Search Publications
Modeling time delays in the X-ray spectrum of the Seyfert galaxy MCG-6-30-15
Ponti, G.; Karas, V.; Czerny, B. +1 more
Aims:We propose a reflection model of the time delays detected during an exceptionally bright, single flare in MCG-6-30-15. We consider a scenario in which the delays of the hard X-rays with respect to the soft X-rays are caused by the presence of the delayed reflection component.
Methods: We employ a model of the flare, which is accompanied b…
Electron density and carriers of the diffuse interstellar bands
Galazutdinov, G. A.; Gnaciński, P.; Sikorski, J. K.
We have used the ionisation equilibrium equation to derive the electron density in interstellar clouds in the direction of 13 stars. A linear relation was found that allows determination of the electron density from the Mg I and Mg II column densities in diffuse clouds. The comparison of a normalised equivalent width of 12 DIBs with the electron d…
The star pile in Abell 545
Richtler, T.; West, M. J.; Salinas, R. +2 more
Context: Struble (1988, ApJ, 330, L25) found what appeared to be a cD halo without cD galaxy in the center of the galaxy cluster Abell 545. This remarkable feature has been passed almost unnoticed for nearly twenty years.
Aims: Our goal is to review Struble's claim by providing a first (preliminary) photometric and spectroscopic analysis of th…
Initial mass function effects on the colour evolution of disk galaxies
Samland, M.; Kautsch, S. J.; Westera, P. +2 more
Aims:In this work, we want to find out if the IMF can be determined from colour images, integrated colours, or mass-to-light ratios, especially at high redshift, where galaxies cannot be resolved into individual stars, which would enable us to investigate dependencies of the IMF on cosmological epoch.
Methods: We use chemo-dynamical models to …
The correlation between coronal Doppler shifts and the supergranular network
Peter, H.; Lemaire, P.; Aiouaz, T.
A 12 µm ISOCAM survey of the ESO-Sculptor field. Data reduction and analysis
Seymour, N.; Rocca-Volmerange, B.; de Lapparent, V.
We present a detailed reduction of a mid-infrared 12 µm (LW10 filter) ISOCAM open time observation performed on the ESO-Sculptor Survey field (Arnouts et al. 1997, A&AS, 124, 163). A complete catalogue of 142 sources (120 galaxies and 22 stars), detected with high significance (equivalent to 5σ), is presented above an integrated flux den…
AGN counts at 15µm. XMM observations of the ELAIS-S1-5 sample
Pozzi, F.; Fiore, F.; Gruppioni, C. +7 more
Context: The counts of galaxies and AGN in the mid infra-red (MIR) bands are important instruments for studying their cosmological evolution. However, the classic spectral line ratios techniques can become misleading when trying to properly separate AGN from starbursts or even from apparently normal galaxies.
Aims: We use X-ray band observatio…
RX J0042.3+4115: a stellar mass black hole binary identified in M 31, and other papers
Osborne, J. P.; Barnard, R.; Kolb, U. C.
RBS1423 - a new QSO with relativistic reflection from an ionised disk
Husemann, B.; Krumpe, M.; Lamer, G. +1 more
Aims:We present the analysis and results of a 20 ks XMM-Newton observation of RBS1423.
Methods: X-ray spectral analysis is used to establish a significantly broadened relativistic iron Kα line from a highly ionised disk.
Results: A QSO at z = 2.262 was considered to be the optical counterpart of this ROSAT Bright Survey X-ray source. Based…
Optimized data masks for focussed solar tomography: background and artificial diagnostic experiments
Thompson, M. J.; Hughes, S. J.; Pijpers, F. P.
Context: The use of solar tomography for detecting subsurface features in the Sun is now well established. It customarily proceeds from an analysis of data on the solar surface given weightings in a predetermined geometric (e.g. centre-annulus) configuration.
Aims: We seek to improve these weightings by developing a scheme for choosing optimal…