We carried out CO(1-0) and CO(2-1) observations of 21 different regions in the vicinity of M86, NGC4438, and along the 120 kpc-long, Ha-emitting filamentary trail that connects them, aiming to test whether molecular gas can survive to be transferred from a spiral to an elliptical galaxy in Virgo's 10^7K intracluster medium (ICM). We targeted Ha-emitting regions that could be associated with the interface between cold molecular clouds and the hot ionized ICM. The data, obtained with the 30m telescope of the Institut de Radioastronomie Millimetrique, led to the detection of molecular gas close to M86. CO gas with a recession velocity that is similar to that of the stars, -265 km/s, and with a corresponding H2 mass of 2*10^7 M_sun, was detected ~10 kpc southeast of the nucleus of M86, near the peak of its HI emission. We argue that it is possible for this molecular gas either to have formed in situ from HI, or to have been stripped from NGC4438 directly in molecular form. In situ formation is nonetheless negligible for the 7*10^6 M_sun of gas detected at 12:26:15.9+12:58:49, at ~10 kpc northeast of M86, where no (strong) HI emission is present. This detection provides evidence for the survival of molecular gas in filaments for timescales of ~100 Myr. An amount equivalent to 5*10^7 M_sun of H2 gas that could be lost to the ICM or to neighboring galaxies was also discovered in the tidal tail northwest of NGC4438. A scenario of gas being alternatively brought to M86 from NGC4388 on its south was also examined but it was considered unlikely due to the non detection of CO below or at the HI stream velocities, 2000-2700 km/s.
Spitzer IRAC Low Surface Brightness Observations of the Virgo Cluster
我们目前的3.6和4.5微米斯皮策IRAC成像超过0.77平方度的室女星系团核心的目的是了解低表面亮度的形成机制的集群内的光功能。比信号高出数百倍的仪器和天体物理背景被仔细表征和去除。我们研究了巨大椭圆星系M87的团内光羽和外晕。对于两个团内光羽，我们使用光学颜色来限制它们的年龄分别大于3和5 Gyr。IRAC通量的上限限制了质量的上限，光学检测限制了质量的下限。在这第一次测量团内轻羽流的质量时，我们发现我们所覆盖的两个羽流的质量范围分别为5.5 x 10^8 - 4.5 x 10^9和2.1 x 10^8 - 1.5 x 10^9太阳质量。考虑到它们的预期寿命很短，以及这些类型的流的恒定生产率，在室女座的一生中，它们可以解释星团的ICL总含量，这意味着我们不需要调用ICL形成机制，而不是引力机制导致明亮的羽流。我们还研究了巨大的椭圆形M87的外晕。从M87的内晕到外晕（160 Kpc）的颜色轮廓与平坦或光学蓝色梯度一致，其中蓝色梯度可能是由于更年轻或更低的金属量恒星在更大的半径。由红外和光学颜色预测的年龄的相似性（>几Gyr）表明，光学测量并没有强烈的尘埃消光的影响。
Gas motion in the intracluster medium of the Virgo cluster replica
Université Paris-Saclay（巴黎萨克雷大学）；CNRS, Institut d’Astrophysique Spatiale（法国国家科学研究中心，空间天体物理研究所）；INAF, Osservatorio di Astrofisica e Scienza dello Spazio（意大利国家天体物理研究所，空间天体物理学与天文台）；INFN, Sezione di Bologna（意大利国家核物理研究所，博洛尼部分部）；Université de Lille（里尔大学）；Centrale Lille（里尔中央理工学院）
From Observations to Simulations: A Neural-Network Approach to Intracluster Medium Kinematics
Max-Planck-Institut für extraterrestrische Physik（马克斯·普朗克地外物理研究所）；Harvard-Smithsonian Center for Astrophysics（哈佛-史密森天体物理中心）；Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, UK（剑桥大学天文研究所）；Institute for Frontiers in Astronomy and Astrophysics, Beijing Normal University（北京师范大学前沿天文与天体物理研究所）；INAF - IASF Palermo（意大利国家天体物理研究所巴勒莫分部）；Department of Physics and Astronomy, University of Alabama in Huntsville（阿拉巴马大学亨茨维尔分校物理与天文学系）
The Evaporation and Survival of Cluster Galaxies' Coronae Part II: The Effectiveness of Anisotropic Thermal Conduction and Survival of Stripped Galactic Tails
