Suzaku observations of SN 1987A

Abstract

We report on Suzaku observations of SN 1987 A 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 SN 1987 A. The spectra were analyzed with two-temperature emission model from shocked gas. For the flux in the soft band (0.5- 2.0 keV) we obtained 25.7+1.4-19 x 10-13ergcm-2 (2005) and 30.8+1.4-1.7x 10-13ergcnT -2 (2006). The exponential rise seen in the soft X-ray light curve of SN 1987 A till ∼6500d after the explosion slowed down significantly between the Suzaku observations. Recent Chandra and XMM-Newton observations confirm this evolution. SN 1987 A continues to brighten exponentially, but with longer characteristic timescale. This must be caused by a less rapidly increasing emission measure. © 2009. Astronomical Society of Japan.