XMM-Newtonobservations of SNR 1987A

Abstract

Aims. We report on the recent observations of the supernova remnant SNR 1987A in the Large Magellanic Cloud with XMM-Newton. Carefully monitoring the evolution of the X-ray light curve allows us to probe the complex circumstellar medium structure observed around the supernova progenitor star. Methods. We analysed all XMM-Newton observations of SNR 1987A from January 2007 to December 2011, using data from the EPIC-pn camera. Spectra from all epochs were extracted and analysed in a homogeneous way. Using a multi-shock model to fit the spectra across the 0.2-10 keV bandm we measured soft and hard X-ray fluxes with high accuracy. In the hard X-ray band we examined the presence and properties of Fe K lines. Our findings have been interpreted in the framework of a hydrodynamics-based model. Results. The soft X-ray flux of SNR 1987A has continuously increased in recent years. Although the light curve shows a mild flattening, there is no sudden break as reported in an earlier work, a picture echoed by a revision of the Chandra light curve. We therefore conclude that material in the equatorial ring and out-of-plane H ii regions are still being swept up. We estimate the thickness of the equatorial ring to be at least 4.5 × 10 16 cm (0.0146 pc). This lower limit will increase as long as the soft X-ray flux has not reached a turn-over. We detect a broad Fe K line in all spectra from 2007 to 2011. The widths and centroid energies of the lines indicate there is a collection of iron ionisation stages. Thermal emission from the hydrodynamic model does not reproduce the low-energy part of the line (6.4-6.5 keV), suggesting that fluorescence from neutral and/or low ionisation Fe might be present.

The Destruction of the Circumstellar Ring of Sn 1987a

“…This may explain the still increasing soft X-ray emission (Maggi et al 2012;Helder et al 2013), in contrast to the optical. Dewey et al (2012) find from modeling of the X-ray observations a filling factor of ∼ 30% for the dense clumps.…”

“…The range of densities in the unshocked ring has been estimated to 1 × 10 2 cm −3 up to 3 × 10 4 cm −3 (Mattila et al 2010), while the shock speed from the X-ray imaging is ∼ 1, 820 km s −1 (Maggi et al 2012;Helder et al 2013), coming from shocks propagating in the lowdensity component of the gas. Assuming that the interaction with the ring started on day 5,600 (Helder et al 2013), the blast wave has expanded by ∼ 7 × 10 16 cm up to day 9,975, or ∼ 10% of the radius of the ring.…”

Chandra Observes the End of an Era in Sn 1987a

“…XMM EPIC-pn fluxes through 2011 are available in Haberl et al (2006) and Maggi et al (2012). However, for consistency with our Chandra analysis and to obtain fluxes for the unpublished 2012 and 2014 XMM observations, we reanalyzed spectra from all EPIC-pn observations since 2001 (day 5100).…”

“…Details of the observations are shown in Table 1. EPIC-pn spectra were extracted using SAS version 14, but otherwise following the procedure used by Maggi et al (2012). It was also necessary to correct most of the EPIC-pn spectra for pileup, using the method described in the relevant SAS data analysis thread 1 .…”

3D MHD modeling of the expanding remnant of SN 1987A

“…Comparison between observed (symbols) and synthetic (lines) X-ray lightcurves in the [0.5, 2] keV (upper panels) and[3, 10] keV (lower panels) bands for the best-fit HD model ofOrlando et al (2015; left panels) and for the MHD model MOD-B1 presented here (right panels). Solid lines show the synthetic lightcurves; dotted, dashed, and dot-dashed lines indicate the contribution to emission from the shocked ejecta, the shocked plasma from the H II region, and the shocked plasma from the ring, respectively; the different symbols show the fluxes measured with Rosat (black diamonds;Haberl et al 2006), ASCA (green;Orlando et al 2015), Chandra (red;Helder et al 2013;Frank et al 2016), and XMM-Newton (cyan;Haberl et al 2006;Maggi et al 2012;Orlando et al 2015).…”