论文标题
NGC1068中的振动激发HC3N发射：追踪Starburst环中最近的恒星形成
Vibrationally excited HC3N emission in NGC1068: Tracing the recent star formation in the starburst ring
论文作者
论文摘要
使用ALMA数据，我们研究了SB/AGN复合星系NGC 1068中的Starburst环（SB环）中的HC $ _3 $ N和连续排放。我们已经从振动的HC $ _3 $ _3 $ _3 $ _3 $ _3 $ _3 $ _3 $ _3 $ _3 $ _3 $ _3 $ _3 $ _3 $ _3 $ _3 $ _3 $ _3 $ _3 $ _3 $ _3 $ _3 $ _3 $ _3 $ _3 $ _3 $ _3 $ _3 $ _3 $ _3 $ _3 $ _3 $ _ 3 $ s.值得注意的是，尽管HC $ _3 $ n*在CND上未检测到其大型HC $ _3 $ n $ v = 0 $列密度。从HC $ _3 $ n*的LTE和非LTE建模中，我们获得了$ t_ \ text {dust} \ sim 250 $ k的灰尘温度和$ n _ {\ text {h} _2} = 6 \ times10^5 $ cm $^{ - 3} $的密度。估计的IR发光度为$ 5.8 \ times10^8 $ l $ _ \ odot $是SB Galaxy NGC 253中观察到的原始Super Star Clusters（Proto-SSC）的典型代表。我们将Continuum Excions以$ 147 $ GHZ和CO和PA $ 350 $ GHZ和PA $ agimatie n evers n evers and and Mighte the Ands n evers and n evers n evers ands n of ssc ssc ands $ ghz $ 147 $ ghz和$ 350 $。我们发现最年轻的SSC与将核条与SB环连接的区域相关联，从而支持顺序恒星形成的情况。对于CND，我们的分析得出$ t_ \ text {dust} \ leqslant 100 $ k和$ n _ {\ text {h} _2} _2} \ sim（3-6）\ times10^5 $ cm $^{ - 3} $。 CND和Proto-SSC发现的完全不同的尘埃温度表明，虽然Proto-SSC中的灰尘正在有效地从内部通过大量原始类型的辐射从内部加热，但CND是由AGN在外部加热的，而AGN在IR上可以将灰尘加热到$ 56 $ k。 NGC 1068关于在SB/AGN复合星系NGC 4418和ARP 220中观察到的HC $ _3 $ N*排放的解释。
Using ALMA data, we have studied the HC$_3$N and continuum emission in the starburst ring (SB ring) and the circumnuclear disc (CND) of the SB/AGN composite galaxy NGC 1068. We have detected emission from vibrationally excited HC$_3$N (HC$_3$N*) only towards one star-forming region of the SB ring. Remarkably, HC$_3$N* was not detected towards the CND despite its large HC$_3$N $v=0$ column density. From LTE and non-LTE modelling of HC$_3$N*, we obtained a dust temperature of $ T_\text{dust} \sim 250$ K and a density of $n_{\text{H}_2}=6\times10^5$ cm$^{-3}$ for this star-forming region. The estimated IR luminosity of $5.8\times10^8$ L$_\odot$ is typical of proto-Super Star Clusters (proto-SSC) observed in the SB galaxy NGC 253. We use the continuum emissions at $147$ GHz and $350$ GHz, along with CO and Pa $α$, to estimate the ages of other $14$ SSCs in the SB ring. We find the youngest SSCs to be associated with the region connecting the nuclear bar with the SB ring, supporting the scenario of sequential star formation. For the CND, our analysis yields $T_\text{dust} \leqslant 100$ K and $n_{\text{H}_2}\sim(3-6)\times10^5$cm$^{-3}$. The very different dust temperatures found for the CND and the proto-SSC indicates that, while the dust in the proto-SSC is being efficiently heated from the inside by the radiation from massive proto-stars, the CND is being heated externally by the AGN, which in the IR optically thin case can only heat the dust to $56$ K. We discuss the implications of the non-detection of HC$_3$N* near the luminous AGN in NGC 1068 on the interpretation of the HC$_3$N* emission observed in the SB/AGN composite galaxies NGC 4418 and Arp 220.
