Search Publications
An alternative hypothesis for the outburst mechanism in supergiant fast X-ray transients: the case of IGR J11215-5952
Götz, D.; Mereghetti, S.; Sidoli, L. +4 more
Context: The physical mechanism responsible for the short outbursts in a recently recognised class of high mass X-ray binaries, the supergiant fast X-ray transients (SFXTs), is still unknown. Two main hypotheses have been proposed to date: the sudden accretion by the compact object of small ejections originating in a clumpy wind from the supergian…
Tracing the evolution in the iron content of the intra-cluster medium
Tozzi, P.; Balestra, I.; Mainieri, V. +5 more
Context: We present a Chandra analysis of the X-ray spectra of 56 clusters of galaxies at z ⪆ 0.3, which cover a temperature range of 3 ⪉ kT ⪉ 15 keV.
Aims: Our analysis is aimed at measuring the iron abundance in the intra-cluster medium (ICM) out to the highest redshift probed to date.
Methods: We made use of combined spectral analysis p…
A model for cyclotron resonance scattering features
Santangelo, A.; Wilms, J.; Kretschmar, P. +5 more
Aims:We study the physics of cyclotron line formation in the high-energy spectra of accreting X-ray pulsars. In particular, we link numerical predictions for the line profiles to results from observational data analysis. Therefore, first we investigate the theoretical predictions and the significance of our model parameters, and second we aim at t…
An evolutionary catalogue of galactic post-AGB and related objects
Szczerba, R.; Siódmiak, N.; Stasińska, G. +1 more
Aims:With the ongoing AKARI infrared sky survey, of much greater sensitivity than IRAS, a wealth of post-AGB objects may be discovered. It is thus time to organize our present knowledge of known post-AGB stars in the galaxy with a view to using it to search for new post-AGB objects among AKARI sources.
Methods: We searched the literature avail…
Constraints on the parameters of radiatively decaying dark matter from the dark matter halos of the Milky Way and Ursa Minor
Nevalainen, J.; Boyarsky, A.; Ruchayskiy, O.
Aims:We improve the earlier restrictions on parameters of the warm dark matter (DM) in the form of a sterile neutrinos.
Methods: The results were obtained from not observing the DM decay line in the X-ray spectrum of the Milky Way (using the recent XMM-Newton PN blank sky data). We also present a similar constraint coming from the recent XMM-N…
Detection of VHE gamma-ray emission from the distant blazar 1ES 1101-232 with HESS and broadband characterisation
Santangelo, A.; Ripken, J.; Carrigan, S. +122 more
Context: The blazar
Aims: VHE observations of blazars are used to investigate…
SPI observations of the diffuse 60Fe emission in the Galaxy
Wang, W.; Strong, A. W.; Knödlseder, J. +12 more
Aims:Gamma-ray line emission from radioactive decay of 60Fe provides constraints on nucleosynthesis in massive stars and supernovae.
Methods: spectrometer SPI on board INTEGRAL has accumulated nearly three years of data on gamma-ray emission from the Galactic plane. We have analyzed these data with suitable instrumental-background m…
The Hα surges and EUV jets from magnetic flux emergences and cancellations
Yang, L. H.; Li, K. J.; Jiang, Y. C. +2 more
We analyzed multi-wavelength observations of three surges with a recurrent period of about 70 min in Hα, EUV, and soft X-ray, which occurred in the quiet-sun region on 2000 November 3. These homologous surges were associated with small flares at the same base, but their exact footpoints were spatially separated from the flare. Each surge consisted…
Constraining supernova models using the hot gas in clusters of galaxies
Kaastra, J. S.; de Plaa, J.; Vink, J. +3 more
Context: The hot X-ray emitting gas in clusters of galaxies is a very large repository of metals produced by supernovae. During the evolution of clusters, billions of supernovae eject their material into this Intra-Cluster Medium (ICM).
Aims: We aim to accurately measure the abundances in the ICM of many clusters and compare these data with me…
Statistical properties of a sample of periodically variable B-type supergiants. Evidence for opacity-driven gravity-mode oscillations
Aerts, C.; Puls, J.; Lefever, K.
Aims:We have studied a sample of 28 periodically variable B-type supergiants selected from the HIPPARCOS mission and 12 comparison stars covering the whole B-type spectral range. Our goal is to test if their variability is compatible with opacity-driven non-radial oscillations.
Methods: We have used the NLTE atmosphere code FASTWIND to derive …