SN 1987A: Model fits to the HETG-2007 observations

Results

The bright lines in the HETG-2007 SN 1987A spectrum were fit by a tilted ring model to measure the "v_ring" based on the 4 spectral views of the line: the HEG and MEG , plus and minus order dispersed data. The zeroth-order data is implicitly used because the ring model is constrained to agree with the zeroth-order.

Plots and parameters for the lines and pairs-of-line fit are given by links in the table below. The plots consist of 4 panels corresponding to the 4 grating spectra (MEG,HEG x plus/minus orders) and show the data in black and model fit in red. Also plotted are the high-T(blue) and low-T(orange) shock models at a higher resolution (no velocity or spatial effects included) for reference. Note that these curves give an idea of whether a line originates mostly in the high or low temperature plasma.

Line	lambda_APED	plots	parameters
Si XIV L-alpha	6.183	plots	parameters
Si XIII r (and i)	6.648	plots	parameters
Si XIII f	6.740	plots	parameters
Mg XII L-alpha	8.422	plots	parameters
Mg XI r (and i)	9.169	plots	parameters
Mg XI f	9.314	plots	parameters
Ne X L-beta	10.239	plots	parameters
Ne IX 3-1	11.544	plots	parameters
Ne X L-alpha	12.135	plots	parameters
Ne IX r (and i)	13.447	plots	parameters
Ne IX f	13.699	plots	parameters
Fe XVII	15.014	plots	parameters
O VIII L-beta	16.006	plots	parameters
Fe XVII	16.780	plots	parameters
Fe XVII (and 17.096)	17.051	plots	parameters
O VIII L-alpha	18.970	plots	parameters
O VII r	21.602	plots	parameters
O VII f	22.098	plots	parameters
N XVII L-alpha	24.782	plots	parameters

Software

The fits here were carried out in ISIS using the nominally processed SN 1987A data sets from the first 13 obsids, with an average roll angle of 263 degrees. The fit model consists of one (or two) lines with a shape based on an azimuthally-varying tilted ring model which agrees with the zeroth-order imaging data. A continuum was included consisting of the nominal 2-shock model with the element of the line being fit's abundance set to zero. The following routines were used:

• sn87a_load_phas_263.sl - read in the data, arfs, and rmfs.
• line_fit_model.i - calculate and save the Hi-T and Low-T nominal spectral models for over plotting.
• i3d_sn1987a.071205.sl - defines the ISIS i3d custom fit function with the azimuthal varying tilted ring model including a ring velocity and turbulent velocity.
  
  
• line_fit_sn1987a.i - the main fitting routine, see it comments for more information.
• line_conf.i - perform confidence limits on the v_ring value.
• line_plot.i - create and save output plots and .par files.
  
  
• line2_fit_sn1987a.i - a 2-line version of line_fit_sn1987a.i for closely spaced lines.
• line2_conf.i - 2-line version of line_conf.i.