Near-Infrared Spectroscopy of the Cassiopeia A and Kepler Supernova Remnants

摘要: Near-infrared spectra (0.95–2.4 μm) of the Cassiopeia A and Kepler supernova remnants (SNRs) are presented. Low-dispersion (R ≈ 700) were obtained for five bright fast-moving ejecta knots (FMKs) at two locations on main shell three circumstellar (quasi-stellar flocculi or QSFs) near southwest rim Cas A. The FMKs in exhibit a sparse near-infrared spectrum dominated by [S II] 1.03 μm emission with handful other, fainter lines. Among these high-ionization silicon lines, [Si VI] 1.96 X] 1.43 μm, which have been detected active galactic nuclei novae but never before remnant. QSFs show much richer spectrum, strong He I 1.083 over dozen [Fe Observed line ratios indicate electron densities 5–9 × 104 cm-3 QSFs. QSF data quite similar to observed knot along northwest SNR, also shows measured density 2.5–3 cm-3. Finally, we present J- K-band images image faint diffuse that has no optical midinfrared counterpart is morphologically radio continuum maps may be infrared synchrotron radiation.