Search Publications
Dust depletion and abundance pattern in damped Lyalpha systems: A sample of Mn and Ti abundances at z < 2.2
Petitjean, P.; Bergeron, J.; Ledoux, C.
We analyse a sample of 24 damped Lyman-alpha (DLA)/moderate DLA systems at intermediate redshifts, 0.3<zabs<2.2, all with measurement of the weak Mn II absorption lines, to investigate which elemental ratios could possibly be used as tracers of either dust depletion or nucleosynthesis effects. We applied a component-by-component a…
A Comparison of Solar p-Mode Parameters from the Michelson Doppler Imager and the Global Oscillation Network Group: Splitting Coefficients and Rotation Inversions
Thompson, M. J.; Howe, R.; Komm, R. +7 more
Using contemporaneous helioseismic data from the Global Oscillation Network Group (GONG) and Michelson Doppler Imager (MDI) onboard SOHO, we compare frequency-splitting data and resulting inversions about the Sun's internal rotation. Helioseismology has been very successful in making detailed and subtle inferences about the solar interior. But the…
A wavy twisted neutral sheet observed by CLUSTER
Balogh, A.; Zhang, T. L.; Glassmeier, K. -H. +2 more
From July to October 2001, the Cluster satellites were located within the magnetotail and crossings of the neutral sheet were frequently observed by the FGM instrument [Balogh et al., 2001]. The neutral sheet often appears to be moving relative to the spacecraft. Multiple crossings of the neutral sheet on August 3, 2001 are analysed. These neutral…
Fast flow during current sheet thinning
Balogh, A.; Zhang, T. L.; Klecker, B. +9 more
In this paper we report Cluster observation of a fast flow event in the plasma sheet associated with a small auroral substorm intensification at 1838 UT on August 12, 2001. Cluster, located in the plasma sheet, experienced significant thinning of the current sheet associated with a high-speed Earthward flow of 900 km/s. By using the four spacecraf…
The Faint Optical Afterglow and Host Galaxy of GRB 020124: Implications for the Nature of Dark Gamma-Ray Bursts
Piro, L.; Axelrod, T. S.; Frontera, F. +24 more
We present ground-based optical observations of GRB 020124 starting 1.6 hr after the burst, as well as subsequent Very Large Array and Hubble Space Telescope (HST) observations. The optical afterglow of GRB 020124 is one of the faintest afterglows detected to date, and it exhibits a relatively rapid decay, Fν~t-1.60+/-0.04, f…
Knots in Nearby Planetary Nebulae
O'Dell, C. R.; Balick, B.; Hajian, A. R. +2 more
HST emission-line images of five of the arguably closest planetary nebulae have shown that there is a progression of characteristics of their knots. This progression begins with dark tangential structures showing no alignment with the central star and location near the main ionization front. At the end of the progression in the largest nebulae, th…
Ice features in the mid-IR spectra of galactic nuclei
Lutz, D.; Tielens, A. G. G. M.; Moorwood, A. F. M. +3 more
Mid infrared spectra provide a powerful probe of the conditions in dusty galactic nuclei. They variously contain emission features associated with star forming regions and absorptions by circumnuclear silicate dust plus ices in cold molecular cloud material. Here we report the detection of 6-8 mu m water ice absorption in 18 galaxies observed by I…
On Be star candidates and possible blue pre-main sequence objects in the Small Magellanic Cloud
Mennickent, R. E.; Gieren, W.; Pietrzyński, G. +1 more
Recently the OGLE experiment has provided accurate light curves and colours for about 2 millions stars in the Small Magellanic Cloud. We have examined this database for its content of Be stars, applying some selection criteria, and we have found a sample of ~ 1000 candidates. Some of these stars show beautiful light curves with amazing variations …
The evolving accretion disc in the black hole X-ray transient XTE J1859+226
Chaty, S.; Cui, W.; Shrader, C. R. +2 more
We present HST, RXTE, and UKIRT observations of the broad-band spectra of the black hole X-ray transient XTE J1859+226 during the decline from its 1999-2000 outburst. Our UV spectra define the 2175-Å interstellar absorption feature very well and based on its strength we estimate E(B-V)=0.58+/-0.12. Hence we deredden our spectra and follow the evol…
An observational study of a magneto-acoustic wave in the solar corona
Mathioudakis, M.; Keenan, F. P.; Phillips, K. J. H. +5 more
The Solar Eclipse Corona Imaging System (SECIS) observed a strong 6-s oscillation in an active region coronal loop, during the 1999 August 11 total solar eclipse. In the present paper we show that this oscillation is associated with a fast-mode magneto-acoustic wave that travels through the loop apex with a velocity of 2100 km s-1. We u…