Diffuse radio sources in galaxy clusters: multi-wavelength observations

星系团中的漫射射电源：多波长观测

• 批准号: 340567605
• 负责人: Professor Dr. Marcus Brüggen, Ph.D.
• 金额: --
• 依托单位: Hamburger Sternwarte
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/340567605?language=en
• 关键词: Diffuse; radio; sources; galaxy; clusters

Radio relics are diffuse, low surface brightness, steep-spectrum sources that are typically located in the periphery of galaxy clusters. While it is known that non-thermal electrons are responsible for the observed synchrotron radiation, the mechanism of particle acceleration as well as the origins of the magnetic fields on these scales are poorly understood.The Low-Frequency Array (LOFAR) is the ideal instrument to find and study radio relics because it is very sensitive at low-frequencies and has a wide field of-view. With recent developments we are now capable of producing exquisite calibrated images that almost reach the thermal noise. As a point in case we have discovered with LOFAR diffuse emission in the low-mass galaxy cluster Abell 1931 which now wish to study in the X-rays and other radio bands (JVLA, GMRT) to investigate the origin of diffuse emission in galaxy clusters. Chandra observations for this target have already been approved. Since we do not know much about diffuse radio emission in lower mass clusters, this underlines the discovery potential of this target. So far, radio halos and relics have been found pre-dominantly in massive galaxy clusters.In a second part of this project, we will search for more steep-spectrum, diffuse emission in LOFAR Tier-1 surveys using direction-dependent calibration and imaging. A preliminary list of targets has been compiled from cross-correlating the area that has been surveyed by LOFAR Tier-1 survey with the Planck Sunyaev-Zeldovich cluster database yielding a total of 31 clusters. The discovery of new diffuse, steep spectrum sources will shed light on the role of old (fossil) relativistic electrons in producing radio relics.

射电遗迹是弥漫的，低表面亮度，陡谱源，通常位于星系团的外围。虽然人们已经知道同步辐射是由非热电子引起的，但是对于粒子加速的机制以及这些尺度上磁场的起源还知之甚少。低频阵列（LOFAR）具有低频灵敏度高、视场宽等优点，是寻找和研究射电遗迹的理想仪器。随着最近的发展，我们现在能够产生几乎达到热噪声的精致校准图像。作为一个点的情况下，我们已经发现了低质量星系团阿贝尔1931年，现在希望在X射线和其他无线电波段（JVLA，GMRT）的研究，以调查星系团的扩散发射的起源。钱德拉对这一目标的观测已经得到批准。由于我们对低质量星系团中的弥散射电辐射知之甚少，这突出了这个目标的发现潜力。到目前为止，射电晕和遗迹主要是在大质量星系团中发现的。在这个项目的第二部分，我们将使用方向相关校准和成像在LOFAR Tier-1调查中寻找更陡的光谱，漫发射。通过将LOFAR一级调查所调查的地区与普朗克Sunyaev-Zeldovich集群数据库进行交叉相关，编制了一份初步目标清单，共产生31个集群。新的扩散，陡峭的频谱源的发现将阐明旧的（化石）相对论电子在产生无线电遗迹中的作用。

项目成果

New constraints on the magnetization of the cosmic web using LOFAR Faraday rotation observations

使用 LOFAR 法拉第旋转观测对宇宙网磁化强度的新约束

• DOI: 10.1093/mnras/staa1395
• 发表时间: 2020
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: O’Sullivan

Simulations and observational tests of primordial magnetic fields from Cosmic Microwave Background constraints

宇宙微波背景约束下原初磁场的模拟和观测测试

• DOI: 10.1093/mnras/staa3532
• 发表时间: 2021
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: Paoletti;Banfi;Finelli;Gheller;O’Sullivan;Brüggen
• 通讯作者: Brüggen

A low-frequency study of linear polarization in radio galaxies

• DOI: 10.1093/mnras/staa3980
• 发表时间: 2020-12
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: V. Mahatma;M. Hardcastle;J. Harwood;Shane O'Sullivan;G. Heald;C. Horellou;Daniel J. B. Smith

The LOFAR view of intergalactic magnetic fields with giant radio galaxies

• DOI: 10.1051/0004-6361/202037635
• 发表时间: 2020-04
• 期刊: Astronomy & Astrophysics
• 影响因子: 6.5
• 作者: C. Stuardi;S. O’Sullivan;A. Bonafede;M. Brüggen;P. Dabhade;C. Horellou;R. Morganti;E. Carretti

Magnetic field at a jet base: extreme Faraday rotation in 3C 273 revealed by ALMA

• DOI: 10.1051/0004-6361/201832587
• 发表时间: 2018-03
• 期刊: Astronomy & Astrophysics
• 影响因子: 6.5
• 作者: T. Hovatta;S. O’Sullivan;I. Martí-Vidal;T. Savolainen;A. Tchekhovskoy;A. Tchekhovskoy