Search Publications
Deep Photometry of the Globular Cluster M5: Distance Estimates from White Dwarf and Main-Sequence Stars
Sarajedini, Ata; Layden, Andrew C.; Cool, Adrienne M. +1 more
We present deep VI photometry of stars in the globular cluster M5 (NGC 5904) based on images taken with the Hubble Space Telescope. The resulting color-magnitude diagram reaches below V~27 mag, revealing the upper 2-3 mag of the white dwarf cooling sequence and main-sequence stars 8 mag and more below the turnoff. We fit the main sequence to subdw…
A Study of Flare-associated X-Ray Plasma Ejections. III. Kinematic Properties
Cho, K. -S.; Moon, Y. -J.; Park, Y. D. +2 more
In this study, we have investigated the kinematic properties of flare-associated X-ray plasma ejections. First, we obtained the speed profiles of well-observed several events and compared them with the GOES soft X-ray flux profiles as well as the HXT hard X-ray flux profiles of their associated flares. Second, we have estimated the Alfvén speed at…
Early signatures of large-scale field line opening. Multi-wavelength analysis of features connected with a "halo" CME event
Vilmer, N.; Pohjolainen, S.; Khan, J. I. +1 more
A fast "halo"-type coronal mass ejection (CME) associated with a two-ribbon flare, GOES class M 1.3, was observed on February 8, 2000. Soft X-ray and EUV images revealed several loop ejections and one wave-like moving front that started from a remote location, away from the flare core region. A radio type-II burst was observed near the trajectory …
Toward magnetic field dissipation during the 23 July 2002 solar flare measured with Solar and Heliospheric Observatory/Michelson Doppler Imager (SOHO/MDI) and Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI)
Zharkova, Valentina V.; Zharkov, Sergey I.; Ipson, Stanley S. +1 more
We analyze the SOHO/MDI high-cadence magnetic field variations that occurred in a bipolar area around the apparent neutral line (ANL) prior to and during the 2B/X4.8 flare on 23 July 2002 and their association with the hard X-ray (HXR) and Hα emission observed with RHESSI and BBSO. Magnetic field changes started 6 min prior to the hard …
Photometric Confirmation of MACHO Large Magellanic Cloud Microlensing Events
Bennett, David P.; Becker, Andrew C.; Tomaney, Austin
We present previously unpublished photometry of three Large Magellanic Cloud (LMC) microlensing events and show that the new photometry confirms the microlensing interpretation of these events. These events were discovered by the MACHO Project alert system and were also recovered by the analysis of the 5.7 yr MACHO data set. This new photometry pr…
Poloidal ULF oscillations in the dayside magnetosphere: a Cluster study
Glassmeier, K. -H.; Blomberg, L. G.; Eriksson, P. T. I. +1 more
Three ULF wave events, all occurring in the dayside magnetopshere during magnetically quiet times, are studied using the Cluster satellites. The multi-point measurements obtained from Cluster are used to determine the azimuthal wave number for the events by means of the phase shift and the azimuthal separation between the satellites. Also, the pol…
The widths of vacuum-ultraviolet spectral lines in the equatorial solar corona observed with CDS and SUMER
Dwivedi, B. N.; Harrison, R. A.; Wilhelm, K. +3 more
Observations of the solar equatorial corona between heights of 36 Mm and 184 Mm above the limb obtained by the SOHO spectrometers CDS and SUMER in December 2003 are presented and discussed with special emphasis on the widths of the spectral lines Mg x at 62.50 nm, Al xi at 55.00 nm and 56.82 nm, Ca x at 55.78 nm, and Si xi at 58.09 nm. SUMER obser…
In situ observations of magnetic field fluctuations
Balogh, André; Erdős, Géza
It is well known that the irregularities of the magnetic field are intimately related to the motion of charged particles. Although transport theories need the spatial and time variations of the magnetic field as input, in situ observations are very limited. Ulysses observations have provided a major step forward by entering the unexplored high lat…
A Revised Geometry for the Magnetic Wind of θ1 Orionis C
Smith, Myron A.; Fullerton, Alex W.
The star θ1 Orionis C (O6-7 V) is often cited as a hot analog of Bp variables, because its optical and UV line and X-ray continuum fluxes modulate over the magnetic/rotational period. In this circumstance, one expects emission and absorption components of the UV resonance lines to vary as a flattened magnetosphere corotates with the sta…
Formation and Evolution of Titan's Atmosphere
Coustenis, Athena
The origin and evolution of Titan’s enigmatic atmosphere is reviewed. Starting with the present-day volatile inventory, the question of what was the original composition on Titan and how a satellite of similar size to other Galilean moons managed to acquire and hold on to the required material is discussed. In particular the possible sources and s…