G. De Francesco

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We monitored the BL Lac object S5 0716+714 in the optical band during the period November 1994 – April 1995, which includes the time of a γ–ray observation by the Energetic Gamma Ray Experiment Telescope (EGRET) on February 14–28, 1995. The light curves in the R and B bands show fast fluctuations superimposed on longer timescale variations. The color index(More)
We present the results of an intensive optical and radio monitoring of the γ-loud blazar S4 0954+65 from November 1994 to May 1998. The optical observations were done at the Torino, Perugia, and Tuorla Astronomical Observatories; in this period, including two pointings by the Energetic Gamma Ray Experiment Telescope (EGRET), the source was very active and(More)
Of the blazars detected by EGRET in GeV γ rays, 3C 279 is not only the best-observed by EGRET, but also one of the best-monitored at lower frequencies. We have assembled eleven spectra, from GHz radio through GeV γ rays, from the time intervals of EGRET observations. Although some of the data have appeared in previous publications, most are new, including(More)
BeppoSAX observations of PKS 0528+134 G. Ghisellini, G. Tagliaferri, L. Costamante, L. Maraschi; a A. Celotti, G. Fossati; b L. Bassani, M. Cappi F. Frontera, E. Pian; c A. Comastri; M. Cavallone, G. De Francesco, L. Lanteri, C.M. Raiteri, G. Sobrito, M. Villata; e S. Giarrusso, B. Sacco; f I.S. Glass; g P. Grandi; h E. Massaro; i S. Molendi; j P. Padovani;(More)
Retinitis pigmentosa (RP) is a group of genetically transmitted diseases that are characterised by a progressive loss of photoreceptors, associated with night blindness, and a progressive restriction of peripheral and mid-peripheral visual field. Investigations demonstrated that totally blind persons, whose blindness depends on retinal lesions, can be(More)
We report on the BeppoSAX observations of the γ–ray blazar PKS 0528+134 performed in Feb and Mar 1997, during a multiwavelength campaign involving EGRET and ground based telescopes. The source was in a faint and hard state, with energy spectral index α = 0.48 ± 0.04 between 0.1 and 10 keV, and [2–10] keV flux of 2.7 × 10 −12 erg cm −2 s −1. No significant(More)
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