Search Publications
Albedo models for the residual south polar cap on Mars: Implications for the stability of the cap under near-perihelion global dust storm conditions
Bjorkman, Jon E.; James, Philip B.; Bonev, Boncho P. +2 more
It is uncertain whether the residual (perennial) south polar cap on Mars is a transitory or a permanent feature in the current Martian climate. While there is no firm evidence for complete disappearance of the cap in the past, clearly observable changes have been documented. Observations suggest that the perennial cap lost more CO 2 mat…
Least-squares multi-spacecraft gradient calculation with automatic error estimation
de Keyser, J.
Multi-spacecraft missions allow the gradient of important physical quantities in the terrestrial environment to be determined. The gradient can be computed from four simultaneous measurements in a straightforward way, but this computation does not produce proper error estimates, making it hard to assess the meaningfulness of the result. Recently d…
Observational Biases Masquerading as Cosmological Effects? a Cautionary tale about Blue Tilts and Other Trends in Globular Cluster Systems
Kundu, Arunav
The high spatial resolution of the Hubble Space Telescope (HST) has led to tremendous progress in many areas of astronomy. The ability of the HST to peer into the bright inner regions of galaxies and distinguish between globular clusters (GCs) and background objects has been particularly beneficial to the study of clusters. However, the very virtu…
Venus Express observations of an atypically distant bow shock during the passage of an interplanetary coronal mass ejection
Russell, C. T.; Zhang, T. L.; Glassmeier, K. -H. +10 more
On 10-11 September 2006 the Venus Express magnetometer detected a very strong Interplanetary Coronal Mass Ejection (ICME) event with an average field about 2 times higher than that of a typical ICME at 0.72 AU. While the effective obstacle to the solar wind is compressed to a smaller dimension during this ICME event, the bow shock is located far u…
Ultra-low-frequency waves and associated wave vectors observed in the plasma sheet boundary layer by Cluster
Glassmeier, K. -H.; RèMe, H.; Keiling, A. +5 more
Waves in the Pc1-Pc2 frequency range (0.1-5 Hz) are studied using Cluster magnetic field data. In the plasma sheet boundary layer, Cluster observed harmonically related waves with the fundamental near the local proton cyclotron frequency (Ωp). These waves had components both parallel and perpendicular to the local magnetic field (B…
The most rapidly rotating He-strong emission line star: HR 7355
Baade, D.; Rivinius, T.; Townsend, R. H. D. +1 more
Aims: We searched for massive stars with Balmer emission consistent with magnetically confined circumstellar material.
Methods: Archival spectroscopic and photometric data were investigated.
Results:
Time dependent model of the interplanetary Lyman α glow: applications to the SWAN data
Izmodenov, V.; Quémerais, E.; Koutroumpa, D. +1 more
Aims: Previous results of the study of interplanetary Lyman α background data obtained by the SWAN-SOHO between 1996 and 2005 clearly show that the solar cycle variations of the solar parameters deeply affect the interplanetary background emission. In this work, we compare these observational results with a time-dependent modeling of the interplan…
Search for cosmic strings in the Great Observatories Origins Deep Survey
Smoot, G. F.; Christiansen, J. L.; Albin, E. +3 more
We search Hubble Space Telescope Treasury Program images collected as part of the Great Observatories Origins Deep Survey for pairs of galaxies consistent with the gravitational lensing signature of a cosmic string. Our technique includes estimates of the efficiency for finding the lensed galaxy pair. In the north (south) survey field we find no e…
XMM-Newton discovery of transient X-ray pulsar in NGC 1313
Trudolyubov, S. P.
We report on the discovery and analysis of the transient X-ray pulsar XMMU J031747.5-663010 detected in the 2004 November 23 XMM-Newton observation of the spiral galaxy NGC 1313. The X-ray source exhibits pulsations with a period P ~ 765.6 s and a nearly sinusoidal pulse shape and pulsed fraction ~38 per cent in the 0.3-7 keV energy range. The X-r…
Effective temperatures of magnetic chemically peculiar stars from full spectral energy distributions
Lipski, Ł.; Stȩpień, K.
New determinations of effective temperatures of 23 magnetic, chemically peculiar (mCP) stars were obtained from a fit of metal-enhanced model atmospheres to the observed spectral energy distributions (SED) from ultraviolet (UV) to red. Temperatures of four more CP stars without magnetic measurements were also obtained, of which three show light va…