Search Publications
Disk populations from HIPPARCOS kinematic data. Discontinuities in the local velocity distribution
Cubarsi, R.; Alcobé, S.
The full space motions including radial velocities of a stellar sample drawn from HIPPARCOS catalogue are used to discriminate differentiated statistical behaviours that are associated with stellar populations in the solar neighbourhood. A sampling parameter is used to build a hierarchical set of nested samples, where a discontinuous pattern, base…
Hubble Space Telescope WFPC2 Photometry of the Globular Clusters M3 and M13: Binaries and Intrinsic Broadening on the Main Sequence
Bailyn, Charles D.; Zhao, Bing
We study the color-magnitude diagram (CMD) morphologies of M3 and M13 using high-precision Hubble Space Telescope photometry. Asymmetric broadening above and to the red of the main sequence is apparent. We use extensive artificial star experiments to synthetically reproduce chance superposition and photometric error and examine whether a main-sequ…
XMM-Newton 13H deep field - I. X-ray sources
McHardy, I.; Page, M. J.; Seymour, N. +10 more
We present the results of a deep X-ray survey conducted with XMM-Newton, centred on the UK ROSAT13H deep field area. This region covers 0.18 deg2, and is the first of the two areas covered with XMM-Newton as part of an extensive multiwavelength survey designed to study the nature and evolution of the faint X-ray source popula…
Cluster observations of sudden impulses in the magnetotail caused by interplanetary shocks and pressure increases
Balogh, A.; Lucek, E.; Rème, H. +6 more
Sudden impulses (SI) in the tail lobe magnetic field associated with solar wind pressure enhancements are investigated using measurements from Cluster. The magnetic field components during the SIs change in a manner consistent with the assumption that an antisunward moving lateral pressure enhancement compresses the magnetotail axisymmetrically. W…
Quasi-monochromatic ULF foreshock waves as observed by the four-spacecraft Cluster mission: 2. Oblique propagation
Balogh, A.; Dandouras, I.; Eastwood, J. P. +2 more
This paper presents the results of a statistical investigation into the nature of oblique wave propagation in the foreshock. Observations have shown that foreshock ULF waves tend to propagate obliquely to the background magnetic field. This is in contrast to theoretical work, which predicts that the growth rate of the mechanism responsible for the…
The Opacity of Spiral Galaxy Disks. III. Automating the Synthetic Field Method
Allen, Ronald J.; Holwerda, B. W.; van der Kruit, P. C. +1 more
Dust extinction in spiral disks can be estimated from the counts of background field galaxies, provided the deleterious effects of confusion introduced by structure in the image of the foreground spiral disk can be calibrated. González et al. developed a method for this calibration, the Synthetic Field Method (SFM), and applied this concept to a H…
Double Star TC-1 observations of component reconnection at the dayside magnetopause: a preliminary study
Zhang, T. L.; Dandouras, I.; Zhang, H. +13 more
In spring 2004 Double Star TC-1 measured a number of reconnection signatures at the dayside low-latitude magnetopause (MP) when there was a notable By component in the magnetosheath. In a number of events we can show that reconnection was operating nearby TC-1 in the subsolar MP region. In this paper we describe three representative eve…
The Early Multicolor Afterglow of GRB 050502a: Possible Evidence for a Uniform Medium with Density Clumps
Pian, E.; Masetti, N.; Steele, I. A. +10 more
The 2 m robotic Liverpool Telescope reacted promptly to the gamma-ray burst GRB 050502a, discovered by INTEGRAL, and started observing 3 minutes after the onset of the burst. The automatic identification of a bright afterglow with r'~15.8 mag triggered, for the first time, an observation sequence in the BVr'i' filters during the first hour after a…
Unraveling the Puzzle of the Eclipsing Polar SDSS J015543.40+002807.2 with XMM and Optical Photometry/Spectropolarimetry
Szkody, Paula; Solheim, Jan-Erik; Schmidt, Gary D. +6 more
The cataclysmic variable SDSS J015543.40+002807.2 is confirmed to be a magnetic system of the AM Herculis type. With an orbital period of 87.13 minutes, it is also the shortest period eclipsing Polar known. Monitoring with XMM-Newton finds a high-state light curve dominated by a single X-ray-emitting accretion pole located slightly prograde of the…
FUSE Observations of Interstellar and Intergalactic Absorption toward the X-Ray-bright BL Lacertae Object Markarian 421
Sembach, Kenneth R.; Savage, Blair D.; Fox, Andrew J. +1 more
High-quality Far Ultraviolet Spectroscopic Explorer (FUSE) observations at 20 km s-1 resolution of interstellar and intergalactic absorption from 910 to 1187 Å are presented for the X-ray-bright BL Lac object Mrk 421. These observations are supplemented with FUSE data for the distant halo stars BD +38°2182 and HD 93521 near the Mrk 421 …