论文标题
Lyman Continuum发射器中Lyman Alpha和电离光子的逃生的起源
The origin of the escape of Lyman alpha and ionizing photons in Lyman Continuum Emitters
论文作者
论文摘要
确定推动Lyman Continuum（LYC）光子逃脱的机制对于找到Lyman Continuum Emitter（LCE）候选者至关重要。为了了解LYC光子泄漏所涉及的物理特性，我们研究了HI覆盖分数，HI速度宽度，Lyman Alpha（Lya）特性和LYC光子在包括13 LCE的22个星形星系样本中的连接。我们适合920至1300 a之间的恒星连续性，灰尘衰减和吸收线，以提取HI覆盖分数和灰尘衰减。此外，我们测量了光学较厚的Lyman系列的HI速度宽度，并得出Lya等效宽度（EW），逃生部分（FESC），峰值和速度速度和最小值的通量。总体而言，我们强调了低HI覆盖分数的存在与（1）低LYA峰值速度之间的牢固相关性； （2）最小剖面的更多助焊剂； （3）较大的EW（LYA），FESC（LYA）和FESC（LYC）。因此，低柱密度通道是LYC和LYA光子泄漏的至关重要的ISM成分。此外，具有较窄的HI吸收速度宽度的星系具有较高的LYA等效宽度，较大的LYA逃生部分和较低的Lya峰值速度分离。这表明这些星系具有低HI柱密度。最后，我们发现尘埃调节了实际逃脱ISM的Lya和Lyc辐射的数量。总体而言，ISM孔隙率是强LYA发射的一种起源，可以使低Z泄漏器中电离光子逃脱。但是，这还不足以解释观察到的最大的FESC（LYC），这表明最极端的LCE可能沿着观察者的所有视线构成密度。总体而言，中性气体孔隙率将LYC和LYA光子的逃生部分的下限限制为电离光子泄漏的关键估计器。
Identifying the mechanisms driving the escape of Lyman Continuum (LyC) photons is crucial to find Lyman Continuum Emitter (LCE) candidates. To understand the physical properties involved in the leakage of LyC photons, we investigate the connection between the HI covering fraction, HI velocity width, the Lyman alpha (LyA) properties and escape of LyC photons in a sample of 22 star-forming galaxies including 13 LCEs. We fit the stellar continua, dust attenuation, and absorption lines between 920 and 1300 A to extract the HI covering fractions and dust attenuation. Additionally, we measure the HI velocity widths of the optically thick Lyman series and derive the LyA equivalent widths (EW), escape fractions (fesc), peak velocities and fluxes at the minimum of the LyA profiles. Overall, we highlight strong correlations between the presence of low HI covering fractions and (1) low LyA peak velocities; (2) more flux at the profile minimum; and (3) larger EW(LyA), fesc(LyA), and fesc(LyC). Hence, low column density channels are crucial ISM ingredients for the leakage of LyC and LyA photons. Additionally, galaxies with narrower HI absorption velocity widths have higher LyA equivalent widths, larger LyA escape fractions, and lower LyA peak velocity separations. This suggests that these galaxies have low HI column density. Finally, we find that dust regulates the amount of LyA and LyC radiation that actually escapes the ISM. Overall, the ISM porosity is one origin of strong LyA emission and enables the escape of ionizing photons in low-z leakers. However, this is not enough to explain the largest fesc(LyC) observed, which indicates that the most extreme LCEs are likely density-bounded along all lines of sight to the observer. Overall, the neutral gas porosity constrains a lower limit to the escape fraction of LyC and LyA photons, providing a key estimator of the leakage of ionizing photons.
