Search Publications
An X-ray view of the active nucleus in NGC 4258
Pietsch, W.; Read, A. M.
XMM-Newton observed the Seyfert 1.9 galaxy
The enigmatic WR46: A binary or a pulsator in disguise. II. The spectroscopy
Crowther, P. A.; van der Hucht, K. A.; van Genderen, A. M. +1 more
We present spectroscopic monitoring of the Wolf-Rayet (WR) star
First orbital elements for the lambda Bootis spectroscopic binary systems HD 84948 and HD 171948. Implications for the origin of the lambda Bootis stars
Kamp, I.; Paunzen, E.; Claret, A. +4 more
We present high-resolution spectroscopic observations of the two lambda Bootis type spectroscopic binary systems HD 84948 and HD 171948. Both systems consist of two true lambda Bootis stars, as has already been proven by a detailed abundance analysis taking into account the binary nature. Nevertheless, we have obtained non-LTE abundances for carbo…
Modeling IR spectra of OH/IR stars at different phases
Suh, Kyung-Won; Kim, H. -Y.
We investigate the spectral energy distributions (SEDs) of OH/IR stars (OH127.8+0.0 and OH26.5+0.6) having thick dust envelopes at different pulsation phases. Using new infrared observational data including the Infrared Space Observatory (ISO) data, we determine the new pulsation parameters. The deep silicate absorption features show significant v…
Diffraction-limited bispectrum speckle interferometry of the Herbig Be star R Mon
Weigelt, G.; Hofmann, K. -H.; Preibisch, T. +1 more
We explore the structures immediately surrounding the intermediate-mass young stellar object R Mon with bispectrum speckle interferometry, conventional near-infrared imaging and by analyzing optical HST archive data. Our near-infrared speckle images with unprecedented diffraction-limited resolution of 55 mas ( ~ 44 AU; H-band) and 76 mas ( ~ 61 AU…
Metal abundances and kinematics of quasar absorbers. I. Absorption systems toward J2233-606
Levshakov, S. A.; Agafonova, I. I.; Centurión, M. +1 more
The metal line profiles of different ions observed in high H I column density systems [N(H I) > 1016 cm-2] in quasar spectra can be used to constrain the ionization structure and kinematic characteristics of the absorbers. For these purposes, a modified Monte Carlo Inversion (MCI) procedure was applied to the study of thre…
Time variation of SWS spectra of M-type Mira variables and its dust optical properties. I. Z Cyg
Onaka, T.; Yamamura, I.; de Jong, T.
The M-type Mira variable star, Z Cyg, was observed with the Short-Wavelength Spectrometer (SWS) on board the Infrared Space Observatory (ISO) 7 times at roughly 60 day intervals over one and a half period. The infrared spectrum (2.38-45.2 mu m) of Z Cyg shows prominent silicate emission bands at 10 mu m and 18 mu m and displays quite large variati…
XMM-Newton detection of Nova Muscae 1991 in quiescence
Kolb, U.; Casares, J.; Osborne, J. P. +7 more
The soft X-ray transient GU Mus has been detected by XMM-Newton in the quiescent state. The source is very faint, with a 0.5-10.0 keV unabsorbed flux of =~ 1.1 x 10-14 ergs cm-2 s-1. The spectra is well fit by an absorbed powerlaw with a photon index of alpha = 1.6 +/- 0.4, close to the value seen when the source w…
The stellar mass to light ratio in the isolated spiral NGC 4414
Braine, J.; Baudry, A.; Vallejo, O.
We present high resolution CO(1-0) interferometric observations and deep HST B-V-I images of the flocculent isolated Sc type spiral NGC 4414. The goal is to determine the stellar mass-to-light (M/L) ratio in a galactic disk. NGC 4414 is an ideal object for this kind of study, as it is an unperturbed object at high galactic latitude with very exten…
Solar cycle variation of the temperature structure within the cores of coronal streamers
Foley, C. R.; Culhane, J. L.; Patsourakos, S. +1 more
We use the Coronal Diagnostic Spectrometer onboard the Solar and Heliospheric Observatory (SOHO) to analyze conditions in coronal streamer structures observed close to solar minimum (1996 July 8) and near maximum (1999 August 5). We measured the intensities of emission lines from Fe IX-XV ions and found the most intense emission to be from Fe XI a…