Learn More
A giant flare from the Soft Gamma-ray Repeater SGR 1806–20 has been discovered with the INTEGRAL gamma-ray observatory on 2004 December 27 and detected by many other satellites. This tremendous outburst, the first one observed from this source, was a hundred times more powerful than the two giant flares previously observed from other Soft Gamma-ray(More)
Soft gamma repeaters (SGRs) and anomalous x-ray pulsars form a rapidly increasing group of x-ray sources exhibiting sporadic emission of short bursts. They are believed to be magnetars, that is, neutron stars powered by extreme magnetic fields, B ~ 10(14) to 10(15) gauss. We report on a soft gamma repeater with low magnetic field, SGR 0418+5729, recently(More)
This paper studies the performance of the precision time protocol (PTP) of the IEEE 1588 standard for drifting slave frequencies. The error expression for the master time estimate at the n<sup>th</sup> slave is analytically derived and demonstrated in simulation runs. We show that single-slave frequency drift is very benign compared to master frequency(More)
Gamma-ray bursts (GRBs) are most probably powered by collimated relativistic outflows (jets) from accreting black holes at cosmological distances. Bright afterglows are produced when the outflow collides with the ambient medium. Afterglow polarization directly probes the magnetic properties of the jet when measured minutes after the burst, and it probes the(More)
We expect that at least one Gamma-Ray Burst per month will be detected in the field of view of INTEGRAL instruments and localized with an accuracy of a few arcminutes. IBIS (the Imager on board INTEGRAL) will be the most sensitive instrument in the soft γ-ray band during the next few years. This will allow INTEGRAL to detect the faintest (and hence the most(More)
We report the discovery of oscillations at 1122 ± 0.3 Hz in an X-ray burst from the X-ray transient XTE J1739-285. The signal has a peak Leahy power of 42.8 and, after consideration of the number of trials, has a chance probability of occurrence of 4×10 −5 , equivalent to a 4.2σ detection. The oscillation frequency suggests that XTE J1739-285 contains the(More)
the date of receipt and acceptance should be inserted later Abstract. Using 2.5 Ms of data obtained by the INTEGRAL satellite in 2003-2004, we discovered persistent hard X-ray emission from the soft gamma-ray repeater SGR 1900+14. Its 20-100 keV spectrum is well described by a steep power law with photon index Γ=3.1±0.5 and flux 1.5×10 −11 erg cm −2 s −1.(More)
— We review the results on Gamma-ray Bursts obtained during the first two and a half years of operations of the INTEGRAL Burst Alert System (IBAS). In many cases GRB coordinates have been distributed with an unprecedented combination of accuracy (3 ′) and speed (20-30 s). The resulting rapid follow-ups at other wavelengths, including sensitive XMM-Newton(More)
We present a catalogue with the properties of all the bursts detected and localized by the IBIS instrument onboard the INTEGRAL satellite from November 2002 to September 2008. The sample is composed of 56 bursts, corresponding to a rate of ∼ 0.8 GRB per month. Thanks to the performances of the INTEGRAL Burst Alert System, 50% of the IBIS GRBs have detected(More)
Context. The physical mechanism responsible for the short outbursts in a recently recognized 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 supergiant donor,(More)