Search Publications
Rosetta target comet 67P/Churyumov-Gerasimenko. Postperihelion gas and dust production rates
Schulz, R.; Boehnhardt, H.; Stüwe, J. A.
The evolution of the activity and composition of the coma of ROSETTA target comet 67P/Churyumov-Gerasimenko was studied along its postperihelion orbit from 2.29 AU to 3.22 AU. The comet had a major drop of activity between 2.5 AU and 2.9 AU, which manifested most obviously in its light curve (the brightness decreased by 3 mag), but is also confirm…
Speckle interferometry of nearby multiple stars. II.
Weigelt, G.; Schertl, D.; Balega, Y. Y. +4 more
This paper is a continuation of diffraction-limited speckle interferometry of binary and multiple stars carried out at the 6-m telescope of the Special Astrophysical Observatory in Zelenchuk. The program has concentrated on nearby (π>10 mas) close binaries discovered or measured during the Hipparcos mission. Here, we present 132 measurements of…
An HST parallax of the distant cataclysmic variable V1223 Sgr, its system parameters, and accretion rate
Gänsicke, B. T.; Beuermann, K.; McArthur, B. E. +2 more
Using the Hubble space Telescope Fine Guidance Sensor, we have measured the trigonometric parallax of the bright cataclysmic variable 1223 Sgr. The absolute parallax is πabs= 1.96± 0.18 mas, making V1223 Sgr the most distant CV with a well-determined trigonometric parallax. This distance, a Lutz-Kelker correction, and the previously mea…
Correlated Infrared and X-ray variability of the transient Anomalous X-ray Pulsar XTE J1810-197
Covino, S.; Campana, S.; Tiengo, A. +10 more
We report on observations aimed at searching for flux variations from the proposed IR counterpart of the Anomalous X-ray Pulsar (AXP) XTE J1810-197. These data, obtained in March 2004 with the adaptive optics camera NAOS-CONICA at the ESO VLT, show that the candidate proposed by Israel et al. (\cite{Israel04}, ApJ, 603, L97) was fainter by Δ H=0.7…
Jet emission in NGC 1052 at radio, optical, and X-ray frequencies
Pogge, R. W.; Kadler, M.; Kerp, J. +3 more
We present a combined radio, optical, and X-ray study of the nearby LINER galaxy NGC 1052. Data from a short (2.3 ks) CHANDRA observation of NGC 1052 reveal the presence of various jet-related X-ray emitting regions, a bright compact core and unresolved knots in the jet structure as well as an extended emitting region inside the galaxy well aligne…
Line profile characteristics of solar explosive event bursts
Solanki, S. K.; Innes, D. E.; Ning, Z.
The spatial structure and temporal evolution of explosive events are explored using spectral observations of the Si IV 1393 Å line obtained with the Solar Ultraviolet Measurements of Emitted Radiation spectrograph (SUMER). Three areas of quiet Sun near disk center, 8 arcsec×120 arcsec each, were rastered with a cadence of less than 1 min for a per…
Menzel 3: Dissecting the ant
Balick, B.; Corradi, R. L. M.; Santander-García, M. +1 more
The structure and kinematics of the bipolar nebula Mz 3 have been investigated by means of HST, CTIO and ESO images and spectra. At least four distinct outflows have been identified which, from the inside to the outside, are the following: a pair of bright bipolar lobes, two opposite highly collimated column-shaped outflows, a conical system of ra…
An XMM-Newton observation of the dynamically active binary cluster A1750
Pratt, G. W.; Bourdin, H.; Sauvageot, J. -L. +1 more
We present results from the XMM-Newton observation of the binary cluster A1750 at z = 0.086. We have performed a detailed study of the surface brightness, temperature and entropy distribution and confirm that the two main clusters of the system (A1750 N and A1750 C) have just started to interact. From the temperature distribution, we calculate tha…
Optical observations of Comet 67P/Churyumov-Gerasimenko
Rauer, H.; Weiler, M.; Helbert, J.
From longslit spectra obtained during the 1996 perihelion passage of Comet 67P/Churyumov-Gerasimenko, a CN production rate of (1.35 ± 0.35) × 1025 molecules s-1 was determined and an upper limit for the C3 production rate of 1 × 1025 molecules s-1 was derived. The dust color and dust activity …
FUSE observations of the H I interstellar gas of I Zw 18
Kunth, D.; Lebouteiller, V.; Lecavelier des Etangs, A. +5 more
We present the analysis of FUSE observations of the metal-deficient dwarf galaxy I Zw 18 . We measured column densities of H I, N I, O I, Ar I, Si II, and Fe II. The O I/H I ratio (\log(O I/H I)=-4.7+0.8-0.6) is consistent with the O/H ratio observed in the H II regions (all uncertainties are 2-σ). If the oxygen is depleted i…