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相关论文: Cooling Flows and Radio Mini-Halos in Clusters of …

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It has recently been proposed a theoretical model which accounts for the origin of radio mini-halos observed in some cooling flow clusters as related to electron re-acceleration by MHD turbulence (Gitti, Brunetti & Setti 2002). The MHD…

天体物理学 · 物理学 2009-11-10 Myriam Gitti , Gianfranco Brunetti , Luigina Feretti , Giancarlo Setti

We have developed a model in which the diffuse synchrotron emission from radio mini-halos, observed in some cooling flow clusters, is due to a relic population of relativistic electrons reaccelerated by MHD turbulence via Fermi-like…

天体物理学 · 物理学 2007-05-23 Myriam Gitti , Gianfranco Brunetti , Giancarlo Setti , Luigina Feretti

We present VLA data at 330 MHz and 1.5 GHz of the radio emission observed in the cooling flow cluster A2626. By producing images at different resolutions we found that the radio source consists of different components: an unresolved core…

天体物理学 · 物理学 2007-05-23 Myriam Gitti

We argue that the presence of diffuse synchrotron emission forming the so-called radio mini-halos in some cooling flow clusters can be explained by reacceleration of relativistic electrons, the necessary energetics being supplied by the…

天体物理学 · 物理学 2009-11-07 Myriam Gitti , Gianfranco Brunetti , Giancarlo Setti

In this work, we present a study of the central regions of cool-core clusters hosting radio mini-halos, which are di use synchrotron sources extended on cluster-scales surrounding the radio-loud brightest galaxy. We aim to investigate the…

宇宙学与河外天体物理 · 物理学 2016-03-02 Luca Bravi , Myriam Gitti , Gianfranco Brunetti

In this letter we present a study of the central regions of cool-core clusters hosting radio mini-halos, which are diffuse synchrotron sources extended on cluster-scales surrounding the radio-loud brightest cluster galaxy. We aim to…

宇宙学与河外天体物理 · 物理学 2015-11-04 Luca Bravi , Myriam Gitti , Gianfranco Brunetti

The radio continuum properties of galaxy clusters with cooling flows are reviewed along with the relationship to the X-ray environment. We find that 60-70% of cD galaxies in cooling flows are radio-loud, a much higher fraction than the 14%…

天体物理学 · 物理学 2007-05-23 Jack O. Burns , Chris Loken , Percy Gomez , Elizabeth Rizza , Mark Bliton , Michael Ledlow , Frazer Owen

Analyses of Chandra's first images of cooling flow clusters find smaller cooling rates than previously thought. Cooling may be occurring preferentially near regions of star formation in central cluster galaxies, where the local cooling and…

天体物理学 · 物理学 2007-05-23 B. R. McNamara

Chandra images of galaxy clusters have revealed a wealth of structure unseen by previous generations of low resolution X-ray observatories. In the cores of clusters, bright, irregular X-ray emission is now routinely seen within central…

天体物理学 · 物理学 2007-05-23 B. R. McNamara

Cool cores of some galaxy clusters exhibit faint radio "minihalos." Their origin is unclear; their study has been limited by their small number. We undertook a systematic search for minihalos in a large sample of X-ray luminous clusters…

宇宙学与河外天体物理 · 物理学 2015-06-18 Simona Giacintucci , Maxim Markevitch , Tiziana Venturi , Tracy Clarke , Rossella Cassano , Pasquale Mazzotta

It has been proposed that the cool cores of galaxy clusters are stably heated by cosmic rays (CRs). If this is the case, radio mini-halos, which are often found in the central regions of cool core clusters, may be attributed to the…

宇宙学与河外天体物理 · 物理学 2015-06-11 Yutaka Fujita , Yutaka Ohira

We discuss new results from the Chandra X-ray Observatory and XMM-Newton on cluster cooling flows, emphasizing early results from our Chandra programs. We find cooling rates reduced by factors of 5-10 compared to those from earlier…

天体物理学 · 物理学 2007-05-23 B. R. McNamara , M. W. Wise , L. P. David , P. E. J. Nulsen , C. L. Sarazin

Recent results on cluster cooling flows are reviewed. Observations of excess soft X-ray provides the only direct evidence for a major repository for the cooled gas. Unfortunately, the frequency of occurrence of large excess columns is…

天体物理学 · 物理学 2007-05-23 Craig L. Sarazin

Radio minihalos are diffuse synchrotron sources of unknown origin found in the cool cores of some galaxy clusters. We use GMRT and VLA data to expand the sample of minihalos by reporting three new minihalo detections (A 2667, A 907 and PSZ1…

Conduction may play an important role in reducing cooling flows in galaxy clusters. We analyse a sample of sixteen objects using Chandra data and find that a balance between conduction and cooling can exist in the hotter clusters (T > 5…

天体物理学 · 物理学 2009-09-17 L. M. Voigt , A. C. Fabian

As more cooling flow clusters of galaxies with central radio sources are observed with the Chandra and XMM-Newton X-ray Observatories, more examples of "bubbles" (low-emission regions in the X-ray coincident with radio emission) are being…

天体物理学 · 物理学 2009-11-07 Noam Soker , Elizabeth L. Blanton , Craig L. Sarazin

The most important evidence of non-thermal phenomena in galaxy clusters comes from Giant Radio Halos (GRHs), synchrotron radio sources extended over Mpc scales, detected in a growing number of massive galaxy clusters. A promising…

天体物理学 · 物理学 2009-11-11 R. Cassano , G. Brunetti , G. Setti

A variety of large-scale diffuse radio structures have been identified in many clusters with the advent of new state-of-the-art facilities in radio astronomy. Among these diffuse radio structures, radio mini-halos are found in the central…

Recent data have radically altered the X-ray perspective on cooling flow clusters. X-ray spectra show that very little of the hot intracluster medium is cooler than about 1 keV, despite having short cooling times. In an increasing number of…

天体物理学 · 物理学 2007-05-23 P. E. J. Nulsen , B. R. McNamara , L. P. David , M. W. Wise

We present new deep, high-resolution radio images of the diffuse minihalo in the cool core of the galaxy cluster RX J1720.1+2638. The images have been obtained with the Giant Metrewave Radio Telescope at 317, 617 and 1280 MHz and with the…

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