We study the X-ray spectra of 114 flat-spectrum radio quasars (FSRQ) using the hardness ratios as given in the WGA catalogue of ROSAT sources. This sample includes all WGA FSRQ with high-quality data and comprises about 20 per cent of presently known such objects, which makes this the largest FSRQ sample ever studied in the X-ray band. We find that FSRQ have a distribution of energy spectral indices ranging between 0 and 3 with a mean value alpha_x 1. This is consistent with that of low-energy cutoff BL Lacs (LBL; alpha_x 1.1), generally found in radio surveys, but significantly different from that of high-energy cutoff BL Lacs (HBL), normally selected in the X-ray band, which display steeper X-ray spectra (alpha_x 1.5). The shape of the optical-to-X-ray continuum is concave (that is alpha_x < alpha_ox) for the majority of FSRQ, as found for LBL, supporting a dominance of inverse Compton emission in the X-ray band in most objects. Our results are at odds with previous studies of the X-ray spectra of FSRQ, which were however plagued by low spectral resolution and/or small number statistics and selection effects, and have important implications for the proposed connections between FSRQ and BL Lacs.

GRB970402 is the fourth gamma-ray burst detected by BeppoSAX simultaneously in the Gamma Ray Burst Monitor (GRBM) and one of the two Wide Field Cameras (WFCs). A rapid pointing of the BeppoSAX Narrow Field Instruments (NFIs) 8 hours after the GRB led to the identification of an unknown weak X-ray source: 1SAX J1450.1-6920. Its position was approximately at the center of the 3 arcmin error circle derived from the WFC image. Both the Medium Energy (MECS, 2-10 keV) and Low Energy (LECS, 0.1-10 keV) concentrators detected the source. A follow-up observation performed 1.5 days later and lasting 54 ks showed that the source had faded almost to, but not below the detectability threshold. The flux decrease between the two observations was a factor =~ 2.5. 1SAX J1450.1-6920 was the second X-ray afterglow associated with a GRB. Searches promptly started at other wavelengths (optical, IR, radio) did not reveal any transient event within the 3 arcmin error circle.

GRB 070724B is the first gamma ray burst localized by SuperAGILE, the hard X-ray monitor aboard the AGILE satellite. The coordinates of the event were published ~19 h after the trigger. The Swift X-Ray Telescope pointed at the SuperAGILE location and detected the X-ray afterglow inside the SuperAGILE error circle. The AGILE gamma-ray Tracker and Minicalorimeter did not detect any significant gamma ray emission associated with GRB 070724B in the MeV and GeV range, neither prompt nor delayed. Searches for the optical afterglow were performed by the Swift UVOT and the Palomar automated 60-inch telescopes, resulting in no significant detection. Similarly, the Very Large Array did not detect any radio afterglow. This is the first GRB event associated with an X-ray afterglow with a firm upper limit in the 100 MeV-30 GeV energy range. Table [see full text] is only available in electronic form at http //www.aanda.org

During an AGILE pointing at the North Galactic Pole region aiming at WComae, started on 2008 June 9 18 00 UT, SuperAGILE detected enhanced hard X-ray emission from the BL Lac source Mkn 421, lying approximately 17 degrees off-axis with respect to the center of the field of view. The measured average 20-60 keV flux was 32 mCrab between 2008 June 10 06 30 UT and 2008 June 11 06 30 UT, and 41 mCrab between 2008 June 11 06 30 UT and 2008 June 12 08 00 UT.