Immacolata Donnarumma

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We present a detailed analysis of the stellar mass content of galaxies up to z = 2.5 as obtained from the K20 spectrophotometric galaxy sample. We have applied and compared two different methods to estimate the stellar mass M∗ from broad–band photometry: a Maximal Age approach, where we maximize the age of the stellar population to obtain the maximal mass(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)
Strong electric discharges associated with thunderstorms can produce terrestrial gamma-ray flashes (TGFs), i.e., intense bursts of x rays and γ rays lasting a few milliseconds or less. We present in this Letter new TGF timing and spectral data based on the observations of the Italian Space Agency AGILE satellite. We determine that the TGF emission above 10(More)
Terrestrial gamma-ray flashes (TGFs) are very short bursts of high-energy photons and electrons originating in Earth's atmosphere. We present here a localization study of TGFs carried out at gamma-ray energies above 20 MeV based on an innovative event selection method. We use the AGILE satellite Silicon Tracker data that for the first time have been(More)
o S ( B L A Z A R S 2 0 0 8 ) 0 3 3 AGILE dete tion of variable gamma-ray a tivity from the blazar S5 0716+714 during September O tober 2007 F. D'Ammando∗ab, A. W. Chenc, M. Villatad, C. M. Raiterid, V. Vittorinia, A. Bulgarellie, I. Donnarummaa, A. Giulianic, F. Longo f , L. Pa iania, G. Pu ellaa, M. Tavania, S. Ver ellonec aINAF/IASF-Roma, Via del Fosso(More)
  • C. M. Raiteri, M. Villata, +57 authors A. Volvach
  • 2008
Context. The quasar-type blazar 3C 454.3 underwent a phase of high activity in summer and autumn 2007 that was intensively monitored in the radio-to-optical bands by the Whole Earth Blazar Telescope (WEBT). The γ-ray satellite Astro-rivelatore Gamma a Immagini LEggero (AGILE) detected this source first in late July, and then in November–December 2007. Aims.(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)
GRB 080514B is the first gamma ray burst (GRB), since the time of EGRET, for which individual photons of energy above several tens of MeV have been detected with a pair-conversion tracker telescope. This burst was discovered with the Italian AGILE gamma-ray satellite. The GRB was localized with a cooperation by AGILE and the interplanetary network (IPN).(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 √ TS = 4.5 on June 9–15, with F (E > 100 MeV) = 42 −12 × 10 photons cm s. This flaring state is brighter than the average(More)