We continue our deep optical imaging survey of the Virgo cluster using the CWRU Burrell Schmidt telescope by presenting B-band surface photometry of the core of the Virgo cluster in order to study the cluster's intracluster light (ICL). We find ICL features down to mu_b ~ 29 mag sq. arcsec, confirming the results of Mihos et al. (2005), who saw a vast web of low-surface brightness streams, arcs, plumes, and diffuse light in the Virgo cluster core using V-band imaging. By combining these two data sets, we are able to measure the optical colors of many of the cluster's low-surface brightness features. While much of our imaging area is contaminated by galactic cirrus, the cluster core near the cD galaxy, M87, is unobscured. We trace the color profile of M87 out to over 2000 arcsec, and find a blueing trend with radius, continuing out to the largest radii. Moreover, we have measured the colors of several ICL features which extend beyond M87's outermost reaches and find that they have similar colors to the M87's halo itself, B-V ~ 0.8. The common colors of these features suggests that the extended outer envelopes of cD galaxies, such as M87, may be formed from similar streams, created by tidal interactions within the cluster, that have since dissolved into a smooth background in the cluster potential.
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)
The study of low surface brightness light in large, deep imaging surveys is still uncharted territory as automated data reduction pipelines over-subtract or eliminate this light. Using archival data of the Abell 85 cluster of galaxies taken with Hyper Suprime-Cam on the Subaru Telescope, we show that using careful data processing can unveil the diffuse light within the cluster, the intracluster light. We reach surface brightness limits of $μ_{g}^{limit}$(3$σ$, 10"x10") = 30.9 mag/arcsec$^2$, and $μ_{i}^{limit}$(3$σ$, 10"x10") = 29.7 mag/arcsec$^2$. We measured the radial surface brightness pro…
The interaction of gas-rich galaxies with the intra-cluster medium (ICM) of galaxy clusters has a remarkable impact on their evolution, mainly due to the gas loss associated with this process. In this work, we use an idealised, high-resolution simulation of a Virgo-like cluster, run with RAMSES and with dynamics reproducing that of a zoom cosmological simulation, to investigate the interaction of infalling galaxies with the ICM. We find that the tails of ram pressure stripped galaxies give rise to a population of up to more than a hundred clumps of molecular gas lurking in the cluster. The num…
Pinning down the ram-pressure-induced halt of star formation in the Virgo cluster spiral galaxy NGC 4388. A joint inversion of spectroscopic and photometric data
在一个星系团中,旋涡星系的演化取决于它们的星系团环境。由于螺旋星系在炽热的团内介质中的快速运动而产生的冲压压力将星系的星际介质从外盘中移走。一旦气体离开了圆盘,恒星的形成就停止了。恒星星族的被动演化应该可以用光谱学和多波长光度学来探测。我们的研究目标是恢复处女座旋涡星系NGC 4388的剥离年龄,即从停止恒星形成的外星系盘使用的光谱和光度学的组合分析经过的时间。我们对NGC 4388的内部恒星形成和外部无气体盘进行了VLT FORS 2长缝光谱学。我们开发了一种非参数反演工具,使我们能够从光谱学和光度学重建星系的恒星形成历史。使用蒙特卡罗模拟在一系列模拟数据上测试该工具。通过应用参数反演方法对非参数反演的结果进行了改进。未受扰动的银盘的恒星形成历史是平坦的。非参数方法得出的结论是,在200万年前,外盘的恒星形成迅速减少。参数方法不能区分瞬时和长期恒星形成截断。恒星形成的时间比剥离前的值下降了两倍,为1.9亿+-3000万年。我们能够给出一个精确的剥离年龄,是符合修订后的动力学模型。
The Next Generation Virgo Cluster Survey - Infrared (NGVS-IR): I. A new Near-UV/Optical/Near-IR Globular Cluster selection tool
NGVS-IR项目(下一代室女座巡天-红外)是对室女星系团进行的连续近红外成像巡天。它补充了室女座的光学广域调查(NGVS)。NGVS-IR的当前状态包括以M87为中心的4度^2的KS波段图像,以及覆盖M49和M87之间区域的16度^2的J和KS波段图像。在本文中,我们给出了以室女座核心区域为中心的中心4度^2的观测结果。这些数据是用加拿大-法国-夏威夷望远镜上的WIRCam获得的,总积分时间为41小时,分布在34个连续的瓦片中。一个特定的调查策略被设计来解释扩展的星系,同时仍然测量调查区域内准确的天空亮度。当仅使用视宁度优于0.7”(视宁度中值为0.54”)的图像时,点源检测的平均5σ极限星等为Ks =24.4 AB mag,50%完整性极限为Ks=23.75 AB mag。在这些图像中,星团的分辨率很低,其中发现了μ_Ks=24.4 AB等角秒^-2的室女座星系。结合Ks数据与光学和紫外数据,我们建立了uiK色-色图,它允许一个非常干净的基于颜色的选择球状星团在室女座。这一诊断图将为继续探索室女座的光度和运动学子结构所需的光谱后续活动提供可靠的球状星团候选者,并将有助于设计未来在河外系统中搜索球状星团的计划。配备了这个强大的新工具,未来基于uiK图的NGVS-IR研究将解决室女座星系及其周围的扩展结构和紧凑恒星系统的映射和分析。
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)