Search Publications
A parametric study of the influence of ion and electron properties on the excitation of electromagnetic ion cyclotron waves in coronal mass ejections
Farrugia, Charles J.; Dasso, Sergio; Gratton, Fausto T.
Interplanetary coronal mass ejections (ICMEs) often possess a negative proton thermal anisotropy, Ap = T⟂,p/T∥,p - 1 < 0 (T∥, T⟂: parallel and perpendicular temperatures, respectively) so that right-hand polarized electromagnetic ion cyclotron waves (EICWs) may be amplified by a kinetic ins…
ISO-SWS calibration and the accurate modelling of cool-star atmospheres. II. General results
Eriksson, K.; Gustafsson, B.; Decin, L. +5 more
The fine calibration of the ISO-SWS detectors (Infrared Space Observatory - Short Wavelength Spectrometer) has proven to be a delicate problem. We therefore present a detailed spectroscopic study in the 2.38-12 mu m wavelength range of a sample of 16 A0-M2 stars used for the calibration of ISO-SWS. By investigating the discrepancies between the IS…
Mid- to far-infrared spectroscopy of Sharpless 171
Okada, Y.; Onaka, T.; Shibai, H. +1 more
We have collected one-dimensional raster-scan observations of the active star-forming region Sharpless 171 (S171), a typical H Ii region-molecular cloud complex, with the three spectrometers (LWS, SWS, and PHT-S) on board ISO. We have detected 8 far-infrared fine-structure lines, [O Iii] 52 mu m, [N Iii] 57 mu m, [O I] 63 mu m, [O Iii] 88 mu m, [N…
The XMM-Newton View of the Nucleus of NGC 4261
Brandt, W. N.; Mushotzky, R.; Gliozzi, M. +2 more
We present the first results from an XMM-Newton observation of the Fanaroff-Riley type I galaxy NGC 4261, which harbors a supermassive black hole and a low-ionization nuclear emission-line region. Here we focus on the X-ray properties of the nucleus, using the European Photon Imaging Camera pn data. The 0.6-10 keV continuum in best fitted by a the…
The FERRUM Project: Experimental transition probabilities of [Fe II] and astrophysical applications
Lundberg, H.; Johansson, S.; Hartman, H. +9 more
We report on experimental transition probabilities for thirteen forbidden [Fe II] lines originating from three different metastable Fe Ii levels. Radiative lifetimes have been measured of two metastable states by applying a laser probing technique on a stored ion beam. Branching ratios for the radiative decay channels, i.e. M1 and E2 transitions, …
Tomography of a stellar X-ray corona: alpha Coronae Borealis
Mewe, R.; Audard, M.; Güdel, M. +1 more
We interpret the X-ray light curve obtained by XMM-Newton during a total X-ray eclipse in the nearby binary star
Astrometry with The Hubble Space Telescope: A Parallax of the Central Star of the Planetary Nebula NGC 6853
McArthur, B. E.; Franz, O. G.; Bradley, A. J. +17 more
We present an absolute parallax and relative proper motion for the central star of the planetary nebula NGC 6853 (the Dumbbell). We obtain these with astrometric data from the Fine Guidance Sensor 3, a white-light interferometer on the Hubble Space Telescope. Spectral classifications and VRIJHKT2M and DDO51 photometry of the stars makin…
Large-scale Dimmings Produced by Solar Coronal Mass Ejections According to SOHO/EIT Data in Four EUV Lines
Grechnev, V. V.; Chertok, I. M.
SOHO/EIT data are used to analyze dimmings, or transient coronal holes (regions of reduced soft-X-ray and EUV emission), which are observed on the solar disk after halo-type coronal mass ejections (CMEs). Simultaneous observations in the 171 Å FeIX/X, 195 Å FeXII, and 284 Å FeIX coronal lines, which are sensitive to temperatures of T e ≈1.2, 1.5, …
Stellar sources in the ISOGAL intermediate bulge fields
Ganesh, S.; Omont, A.; Schultheis, M. +3 more
We present a study of ISOGAL sources in the ``intermediate'' galactic bulge (|l|< 2o, |b| ~ 1o-4o), observed by ISOCAM at 7 and 15 mu m. In combination with near-infrared (I, J, Ks) data of DENIS survey, complemented by 2MASS data, we discuss the nature of the ISOGAL sources, their luminosities, the i…
On the measurement bias of low-l solar p-mode excitation parameters: The impact of a ground-based window function
Chaplin, W. J.; Elsworth, Y.; Isaak, G. R. +4 more
We present a study of the impact of a ground-based, multi-station window function on estimates of the power and damping of low-l solar p modes extracted from fits to resonant structure in the frequency domain. The window functions come from six-site observations made by the Birmingham Solar-Oscillations Network (BiSON) over the 10-yr period beginn…