Search Publications
Development of the 3-D MHD model of the solar corona-solar wind combining system
Tanaka, T.; Kubo, Y.; Shinagawa, H. +3 more
In the framework of integrated numerical space weather prediction, we have developed a 3-D MHD simulation model of the solar surface-solar wind system. We report the construction method of the model and its first results. By implementing a grid system with angularly unstructured and increasing radial spacing, we realized a spherical grid that has …
Survey of cold ionospheric outflows in the magnetotail
André, M.; Eriksson, A. I.; Cully, C. M. +4 more
Low-energy ions escape from the ionosphere and constitute a large part of the magnetospheric content, especially in the geomagnetic tail lobes. However, they are normally invisible to spacecraft measurements, since the potential of a sunlit spacecraft in a tenuous plasma in many cases exceeds the energy-per-charge of the ions, and little is theref…
Discovery of a 112 ms X-Ray Pulsar in Puppis A: Further Evidence of Neutron Stars Weakly Magnetized at Birth
Gotthelf, E. V.; Halpern, J. P.
We report the discovery of 112 ms X-ray pulsations from RX J0822-4300, the compact central object (CCO) in the supernova remnant (SNR) Puppis A, in two archival Newton X-Ray Multi-Mirror Mission observations taken in 2001. The sinusoidal light curve has a pulsed fraction of 11% with an abrupt 180° change in phase at 1.2 keV. The observed phase shi…
The C+N+O abundances and the splitting of the subgiant branch in the globular cluster NGC 1851
D'Antona, F.; Ventura, P.; Caloi, V. +3 more
Among the newly discovered features of multiple stellar populations in globular clusters (GCs), the cluster NGC 1851 harbours a double subgiant branch (SGB), that can be explained in terms of two stellar generations, only slightly differing in age, the younger one having an increased total C+N+O abundance. Thanks to this difference in the chemistr…
Fine jet structure of electrically charged grains in Enceladus' plume
Lewis, G. R.; Coates, A. J.; Russell, C. T. +18 more
By traversing the plume erupting from high southern latitudes on Saturn's moon Enceladus, Cassini orbiter instruments can directly sample the material therein. Cassini Plasma Spectrometer, CAPS, data show that a major plume component comprises previously-undetected particles of nanometer scales and larger that bridge the mass gap between previousl…
The Fifth Data Release Sloan Digital Sky Survey/XMM-Newton Quasar Survey
Elvis, M.; Risaliti, G.; Young, M.
We present a catalog of 792 Fifth Data Release Sloan Digital Sky Survey quasars with optical spectra that have been observed serendipitously in the X-rays with the XMM-Newton. These quasars cover a redshift range of z = 0.11-5.41 and a magnitude range of i = 15.3-20.7. Substantial numbers of radio-loud (70) and broad absorption line (51) quasars e…
Size and Shape of Saturn's Moon Titan
Kirk, Randolph L.; Hensley, Scott; Zebker, Howard A. +3 more
Cassini observations show that Saturn’s moon Titan is slightly oblate. A fourth-order spherical harmonic expansion yields north polar, south polar, and mean equatorial radii of 2574.32 ± 0.05 kilometers (km), 2574.36 ± 0.03 km, and 2574.91 ± 0.11 km, respectively; its mean radius is 2574.73 ± 0.09 km. Titan’s shape approximates a hydrostatic, sync…
Altimetry of the Venus cloud tops from the Venus Express observations
Roatsch, Th.; Drossart, P.; Piccioni, G. +6 more
Simultaneous observations of Venus by Visible and Infrared Thermal Imaging Spectrometer and Venus Monitoring Camera onboard the Venus Express spacecraft are used to map the cloud top altitude and to relate it to the ultraviolet (UV) markings. The cloud top altitude is retrieved from the depth of CO2 absorption band at 1.6 µm. In l…
The onset of solar cycle 24. What global acoustic modes are telling us
Jiménez-Reyes, S. J.; García, R. A.; Pallé, P. L. +1 more
We study the response of the low-degree, solar p-mode frequencies to the unusually extended minimum of solar surface activity since 2007. A total of 4768 days of observations collected by the space-based, Sun-as-a-star helioseismic GOLF instrument are analyzed. A multi-step iterative maximum-likelihood fitting method is applied to subseries of 365…
Deep 2MASS Photometry of M67 and Calibration of the Main-Sequence J - KS Color Difference as an Age Indicator
Kirkpatrick, Allison; Dotter, Aaron; Sarajedini, Ata
We present an analysis of Two Micron All Sky Survey (2MASS) calibration photometry of the old open cluster M67 (NGC 2682). The proper-motion-cleaned color-magnitude diagram (CMD) resulting from these data extends ~3 mag deeper than one based on data from the point source catalog. The CMD extends from above the helium-burning red clump to a faint l…