仙女座Z星和天龙座AG星中H $α$和H $β$周围的宽翼
Broad Wings around H$α$ and H$β$ in the Two S-Type Symbiotic Stars Z Andromedae and AG Draconis
摘要：
共生星通常在巴耳末发射线周围展现出宽阔的翅膀，其起源仍然存在争议。利用ESPaDOnS和3.6 m加拿大-法国-夏威夷望远镜获得了S型共生星仙女座Z和天龙座AG的高分辨率光谱，研究了H $α$和H $β$的宽翼。当H $α$和H $β$线在多普勒空间中重叠绘制时，注意到在这两个对象中H $α$轮廓总体上比H $β$宽。采用Monte Carlo方法，我们考虑了H $α$和H $β$宽翼的形成是通过远紫外辐射在Ly $β$和Ly $γ$周围的Raman散射和自由电子的Thomson散射.拉曼散射翼是通过选择具有中性氢柱密度$N_{HI}$和覆盖因子$CF$的H I区域来模拟的。对于汤姆逊翼，电离散射区被假定为完全覆盖巴耳末发射星云，其特征在于电子温度$T_e$和电子柱密度$N_e$。H $α$和H $β$的汤姆逊翼具有与$T_e^{1/2}$成比例的相同宽度。然而，H $α$的拉曼翼总体上比H $β$对应物宽三倍，这归因于Ly $β$和Ly $γ$的不同横截面。归一化为具有相同的峰值并在多普勒因子空间中呈现。观察到Z And和AG Dra的H $α$翼明显宽于H $β$对应物，有利于宽巴耳末翼的拉曼散射起源。
英文摘要：
Symbiotic stars often exhibit broad wings around Balmer emission lines, whose origin is still controversial. We present the high resolution spectra of the S type symbiotic stars Z Andromedae and AG Draconis obtained with the ESPaDOnS and the 3.6 m Canada France Hawaii Telescope to investigate the broad wings around H$α$ and H$β$. When H$α$ and H$β$ lines are overplotted in the Doppler space, it is noted that H$α$ profiles are overall broader than H$β$ in these two objects. Adopting a Monte Carlo approach, we consider the formation of broad wings of H$α$ and H$β$ through Raman scattering of far UV radiation around Ly$β$ and Ly$γ$ and Thomson scattering by free electrons. Raman scattering wings are simulated by choosing an H I region with a neutral hydrogen column density $N_{HI}$ and a covering factor $CF$. For Thomson wings, the ionized scattering region is assumed to cover fully the Balmer emission nebula and is characterized by the electron temperature $T_e$ and the electron column density $N_e$. Thomson wings of H$α$ and H$β$ have the same width that is proportional to $T_e^{1/2}$. However, Raman wings of H$α$ are overall three times wider than H$β$ counterparts, which is attributed to different cross section for Ly$β$ and Ly$γ$. Normalized to have the same peak values and presented in the Doppler factor space. H$α$ wings of Z And and AG Dra are observed to be significantly wider than H$β$ counterpart, favoring the Raman scattering origin of broad Balmer wings.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
