Early AGILE gamma-ray observations of the recent Glitch in the Crab Pulsar

ATel #10965; F. Verrecchia (SSDC and INAF/OAR), G. Piano (INAF/IAPS), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), M. Pilia (INAF/OA-Cagliari), C. Pittori, F. Lucarelli (SSDC and INAF/OAR), A. Bulgarelli (INAF/IASF-Bo), M. Cardillo (INAF/IAPS), V. Fioretti, N. Parmiggiani (INAF/IASF-Bo), E. Striani (CIFS and INAF/IAPS), S. Vercellone (INAF/OA-Brera), I. Donnarumma (ASI), F. Gianotti, M. Trifoglio (INAF/IASF-Bo), A. Giuliani, S. Mereghetti, P. Caraveo, F. Perotti (INAF/IASF-Mi), A. Chen (Wits University), A. Argan, E. Costa, E. Del Monte, Y. Evangelista, M. Feroci, F. Lazzarotto, I. Lapshov, L. Pacciani, P. Soffitta, S. Sabatini, V. Vittorini (INAF/IAPS), G. Pucella, M. Rapisarda (ENEA-Frascati), G. Di Cocco, F. Fuschino, M. Galli, C. Labanti, M. Marisaldi (INAF/IASF-Bo), A. Pellizzoni, A. Trois (INAF/OA-Cagliari), G. Barbiellini, E. Vallazza (INFN Trieste), F. Longo (Univ. Trieste and INFN Trieste), A. Morselli, P. Picozza (INFN and Univ. Roma Tor Vergata), M. Prest (Univ. dell'Insubria), P. Lipari, D. Zanello (INFN and Univ. Roma Sapienza), P. W. Cattaneo, A. Rappoldi (INFN Pavia), S. Colafrancesco (INAF/OAR and Wits University), A. Ferrari (Univ. Torino and CIFS), F. Paoletti (East Windsor RSD Hightstown and INAF/IAPS), A. Antonelli (SSDC), P. Giommi, L. Salotti, G. Valentini, and F. D'Amico (ASI)
on 13 Nov 2017; 16:05 UT
Credential Certification: Francesco Verrecchia (francesco.verrecchia@asdc.asi.it)

Subjects: Gamma Ray, >GeV, Pulsar

AGILE observed the Crab region in its spinning mode after the large glitch recently reported in the radio band (ATel #10939). At the glitch event time (T_0) the AGILE satellite was occulted by the Earth, and no observation of any relevant gamma-ray signal could be obtained by the GRID detector. The first useful exposure by the imaging GRID detector of the Crab position started at time t = +400 s after T_0, with the source position falling near the exposed field-of-view border.

The AGILE GRID in its sky-scanning mode repeatedly exposed the Crab position before and after T_0. Combining the early GRID observations by integrating over the first +3000 sec after T_0, we obtain the following 2-sigma gamma-ray flux upper limit (UL) above 100 MeV in the GRB-detection mode UL = 0.7 x10^-8 erg cm^-2 s^-1.

We monitored the source over longer integration intervals following the event (from 1 to 12 hrs); we obtain by the standard likelihood method above 100 MeV a flux compatible with the average standard source flux.

This measurement was obtained with AGILE observing a large portion of the sky in spinning mode.