ChandraHigh‐Resolution X‐Ray Spectrum of Supernova Remnant 1E 0102.2−7219

Abstract

Chandra High Energy Transmission Grating Spectrometer observations of the supernova remnant (SNR) 1E 0102.2À7219 in the Small Magellanic Cloud reveal a spectrum dominated by X-ray emission lines from hydrogen-like and helium-like ions of oxygen, neon, magnesium, and silicon, with little iron. The dispersed spectrum shows a series of monochromatic images of the source in the light of individual spectral lines. Detailed examination of these dispersed images reveals Doppler shifts within the SNR, indicating bulk matter velocities on the order of 1000 km s À1 . These bulk velocities suggest an expanding ringlike structure with additional substructure, inclined to the line of sight. A two-dimensional spatial/velocity map of the SNR shows a striking spatial separation of redshifted and blueshifted regions and indicates a need for further investigation before an adequate three-dimensional model can be found. The radii of the ringlike images of the dispersed spectrum vary with ionization stage, supporting an interpretation of progressive ionization due to passage of the reverse shock through the ejecta. Plasma diagnostics with individual emission lines of oxygen are consistent with an ionizing plasma in the low-density limit and provide temperature and ionization constraints on the plasma. Assuming a pure metal plasma, the mass of oxygen is estimated at $6 M , consistent with a massive progenitor.

SNR 1E 0102.2-7219 as an X-ray calibration standard in the 0.5−1.0 keV bandpass and its application to the CCD instruments aboardChandra,Suzaku,SwiftandXMM-Newton

“…The HETG spectrum (Flanagan et al 2004) and the RGS spectrum both show strong lines of O, Ne, and Mg with little or no Fe, consistent with the spectra at other wavelengths. E0102's spectrum is relatively simple compared to a typical SNR spectrum.…”

“…The line widths were also allowed to vary. In most cases the line widths are small but non-zero, consistent with the Doppler widths seen in the RGS and HETG (Flanagan et al 2004) data, σ E ≈ 0.003 × E; however, in a few cases noted in the Table, the widths are larger than this value. This is most likely due to weak, nearby lines which our model has ignored.…”

“…Since our objective is calibration, we decided against using any of the available plasma emission models for several reasons. First, the Chandra results on E0102 (Flanagan et al 2004;Gaetz et al 2000;Hughes et al 2000) have shown there are significant spectral variations within the SNR, implying that the plasma conditions are varying throughout the remnant. Since the other missions considered Suzaku XIS 6' 50.7" Fig.…”

“…The roll angles of these epochs were deliberately chosen to differ with a view toward future spectral-tomographic analyses. The HETG view of E0102 is presented in Flanagan et al (2004) using the first epoch observations: the bright ring of E0102 is dispersed and shows multiple ring-like images due to the prominent emission lines in the spectrum. The combination of all three epoch's MEG data is shown in Fig.…”

The population of X-ray supernova remnants in the Large Magellanic Cloud

“…However, this method cannot give definite results for individual objects: Prominent counterexamples include SNR 1E 0102.2−7219, a textbook CC SNR which is highly symmetric (Flanagan et al 2004), and MCSNR J0547−7025, which is a type Ia SNR (based on its X-ray spectrum Hendrick et al 2003, this work) with "anomalous" ejecta distribution (Lopez et al 2009). …”