Evolution and Hydrodynamics of the Very-Broad X-ray Line Emission in SN1987A
Author(s)Dewey, Dan; Dwarkadas, V. V.; Haberl, F.; Sturm, R.; Canizares, Claude R.
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Observations of SN 1987A by the Chandra High Energy Transmission Grating (HETG) in 1999 and the XMM-Newton Reflection Grating Spectrometer (RGS) in 2003 show very broad (v-b) lines with a full width at half-maximum (FWHM) of order 10[superscript 4] km s[superscript –1]; at these times the blast wave (BW) was primarily interacting with the H II region around the progenitor. Since then, the X-ray emission has been increasingly dominated by narrower components as the BW encounters dense equatorial ring (ER) material. Even so, continuing v-b emission is seen in the grating spectra suggesting that the interaction with H II region material is ongoing. Based on the deep HETG 2007 and 2011 data sets, and confirmed by RGS and other HETG observations, the v-b component has a width of 9300 ± 2000 km s[superscript –1] FWHM and contributes of order 20% of the current 0.5-2 keV flux. Guided by this result, SN 1987A's X-ray spectra are modeled as the weighted sum of the non-equilibrium-ionization emission from two simple one-dimensional hydrodynamic simulations; this "2 × 1D" model reproduces the observed radii, light curves, and spectra with a minimum of free parameters. The interaction with the H II region (ρinit ≈ 130 amu cm[superscript –3], ± 15° opening angle) produces the very broad emission lines and most of the 3-10 keV flux. Our ER hydrodynamics, admittedly a crude approximation to the multi-D reality, gives ER densities of ~10[superscript 4] amu cm[superscript –3], requires dense clumps (×5.5 density enhancement in ~30% of the volume), and predicts that the 0.5-2 keV flux will drop at a rate of ~17% per year once no new dense ER material is being shocked.
Author Manuscript 20 Apr 2012.
DepartmentMIT Kavli Institute for Astrophysics and Space Research
Dewey, D. et al. “EVOLUTION AND HYDRODYNAMICS OF THE VERY BROAD X-RAY LINE EMISSION IN SN 1987A.” The Astrophysical Journal 752.2 (2012): 103. © 2012 IOP Publishing
Author's final manuscript