论文标题
宇宙莱曼连续体从星形星系中吸收伽马射线
Gamma-Ray Absorption By The Cosmic Lyman Continuum From Star-forming Galaxies
论文作者
论文摘要
由于发现了被称为“绿色豌豆星系”的超强排放线星星星系（EELGS）的动机，我们在这里考虑它们对高红移在高红移的电离紫外线的造成贡献。观察到的大多数星系表明，其莱曼极限的蓝色幅度急剧下降。然而，最近对EELG的观察结果发现，比以前怀疑，许多莱曼连续光子从中逃脱到了伴形的空间。我们计算它们对乳乳外背景光（EBL）的贡献。我们还计算了这些光子对吸收高能$γ$ rays的影响。对于更遥远的$γ$ ray来源，尤其是在$ z \ ge 3 $的情况下，高于几个GEV的近视不透明度明显高于以前忽略Lyman Continuum Photons的估计。我们计算了这种观察到的$γ$ ray光谱的不透明度的结果，该光谱从比以前想象的要低的能量开始产生高能量的周转，并且也可以观察到的逐渐频谱陡峭。
Motivated by the discovery of the ultra-strong emission line starburst galaxies (EELGs) known as "green pea galaxies", we consider here their contribution to the intergalactic flux of ionizing UV at high redshifts. Most galaxies that have been observed show a precipitous drop in their flux blueward of the Lyman limit. However, recent observations of EELGs have discovered that many more Lyman continuum photons escape from them into intergalactic space than was previously suspected. We calculate their contribution to the extragalactic background light (EBL). We also calculate the effect of these photons on the absorption of high energy $γ$-rays. For the more distant $γ$-ray sources, particularly at $z \ge 3$, the intergalactic opacity above a few GeV is significantly higher than previous estimates which ignored the Lyman continuum photons. We calculate the results of this increased opacity on observed $γ$-ray spectra, which produces a high-energy turnover starting at lower energies than previously thought, and a gradual spectral steepening that may also be observable.
