Search Publications
XMM-Newton observations of SN 1987 A
Haberl, F.; Hasinger, G.; Aschenbach, B. +1 more
Context: .We report on XMM-Newton observations of SN 1987 A in the Large Magellanic Cloud.
Aims: .The large collecting area telescopes together with the European Photon Imaging Cameras (EPIC) provide X-ray spectra with unprecedented statistical quality and make it possible to investigate the spectral evolution during the brightening observed s…
Quasars near the line of sight towards Q 0302-003 and the transverse proximity effect
Worseck, G.; Wisotzki, L.
We report the discovery of the faint (V≃ 21.7) quasar QSO 03027-0010 at z=2.808 in the vicinity of Q 0302-003, one of the few quasars observed with STIS to study intergalactic He II absorption. Together with another newly discovered QSO at z=2.29, there are now 6 QSOs known near the line of sight towards Q 0302-003, of which 4 are located within t…
Active galactic nuclei in the mid-IR. Evolution and contribution to the cosmic infrared background
Pozzi, F.; Gruppioni, C.; Zamorani, G. +3 more
Aims.We study the evolution of the luminosity function (LF) of type-1 and type-2 Active Galactic Nuclei (AGN) in the mid-infrared, derive the contribution of the AGN to the Cosmic InfraRed Background (CIRB) and the expected source counts to be observed by Spitzer at 24 µm. Methods: We used a sample of type-1 and type-2 AGN selected at 15 &mi…
Observations of a soft X-ray rising loop associated with a type II burst and a coronal mass ejection in the 03 November 2003 X-ray flare
Krucker, S.; Vilmer, N.; Dauphin, C.
Context: .We report observations of a type II burst - the signature of a shock wave - starting at the unusual high frequency of 650 MHz during the 03 November 2003 flare. This flare is associated with the propagation of a soft X-ray coronal loop and with a coronal mass ejection (CME).
Aims: .We study in this paper the origin of the shock wave …
3D spectroscopy with VLT/GIRAFFE. II. Are luminous compact galaxies merger remnants?
Östlin, G.; Flores, H.; Hammer, F. +2 more
Luminous Compact Galaxies (LCGs) are enigmatic sources in many aspects. They can reach the luminosity of the Milky Way within a radius of only a few kpc. They also represent one of the most rapidly evolving populations of galaxies since they represent up to 1/5 of the luminous galaxies at redshift z= 0.7, while being almost absent in the local Uni…
Two years of INTEGRAL monitoring of the soft gamma-ray repeater SGR 1806-20: from quiescence to frenzy
Hurley, K.; Sunyaev, R.; Götz, D. +16 more
SGR 1806-20 has been observed for more than 2 years with the INTEGRAL satellite. In this period the source went from a quiescent state into a very active one culminating in a giant flare on December 27, 2004. Here we report on the properties of all the short bursts detected with INTEGRAL before the giant flare. We derive their number-intensity dis…
Large-scale source regions of earth-directed coronal mass ejections
Zhang, J.; Wang, J. X.; Zhou, G. P.
Based on SOHO/MDI, EIT, Yohkoh/SXT, Hα, and other relevant observations, we analyzed all the earth-directed halo coronal mass ejections (CMEs) in the interval from Mar. 1997 to Dec. 2003. A total of 288 earth-directed CMEs were studied and their associated surface activity events identified. Unlike the previous studies that often attributed a surf…
A high-resolution spectroscopy survey of β Cephei pulsations in bright stars
Uytterhoeven, K.; De Ridder, J.; Aerts, C. +4 more
We present a study of absorption line-profile variations in early-B type near-main-sequence stars without emission lines. We have surveyed a total of 171 bright stars using the Nordic Optical Telescope (NOTSA), William Herschel Telescope (ING) and Coudé Auxiliary Telescope (ESO). Our sample contains 75% of all O9.5-B2.5 III-V non-emission-line sta…
Coronal activity cycles in 61 Cygni
Schmitt, J. H. M. M.; Robrade, J.; Favata, F. +3 more
Context: .While the existence of stellar analogues of the 11 years solar activity cycle is proven for dozens of stars from optical observations of chromospheric activity, the observation of clearly cyclical coronal activity is still in its infancy.
Aims: .In this paper, long-term X-ray monitoring of the binary 61 Cygni is used to investigate p…
A posteriori detection of the planetary transit of HD 189733 b in the Hipparcos photometry
Hébrard, G.; Lecavelier Des Etangs, A.
Context: Aims: Using observations performed at the Haute-Provence Observatory, the detection of a 2.2-day orbital period extra-solar planet that transits the disk of its parent star, HD 189733, has been recently reported. We searched in the Hipparcos photometry Catalogue for possible detections of those transits. Methods: Statistic studies were pe…