Marco Feroci

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Received ; accepted – 2 – ABSTRACT The gamma–ray burst of 1997 February 28 was localized using the arrival– time analysis method with the Ulysses, BeppoSAX, and WIND spacecraft. The result is a ±31.5 ′′ (3σ) wide annulus of possible arrival directions which intersects both the position of the burst determined independently by the SAX Wide Field Camera, and(More)
We present optical, X-ray, high energy (30 GeV) and very high energy (100 GeV; VHE) observations of the high-frequency peaked blazar Mrk 421 taken between 2008 May 24 and June 23. A high energy γ-ray signal was detected by AGILE with √ T S = 4.5 on June 9–15, with F (E > 100 MeV) = 42 +14 −12 × 10 −8 photons cm −2 s −1. This flaring state is brighter than(More)
The Italian-Dutch satellite for X-ray Astronomy BeppoSAX is successfully operating on a 600 km equatorial orbit since May 1996. We present here the in-flight performances of the Gamma Ray Burst Monitor experiment during its first year of operation. The GRBM is the secondary function of the four CsI(Na) slabs primarily operating as an active anticoincidence(More)
In this paper we present BeppoSAX and XMM-Newton observations of two long Gamma-ray bursts, the X-ray rich event of December 11, 2001 (GRB011211) and the hard and very bright event of November 21, 2001 (GRB011121). In both events we find evidence of a late X-ray burst, taking place several minutes after the prompt emission. In the November burst the(More)
We report the discovery of a radio counterpart to GRB 990123. In contrast to previous well-studied radio afterglows which rise to peak flux on a timescale of a week and then decay over several weeks to months, the radio emission from this GRB was clearly detected one day after the burst, after which it rapidly faded away. The simplest interpretation of this(More)
We report high-energy spectral data of the prompt emission of GRB970228 and its X–ray afterglow. We establish that the nature of the X–ray afterglow emission is non-thermal and similar to the later portion of GRB970228. Our data can be used to discriminate different emission models of GRB afterglows. While cooling of excited compact objects can be ruled(More)
SuperAGILE is a coded mask experiment based on silicon microstrip detectors. It operates in the 15-45 keV nominal energy range, providing crossed one-dimensional images of the X-ray sky with an on-axis angular resolution of 6 arcmin, over a field of view in excess of 1 steradian. It was designed as the hard X-ray monitor of the AGILE space mission, a small(More)
The well-known Crab Nebula is at the center of the SN1054 supernova remnant. It consists of a rotationally powered pulsar interacting with a surrounding nebula through a relativistic particle wind. The emissions originating from the pulsar and nebula have been considered to be essentially stable. Here, we report the detection of strong gamma-ray (100(More)
High-time-resolution X-ray observations of compact objects provide direct access to strong-field gravity, to the equation of state of ultra-dense matter and to black hole masses and spins. A 10 m 2-class instrument in combination with good spectral resolution is required to exploit the relevant diagnostics and answer two of the fundamental questions of the(More)