Search Publications
The second INTEGRAL AGN catalogue
Mas-Hesse, J. M.; Gehrels, N.; Ricci, C. +7 more
Aims: The INTEGRAL mission provides a large data set for studying the hard X-ray properties of AGN and allows testing of the unified scheme for AGN.
Methods: We present analysis of INTEGRAL IBIS/ISGRI, JEM-X, and OMC data for 199 AGN supposedly detected by INTEGRAL above 20 keV.
Results: The data analysed here allow significant spectral ex…
The redshift and afterglow of the extremely energetic gamma-ray burst GRB 080916C
Cenko, S. B.; Greiner, J.; Berger, E. +22 more
Context: The detection of GeV photons from gamma-ray bursts (GRBs) has important consequences for the interpretation and modelling of these most-energetic cosmological explosions. The full exploitation of the high-energy measurements relies, however, on accurate knowledge of the distance to the events.
Aims: Here we report on the discovery of …
Generation of highly energetic electrons at reconnection outflow shocks during solar flares
Mann, G.; Aurass, H.; Warmuth, A.
Context: During solar flares a large amount of energy is suddenly released and partly transferred into energetic electrons. They are of special interest since a substantial part of the energy released during a flare is deposited into the energetic electrons. RHESSI observations, e.g. of the 2003 October 28 solar event, show that 1036 el…
Unveiling the nature of INTEGRAL objects through optical spectroscopy. VII. Identification of 20 Galactic and extragalactic hard X-ray sources
Palazzi, E.; Minniti, D.; Masetti, N. +17 more
Within the framework of our program of assessment of the nature of unidentified or poorly known INTEGRAL sources, we present here spectroscopy of optical objects, selected through positional cross-correlation with soft X-ray detections (afforded with satellites such as Swift, ROSAT, Chandra and/or XMM-Newton) as putative counterparts of hard X-ray…
Intermediate polars in the Swift/BAT survey: spectra and white dwarf masses
Greiner, J.; Ajello, M.; Osborne, J. +1 more
Context: White dwarf masses in cataclysmic variables are difficult to determine accurately, but are fundamental for understanding binary system parameters, as well as binary evolution.
Aims: We investigate the X-ray spectral properties of a sample of Intermediate Polars (IP) detected above 15 keV to derive the masses of their accreting white d…
Spectral and intensity variations of Galactic 26Al emission
Wang, W.; Strong, A. W.; Knödlseder, J. +9 more
Aims: Gamma-ray line emission from the radioactive decay of 26Al reflects nucleosynthesis in massive stars and supernovae. We use INTEGRAL 26Al measurements to characterize the distribution and characteristics of 26Al source regions throughout the Galaxy.
Methods: The spectrometer SPI aboard INTEGRAL has accumu…
High-energy characteristics of the schizophrenic pulsar PSR J1846-0258 in Kes 75. Multi-year RXTE and INTEGRAL observations crossing the magnetar-like outburst
Kuiper, L.; Hermsen, W.
Aims: PSR J1846-0258 is a young rotation-powered pulsar with one of the highest surface magnetic field strengths, located in the centre of SN-remnant Kes-75. In June 2006 a magnetar-like outburst took place. Using multi-year RXTE and INTEGRAL observations covering the epoch of the outburst, we aim to study the temporal and spectral characteristics…
Temporal comparison of nonthermal flare emission and magnetic-flux change rates
Veronig, A. M.; Vršnak, B.; Miklenic, C. H.
Context: To understand the mechanisms that trigger solar flares, we require models describing and quantifying observable responses to the original energy release process, since the coronal energy release site itself cannot be resolved with current technical equipment. Testing the usefulness of a particular model requires the comparison of its pred…
Updating the orbital ephemeris of Hercules X-1; rate of decay and eccentricity of the orbit
Klochkov, D.; Wilms, J.; Staubert, R.
We present an update of the orbital ephemeris of the binary X-ray pulsar Her X-1 and determine an improved value for the rate of orbital decay. In addition, we report the first measurement of the orbital eccentricity. We analyzed pulse timing data of Her X-1 from X-ray observations by RXTE (Rossi X-Ray Timing Explorer) and INTEGRAL over the period…
The Compton-thick AGN in the Chandra Deep Field North
Georgakakis, A.; Georgantopoulos, I.; Rowan-Robinson, M. +1 more
We present X-ray spectral analysis of the brightest sources (f2{-10 keV} > 10-15 erg cm-2 s-1) in the Chandra Deep Field North. Our sample consists of 222 sources; for the vast majority (171) either a spectroscopic or a photometric redshift is available. Our goal is to discover the Compton-thick AGN i…