As part of the Early Science Large Millimeter Telescope projects, we report the detection of nine double-peaked molecular lines, produced by a rotating molecular torus, in the ultraluminous infrared galaxies (ULIRG) – Compton-thick active galactic nuclei (AGN) galaxy UGC 5101. The double-peaked lines we report correspond to molecular transitions of HCN, HCO⁺, HNC, N₂H⁺, CS, C¹⁸O, ¹³CO, and two CN lines; plus the detection of C₂H that is a blend of six lines. The redshift search receiver spectra covers the 73–113 GHz frequency window. Low- and high-density gas tracers of the torus have different implied rotational velocities, with a rotational velocity of 149 ± 3 km s⁻¹ for the low-density ones (C¹⁸O, ¹³CO) and 174 ± 3 km s⁻¹ for high-density tracers (HCN, HCO⁺, HNC, N₂H⁺, CS, and CN). In UGC 5101, we find that the ratio of integrated intensities of HCN to ¹³CO to be unusually large, probably indicating that the gas in the torus is very dense. Both the column densities and abundances are consistent with values found in AGN, starburst, and ULIRG galaxies. The observed abundance ratios cannot discriminate between X-ray and UV-field-dominated regions.

中文翻译：

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LMT的早期科学：UGC 5101中的分子圆环

作为“早期科学大毫米波望远镜”项目的一部分，我们报告了在超发光红外星系（ULIRG）–康普顿厚活动星系核（AGN）星系UGC中检测到由旋转的分子环产生的9条双峰分子线的过程。 5101.我们报告的双峰线对应于HCN，HCO ⁺，HNC，N ₂ H ⁺，CS，C ¹⁸ O，¹³ CO和两条CN线的分子跃迁；加上六行混合的C ₂ H检测。红移搜索接收器频谱覆盖73–113 GHz频率窗口。圆环的低密度和高密度气体示踪剂具有不同的隐含旋转速度，旋转速度为149±3 km s ^-1对于低密度示踪剂（HCN，HCO ⁺，HNC，N ₂ H ⁺，CS和CN），低密度示踪剂（C ¹⁸ O，¹³ CO）的浓度为174±3 km s ^-1。在UGC 5101中，我们发现HCN与¹³ CO的积分强度之比异常大，这可能表明圆环中的气体非常稠密。列密度和丰度都与AGN，星爆和ULIRG星系中的值一致。观察到的丰度比无法区分X射线和UV场为主的区域。