ISO SWS/LWS observations of SN 1987A
Sollerman, J.; Lundqvist, P.; Spyromilio, J.; Kozma, C.; Danziger, J.; Larsson, B.; Kunze, D.; Crotts, A. P. S.
Sweden, Germany, United States, Italy
Abstract
We report on observations of SN 1987A with ISO SWS/LWS made 9-11 years after the explosion. No emission from the supernova was seen. In particular, the upper limits on the fluxes of [Fe I] 24.05 μm and [Fe II] 25.99 μm on day 3 999 are ~ 1.1 Jy and ~ 1.4 Jy, respectively. Assuming a homogeneous distribution of (44) Ti inside 2 000 km s(-1) , we have made theoretical models to estimate the mass of ejected (44) Ti. Assessing various uncertainties of the model, we obtain an upper limit of =~ 1.5EE {-4}M_sun. The implications of this are discussed. The LWS data display continuum emission as well as nebular lines of [O I], [C II] and [O III] from neighboring photoexcited regions in the LMC. The [O III] lines indicate an electron density of 120+/-75 cm(-3) , and the continuum can be explained by dust with a temperature of ~ 37 K. A second dust component with ~ 10 K may also be present. ISO is an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, the Netherlands and the United Kingdom) and with the participation of ISAS and NASA.