Ionization age of iron ejecta in the Galactic Type Ia supernova remnant G306.3-0.9. (arXiv:1903.02554v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Sawada_M/0/1/0/all/0/1">Makoto Sawada</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tachibana_K/0/1/0/all/0/1">Katsuhiro Tachibana</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Uchida_H/0/1/0/all/0/1">Hiroyuki Uchida</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ito_Y/0/1/0/all/0/1">Yuta Ito</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Matsumura_H/0/1/0/all/0/1">Hideaki Matsumura</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bamba_A/0/1/0/all/0/1">Aya Bamba</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tsuru_T/0/1/0/all/0/1">Takeshi Go Tsuru</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tanaka_T/0/1/0/all/0/1">Takaaki Tanaka</a>
We present a 190 ks observation of the Galactic supernova remnant (SNR)
G306.3-0.9 with Suzaku. To study ejecta properties of this possible Type Ia
SNR, the absolute energy scale at the Fe-K band was calibrated to a level of
uncertainty less than 10 eV by a cross-calibration with the Hitomi
microcalorimeter using the Perseus cluster spectra. This enabled us for the
first time to accurately determine the ionization state of the Fe K$alpha$
line of this SNR. The ionization timescale ($tau$) of the Fe ejecta was
measured to be $log_{10} tau$ (cm$^{-3}$ s) $=10.24pm0.03$, significantly
smaller than previous measurements. Marginally detected K$alpha$ lines of Cr
and Mn have consistent ionization timescales with Fe. The global spectrum was
well fitted with shocked interstellar matter (ISM) and at least two ejecta
components with different ionization timescales for Fe and intermediate mass
elements (IME) such as S and Ar. One plausible interpretation of the
one-order-of-magnitude shorter timescale of Fe than that of IME ($log_{10}
tau = 11.17pm0.07$) is a chemically stratified structure of ejecta. By
comparing the X-ray absorption column to the HI distribution decomposed along
the line of sight, we refined the distance to be $sim$20 kpc. The large
ISM-to-ejecta shocked mass ratio of $sim$100 and dynamical timescale of
$sim$6 kyr place the SNR in the late Sedov phase. These properties are
consistent with a stratified ejecta structure that has survived the mixing
processes expected in an evolved supernova remnant.
We present a 190 ks observation of the Galactic supernova remnant (SNR)
G306.3-0.9 with Suzaku. To study ejecta properties of this possible Type Ia
SNR, the absolute energy scale at the Fe-K band was calibrated to a level of
uncertainty less than 10 eV by a cross-calibration with the Hitomi
microcalorimeter using the Perseus cluster spectra. This enabled us for the
first time to accurately determine the ionization state of the Fe K$alpha$
line of this SNR. The ionization timescale ($tau$) of the Fe ejecta was
measured to be $log_{10} tau$ (cm$^{-3}$ s) $=10.24pm0.03$, significantly
smaller than previous measurements. Marginally detected K$alpha$ lines of Cr
and Mn have consistent ionization timescales with Fe. The global spectrum was
well fitted with shocked interstellar matter (ISM) and at least two ejecta
components with different ionization timescales for Fe and intermediate mass
elements (IME) such as S and Ar. One plausible interpretation of the
one-order-of-magnitude shorter timescale of Fe than that of IME ($log_{10}
tau = 11.17pm0.07$) is a chemically stratified structure of ejecta. By
comparing the X-ray absorption column to the HI distribution decomposed along
the line of sight, we refined the distance to be $sim$20 kpc. The large
ISM-to-ejecta shocked mass ratio of $sim$100 and dynamical timescale of
$sim$6 kyr place the SNR in the late Sedov phase. These properties are
consistent with a stratified ejecta structure that has survived the mixing
processes expected in an evolved supernova remnant.
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