Absorption of Millimeter-band CO and CN in the Early Universe: Molecular Clouds in Radio Galaxy B2 0902+34 at Redshift 3.4
Bjorn Emonts, Steve Curran, George Miley, Matthew Lehnert, Chris Carilli, Ilsang Yoon, Raffaella Morganti, Reinout van Weeren, Montserrat Villar-Martin, Pierre … 展开作者
Bjorn Emonts, Steve Curran, George Miley, Matthew Lehnert, Chris Carilli, Ilsang Yoon, Raffaella Morganti, Reinout van Weeren, Montserrat Villar-Martin, Pierre Guillard, Cristina Cordun, Tom Oosterloo
备注：
Accepted by ApJ (submitted 25-Sept-2023, accepted 27-Dec-2023)
使用Karl G. Jansky Very Large Array (VLA)，我们探测到了与红移z=3.4的射电星系B2 0902+34相关的一氧化碳CO(J=0-1)和氰基自由基CN(N=0-1)的吸收线。在大爆炸后1.5 Gyr观测到的毫米波段吸收，使得研究低至发射线观测无法触及的气体质量的分子云成为可能。B2 0902+34中的CO吸收具有$τ$ $\ge$ 8.6%的峰值光深，并由两个成分组成，其中一个成分与先前探测到的中性氢(HI)气体的21-cm吸收具有相同的红移。每个CO成分对应的积分H$_2$柱密度为N(H2) $\ge$ 3x10$^{20}$ cm$^{-2}$。在两个CO成分以及一个CO未探测到的蓝移成分中均探测到了CN吸收，CO/CN谱线比范围从$\le$0.4到2.4。我们讨论了这种情景：吸收成分源自嵌入在具有更多弥漫气体和高湍流区域中的小而致密的分子云集合，可能处于中央活动星系核或星暴区域的影响范围内。B2 0902+34的红化程度，其静止参考系颜色B-K ~ 4.2，低于其他已知z<1红移CO吸收系统中发现的极红颜色(B-K > 6)。然而，当纳入文献中的许多未探测结果时，吸收线强度与B-K颜色之间的潜在相关性是明显的，这支持了CO吸收体的红色源于高尘埃含量的观点。
英文摘要：
Using the Karl G. Jansky Very Large Array (VLA), we have detected absorption lines due to carbon-monoxide, CO(J=0-1), and the cyano radical, CN(N=0-1), associated with radio galaxy B2 0902+34 at redshift z=3.4. The detection of millimeter-band absorption observed 1.5 Gyr after the Big Bang facilitates studying molecular clouds down to gas masses inaccessible to emission-line observations. The CO absorption in B2 0902+34 has a peak optical depth of $τ$ $\ge$ 8.6% and consists of two components, one of which has the same redshift as previously detected 21-cm absorption of neutral hydrogen (HI) gas. Each CO component traces an integrated H$_2$ column density of N(H2) $\ge$ 3x10$^{20}$ cm$^{-2}$. CN absorption is detected for both CO components, as well as for a blueshifted component not detected in CO, with CO/CN line ratios ranging from $\le$0.4 to 2.4. We discuss the scenario that the absorption components originate from collections of small and dense molecular clouds that are embedded in a region with more diffuse gas and high turbulence, possibly within the influence of the central Active Galactic Nucleus or starburst region. The degree of reddening in B2 0902+34, with a rest-frame color B-K ~ 4.2, is lower than the very red colors (B-K > 6) found among other known redshifted CO absorption systems at z<1. Nevertheless, when including also the many non-detections from the literature, a potential correlation between the absorption-line strength and B-K color is evident, giving weight to the argument that the red colors of CO absorbers are due to a high dust content.
Report of the Kavli-IAU Workshop on Global Coordination, "Probing the Universe from far-infrared to millimeter wavelengths: future facilities and their synergies"
From the Intergalactic to the Interstellar Scales -- EQUALS: a High-resolution Legacy Survey of Gas in the Distant Universe Using ESPRESSO
Camosun College（卡莫森学院）；INAF–Trieste Astronomical Observatory（意大利国家天体物理研究所的里雅斯特天文台）；University of Chile（智利大学）；University of Trieste（的里雅斯特大学）；INAF–Padua Astronomical Observatory（意大利国家天体物理研究所帕多瓦天文台）；Hamburg University（汉堡大学）；University of Hertfordshire（赫特福德大学）；IAP, Paris（巴黎天体物理研究所）；ESO（欧洲南方天文台）；SISSA（国际高等研究学院）；Durham University（杜伦大学）
The role of neutral hydrogen in setting the abundances of molecular species in the Milky Way's diffuse interstellar medium. I. Observational constraints from ALMA and NOEMA
The Bolocam Galactic Plane Survey. VIII. A Mid-Infrared Kinematic Distance Discrimination Method
我们提出了一种新的距离估计方法尘埃连续识别分子云团块。最近的（亚）毫米银河平面调查已经编目了数万个这样的物体，但对其物理特性的详细研究需要可靠的距离测定。我们推导出贝叶斯距离概率密度函数（DPDF）的770个对象从Bolocam银河平面调查在经度范围7.5 < l < 65。DPDF形式主义是基于运动学距离，并使用外部数据集放置先验距离概率，以解决运动学距离模糊（KDA）的对象在银河系内部。我们目前的先验知识与致密分子区尘埃的中红外吸收和分子气体的银河系分布有关。通过假设银河系中红外辐射的数值模型和简单的辐射转移，我们匹配的毫米热尘埃发射的形态与中红外吸收计算距离歧视的先验DPDF。首先从（亚）毫米源目录中选择对象，避免了对最暗红外暗云（IRDC）的偏见，并扩展了中红外消光探测的日心距离和对比度范围。我们推导出618个分子云团簇的约束良好的KDA分辨率，其中大约15%位于切向距离或超出切向距离。暗到足以被编目为IRDC的天体通常位于近运动学距离处。与银河环巡天KDA分辨率的距离比较产生了92%的一致性，银河正面视图显示了人马座和盾牌-半人马座臂的部分。这种KDA分辨率的方法，通过结合（亚）毫米和中红外观测的分子云团块的大目录的来源，一般适用于其他尘埃连续星系平面调查。
Millimeter Wave and Terahertz Spectra and Global Fit of Torsion-Rotation Transitions in the Ground, First and Second Excited Torsional States of 13CH3OH Methanol
Star formation traced by optical and millimeter hydrogen recombination lines and free-free emissions in the dusty merging galaxy NGC 3256 -- MUSE/VLT and ALMA synergy
