Search Publications
Suzaku Observation of the Metallicity Distribution in the Elliptical Galaxy NGC 4636
Fukazawa, Yasushi; Nishino, Sho; Hayashi, Katsuhiro +4 more
NGC 4636, an X-ray bright elliptical galaxy, was observed for 70 ks with Suzaku. The low background and good energy resolution of the XIS enable us to estimate the foreground Galactic emission accurately and hence measure, for the first time, the O, Mg, Si and Fe abundances out to a radius of ~28 arcmin ($\simeq$ 140 kpc). These metal abundances a…
Shape, size, velocity and field-aligned currents of dayside plasma injections: a multi-altitude study
Pitout, F.; Fazakerley, A. N.; Dunlop, M. W. +3 more
On 20 February 2005, Cluster in the outer magnetosphere and Double Star-2 (TC-2) at mid-altitude are situated in the vicinity of the northern cusp/mantle, with Cluster moving sunward and TC-2 anti-sunward. Their magnetic footprints come very close together at about 15:28 UT, over the common field-of-view of SuperDARN radars. Thanks to this conjunc…
Studying geoeffective interplanetary coronal mass ejections between the Sun and Earth: Space weather implications of Solar Mass Ejection Imager observations
Webb, D. F.; Jackson, B. V.; Fry, C. D. +4 more
Interplanetary coronal mass ejections (ICMEs) are the primary cause of severe space weather at Earth because they drive shocks and trigger geomagnetic storms that can damage spacecraft and ground-based systems. The Solar Mass Ejection Imager (SMEI) is a U. S. Air Force experiment with the ability to track ICMEs in white light from near the Sun to …
G 112-29 (=NLTT 18149): A Very Wide Companion to GJ 282 AB with a Common Proper Motion, Common Parallax, Common Radial Velocity, and Common Age
Costero, R.; Poveda, A.; Echevarría, J. +2 more
We have made a search for common proper motion (CPM) companions to the wide binaries in the solar vicinity. We found that the binary GJ 282AB has a very distant CPM companion (NLTT 18149) at a separation s = 1fdg09. Improved spectral types and radial velocities are obtained, and ages determined for the three components. The Hipparcos trigonometric…
Non-thermal emission in the core of Perseus: results from a long XMM-Newton observation
Molendi, S.; Gastaldello, F.
We employ a long XMM-Newton observation of the core of the Perseus cluster to validate claims of a non-thermal component discovered with Chandra. From a meticulous analysis of our dataset, which includes a detailed treatment of systematic errors, we find the 2-10 keV surface brightness of the non-thermal component to be less than about 5 × 10…
Thermal Conductivity and Element Fractionation in EV Lac
Hwang, Una; Laming, J. Martin
We present a 100 ks Suzaku observation of the dMe flare star EV Lac, in which the star was captured undergoing a moderate 1500 s flare. During the flare, the count rate increased by about a factor of 50 and the spectrum showed overall enhanced element abundances relative to quiescence. While the quiescent element abundances confirm the inverse fir…
The environment of the fast rotating star Achernar. II. Thermal infrared interferometry with VLTI/MIDI
Meilland, A.; Kervella, P.; Domiciano de Souza, A. +3 more
Context: As is the case of several other Be stars, Achernar is surrounded by an envelope, recently detected by near-IR interferometry.
Aims: We search for the signature of circumstellar emission at distances of a few stellar radii from Achernar, in the thermal IR domain.
Methods: We obtained interferometric observations on three VLTI basel…
A simulation study of particle energization observed by THEMIS spacecraft during a substorm
Bosqued, Jean-Michel; El-Alaoui, Mostafa; Zhou, Meng +6 more
Energetic ions with hundreds of keV energy are frequently observed in the near-Earth tail during magnetospheric substorms. We examined the sources and acceleration of ions during a magnetospheric substorm on 1 March 2008 by using Time History of Events and Macroscale Interactions during Substorms (THEMIS) and Cluster observations and numerical sim…
Hydrogen Lyα and Lyβ Radiances and Profiles in Polar Coronal Holes
Teriaca, Luca; Tian, Hui; Curdt, Werner +1 more
The hydrogen Lyα plays a dominant role in the radiative energy transport in the lower transition region, and is important for the studies of transition-region structure as well as solar wind origin. We investigate the Lyα profiles obtained by the Solar Ultraviolet Measurement of Emitted Radiation spectrograph on the Solar and Heliospheric Observat…
Redshifts and lens profile for the double quasar QJ 0158-4325
Kneib, J. -P.; Faure, C.; Alloin, D. +5 more
Aims: We report on the redshift of the lensing galaxy and of the quasar QJ 0158-4325 and on the lens model of the system.
Methods: A deep VLT/FORS2 spectrum and HST/NICMOS-F160W images are deconvolved. From the images we derive the light profile of the lensing galaxy and an accurate relative astrometry for the system. In addition we measure th…