Search Publications
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…
Wind accretion in the massive X-ray binary 4U 2206+54 : abnormally slow wind and a moderately eccentric orbit
Reig, P.; Torrejón, J. M.; Negueruela, I. +2 more
Massive X-ray binaries are usually classified by the properties of the donor star in classical, supergiant and Be X-ray binaries, the main difference being the mass transfer mechanism between the two components. The massive X-ray binary
Repetitive occurrence of explosive events at a coronal hole boundary
Doyle, J. G.; Popescu, M. D.; Taroyan, Y.
SUMER/SoHO data taken at a coronal hole boundary show a repetitive explosive event occurrence rate of around 3 min increasing to over 5 min towards the end of the activity. We suggest that the neighbouring oppositely directed closed and open field lines at the coronal hole boundary undergo repetitive reconnection seen as a sequence of explosive ev…
VLT spectroscopy and non-LTE modeling of the C/O-dominated accretion disks in two ultracompact X-ray binaries
Rauch, T.; Werner, K.; Dreizler, S. +2 more
Aims.We present new medium-resolution high-S/N optical spectra of the ultracompact low-mass X-ray binaries 4U 0614+091 and 4U 1626-67, taken with the ESO Very Large Telescope. They are pure emission line spectra and the lines are identified as due to CII-IV and OII-III.
Methods: .Line identification is corroborated by first results from modeli…
Power spectrum of the SDSS luminous red galaxies: constraints on cosmological parameters
Hütsi, G.
In this paper we determine the constraints on cosmological parameters using the CMB data from the Wmap experiment together with the recent power spectrum measurement of the SDSS Luminous Red Galaxies (LRGs). Specifically, we focus on spatially flat, low matter density models with adiabatic Gaussian initial conditions. The spatial flatness is achie…
The size and albedo of Rosetta fly-by target 21 Lutetia from new IRTF measurements and thermal modeling
Hora, J. L.; Mueller, M.; Adams, J. D. +3 more
Recent spectroscopic observations indicate that the M-type asteroid 21 Lutetia has a primitive, carbonaceous-chondrite-like (C-type) surface composition for which a low geometric albedo would be expected; this is incompatible with the IRAS albedo of 0.221± 0.020. From new thermal-infrared spectrophotometric measurements and detailed thermophysical…