Search Publications
A search for possible interactions between ejections from GRS 1915+105 and the surrounding interstellar medium
Chaty, S.; Fuchs, Y.; Mirabel, I. F. +5 more
We have observed an extended region surrounding the first discovered galactic superluminal source GRS 1915+105, seeking evidence of interaction between the relativistic ejecta of that object and the interstellar medium. We find two radio sources axisymmetrically aligned along the sub-arcsecond relativistic ejecta of GRS 1915+105 and roughly 17amin…
The geometry of stellar motions in the nucleus region of the Ursa Major kinematic group
Vereshchagin, S. V.; Reva, V. G.; Chupina, N. V.
The structure of the central part of the UMa stellar kinematic group was considered according to the data from Hipparcos, Tycho and ACT catalogues. We have shown that in the space occupied by the nucleus there are several populations of stars. The first includes ten stars which are very compactly located in the proper motion diagram and have a nor…
XMM-Newton observations of Markarian 421
Tiengo, A.; Molendi, S.; Branduardi-Raymont, G. +6 more
The BL Lac object Mrk 421 was observed on May 25, 2000 during the XMM-Newton Cal/PV phase. The high throughput of the X-ray telescopes and the spectral capabilities of the instruments allow an uninterrupted temporal and spectral study of the source with unprecedented time resolution. Mrk 421 was found at a relatively high state with a 2-6 keV flux…
Spectroscopy of B-type emission-line stars with compact dusty envelopes: HD 85567, Hen 3-140, and Hen 3-1398
Miroshnichenko, A. S.; Levato, H.; Bjorkman, K. S. +1 more
We report the results of our spectroscopic observations (3600-5900 Å, R =~ 16 000 and 5750-8750 Å, R =~ 11 000) of three southern emission-line B-type stars associated with IRAS sources, HD 85567, Hen 3-140, and Hen 3-1398, whose nature and evolutionary state are not well-established yet. We also obtained new multicolour photometry of HD 85567 (UB…
XMM-Newton optical monitor observations of LMC X-3
Page, M. J.; Soria, R.; Wu, K. +1 more
We study the optical counterpart of the black-hole X-ray binary LMC X-3, by using XMM-Newton/OM observations carried out during a low-hard X-ray state. We derive a better constraint for the temperature, mass and radius of the companion star, and we show that the star is likely to be a ~ B5 subgiant filling its Roche lobe. Taking into account the e…
Long-term monitoring of active stars. IX. Photometry collected in 1993
Messina, S.; Rodonò, M.; Cutispoto, G.
As a part of an extensive program focused on the global properties and evolution of active stars, high-precision UBV(RI)_c and UBV photometry of 31 selected stars is presented. The UBV(RI)_c observations were collected at the European Southern Observatory over the 31 December 1992-18 January 1993 and the 20 November-3 December 1993 intervals. Addi…
XMM-Newton first-light observations of the Hickson galaxy group 16
Arnaud, M.; Clavel, J.; Priedhorsky, W. +40 more
This paper presents the XMM-Newton first-light observations of the Hickson-16 compact group of galaxies. Groups are possibly the oldest large-scale structures in the Universe, pre-dating clusters of galaxies, and are highly evolved. This group of small galaxies, at a redshift of 0.0132 (or 80 Mpc) is exceptional in the having the highest concentra…
Low-excitation atomic gas around evolved stars. II. ISO observations of O-rich nebulae
Barlow, M. J.; Bujarrabal, V.; Tielens, A. G. G. M. +4 more
We have observed atomic fine-structure lines in the far-infrared (FIR) from 12 oxygen-rich evolved stars. The sample is composed of mostly proto-planetary nebulae (PPNe) and some planetary nebulae (PNe) and asymptotic giant branch (AGB) stars. ISO LWS and SWS observations of [O I], [C II], [N II], [Si I], [Si II], [S I], [Fe I], and [Fe II] lines …
The PAH 7.7 mu m/850 mu m ratio as new diagnostics for high extinction in ULIRGs - increasing evidence for a hidden quasar in Arp 220
Klaas, U.; Haas, M.; Chini, R. +2 more
A new method is presented to reveal high mid-infrared (MIR) extinction in ultraluminous infrared galaxies (ULIRGs): the ratio between the PAH 7.7 mu m feature and the sub-mm continuum at 850 mu m. While the sub-mm radiation is optically thin and serves for normalization, any high MIR extinction reduces the observed PAH 7.7 mu m strength. Since the…
The discovery of the ``21'' mu m and ``30'' mu m emission features in Planetary Nebulae with Wolf-Rayet central stars
Waters, L. B. F. M.; Hony, S.; Tielens, A. G. G. M.
We report the discovery of the ``21'' mu m and ``30'' mu m features in the planetary nebulae around the hydrogen-deficient stars HD 826 and HD 158269. The carriers of these features are known to be produced in outflows around carbon-rich stars. This discovery demonstrates that the bulk of the dust in these nebulae has been produced during a carbon…