wind pressure enhancement

Shi, Q. Q.; Fu, S. Y.; Pu, Z. Y. +3 more

A series of earthward-moving (∼140 km/s) plasma flow vortices with anticlockwise (when viewed from above the ecliptic plane) rotation was detected in the dawnside tail plasma sheet between 1255 and 1400 UT on 6 July 2003. These flow vortices were observed under the condition of northward interplanetary magnetic field with an enhanced solar wind dy…

An Analytical Model to Predict the Arrival Time of Interplanetary CMEs

Song, W. B.

Referring to the aerodynamic drag force, we present an analytical model to predict the arrival time of coronal mass ejections (CMEs). All related calculations are based on the expression for the deceleration of fast CMEs in the interplanetary medium (ICMEs), \dot{v}=-1/15 700(v-V_{SW})² , where V_SW is the solar wind speed. Th…

SN 2010U: A Luminous Nova in NGC 4214

Humphreys, Roberta M.; Stanek, K. Z.; Kochanek, Christopher S. +12 more

The luminosity, light curve, post-maximum spectrum, and lack of a progenitor on deep pre-outburst images suggest that SN 2010U was a luminous, fast nova. Its outburst magnitude is consistent with that for a fast nova using the maximum magnitude-rate of decline relationship for classical novae.

Some of the data presented in this Letter were ob…

Influence of the electric field perpendicular to the current sheet on ion beamlets in the magnetotail

Zimbardo, G.; Greco, A.; Dolgonosov, M. S.

Several studies, both experimental, analytical, and numerical, show that a substantial electrostatic field E_z perpendicular to the magnetotail current sheet can be found. This electric field has a typical bipolar structure. We propose a theoretical analysis describing the ion behavior in the vicinity of the current sheet under the influ…

The Influence of Solar Flares on the Lower Solar Atmosphere: Evidence from the Na D Absorption Line Measured by GOLF/SOHO

Kretzschmar, M.; Dudok de Wit, T.; Cessateur, G. +1 more

Solar flares presumably have an impact on the deepest layers of the solar atmosphere and yet the observational evidence for such an impact is scarce. Using ten years of measurements of the Na D₁ and Na D₂ Fraunhofer lines, measured by GOLF onboard SOHO, we show that this photospheric line is indeed affected by flares. The eff…

Asymmetry in the bipolar signatures of flux transfer events

Milan, S. E.; Fear, R. C.; Raeder, J. +1 more

Several conceptual models have been proposed for the formation of flux transfer events (FTEs), including models based on reconnection at a single reconnection line (X line) and at multiple X lines. Two-dimensional magnetohydrodynamic models have previously been used to simulate both scenarios and have found a tendency for FTEs generated by single …

X-ray Observation of AM Herculis in a Very Low State with Suzaku

Mukai, K.; Bamba, A.; Terada, Y. +3 more

The X-ray observation of AM Herculis (AM Her) in a very low state was performed with Suzaku in 2008 October. One flare event with a timescale of ~3700 s was detected at the X-ray luminosity of 6.0 × 10²⁹ erg s^-1 in the 0.5-10 keV band at the assumed distance of 91 pc. The X-ray spectrum is represented by a thermal plasma emis…

XMM-Newton Detection of a Transient X-ray Source in the Vicinity of V838 Monocerotis

Soker, Noam; Bond, Howard E.; Kastner, Joel H. +5 more

We report the XMM-Newton/EPIC detection in 2008 March of a luminous (L_X ~ 10^32-33 erg s^-1), variable X-ray source in the vicinity (within ~6'') of the enigmatic star V838 Mon, which underwent a spectacular outburst in early 2002. Spectral modeling of the XMM-Newton X-ray source indicates the presence of two plasma …

New photometry and astrometry of the isolated neutron star RX J0720.4-3125 using recent VLT/FORS observations

Neuhäuser, R.; Schmidt, T. O. B.; Ginski, C. +3 more

Since the first optical detection of RX J0720.4-3125 various observations have been performed to determine astrometric and photometric data. We present the first detection of the isolated neutron star in the V Bessel filter to study the spectral energy distribution and derive a new astrometric position. At ESO Paranal we obtained very deep images …