Suzaku Observations of SN 1987A

Abstract

We report on Suzaku observations of SN1987A in the Large Magellanic Cloud, performed in 2005 November and 2006 June. The observations provide medium resolution X-ray spectra during the phase of the interaction between the supernova blast wave and the inner circumstellar ring. The Suzaku observations complement XMM-Newton and Chandra observations and were used to investigate the spectral evolution of SN1987A. The spectra were analyzed with two-temperature emission model from shocked gas. For the flux in the soft band (0.5--2.0keV) we obtained 25.7_-1.9^+1.4 × 10^-13 erg cm^-2 (2005) and 30.8_-1.7^+1.4 × 10^-13erg cm^-2 (2006). The exponential rise seen in the soft X-ray light curve of SN1987A till ∼6500d after the explosion slowed down significantly between the Suzaku observations. Recent Chandra and XMM-Newton observations confirm this evolution. SN1987A continues to brighten exponentially, but with longer characteristic timescale. This must be caused by a less rapidly increasing emission measure.