Search Publications
Detection of the Neupert Effect in the Corona of an RS Canum Venaticorum Binary System by XMM-Newton and the Very Large Array
Güdel, Manuel; Behar, Ehud; Audard, Marc +3 more
The RS CVn-type binary σ Geminorum was observed during a large, long-duration flare simultaneously with XMM-Newton and the Very Large Array. The light curves show a characteristic time dependence that is compatible with the Neupert effect observed in solar flares: the time derivative of the X-ray light curve resembles the radio light curve. This o…
Hipparcos open clusters and stellar evolution
Prada Moroni, P. G.; Degl'Innocenti, S.; Castellani, V. +1 more
By relying on recently improved Hipparcos parallaxes for the Hyades, Pleiades and Ursa Major clusters we find that stellar models with updated physical inputs reproduce nicely the location in the colour-magnitude diagram of main-sequence stars of different metallicities. Stars in the helium-burning phase are also discussed, showing that the lumino…
Dual-filament initiation of a Coronal Mass Ejection: Observations and Model
Grechnev, V. V.; Uralov, A. M.; Lesovoi, S. V. +1 more
We propose a new model for the initiation of solar coronal mass ejections (CMEs) and CME-associated flares. The model is inferred from observations of a quiescent filament eruption in the north-western quadrant of the solar disk on 4 September 2000. The event was observed with the Siberian Solar Radio Telescope (5.7 GHz), the Nobeyama Radioheliogr…
A New Measurement of the Average Far-Ultraviolet Extinction Curve
Hurwitz, M.; Dixon, W. V.; Sasseen, T. P. +1 more
We have measured the extinction curve in the far-ultraviolet wavelength region of (900-1200 Å) using spectra obtained with the Berkeley EUV/FUV spectrometer during the ORFEUS I and the ORFEUS II (Orbiting and Retrievable Far and Extreme Ultraviolet Spectrometer) missions in 1993 and 1996. From the complete sample of early-type stars observed durin…
XMM-Newton observations of the isolated neutron star RX J0806.4-4123
Haberl, F.; Zavlin, V. E.
The isolated neutron star
Transition Region Blinkers I. Quiet-Sun Properties
Harrison, R. A.; Parnell, C. E.; Bewsher, D.
An automated method of identifying transition region blinkers is presented. The distribution and general properties of blinkers identified in the quiet Sun are discussed. The blinkers are seen most clearly in the O v (629 Å) transition region emission line, but they also have strong signatures in O iv (554 Å), and the chromospheric line, He i (584…
Isolating Clusters with Wolf-Rayet Stars in I Zw 18
Brown, Thomas M.; Hubeny, Ivan; Heap, Sara R. +2 more
We present UV images and spectra of the starburst galaxy I Zw 18, taken with the Space Telescope Imaging Spectrograph. The high spatial resolution of these data allows us to isolate clusters containing Wolf-Rayet stars of the subtype WC. Our far-UV spectra clearly show C IV λλ1548, 1551 and He II λ1640 emission of WC stars in two clusters: one wit…
High-Resolution X-ray imaging and spectroscopy of N 103B
Kaastra, J. S.; Mewe, R.; Behar, E. +5 more
The X-ray emission from the young supernova remnant (SNR) N 103B is measured and analysed using the high-resolution cameras and spectrometers on board XMM-Newton and Chandra. The spectrum from the entire remnant is reproduced very well with three plasma components of kTe = 0.55, 0.65, and 3.5 keV, corresponding roughly to line emission …
Deep Radio, Optical, and Infrared Observations of SGR 1900+14
Frail, D. A.; Kulkarni, S. R.; van Kerkwijk, M. H. +1 more
We present Hubble Space Telescope/STIS, Keck J- and Ks-band, and VLA 332 and 1400 MHz images of the region around the soft γ-ray Repeater SGR 1900+14. No nonstellar sources were detected at the position of SGR 1900+14, giving 3 σ limits of S332MHz<6 mJy, S1.4GHz<1.5 mJy, m50CCD>~29.0 mag, J>~…
The physical structure of Magellanic Cloud H II regions. I. Dataset
van der Hulst, J. M.; Vermeij, R.; Damour, F. +1 more
We present infrared and optical spectroscopic data for 11 H Ii regions and one Supernova Remnant in the Large and Small Magellanic Cloud. The infrared data have been obtained with the Short Wavelength Spectrometer and Long Wavelength Spectrometer on board the Infrared Space Observatory as part of a Guaranteed Time Program on H Ii regions in Local …