The spectroscopic evolution of the symbiotic-like recurrent nova V407 Cygni during its 2010 outburst II. The circumstellar environment and the aftermath
The spectroscopic evolution of the symbiotic-like recurrent nova V407 Cygni during its 2010 outburst II. The circumstellar environment and the aftermath
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类似共生的复发新星天鹅座 V407 在 2010 年爆发 II 期间的光谱演化。
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发表时间：
2011
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通讯作者：
V. Votruba
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作者：
S. Shore;G. Wahlgren;G. Wahlgren;T. Augusteijn;T. Liimets;P. Koubský;M. Šlechta;V. Votruba
上下文。2010年3月10日，天鹅座V407的新星爆发是首次观测到这颗恒星，但它与众所周知的共生类复发新星蛇夫座RS的相似之处表明，它也是这种罕见类型的银河系新星的一员。这颗新星是第一个以γ射线能量探测到的新星，也是这个系统中第一个已知的新星爆炸。这次爆发的广泛的多波长覆盖范围使它成为与其他几个已知的类似系统爆发的理想比较。目标。我们扩展了之前对Mira和爆炸产生的膨胀激波的分析，详细介绍了光电离Mira风、星周介质和激波星周环境的时间发展，得出了它们的物理参数以及它们与大尺度环境结构的关系，将之前的覆盖范围扩展到爆发后500多天。方法。我们使用北欧光学望远镜（NOT） （R≈45000至65000）和中分辨率仅迪天文台（R≈12000）数据获得的高分辨率光谱，并将爆发前4个月至强XR发射时代结束期间的30 GHz OVNR和Swift x射线的公开档案测量结果与谱线变化进行比较。我们使用星云诊断和高分辨率剖面变化来推导密度和扩展发射的位置。结果。我们发现，电离越高和/或激发能越高，谱线越接近论文1中讨论的He II/Ca v型高速激波谱线。这也解释了[N II]和[O III]等电子跃迁的比较发展：[O III] 4363 A谱线没有低速峰，而[N II] 5754 A有低速峰。如果激波中的氮主要是N +3或更高，则[N II]星云线的上部状态将起作用，但如果氧是O +2，则这条线是通过重组形成的，掩盖了星云的贡献者，而较低的状态则被碰撞淬火，但从低密度环境中发射出来。在第69天之前，大约在x射线峰出现的时间，在Mira风中形成的铁峰离子的吸收谱线在低速的P Cyg剖面上是可见的，我们发现了许多没有伴随金属谱线发射的吸收转变。巴尔默谱线显示出强烈的P - Cyg吸收波谷，在2010年的观测期间减弱，一直持续到第128天。允许和禁止跃迁的铁峰线轮廓和通量变化是不同的：E1跃迁在第128天之后不可见，但在扩展（200 km s - 1）的蓝翼上叠加了一个窄峰，而M1和E2跃迁持续到第529天，即最后一次观测，并显示出相同速度的扩展红移翼。我们利用爆发后一年多的光谱来区分激波、光电离环境、色球层和内部米拉风的成分。多重壳层和辐射激发现象与最近引用的grb和SNIa相似。
Context. The nova outburst of V407 Cyg in 2010 Mar. 10 was the first observed for this star but its close resemblance to the well known symbiotic-like recurrent nova RS Oph suggests that it is also a member of this rare type of Galactic novae. The nova was the first detected at γ-ray energies and is the first known nova explosion for this system. The extensive multiwavelength coverage of this outburst makes it an ideal comparison with the few other outbursts known for similar systems. Aims. We extend our previous analysis of the Mira and the expanding shock from the explosion to detail the time development of the photoionized Mira wind, circumstellar medium, and shocked circumstellar environment to derive their physical parameters and how they relate to large scale structure of the environment, extending the previous coverage to more than 500 days after outburst. Methods. We use optical spectra obtained at high resolution with the Nordic Optical Telescope (NOT) (R ≈ 45 000 to 65 000) and medium resolution Ondy Observatory (R ≈ 12 000) data and compare the line variations with publicly available archival measurements at 30 GHz OVNR and at X-rays with Swift during the first four months of the outburst, through the end of the epoch of strong XR emission. We use nebular diagnostics and high resolution profile variations to derive the densities and locations of the extended emission. Results. We find that the higher the ionization and/or the higher the excitation energy, the more closely the profiles resemble the He II/Ca V-type high velocity shock profile discussed in Paper I. This also accounts for the comparative development of the [N II] and [O III] isoelectronic transitions: the [O III] 4363 A profile does not show the low velocity peaks while the excited [N II] 5754 A does. If nitrogen is mainly N +3 or higher in the shock, the upper state of the [N II] nebular lines will contribute but if the oxygen is O +2 then this line is formed by recombination, masking the nebular contributor, and the lower states are collisionally quenched but emit from the low density surroundings. Absorption lines of Fe-peak ions formed in the Mira wind were visible as P Cyg profiles at low velocity before Day 69, around the time of the X-ray peak and we identified many absorption transitions without accompanying emission for metal lines. The H Balmer lines showed strong P Cyg absorption troughs that weakened during the 2010 observing period, through Day 128. The Fe-peak line profiles and flux variations were different for permitted and forbidden transitions: the E1 transitions were not visible after Day 128 but had shown a narrow peak superimposed on an extended (200 km s −1 ) blue wing, while the M1 and E2 transitions persisted to Day 529, the last observation, and showed extended redshifted wings up of the same velocity. We distinguish the components from the shock, the photoionized environment, and the chromosphere and inner Mira wind using spectra taken more than one year after outburst. The multiple shells and radiative excitation phenomenology are similar to those recently cited for GRBs and SNIa.