ISO observations of the GRB 970402 error box
A. J. Castro-Tirado, L. Metcalfe, R. Laureijs, B. Altieri, J. Gorosabel, L. Hanlon, B. McBreen, N. Smith, E. Costa, M. Feroci, E. Palazzi, L. Nicastro, F. Frontera, A. Claret, M. Kessler;
AaA, 1998, 330, 14
ABSTRACT:Following the detection by BeppoSAX of GRB 970402, a Target-of-Opportunity Observation by ISO was scheduled for 5 April, about 55-hours after the
event, i.e.
simultaneous with a second BeppoSAX pointing.
The CAM
instrument was used in the 6('') /pixel mode, in the 8-15 mu m band (IRAS) for
covering the entire BeppoSAX GRB error box.
A further observation was carried
out on 13 April, with a similar set-up.
Imaging was performed with the
6('') /pixel mode in the GRB error box, and with the 1.5('') /pixel field of
view, in the smaller X-ray source error box.
A PHT observation was also
performed on 5 April.
About 50 sources were detected with ISOCAM in a field
centred in the GRB error box.
7 of them lie within the smaller X-ray error
circle.
With the exception of the variable star BL Cir, no other variable object was
found in the entire GRB error box.
5-sigma upper limits for any new object are
F_{(12microns )} <= 0.14 mJy and F_{(174microns )} <= 350 mJy.
Based on observations
obtained with ISO, an ESA project with instruments funded by ESA Member States
(especially the PI countries: France, Germany, the Netherlands and the United
Kingdom) with the participation of ISAS and NASA.
KEYWORDS: gamma rays: bursts, stars: bl cir, infrared: general
CODE: castro-tirado98