Stefano Del Sordo

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Over the last decade, cadmium telluride (CdTe) and cadmium zinc telluride (CdZnTe) wide band gap semiconductors have attracted increasing interest as X-ray and gamma ray detectors. Among the traditional high performance spectrometers based on silicon (Si) and germanium (Ge), CdTe and CdZnTe detectors show high detection efficiency and good room temperature(More)
We report on results of a target of opportunity observation of the X-ray transient XTE J1118+480 performed on 2000 April 14–15 with the Narrow Field Instruments (0.1–200 keV) of the BeppoSAX satellite. The measured spectrum is a power law with a photon index of ∼ 1.7 modified by an ultrasoft X-ray excess and a high-energy cutoff above ∼ 100 keV. The soft(More)
We report on an observation of the low-mass X–ray binary 4U1626–67 performed during the BeppoSAX Science Verification Phase. An absorption feature at ∼ 37 keV, attributable to electron cyclotron resonance, has been discovered in its pulse averaged spectrum. The inferred neutron star magnetic field strength is 3.2 · (1 + z) × 10 12 G, where z is the(More)
We present the result of three BeppoSAX observations of the X–ray binary pulsar A0535+26 in its quiescent state. The source is quite well detected up to 200 keV (6σ detection in the stronger observation). No Iron line is detected in the MECS data (3σ upper limit on its equivalent width of 150 eV). There is evidence of a soft excess below 2 keV. Pulsation is(More)
BeppoSAX observed several galactic binary X–ray pulsars during the Science Verification Phase and in the first year of the regular program. The complex emission spectra of these sources are an ideal target for the BeppoSAX instrumentation, that can measure the emission spectra in an unprecedented broad energy band. Using this capability of BeppoSAX a(More)
The X-ray source 4U1700+24/HD154791 is one of the few galactic sources whose counterpart is an evolved M star [1–3]. In X-rays the source shows extreme erratic variability and a complex and variable spectrum. While this strongly suggests accretion onto a compact object, no clear diagnosis of binarity was done up to now. We report on ASCA and BeppoSAX X–ray(More)
We report on the 0.5–200 keV spectral properties of Cyg X-1 observed at different epochs with the Narrow Field Instruments of the BeppoSAX satellite. The source was in its soft state during the first observation of 1996 June. In the second observation of 1996 September, the source had parameters characteristic to its hard state. A soft X-ray excess, a broad(More)
We report on results of BeppoSAX Target Of Opportunity (TOO) observations of the source MXB 1730-335, also called the Rapid Burster (RB), made during its outburst of February–March 1998. We monitored the evolution of the spectral properties of the RB from the outburst decay to quiescence. During the first TOO, the X–ray light curve of the RB showed many(More)
The X–ray telescopes on board BeppoSAX are an optimal set of instruments to observe bright galactic binary pulsars. These sources emit very hard and quite complex X–ray spectra that can be accurately measured with BeppoSAX between 0.1 and 200 keV. A prototype of this complexity, the source Her X–1, shows at least seven different components in its spectrum.(More)
The BeppoSAX Narrow Field Instruments observed the galactic source GS 1826-238 in October 1997, following a hard X-ray burst with a peak flux of about 100 mCrab detected by BATSE. Two short X-ray bursts (∼150 seconds) were detected up to 60 keV, with larger amplitude and duration at lower energies (up to a factor 20 times the persistent emission). This(More)