论文标题
活性SGR A*对银河系中水和有机分子的合成的影响
Impact of an Active Sgr A* on the Synthesis of Water and Organic Molecules Throughout the Milky Way
论文作者
论文摘要
SGR A*是我们银河系中的超大型黑洞（SMBH），如今处于休眠状态，但在过去数十亿年中，它应该经历多个气体核心发作，以增长到目前的$ 4 \ times10^6 \，m_ \ odot $。每个发作暂时点燃SMBH，并将银河系中心变成活性银河核（AGN）。最近，我们表明AGN可以产生大量的硬X射线，这些X射线可以穿透银河平面中的密集星际介质。在这里，我们进一步研究了X射线对银河系中分子化学的影响。我们使用化学反应网络在气相和灰尘晶粒的表面上模拟了几种分子物种（包括H2O，CH3OH和H2CO）的演变。我们发现X射线照射可以显着增强这些物种的丰富性。在那些年轻的高密度分子云中，其效果最为重要，并且可能在$ 8 $ kpc或更小的银河系距离下突出。 AGN关闭几百万年后，可以看到化学丰度的烙印。
Sgr A*, the supermassive black hole (SMBH) in our Galaxy, is dormant today, but it should have gone through multiple gas-accretion episodes in the past billions of years to grow to its current mass of $4\times10^6\,M_\odot$. Each episode temporarily ignites the SMBH and turns the Galactic Center into an active galactic nucleus (AGN). Recently, we showed that the AGN could produce large amount of hard X-rays that can penetrate the dense interstellar medium in the Galactic plane. Here we further study the impact of the X-rays on the molecular chemistry in our Galaxy. We use a chemical reaction network to simulate the evolution of several molecular species including H2O, CH3OH, and H2CO, both in the gas phase and on the surface of dust grains. We find that the X-ray irradiation could significantly enhance the abundances of these species. The effect is the most significant in those young, high-density molecular clouds, and could be prominent at a Galactic distance of $8$ kpc or smaller. The imprint in the chemical abundance is visible even several million years after the AGN turns off.
