Fossil group origins - VI. Global X-ray scaling relations of fossil galaxy clusters
A. Kundert, F. Gastaldello, E. D'Onghia, M. Girardi, J. A. L. Aguerri, R. Barrena, E. M. Corsini, S. De Grandi, E. Jiménez-Bailón, M. Lozada-Muñoz, J. Méndez-Ab… 展开作者
A. Kundert, F. Gastaldello, E. D'Onghia, M. Girardi, J. A. L. Aguerri, R. Barrena, E. M. Corsini, S. De Grandi, E. Jiménez-Bailón, M. Lozada-Muñoz, J. Méndez-Abreu, R. Sánchez-Janssen, E. Wilcots, S. Zarattini
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17 pages, 7 figures, 8 tables. Accepted for publication in MNRAS
We present the first pointed X-ray observations of 10 candidate fossil galaxy groups and clusters. With these Suzaku observations, we determine global temperatures and bolometric X-ray luminosities of the intracluster medium (ICM) out to $r_{500}$ for six systems in our sample. The remaining four systems show signs of significant contamination from non-ICM sources. For the six objects with successfully determined $r_{500}$ properties, we measure global temperatures in the range $2.8 \leq T_{\mathrm{X}} \leq 5.3 \ \mathrm{keV}$, bolometric X-ray luminosities of $0.8 \times 10^{44} \ \leq L_{\mathrm{X,bol}} \leq 7.7\times 10^{44} \ \mathrm{erg} \ \mathrm{s}^{-1}$, and estimate masses, as derived from $T_{\mathrm{X}}$, of $M_{500} > 10^{14} \ \mathrm{M}_{\odot}$. Fossil cluster scaling relations are constructed for a sample that combines our Suzaku observed fossils with fossils in the literature. Using measurements of global X-ray luminosity, temperature, optical luminosity, and velocity dispersion, scaling relations for the fossil sample are then compared with a control sample of non-fossil systems. We find the fits of our fossil cluster scaling relations are consistent with the relations for normal groups and clusters, indicating fossil clusters have global ICM X-ray properties similar to those of comparable mass non-fossil systems.
We review the formation and evolution of fossil groups and clusters from both the theoretical and the observational points of view. In the optical band, these systems are dominated by the light of the central galaxy. They were interpreted as old systems that had enough time to merge all the M* galaxies within the central one. During the last two decades many observational studies were performed to prove the old and relaxed state of fossil systems. The majority of these studies, that spans a wide range of topics including halos global scaling relations, dynamical substructures, stellar populati…
Fossil Groups Origins III. The relation between optical and X-ray luminosities
这项研究是化石群起源（FOGO）项目的一部分，该项目旨在对大量化石系统进行系统的多波长研究。在这里，我们专注于光学光度（Lopt）和X射线光度（Lx）之间的关系。在28个候选化石系统的样本中，我们考虑了12个系统的样本，其化石分类已被同伴研究证实。它们进行了比较，与16个系统的化石性质尚未得到证实的补充样本，并与RASS-SDSS星系团调查的102个星系系统的子样本。化石和正常系统跨越相同的红移范围0<z<0.5，并具有相同的Lx分布。对于每一个化石系统，在0.1-2.4千电子伏波段的Lx计算使用的数据从ROSAT全天巡天。对于每个化石和正常的系统，我们均匀计算Lopt在r波段内的特征集群半径，使用数据从SDSS DR 7。我们在Lx的两个数量级上对Lx-Lopt关系进行采样。我们的分析表明，化石系统是不统计区分从正常系统通过二维KS测试和Lx-Lopt关系的拟合。星系系统的光学光度确实与热气体成分的X射线光度密切相关，而与系统是否为化石无关。我们的结论是，我们的研究结果是一致的经典的“合并方案”的最亮的星系通过合并/同类相食的其他组星系，与保守的光学。我们没有发现一个特殊的状态的热集群内介质的证据。
We want to study how the velocity segregation and the radial profile of the velocity dispersion depend on the prominence of the brightest cluster galaxies (BCGs). We divide a sample of 102 clusters and groups of galaxies into four bins of magnitude gap between the two brightest cluster members. We then compute the velocity segregation in bins of absolute and relative magnitudes. Moreover, for each bin of magnitude gap we compute the radial profile of the velocity dispersion. When using absolute magnitudes, the segregation in velocity is limited to the two brightest bins and no significant diff…
We aim to study how the orbits of galaxies in clusters depend on the prominence of the corresponding central galaxies. We divided our data set of $\sim$ 100 clusters and groups into four samples based on their magnitude gap between the two brightest members, $Δm_{12}$. We then stacked all the systems in each sample, in order to create four stacked clusters, and derive the mass and velocity anisotropy profiles for the four groups of clusters using the MAMPOSSt procedure. Once the mass profile is known, we also obtain the (non parametric) velocity anisotropy profile via the inversion of the Jean…
It is well established that particle acceleration by shocks and turbulence in the intra-cluster medium can produce cluster-scale synchrotron emitting sources. However, the detailed physics of these particle acceleration processes is still not well understood. One of the main open questions is the role of fossil relativistic electrons that have been deposited in the intra-cluster medium by radio galaxies. These synchrotron-emitting electrons are very difficult to study, as their radiative life time is only tens of Myrs at GHz frequencies, and are therefore a relatively unexplored population. De…
Resurging from the ashes: A spectral study of seven candidate revived radio fossils in nearby low-mass galaxy clusters
Istituto Nazionale di Astrofisica (INAF) - Istituto di Radioastronomia (IRA)（意大利国家天体物理研究所-射电天文研究所）；Dipartimento di Fisica e Astronomia (DIFA), Università di Bologna（博洛尼亚大学物理与天文学系）；Istituto Nazionale di Astrofisica – Istituto di Astrofisica Spaziale e Fisica cosmica (IASF)（意大利国家天体物理研究所-空间天体物理学与宇宙物理学研究所）；Thüringer Landessternwarte（图林根州天文台）；Hamburger Sternwarte, Universität Hamburg（汉堡大学汉堡天文台）；Center for Radio Astronomy Techniques and Technologies, Rhodes University（罗德斯大学射电天文技术与方法中心）
Fossil groups (FG) of galaxies still present a puzzle to theories of structure formation. Despite the low number of bright galaxies, they have relatively high velocity dispersions and ICM temperatures often corresponding to cluster-like potential wells. Their measured concentrations are typically high, indicating early formation epochs as expected from the originally proposed scenario for their origin as being older undisturbed systems. This is, however, in contradiction with the typical lack of expected well developed cool cores. Here, we apply a cluster dynamical indicator recently discovere…
Galaxy clusters have been found to host a range of diffuse, non-thermal emission components, generally with steep, power law spectra. In this work we report on the detection and follow-up of radio halos, relics, remnant radio galaxies, and other fossil radio plasmas in Southern Sky galaxy clusters using the Murchison Widefield Array and the Australian Square Kilometre Array Pathfinder. We make use of the frequency coverage between the two radio interferometers - from 88 to $\sim 900$ MHz - to characterise the integrated spectra of these sources within this frequency range. Highlights from the …
The vast thin plane of M31 co-rotating dwarfs: an additional fossil signature of the M31 merger and of its considerable impact in the whole Local Group
J1248+4826: A diffuse radio source consistent with re-energized fossil plasma in a galaxy group
INAF - Istituto di Astrofisica Spaziale e Fisica cosmica (IASF)（意大利国家天体物理研究所空间天体物理学与宇宙学研究所）；University of California, San Diego（加利福尼亚大学圣地亚哥分校）；University of Arizona（亚利桑那大学）；Université Paris-Saclay（巴黎萨克雷大学）
