Search Publications
The Low-Mass Initial Mass Function of the Field Population in the Large Magellanic Cloud with Hubble Space Telescope WFPC2 Observations
Henning, Th.; Brandner, W.; Gouliermis, D.
We present V- and I-equivalent HST WFPC2 stellar photometry of an area in the Large Magellanic Cloud (LMC), located to the west of the bar of the galaxy, which accounts for the general background field of its inner disk. The WFPC2 observations reach magnitudes as faint as V=25 mag, and the large sample of more than 80,000 stars allows us to determ…
Kinetic signatures during a quasi-continuous lobe reconnection event: Cluster Ion Spectrometer (CIS) observations
Lundin, R.; Balogh, A.; Dandouras, I. +10 more
On 3 December 2001 the Cluster spacecraft observed a long-lasting lobe reconnection event in the southern high-latitude dusk magnetopause (MP) tailward of the cusp, during a 4 hour interval of mainly northward interplanetary magnetic field (IMF) and of sub-Alfvénic magnetosheath flow. Almost all the MP encounters have accelerated flows (for which …
UBVI CCD Photometry of the Old Open Cluster Berkeley 17
Chaboyer, Brian; Krusberg, Zosia A. C.
Photometric UBVI CCD photometry is presented for NGC 188 and Berkeley 17. Color-magnitude diagrams (CMDs) are constructed and reach well past the main-sequence turnoff for both clusters. Cluster ages are determined by means of isochrone fitting to the cluster CMDs. These fits are constrained to agree with spectroscopic metallicity and reddening es…
Astrometry of Saturn's Satellites from the Hubble Space Telescope WFPC2
French, R. G.; Verbiscer, A.; McGhee, C. A. +4 more
Highly accurate astrometric positions of 14 of Saturn's satellites have been obtained from 444 Hubble Space Telescope images taken with the Wide Field Planetary Camera 2 (WFPC2) between 1996 and 2005. In all, 1036 satellite positions were measured in Planetary Camera (PC) frames, with a typical uncertainty of σPC=0.014" (80 km at Saturn…
Cluster satellite observations of mHz pulsations in the dayside magnetosphere
Glassmeier, K. -H.; Blomberg, L. G.; Eriksson, P. T. I.
On 17 August 2002 the Cluster spacecraft moved through the dayside magnetosphere. Between 16:00 and 18:30 UT clear monochromatic oscillations are seen in both electric field and magnetometer data. The frequency is 4.2 mHz in the spacecraft frame of reference. The oscillations have a clear spatial localisation. The magnetic field oscillations are r…
Observational evidence for AGN fueling: I. The case of NGC 6104â€''Merging with a companion
Moiseev, A. V.; Afanasiev, V. L.; Smirnova, A. A.
We investigate in detail the kinematics and morphology of the Seyfert galaxy NGC 6104 in order to identify the mechanism of gas transportation to the active galactic nucleus (AGN). Our observational data were obtained at the 6-m Special Astrophysical Observatory telescope with the MPFS integral-field spectrograph and the SCORPIO universal device i…
Energetic nitrogen ions within the inner magnetosphere of Saturn
Johnson, R. E.; Paranicas, C.; Sittler, E. C. +9 more
We investigate the importance of nitrogen ions within Saturn's magnetosphere and their contribution to the energetic charged particle population within Saturn's inner magnetosphere. This study is based on the Voyager observations of Saturn's magnetosphere and Cassini observations. The latter have shown that water group ions dominate both the plasm…
Three Gravitational Lenses for the Price of One: Enhanced Strong Lensing through Galaxy Clustering
McKean, J. P.; Treu, T.; Blandford, R. D. +7 more
We report the serendipitous discovery of two strong gravitational lens candidates (ACS J160919+6532 and ACS J160910+6532) in deep images obtained with the Advanced Camera for Surveys on the Hubble Space Telescope, each less than 40" from the previously known gravitational lens system CLASS B1608+656. The redshifts of both lens galaxies have been m…
Energy-dispersed ions in the plasma sheet boundary layer and associated phenomena: Ion heating, electron acceleration, Alfvén waves, broadband waves, perpendicular electric field spikes, and auroral emissions
Dandouras, I.; Lucek, E.; Fazakerley, A. N. +8 more
Recent Cluster studies reported properties of multiple energy-dispersed ion structures in the plasma sheet boundary layer (PSBL) that showed substructure with several well separated ion beamlets, covering energies from 3 keV up to 100 keV (Keiling et al., 2004a, b). Here we report observations from two PSBL crossings, which show a number of identi…
The ZZ Ceti star G 185-32: new insight from asteroseismology
Pech, D.; Vauclair, G.
One of the brightest pulsating DA white dwarfs (ZZ Ceti stars), G 185-32, shows 19 periods in its power spectrum, from 71 s to 651 s. Its short periods are among the shortest ones observed in a ZZ Ceti star. The one at 141.9 s shows an amplitude which does not vary with wavelength, in contrast with what the linear theory predicts for ℓ=1 or ℓ=2 no…