Search Publications
Modeling the emission processes in blazars
Böttcher, Markus
Blazars are the most violent steady/recurrent sources of high-energy gamma-ray emission in the known Universe. They are prominent emitters of electromagnetic radiation throughout the entire electromagnetic spectrum. The observable radiation most likely originates in a relativistic jet oriented at a small angle with respect to the line of sight. Th…
Resonant Compton upscattering in anomalous X-ray pulsars
Baring, Matthew G.; Harding, Alice K.
A significant new development in the study of Anomalous X-ray Pulsars (AXPs) has been the recent discovery by INTEGRAL and RXTE of flat, hard X-ray components in three AXPs. These non-thermal spectral components differ dramatically from the steeper quasi-power-law tails seen in the classic X-ray band in these sources. A prime candidate mechanism f…
Nucleonic gamma-ray production in pulsar wind nebulae
Santangelo, A.; Aharonian, F.; Horns, D. +1 more
Observations of the inner radian of the Galactic disk at very high energy (VHE) gamma-rays have revealed at least 16 new sources. Besides shell type super-nova remnants, pulsar wind nebulae (PWN) appear to be a dominant source population in the catalogue of VHE gamma-ray sources. Except for the Crab nebula, the newly discovered PWN are resolved at…
The first multi-wavelength campaign of AXP 4U 0142+61 from radio to hard X-rays
Rea, N.; Stappers, B.; Kuiper, L. +5 more
For the first time a quasi-simultaneous multi-wavelength campaign has been performed on an Anomalous X-ray Pulsar from the radio to the hard X-ray band. 4U 0142+61 was an INTEGRAL target for 1 Ms in July 2005. During these observations it was also observed in the X-ray band with Swift and RXTE, in the optical and NIR with Gemini North and in the r…
Unveiling soft gamma-ray repeaters with INTEGRAL
Mereghetti, Sandro; Hurley, Kevin; Götz, Diego
Thanks to INTEGRAL's long exposures of the Galactic Plane, the two brightest Soft Gamma-Ray Repeaters, SGR 1806-20 and SGR 1900+14, have been monitored and studied in detail for the first time at hard-X/soft gamma rays. This has produced a wealth of new scientific results, which we will review here. Since SGR 1806-20 was particularly active during…
New INTEGRAL sources and TeV emission
Walter, Roland
INTEGRAL is operational since more than three years and producing high quality data that allows to detect fainter new hard X-ray sources. The new sources, identified until now, are mostly active galactic nuclei and absorbed or transient high mass X-ray binaries. TeV emission could be expected from the new high mass X-ray binaries accreting dense c…
INTEGRAL observations of TeV plerions
Santangelo, A.; Horns, D.; Hoffmann, A. I. D.
Amongst the sources seen in very high gamma-rays several are associated with Pulsar Wind Nebulae ("TeV plerions"). The study of hard X-ray/soft gamma-ray emission is providing an important insight into the energetic particle population present in these objects. The unpulsed emission from pulsar/pulsar wind nebula systems in the energy range access…
The black-hole candidate XTE J1817-330 as seen by XMM-Newton and INTEGRAL
Haberl, Frank; Greiner, Jochen; Sala, Gloria +1 more
The new black hole candidate XTE J1817-330, discovered on 26 January 2006 with RXTE, was observed with XMM-Newton and INTEGRAL in February and March 2006, respectively. The X-ray spectrum is dominated by the thermal emission of the accretion disk in the soft band, with a low absorption column density (NH=1.77(±0.01)×1021 cm
Jet disc coupling in black hole binaries
Malzac, Julien
In the last decade multi-wavelength observations have demonstrated the importance of jets in the energy output of accreting black hole binaries. The observed correlations between the presence of a jet and the state of the accretion flow provide important information on the coupling between accretion and ejection processes. After a brief review of …
QED can explain the non-thermal emission from SGRs and AXPs: variability
Heyl, Jeremy S.
Owing to effects arising from quantum electrodynamics (QED), magnetohydrodynamical fast modes of sufficient strength will break down to form electron-positron pairs while traversing the magnetospheres of strongly magnetised neutron stars. The bulk of the energy of the fast mode fuels the development of an electron-positron fireball. However, a sma…