论文标题
SN2014C协调的Chandra-Nustar观察七年
Seven years of coordinated Chandra-NuSTAR observations of SN2014C unfold the extreme mass-loss history of its stellar progenitor
论文作者
论文摘要
我们通过\ emph {chandra}和\ emph {nustar}介绍了我们为期七年的Broad Band X射线观测活动的结果。这些协调的观察结果代表了核心崩溃后几年中0.3-80 keV能量范围内的年轻型外术SN的演变。我们发现，SN \，2014c的光谱变态从普通型IB SN到与大量氢发射的SN相互作用的SN伴随着$ L_X \ $ l_x \约5.6 \ times10^{40} {40} \ rm {erg rm {erg rm {爆炸，以$ l_x \ propto t^{ - 1} $下降。宽带X射线光谱是热源，并显示出峰值后冷却的明确证据，$ t（t）\ oft 20 \，{\ rm kev}（t/t _ {\ rm pk}）^{ - 0.5} $。 sub-kev能量的软X射线具有较大的光电吸收，源自本地SN环境，$ nh _ {\ rm int}（t）（t）（t）\ oft 3 \ times 10^{22} {22}（t/400 \，\ rm {days} days}）我们将这些发现解释为Sn冲击与致密（$ n \ of 10^{5} -10^{6} \，\ rm {cm^{ - 3}} $）的结果 厘米。基于$ nh _ {\ rm int}（t）$和X射线光度演变的下降，我们推断出$ \ sim的CSM质量（1.2 \，f $ - 2.0 $ \ sqrt {f} {f}）\ rm {m _ {m _ {\ odot}} $，其中$ f $ ins $ f $ ins ins the comles insome bum ins polums。最后，我们将SN \，2014c放置在119个核心崩溃SNE的背景下，有证据表明与厚实的杂物介质进行了强烈的冲击相互作用，我们强调了当前的质量损失理论（包括波浪驱动的质量损失，二进制互动和线路驱动的风），即解释了CSM参数的广泛动态范围，从而使CSM参数从观察者中进行了分解。
We present the results from our seven-year long broad-band X-ray observing campaign of SN\,2014C with \emph{Chandra} and \emph{NuSTAR}. These coordinated observations represent the first look at the evolution of a young extragalactic SN in the 0.3-80 keV energy range in the years after core collapse. We find that the spectroscopic metamorphosis of SN\,2014C from an ordinary type Ib SN into an interacting SN with copious hydrogen emission is accompanied by luminous X-rays reaching $L_x\approx 5.6\times10^{40}\, \rm{erg\,s^{-1}}$ (0.3--100 keV) at $\sim 1000$ days post explosion and declining as $L_x\propto t^{-1}$ afterwards. The broad-band X-ray spectrum is of thermal origin and shows clear evidence for cooling after peak, with $T(t)\approx 20 \,{\rm keV}(t/t_{\rm pk})^{-0.5}$. Soft X-rays of sub-keV energy suffer from large photoelectric absorption originating from the local SN environment with $NH_{\rm int}(t)\approx3\times 10^{22}(t/400 \,\rm{days})^{-1.4}\,\rm{cm^{-2}}$. We interpret these findings as the result of the interaction of the SN shock with a dense ($n\approx 10^{5}-10^{6}\,\rm{cm^{-3}}$), H-rich disk-like circumstellar medium (CSM) with inner radius $\sim2\times 10^{16}$ cm and extending to $\sim 10^{17}$ cm. Based on the declining $NH_{\rm int}(t)$ and X-ray luminosity evolution, we infer a CSM mass of $\sim(1.2\,f$--2.0$\sqrt{f}) \rm{M_{\odot}}$, where $f$ is the volume filling factor. Finally, we place SN\,2014C in the context of 119 core-collapse SNe with evidence for strong shock interaction with a thick circumstellar medium and we highlight the challenges that the current mass-loss theories (including wave-driven mass loss, binary interaction and line-driven winds) face when interpreting the wide dynamic ranges of CSM parameters inferred from observations.
