Search Publications
Ionized gas diagnostics from protoplanetary discs in the Orion nebula and the abundance discrepancy problem
Tsamis, Y. G.; Henney, W. J.; García-Rojas, J. +5 more
We present results from integral field spectroscopy of a field located near the Trapezium Cluster using the Potsdam Multi-Aperture Spectrophotometer (PMAS). The observed field contains a variety of morphological structures: five externally ionized protoplanetary discs (also known as proplyds), the high-velocity jet HH 514 and a bowshock. Spatial d…
Temporal variations in the acoustic signal from faculae
Karoff, C.
The integrated brightness of the Sun shows variability on time-scales from minutes to decades. This variability is mainly caused by pressure mode oscillations, by granulation and by dark spots and bright faculae on the surface of the Sun. By analysing the frequency spectrum of the integrated brightness, we can obtain greater knowledge about these …
Formation of unsaturated hydrocarbons in interstellar ice analogues by cosmic rays
Pilling, S.; da Silveira, E. F.; Rothard, H. +3 more
The formation of C=C and C≡C bonds from the processing of pure c-C6H12 (cyclohexane) and mixed H2O:NH3:c-C6H12 (1:0.3:0.7) ices by highly charged and energetic ions (219-MeV 16O7 + and 632-MeV 58Ni24 +) is studied. The experiments simulate…
Physical properties of Herschel selected galaxies in a semi-analytic galaxy formation model
Ferguson, Henry C.; Koekemoer, Anton M.; Somerville, Rachel S. +3 more
We make use of a semi-analytic cosmological model that includes simple prescriptions for dust attenuation and emission to make predictions for the observable and physical properties of galaxies that may be detected by the recently launched HerschelSpace Observatory in deep fields such as Great Observatories Origins Deep Survey-Herschel. We compare…
The cosmological analysis of X-ray cluster surveys - I. A new method for interpreting number counts
Pierre, M.; Clerc, N.; Pacaud, F. +1 more
We present a new method aimed at simplifying the cosmological analysis of X-ray cluster surveys. It is based on purely instrumental observable quantities considered in a two-dimensional X-ray colour-magnitude diagram (hardness ratio versus count rate). The basic principle is that even in rather shallow surveys, substantial information on cluster r…
Time-dependent modelling of the molecular line emission from shock waves in outflow sources
Pineau des Forêts, G.; Flower, D. R.
We have developed further the technique of time-dependent modelling of magnetohydrodynamic shock waves, with a view to interpreting the molecular line emission from outflow sources. The extensively observed source L1157 B1 was chosen as an exemplar of the application of this technique. The dynamical age of the shock wave model was varied in the ra…
Herschel observations of Cen A: stellar heating of two extragalactic dust clouds
Elbaz, D.; Cooray, A.; Galametz, M. +18 more
We present the first results of a multiwavelength survey, incorporating Herschel-?, Spitzer, GALEX and <fr>Australian Telescope Compact Array (ATCA)</fr> observations, of a 1°× 1° field centred on Centaurus A. As well as detecting the inner lobes of the active galactic nucleus (AGN) jet and counterjet, we have found two clouds, bright …
X-rays from colliding stellar winds: the case of close Wolf-Rayet+O binary systems
Zhekov, Svetozar A.
We have analysed the X-ray emission from a sample of close Wolf-Rayet+O (WR+O) binaries using data from the public Chandra and XMM-Newton archives. Global spectral fits show that two-temperature plasma is needed to match the X-ray emission from these objects, because the hot component (kT > 2 keV) is an important ingredient of the spectral mode…
Globular cluster systems as tracers of environmental effects on Virgo early-type dwarfs
Aguerri, J. A. L.; Sánchez-Janssen, R.
Early-type dwarfs (dEs) are by far the most abundant galaxy population in nearby clusters. Whether these objects are primordial, or the recent end products of the different physical mechanisms that can transform galaxies once they enter these high-density environments, is still a matter of debate. Here we present a novel approach to test these sce…
Principal component analysis of background and sunspot magnetic field variations during solar cycles 21-23
Zharkova, V. V.; Shepherd, S. J.; Zharkov, S. I.
The aim of this paper is to derive the principal components (PCs) in variations of (i) the solar background magnetic field (SBMF), measured by the Wilcox Solar Observatory with low spatial resolution for solar cycles 21-23, and (ii) the sunspot magnetic field (SMF) in cycle 23, obtained by SOHO/MDI. For reduction of the component dimensions, princ…