Search Publications
The nature of ultraviolet spectra of AG Pegasi and other symbiotic stars: locations, origins, and excitation mechanisms of emission lines
Wahlgren, G. M.; Johansson, S.; Eriksson, M.
A detailed study of ultraviolet spectra of the symbiotic star AG Peg has been undertaken to derive the atomic excitation mechanisms and origin of formation for the lines common in symbiotic systems. More than 600 emission lines are observed in spectra from {IUE}, {HST} and {FUSE} of which 585 are identified. Population mechanisms and origin of for…
Warm-hot intergalactic medium contribution to baryonic matter
Sołtan, A. M.
Context: .Hydrodynamical simulations indicate that a substantial fraction of baryons in the universe remains in a diffuse component - warm-hot intergalactic medium (WHIM).
Aims: .The goal of this paper is to determine the physical properties (spatial distribution, temperature, and density) of the WHIM.
Methods: .Spatial structure of the so…
Supersoft sources in XMM-Newton Small Magellanic Cloud fields. A symbiotic and a close binary or cooling neutron star
Haberl, F.; Kahabka, P.
We report the detection and study of two faint ROSAT supersoft X-ray sources in the SMC field with XMM-Newton, RX J0059.1-7505 and RX J0059.4-7118. Due to the larger effective area of XMM-Newton we can constrain the X-ray spectra of both sources. RX J0059.1-7505 is optically identified with the symbiotic LIN 358 in the SMC. A 20 eV blackbody compo…
Mass segregation in rich LMC clusters from modelling of deep HST colour-magnitude diagrams
Santiago, B. X.; Kerber, L. O.
Aims.We used the deep colour-magnitude diagrams (CMDs) of five rich LMC clusters (NGC 1805, NGC 1818, NGC 1831, NGC 1868, and Hodge 14) observed with HST/WFPC2 to derive their present day mass function (PDMF) and its variation with position within the cluster.
Methods: .The PDMF was parameterized as a power law in the available main-sequence …
The ZZ Ceti star G 185-32: new insight from asteroseismology
Pech, D.; Vauclair, G.
One of the brightest pulsating DA white dwarfs (ZZ Ceti stars), G 185-32, shows 19 periods in its power spectrum, from 71 s to 651 s. Its short periods are among the shortest ones observed in a ZZ Ceti star. The one at 141.9 s shows an amplitude which does not vary with wavelength, in contrast with what the linear theory predicts for ℓ=1 or ℓ=2 no…
Analysis of a multi-wavelength time-resolved observation of a coronal loop
Ciaravella, A.; Reale, F.
Aims.We analyze a well-defined loop system detected in a time-resolved observation in several spectral bands to characterize the structure and evolution of coronal loops. Methods.The dataset includes simultaneous sequences of images in the 171 Å, 195 Å and 284 Å filter bands of TRACE, and in one filter of Yohkoh/SXT, with a time coverage of about …
4U 1344-60: a bright intermediate Seyfert galaxy at z = 0.012 with a relativistic Fe Kα emission line
Motch, C.; Bianchi, S.; Guainazzi, M. +6 more
We present analysis of the optical and X-ray spectra of the low Galactic latitude bright (F_2-10 = 3.6 × 10-11 erg cm-2 s-1) source 4U 1344-60. On the basis of the optical data we propose to classify 4U 1344-60 as an intermediate type Seyfert galaxy and we measure a value of z = 0.012±0.001 for its redshift. From t…
Star-forming QSO host galaxies
Barthel, P. D.
Context: .The recent finding of substantial masses of cold molecular gas as well as young stellar populations in the host galaxies of intermediate luminosity quasars is at odds with results of Hubble Space Telescope imaging studies since the latter appear to yield mature, quiescent early type hosts.
Aims: .The characterization as "quiescent" f…
The coronal Ne/O abundance of α Centauri
Liefke, C.; Schmitt, J. H. M. M.
Recent improvements in the modeling of solar convection and line formation led to downward revisions of the solar photospheric abundances of the lighter elements, which in turn led to changes in the radiative opacity of the solar interior and hence to conflicts with the solar convection zone depth as inferred from helioseismic oscillation frequenc…
Warm molecular gas in the envelope and outflow of IRAS 12496-7650 (DK Chamaeleontis)
van Dishoeck, E. F.; Schilke, P.; Güsten, R. +3 more
Aims.To obtain insight into the physical structure of the warm gas in the inner envelope of protostars and the interaction with the outflow.
Methods: .Sub-millimeter observations of 12CO, 13CO and/or C18O in J=3-2, J=4-3 and J=7-6 were obtained with the APEX Telescope towards IRAS 12496-7650, an intermediate ma…