论文标题
超新星冒名顶替者的蓝色超级祖先在〜2019Krl
The Blue Supergiant Progenitor of the Supernova Imposter AT~2019krl
论文作者
论文摘要
广泛的存档\ TextIt {Hubble Space望远镜},\ TextIt {Spitzer Space望远镜}以及M74中最新中间luminosie Transient的大型双筒望远镜成像,M74中的〜20KRLL,显示出明亮的光学光学和中帧的光学和中间的前胎恒星。虽然错过了事件的光峰,但在红外线中检测到峰值,绝对幅度为$ m_ {4.5 \,μ{\ rm m}} = -18.4 $ mag,导致我们推断出视觉波长的绝对幅度$ -13.5至$ -14.5 $ -14.5 $ 13.5至$ 14.5。前发现的光曲线表明在前16 \ yr上没有爆发。如果仅考虑到任何其他局部灭绝,则祖先的颜色,幅度和推断的温度最佳与13--14 m $ $ _ {\ sun} $黄色或蓝色的超级巨人(BSG)匹配,或者仅考虑前景灭绝或更热的恒星,或者更热的恒星。恒星的爆发光谱显示出强大的H $α$和[n〜 {\ sc ii}]发射,翅膀延伸至$ \ pm 2000 $ \,km \,s $^{ - 1} $。爆发后的频谱相当平坦且毫无特色,只有H $α$,\ ion {Na} {1} 〜D,[\ ion {Ca} {2}],而\ ion {Ca} {Ca} {2} {2} {2} {2}发射中的三重态。与许多以前的中间发光瞬变一样,在〜2019krl上表现出与发光蓝色变量(LBV)巨型喷发,SN〜2008类似事件和大规模明星合并的显着观察性相似性。但是,有关爆发前星的信息偏爱相对毫不掩饰的BSG或更熄灭的LBV,$ m> 20 $ \,m $ _ {\ sun} $可能会查看。
Extensive archival \textit{Hubble Space Telescope}, \textit{Spitzer Space Telescope}, and Large Binocular Telescope imaging of the recent intermediate-luminosity transient, AT~2019krl in M74, reveal a bright optical and mid-infrared progenitor star. While the optical peak of the event was missed, a peak was detected in the infrared with an absolute magnitude of $M_{4.5\,μ{\rm m}} = -18.4$ mag, leading us to infer a visual-wavelength peak absolute magnitude of $-$13.5 to $-$14.5. The pre-discovery light curve indicated no outbursts over the previous 16\,yr. The colors, magnitudes, and inferred temperatures of the progenitor best match a 13--14 M$_{\sun}$ yellow or blue supergiant (BSG), if only foreground extinction is taken into account, or a hotter and more massive star, if any additional local extinction is included. A pre-eruption spectrum of the star reveals strong H$α$ and [N~{\sc ii}] emission with wings extending to $\pm 2000$\,km\,s$^{-1}$. The post-eruption spectrum is fairly flat and featureless with only H$α$, \ion{Na}{1}~D, [\ion{Ca}{2}], and the \ion{Ca}{2} triplet in emission. As in many previous intermediate-luminosity transients, AT~2019krl shows remarkable observational similarities to luminous blue variable (LBV) giant eruptions, SN~2008S-like events, and massive-star mergers. However, the information about the pre-eruption star favors either a relatively unobscured BSG or a more extinguished LBV with $M > 20$\,M$_{\sun}$ likely viewed pole-on.