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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…
Inner-shell ionization, radiative losses and thermal conductivity in young SNRs
Kosenko, D. I.
Self-consistent treatment of time-dependent ionization in hydrodynamical calculations of the X-ray emission from young supernova remnants (SNRs) has been performed. The novel feature of the calculations is that Kα lines from species produced by inner-shell collisional ionization are included. Parameters of the shocked ejecta are found from fitting…
Did galaxy assembly and supermassive black-hole growth go hand-in-hand?
Ryan, R. E.; Koekemoer, A. M.; Mobasher, B. +10 more
In this paper, we address whether the growth of supermassive black-holes has kept pace with the process of galaxy assembly. For this purpose, we first searched the Hubble Ultra Deep Field (HUDF) for "tadpole galaxies", which have a knot at one end plus an extended tail. They appear dynamically unrelaxed-presumably early-stage mergers-and make up ∼…
The globular cluster system of NGC 5846 revisited: colours, sizes and X-ray counterparts
Santiago, B. X.; Pastoriza, M. G.; Chies-Santos, A. L. +1 more
Context.NGC 5846 is a giant elliptical galaxy with a previously well studied globular cluster system (GCS), known to have a bimodal colour distribution with a remarkably high red fraction.
Aims.Here we revisit the central galaxy regions searching for new globular cluster (GC) candidates, and measure magnitudes, colours and sizes for them. We al…