Search Publications
Fe Kα line emission from the Arches cluster region - evidence for ongoing particle bombardment?
Capelli, R.; Warwick, R. S.; Porquet, D. +2 more
Context. Bright Fe-Kα line emission at 6.4 keV is a unique characteristic of some of the dense molecular complexes present in the Galactic center region. Whether this X-ray fluorescence is due largely to the irradiation of the clouds by X-ray photons or is, at least in part, the result of cosmic-ray particle bombardment, remains an inte…
Imaging the Time Evolution of Eta Carinae's Colliding Winds with HST
Corcoran, Michael F.; Gull, Theodore R.; Madura, Thomas I. +1 more
We report new Hubble Space Telescope/Space Telescope Imaging Spectrograph observations that map the high-ionization forbidden line emission in the inner arcsecond of Eta Car, the first that fully image the extended wind-wind interaction region of the massive colliding wind binary. These observations were obtained after the 2009.0 periastron at orb…
Infrared two-colour diagrams for AGB stars using AKARI, MSX, IRAS and near-infrared data
Suh, Kyung-Won; Kwon, Young-Joo
Using a revised version of the catalogue of asymptotic giant branch (AGB) stars by Suh & Kwon, we present various infrared two-colour diagrams (2CDs) for 3003 O-rich, 1168 C-rich, 362 S-type and 35 silicate carbon stars in our Galaxy. For each object in the new catalogue, we cross-identify the AKARI, Midcourse Space Experiment (MSX) and Two-Mi…
Inhomogeneous metal distribution in the intracluster medium
Lovisari, L.; Schindler, S.; Kapferer, W.
Context. The hot gas that fills the space between galaxies in clusters is rich in metals. In their large potential wells, galaxy clusters accumulate metals over the whole cluster history and hence retain important information on cluster formation and evolution.
Aims: We use a sample of five cool core clusters to study the distribution of meta…
Modelling the broad-band spectra of MCG-6-30-15 with a relativistic reflection model
Fabian, A. C.; Chiang, Chia-Ying
The spectrum of the bright Seyfert I galaxy MCG-6-30-15 shows a broad Fe Kα emission line, generally interpreted to originate very close to the central black hole which must then have a high spin. The observed X-ray variability is driven by a power-law component, with little variability found in the iron line energy band. The disconnection of cont…
Four New Black Hole Candidates Identified in M31 Globular Clusters with Chandra and XMM-Newton
Murray, S. S.; Barnard, R.; Garcia, M. +2 more
We have identified four new black hole candidates (BHCs) in M31 globular clusters (GCs) using 123 Chandra and 4 XMM-Newton observations of the M31 central region. The X-ray source associated with Bo 163 (XB163) is a recurrent transient with the highest observed luminosity, ~1.4× 1038 erg s-1, considerably brighter than any ou…
Streamer Wave Events Observed in Solar Cycle 23
Feng, S. W.; Chen, Y.; Li, B. +4 more
In this paper we conduct a data survey searching for well-defined streamer wave events observed by the Large Angle and Spectrometric Coronagraph (LASCO) on-board the Solar and Heliospheric Observatory (SOHO) throughout Solar Cycle 23. As a result, eight candidate events are found and presented here. We compare different events and find that in mos…
Large-scale nested stellar discs in NGC 7217
Chilingarian, Igor V.; Sil'Chenko, Olga K.; Sotnikova, Natalia Ya. +1 more
NGC 7217 is an unbarred early-type spiral galaxy having a multisegment exponential light profile and a system of star-forming rings of the unknown origin; it also possesses a circumnuclear gaseous polar disc. We analysed new long-slit spectroscopic data for NGC 7217 and derived the radial distributions of its stellar population parameters, and ste…
Cluster observations of whistler mode ducts and banded chorus
Pickett, J. S.; Facskó, G.; Inan, U. S. +3 more
Bell et al. (2009) proposed that the source region for banded chorus consists of whistler mode ducts of depleted electron density (Ne) for upper band (UB) chorus for all wave normal angles ($\theta$) and ducts of either enhanced or depleted Ne for lower band (LB) chorus for small $\theta$ and $\theta$ near or greater than the…
Suprathermal electron spectra in the Venus ionosphere
Coates, A. J.; Zhang, T. L.; Galand, M. +2 more
In this study, a multistream kinetic model is used to derive the suprathermal electron intensity in the Venus ionosphere, to be compared with the observations made by the Analyzer of Space Plasmas and Energetic Atoms (ASPERA-4) Electron Spectrometer (ELS) instrument onboard Venus Express (VEx) on 18 May 2006. Input parameters of the model are chos…