Revealing the magnetic field in a distant galaxy cluster: discovery of the complex radio emission from MACS J0717.5+3745

被引：111

作者：

Bonafede, A. ^{[1
,2
]}

Feretti, L. ^{[2
]}

Giovannini, G. ^{[1
,2
]}

Govoni, F. ^{[3
]}

Murgia, M. ^{[2
,3
]}

Taylor, G. B. ^{[4
]}

Ebeling, H. ^{[5
]}

Allen, S. ^{[6
]}

Gentile, G. ^{[7
,8
]}

Pihlstroem, Y. ^{[4
]}

机构：

[1] Univ Bologna, Dip Astron, I-40126 Bologna, Italy

[2] Ist Radioastron, INAF, I-40129 Bologna, Italy

[3] Osservatorio Astron Cagliari, INAF, I-09012 Capoterra, Ca, Italy

[4] Univ New Mexico, Dept Phys & Astron, Albuquerque, NM 87131 USA

[5] Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA

[6] Stanford Univ, Kavli Inst Particle Astrophys & Cosmol, Stanford, CA 94305 USA

[7] Univ Libre Bruxelles, Fac Sci, Inst Astron & Astrophys, B-1050 Brussels, Belgium

[8] Univ Ghent, Sterrenkundig Observ, B-9000 Ghent, Belgium

来源：

ASTRONOMY & ASTROPHYSICS | 2009年 / 503卷 / 03期

基金：

美国国家航空航天局; 美国国家科学基金会;

关键词：

galaxies: clusters: general; galaxies: clusters: individual: MACS J0717+3745; radiation mechanisms: non-thermal; polarization; magnetic fields; FARADAY-ROTATION; LOW-FREQUENCY; SKY SURVEY; COMA CLUSTER; SHOCK-WAVES; X-RAYS; HALO; REACCELERATION; ALGORITHM; ORIGIN;

D O I：

10.1051/0004-6361/200912520

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

Aims. To study at multiple frequencies the radio emission arising from the massive galaxy cluster MACS J0717.5+3745 (z = 0.55). Known to be an extremely complex cluster merger, the system is uniquely suited for an investigation of the phenomena at work in the intra-cluster medium (ICM) during cluster collisions. Methods. We use multi-frequency and multi-resolution data obtained with the Very Large Array radio telescope, and X-ray features revealed by Chandra, to probe the non-thermal and thermal components of the ICM, their relations and interactions. Results. The cluster shows highly complex radio emission. A bright, giant radio halo is detected at frequencies as high as 4.8 GHz. MACS J0717.5+3745 is the most distant cluster currently known to host a radio halo. This radio halo is also the most powerful ever observed, and the second case for which polarized radio emission has been detected, indicating that the magnetic field is ordered on large scales.

引用

页码：707 / 720

页数：14

共 48 条

[1] Deep images of cluster radio halos [J].