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Astrometric monitoring of the binary brown dwarf DENIS-P J1228.2-1547
Martín, E. L.; Bouy, H.; Brandner, W. +4 more
We present astrometric monitoring data of the binary brown dwarf DENIS-P J1228.2-1547. The data have been obtained with the Hubble Space Telescope over a time span of 5.5 yr, and confirm that DENIS-P J1228.2-1547 is indeed a common proper motion, i.e., physical, binary. The data cover about 1/8th of the binary orbit, indicating an orbital period o…
Acceleration of electrons by interacting CMEs
Odstrcil, D.; Vandas, M.
There is growing observational evidence that interaction of coronal mass ejections (CMEs) near the Sun is a common phenomenon, particularly during the solar cycle's maximum years. Recently, we performed 2.5-D MHD simulations of the interaction between two magnetic flux ropes. The aim was to provide some qualitative picture of the shock-cloud and c…
The tidally disturbed luminous compact blue galaxy Mkn 1087 and its surroundings
Esteban, C.; López-Sánchez, Á. R.; Rodríguez, M.
We present new broad-band optical and near-infrared CCD imaging together with deep optical intermediate-resolution spectroscopy of Mkn 1087 and its surrounding objects. We analyze the morphology and colors of the stellar populations of the brightest objects, some of them star-formation areas, as well as the kinematics, physical conditions and chem…
Gamma-ray all-sky imaging with the Burst and Transient Source Experiment
Hill, A. B.; Knödlseder, J.; Bird, A. J. +6 more
The BATSE mission aboard CGRO monitored the whole sky in the 20 keV-1 MeV energy band continuously from April 1991 until June 2000. Although BATSE had very poor intrinsic angular resolution, the data can be used to survey the entire soft gamma-ray sky with <1° angular resolution and ∼mCrab sensitivity by using the Earth occultation m…
The XMM-Newton observation of GRB 040106: Evidence for an afterglow in a wind environment
Piro, L.; De Pasquale, M.; Gendre, B.
We present the XMM-Newton observation of GRB 040106. From the X-ray spectral index and temporal decay, we argue that the afterglow is consistent with a fireball expanding in a wind environment. A constant density environment is excluded by the data. This is one of the very few cases in which this conclusion can be drawn.
VLT FORS-1 observations of NGC 6397: Evidence for mass segregation
Testa, V.; Marconi, G.; Buonanno, R. +3 more
We present (V, V-I) VLT-FORS1 observations of the Galactic Globular Cluster NGC 6397. We derive accurate color-magnitude diagrams and luminosity functions (LFs) of the cluster Main Sequence (MS) for two fields extending from a region near the centre of the cluster out to ≃10 arcmin. The photometry of these fields produces a narrow MS extending dow…
Inference of hot star density stream properties from data on rotationally recurrent DACs
Owocki, S. P.; Kaper, L.; Hamann, W. -R. +5 more
The information content of data on rotationally periodic recurrent discrete absorption components (DACs) in hot star wind emission lines is discussed. The data comprise optical depths τ(w,φ) as a function of dimensionless Doppler velocity w=(Δλ/λ0)(c/v&infy) and of time expressed in terms of stellar rotation angle φ. This…
SOHO CDS and SUMER observations of quiescent filaments and their interpretation
Parenti, S.; Del Zanna, G.; Chiuderi Drago, F.
Three quiescent filaments located at different positions on the solar disk were selected from the SOHO CDS data archive: one of them was also observed by SUMER in the raster mode. We investigate the filament-corona transition region (PCTR) emission, to determine whether it is indeed negligible, as found in one previously-analysed case. The observa…
The analysis of Abell 1835 using a deprojection technique
Chen, Y.; Chen, L.; Lu, F. J. +2 more
We present the results from a detailed deprojection analysis of Abell 1835 as observed by XMM-Newton. If we fit the spectra with an isothermal plasma model, the deprojected temperature profile is flat in the outer region around 7.6 keV and decreases to ∼5.6 keV in the center, which may be connected with the gas cooling. In the central part, a two-…
Identifying a black hole X-ray transient in M 31 with XMM-Newton and Chandra
Kolb, U.; Osborne, J. P.; Barnard, R.
Stochastic variability in two out of four XMM-Newton observations of XMMU J004303+4115 along with its power spectra and X-ray luminosities suggest a low-mass X-ray binary (LMXB) with a black hole primary. However, Chandra observations resolve the object into two point sources. We use data from 35 Chandra observations to analyse the contributions o…