Search Publications
On the nature of the X-ray source in GK Persei
Schmitt, J. H. M. M.; Ness, J. -U.; Vrielmann, S.
We report XMM-Newton observations of the intermediate polar (IP) GK Per on the rise to the 2002 outburst and compare them to Chandra observations during quiescence. The asymmetric spin light curve implies an asymmetric shape of a semi-transparent accretion curtain and we propose a model for its shape. A low Fe xvii (λλ15.01/15.26 Å) line flux rati…
On the "injection problem" at the solar wind termination shock
Hilchenbach, M.; Kallenbach, R.; Bamert, K. +2 more
This article presents an integrated analytical model on the injection efficiencies of the different ion species of the Anomalous component of the Cosmic Rays (ACRs) at the solar wind termination shock. We find that the injection into diffusive (first-order Fermi) acceleration is dominated by parallel ion diffusion and not by perpendicular diffusio…
Extreme solar-terrestrial events of October 2003: High-latitude and Cluster observations of the large geomagnetic disturbances on 30 October
Buchert, S.; Amm, O.; Rosenqvist, L. +3 more
The extremely large solar eruption on 28 October 2003 caused an intense geomagnetic storm at Earth. A second solar eruption on 29 October resulted in a reintensification of the storm about a day later. Similarities and differences between these two events in terms of solar eruption, solar wind driver, and their resulting effect on the near-Earth e…
Emission-Line Spectroscopy of Damped Lyα Systems: The Case of SBS 1543+593/HS 1543+5921
Turnshek, David A.; Hopkins, Andrew M.; Miller, Christopher J. +4 more
We report HST/STIS spectroscopy and Gemini/GMOS-N imaging of the Damped Lyα (DLA) system toward HS 1543+5921 caused by the host star-forming galaxy (SFG) SBS 1543+593. The Gemini image shows new morphological details of this well-resolved DLA galaxy. In combination with previous optical spectra, the new UV spectra enable us to compare, for the fir…
Stagnant exterior cusp region as viewed by energetic electrons and ions: A statistical study using Cluster Research with Adaptive Particle Imaging Detectors (RAPID) data
Zhang, H.; Zong, Q. -G.; Daly, P. W. +1 more
We present statistical results based on the data set obtained by Cluster when these spacecraft were in the dayside cusp and magnetopause. Forty clearest stagnant exterior cusp (SEC) events have been selected from ∼150 cusp crossings from 1 January to 30 April 2001 and from 1 March to 30 April 2002. The identification of the SECs was made on the ba…
From young massive star cluster to old globular: the LV-σ0 relationship as a diagnostic tool
de Grijs, Richard; Tadhunter, Clive N.; Wilkinson, Mark I.
We present a new analysis of the properties of the young massive star clusters (YMCs) forming profusely in intense starburst environments, which demonstrates that these objects are plausible progenitors of the old globular clusters (GCs) seen abundantly in the Local Group. The method is based on the tight relationship for old GCs between their V-b…
The influence of the solar particle and radiation environment on Titan’s atmosphere evolution
Lammer, H.; Penz, T.; Biernat, H. K. +1 more
Measurements of the 15N/ 14N isotope ratio in Titan's atmosphere by Earth-based millimetric wavelength spectroscopic observations of HC 15N/HC 14N indicate that the bulk nitrogen may be enriched in the heavy isotope 15N by about 3.9-4.5 times relative to the terrestrial value. For the explanat…
The fingerprint of binary intermediate-mass black holes in globular clusters: suprathermal stars and angular momentum alignment
Possenti, A.; Mapelli, M.; Sigurdsson, S. +1 more
We explore the signatures that a binary intermediate-mass black hole (IMBH) imprints on the velocity and on the angular momentum of globular cluster (GC) stars. Simulating three-body encounters between a star and a binary IMBH, we find that the binary IMBH generates a family of a few hundred stars (~100-300) which remain bound to the GC and have v…
16 µm Imaging around the Hubble Deep Field-North with the Spitzer IRS
Chary, R.; Armus, L.; Charmandaris, V. +3 more
We present a pilot study of 16 µm imaging within the GOODS northern field. Observations were obtained using the ``peak-up'' imaging capability of the Spitzer IRS. We survey 35 arcmin2 to an average 3 σ depth of 0.075 mJy and detect 149 sources. The survey partially overlaps the area imaged at 15 µm by the ISO, and we demonst…
HD 121190: A cool multiperiodic slowly pulsating B star with moderate rotation
Aerts, C.; Kolenberg, K.
We have gathered and analysed multicolour Geneva photometry and high-resolution spectroscopy of the stars HD 121190 (B9V) and HD 106419 (B9III) whose short-term periodic variability had become evident from their HIPPARCOS data. We find three significant frequencies for HD 121190 in the Geneva data: 2.6831, 2.6199 and 2.4713 c d-1 and cl…