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Crab pulsar photometry and the signature of free precession
Vidrih, S.; Carramiñana, A.; Čadež, A. +1 more
Optical photometry for the pulsar PSR 0531+21 has been extended with new observations that strengthen evidence for a previously observed 60 s periodicity. This period is found to be increasing with time at approximately the same rate as the rotational period of the pulsar. The observed period and its time dependence fit a simple free precession mo…
A Burst from the Direction of UZ Fornacis with XMM-Newton
Mukai, Koji; Still, Martin
The XMM-Newton pointing toward the magnetic cataclysmic variable UZ For finds the source to be a factor of greater than 103 fainter than previous EXOSAT and ROSAT observations. The source was not detected for the majority of a 22 ks exposure with the European Photon Imaging Cameras, suggesting that the accretion rate either decreased or…
Tracing the magnetic topology of coronal mass ejection events by Ulysses/HI-SCALE energetic particle observations in and out of the ecliptic
Pick, M.; Lanzerotti, L. J.; Sarris, E. T. +3 more
In January 2000, the Ulysses spacecraft observed an ICME event at 43° S heliographic latitude and ∼ 4.1 AU. We use electron (E e>38 keV) observations to trace the topology of the IMF embedded within the ICME. The still controversial issue of whether ICMEs have been detached from the solar corona or are still magnetically anchored to …
Long term evolution of a non-active region sigmoid and its CME activity
Culhane, J. L.; Harra, L. K.; Matthews, S. A. +2 more
Recent studies have considered sigmoidal features in the Solar corona to possess a high probability of eruption. Unlike these studies which have focussed only on active region sigmoids, the present work centres on a large area which developed S-like morphology unconfined by a single active region. The S-like feature formed near the central meridia…
Populating the inner heliosphere (<5 AU) with heavy ions
Lanzerotti, L. J.; Maclennan, C. G.; Hawkins, S. E.
Heavy ion (Z > 2) and electron measurements were made on the ACE (1 AU) and Ulysses (3.2 AU) spacecraft in the inner heliosphere during the July 14, 2000 solar events. Following the last interplanetary shock event at ∼1437 UT on July 15, the heavy ion fluxes at 1 AU began to decay with an e-folding decay time for both O and Fe ions (0.5-1 MeV/n…
X-Ray and Ultraviolet Orbital Phase Dependence in LMC X-3
Boyd, Patricia T.; Smale, Alan P.; Dolan, Joseph F.
The black hole binary LMC X-3 is known to be variable on timescales of days to years. We investigate X-ray and ultraviolet variability in the system as a function of the 1.7 day binary phase using a 6.4 day observation with the Rossi X-Ray Timing Explorer (RXTE) from 1998 December. An abrupt 14% flux decrease, lasting nearly an entire orbit, is fo…
SX Phœnicis stars in the core of 47 Tucanae
Christensen-Dalsgaard, J.; Edmonds, P. D.; Bono, G. +5 more
We present new results on five of six known SX Phœnicis stars in the core of the globular cluster 47 Tucanae. We give interpretations of the light curves in the V and I bands from 8.3 days of observations with the Hubble Space Telescope near the core of 47 Tuc. The most evolved SX Phe star in the cluster is a double-mode pulsator (V2) and we deter…
Broad-line radio galaxies: Old and feeble?
van Bemmel, I.; Barthel, P.
Far-infrared photometry of broad-line radio galaxies shows this class of AGN to consist of many hot and some cool infrared emitters, with peaks in their spectral energy distributions around 25 mu m or longward of 60 mu m, respectively. Quantitative analysis indicates that this distribution relates to a substantial dispersion in the strength of the…
The Influence of Tilt Angle and Magnetic Field Variations on Cosmic ray Modulation
Wibberenz, G.; Cane, H. V.; Richardson, I. G. +1 more
The maximum inclination of the heliospheric current sheet (the tilt angle) and the magnitude B of the heliospheric magnetic field are often used to characterize cosmic ray (CR) modulation. The relevance of B is likely to be the coupling of the interplanetary diffusion coefficients K to the field magnitude in a relation K∝ B -n. In this …
Acceleration and Transport of Energetic Charged Particles in Space
Jokipii, J. R.
Energetic charged particles or cosmic rays are found in space wherever the ambient matter density is small enough to allow them to exist. Their observed kinetic energies vary from just above the local thermal energies to in excess of 1020 eV. The energy spectrum is quite smooth, suggesting that a common mechanism is responsible for part…