Letter to the Editor

GRB 070724B: the first gamma ray burst localized by SuperAGILE and its Swift X-ray afterglow^*

¹ INAF IASF Roma, via Fosso del Cavaliere 100, 00133 Roma, Italy e-mail: ettore.delmonte@iasf-roma.inaf.it
² Dip. di Fisica, Università degli Studi di Roma “La Sapienza”, P.le A. Moro 5, 00185 Roma, Italy
³ ENEA UTS Fusione Tecnologie, via E. Fermi 45, 00044 Frascati (Rm), Italy
⁴ INFN Trieste, Padriciano 99, 34012 Trieste, Italy
⁵ Dip. di Fisica, Università di Trieste, via Valerio 2, 34127 Trieste, Italy
⁶ INAF IASF Bologna, via Gobetti 101, 40129 Bologna, Italy
⁷ INAF IASF Milano, via E. Bassini 15, 20133 Milano, Italy
⁸ ENEA C.R. “E. Clementel”, via don Fiammelli 2, 40128 Bologna, Italy
⁹ INFN Pavia, via Bassi 6, 27100 Pavia, Italy
¹⁰ Dip. di Fisica, Università degli Studi di Roma “Tor Vergata”, via della Ricerca Scientifica 1, 00133 Roma, Italy
¹¹ Dip. di Fisica e Matematica, Università dell'Insubria, via Valleggio 11, 20100 Como, Italy
¹² Consorzio Interuniversitario per la Fisica Spaziale, Viale Settimio Severo 63, 10133 Torino, Italy
¹³ INAF - Osservatorio Astronomico di Brera, via E. Bianchi 46, 23807 Merate (LC), Italy
¹⁴ Università degli Studi di Milano-Bicocca, Piazza delle Scienze 3, 20126 Milano, Italy
¹⁵ Department of Astronomy & Astrophysics, Pennsylvania State University, DNBurrows 525 Davey Lab, University Park, PA 16802, USA
¹⁶ NASA/Goddard Space Flight Center, Greenbelt, MD 20771, USA
¹⁷ INAF IASF Palermo, via U. La Malfa 153, 90146 Palermo, Italy
¹⁸ Department of Physics & Astronomy, University of Leicester, LE1 7RH, UK
¹⁹ ASI Science Data Center, via G. Galilei, 00044 Frascati (Rm), Italy
²⁰ INAF personnel resident at ASI Science Data Center
²¹ Osservatorio Astronomico di Roma, via di Frascati 33, 00040 Monte Porzio Catone (Rm), Italy
²² Agenzia Spaziale Italiana, Unità Osservazione dell'Universo, Viale Liegi 26, 00198 Roma, Italy

Received: 9 October 2007
Accepted: 15 November 2007

Abstract

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.