Search Publications
The GM Values of Mimas and Tethys and the Libration of Methone
Porco, C. C.; Jacobson, R. A.; Spitale, J. +1 more
We have determined the GM of the Saturnian satellite Mimas from an analysis of its resonance with Tethys and with the newly discovered satellite Methone (GM is the product of the Newtonian constant of gravitation G and the satellite's mass M). Observations of the latter permit a factor of 5 improvement in our knowledge of Mimas's GM; its value is …
Absolute parameters of the Algol binary V505 Sgr from infrared JK light curves
Arévalo, M. J.; Lázaro, C.; Antonopoulou, E.
We present the first light curves of V505 Sgr in the infrared (IR) J and K bands. The light curves are analysed with a code based on Roche geometry and stellar model atmosphere fluxes in order to determine a new set of stellar and orbital parameters. From the visual-IR photometry we find no evidence of IR excess in the system. We study the effect …
X-Ray Number Counts of Normal Galaxies
Zezas, A.; Georgakakis, A.; Georgantopoulos, I. +2 more
We use the number counts of X-ray-selected normal galaxies to explore their evolution by combining the most recent wide-angle shallow and pencil-beam deep samples available. The differential X-ray number counts, dN/dS, for early- and late-type normal galaxies are constructed separately and then compared with the predictions of the local X-ray lumi…
A search for stellar X-ray sources in the Sagittarius and Carina dwarf galaxies. I. X-ray observations
Ramsay, G.; Wu, K.
ROSAT observations found no convincing evidence for X-ray sources located in local dwarf spheroidal galaxies (dSph). Now with more sensitive instruments on board Chandra and XMM-Newton we can reach fainter luminosity levels. We report on an observation of the Sagittarius (Sgr) dSph made using Chandra and an observation of the Carina (Car) dSph mad…
XMM-Newton and Chandra observations of the ultra-compact binary RX J1914 + 24
Cropper, Mark; Ramsay, Gavin; Hakala, Pasi
The nature of the X-ray source RX J1914 + 24 has been the subject of much debate. It shows a prominent period of 569 s in X-rays and the optical/infrared: in most models this has been interpreted as the binary orbital period. We present our analysis of new XMM-Newton and Chandra data. We find a longer term trend in the XMM-Newton data and power at…
Rapidly moving sources of upper band ELF/VLF chorus near the magnetic equator
Pickett, J. S.; Inan, U. S.; Platino, M. +2 more
Multiple simultaneous wideband (Gurnett et al., 2001) measurements on the Cluster spacecraft of upper band chorus emissions near the magnetic equator (at magnetic latitudes between -20° and 10° and L shells ranging between L = 4 and L = 5) are used to deduce the properties of the compact source regions of ELF/VLF chorus emissions. The frequency di…
Magnetic turbulence in space plasmas: in and around the Earth's magnetosphere
Zimbardo, Gaetano
In collisionless space plasmas most phenomena are governed by wave particle interaction and by the interaction with the large scale fields. Low frequency magnetic turbulence in the solar wind is relatively well characterized and understood. The situation is more complicated for magnetic turbulence in and around the Earth's magnetosphere, where the…
Multi-point study of the magnetotail current sheet
Nakamura, R.; Baumjohann, W.; Runov, A.
This review summarizes the magnetotail current sheet observations by the Cluster spacecraft during July-October 2001. Due to four-point measurements and the tetrahedron configuration of the spacecraft constellation we are able to separate spatial and temporal variations and to estimate gradients and characteristic scales of structures in the curre…
Dynamical Masses of the Components in o Andromedae
Cvetković, Z.; Olević, D.
It has been shown in earlier papers that o And is a quadruple star. Based on spectroscopic observations, Hill and coworkers calculated the orbital elements for a binary, assigning it to the B component. We have calculated the orbital elements for the subsystems Aa-B and Aa using speckle interferometry measurements. The individual masses of the o A…
The EUV Unresolved Corona
Martens, P. C. H.; Weber, Mark; Cirtain, Jonathan +1 more
The unresolved corona for three active regions (ARs) above the solar limb is investigated. Intensities measured for ions formed above 1 MK are presented as a function of height above the solar surface. The observed decrease in intensity with altitude is found to be best fit by an exponential. Furthermore, this exponential decrease is approximately…