Search Publications
A Comparative Study of Jovian Anticyclone Properties from a Six-Year (1994-2000) Survey
Colas, F.; Lecacheux, J.; Morales-Juberías, Raúl +1 more
We have used the Hubble Space Telescope archived images of Jupiter for the period 1994-2000, complemented by ground-based telescopic observations, to study in detail the long-term properties of synoptic-scale anticyclonic vortices (size > 1500 km, lifetime > months). We have also analyzed a set of Voyager 1 and 2 images obtained in 1979 to c…
XMM-Newton Observations of a Possible Light Echo in the Seyfert 1 Nucleus of NGC 4051
Maraschi, L.; Page, M. J.; Uttley, P. +6 more
We discuss a 1.5 day long observation of the bright variable Seyfert 1 galaxy NGC 4051 that was obtained with the X-ray and ultraviolet telescopes on XMM-Newton and extended in the X-ray band using the Rossi X-Ray Timing Explorer. The ultraviolet (2900 Å) and X-ray (2-10 keV) light curves varied with peak-to-peak amplitudes of 5% and a factor of ~…
Narrow-Angle Astrometry with the Space Interferometry Mission: The Search for Extrasolar Planets. I. Detection and Characterization of Single Planets
Sozzetti, A.; Lattanzi, M. G.; Casertano, S. +1 more
A decade after the publication of the Hipparcos Catalogue, the Space Interferometry Mission (SIM) will be capable of making selected high-precision astrometric measurements about 3 orders of magnitude more accurate than the Hipparcos survey. We present results from a detailed set of end-to-end numerical simulations of SIM narrow-angle astrometric …
The Discovery of a 2.78 Hour Periodic Modulation of the X-Ray Flux from Globular Cluster Source Bo 158 in M31
Mason, Keith O.; Watson, Michael G.; Cordova, France A. +4 more
We report the discovery of periodic intensity dips in the X-ray source XMMU J004314.1+410724, in the globular cluster Bo 158 in M31. The X-ray flux was modulated by ~83% at a period of 2.78 hr (10,017 s) in an XMM-Newton observation taken 2002 January 6-7. The X-ray intensity dips show no energy dependence. We detected weaker dips with the same pe…
A telescopic and microscopic view of a magnetospheric substorm on 31 March 2001
Mitchell, D. G.; Daly, P. W.; Baker, D. N. +6 more
On March 31, 2001 at ~0635 UT when the CLUSTER constellation was near local midnight and at ~4 RE geocentric distance, sensors observed an energetic electron injection event associated with a strong (AE ~ 1200 nT) magnetospheric substorm. Geostationary spacecraft 1991-080 located at ~20 LT also saw an abrupt electron injection event at …
The Structure and Stellar Content of the Central Region of M33
Frogel, Jay A.; Stephens, Andrew W.
Using Gemini QuickStart infrared observations of the central 22" of M33, we analyze the stellar populations in this controversial region. Based on the slope of the giant branch we estimate the mean metallicity to be -0.26+/-0.27, and from the luminosities of the most luminous stars, we estimate that there were two bursts of star formation, ~2 and …
Sudden Disappearance of a Small Sunspot Associated with the 2002 February 20 M2.4 Flare
Liu, Chang; Qiu, Jiong; Wang, Haimin +3 more
In this Letter, we present the evidence of rapid disappearance of a small sunspot associated with a M2.4 flare, which occurred in NOAA Active Region 9830, at 2106 UT, on 2002 February 20. The sunspot, in the size of about 45 arcsec2, completely disappeared in about 60 minutes, coinciding with the onset of the flare. The magnetic flux of…
Huygens Probe Aerosol Collector Pyrolyser Experiment
Israel, G.; Steller, M.; Riedler, W. +6 more
ACP's main objective is the chemical analysis of the aerosols in Titan's atmosphere. For this purpose, it will sample the aerosols during descent and prepare the collected matter (by evaporation, pyrolysis and gas products transfer) for analysis by the Huygens Gas Chromatograph Mass Spectrometer (GCMS). A sampling system is required for sampling t…
Cool White Dwarfs in Cataclysmic Variables: Hubble Space Telescope Results on EG Cancri and HV Virginis
Szkody, Paula; Howell, Steve B.; Sion, Edward M. +1 more
Our Hubble Space Telescope (HST) ultraviolet spectra of the low mass transfer rate cataclysmic variables EG Cnc and HV Vir at 4 yr and 8 yr past their last superoutburst have shown that the white dwarfs in these systems are among the coolest yet observed in disk-accreting close binaries. The UV-optical fluxes of EG Cnc are consistent with a 11,700…
Formation of the Three-Ring Structure Around Supernova 1987A
Tanaka, T.; Washimi, H.
From a magnetohydrodynamic simulation, we reproduce a three-ring structure in the circumstellar space of the supernova (SN) 1987A observed by the Hubble Space Telescope. When a star develops from a red supergiant (RSG) to a blue supergiant (BSG) just before the SN explosion, a wind-wind interaction occurs between the slow stellar wind from the RSG…