The low density and magnetization of a massive galaxy halo exposed by a fast radio burst
The low density and magnetization of a massive galaxy halo exposed by a fast radio burst
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DOI：
10.1126/science.aay0073
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发表时间：
2019-09
期刊：
影响因子：
56.9
通讯作者：
J. Prochaska;J. Macquart;M. McQuinn;S. Simha;R. Shannon;C. Day;L. Marnoch;S. Ryder;A. Deller;K. Bannister;S. Bhandari;R. Bordoloi;J. Bunton;Hyerin Cho;C. Flynn;E. Mahony;C. Phillips;H. Qiu;N. Tejos
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文献类型：
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作者：
J. Prochaska;J. Macquart;M. McQuinn;S. Simha;R. Shannon;C. Day;L. Marnoch;S. Ryder;A. Deller;K. Bannister;S. Bhandari;R. Bordoloi;J. Bunton;Hyerin Cho;C. Flynn;E. Mahony;C. Phillips;H. Qiu;N. Tejos
用射电爆发探测星系晕快速射电爆发（FRB）是来自遥远星系的射电发射的毫秒闪光。直到最近才能够精确地定位单次爆发以确定宿主星系。普罗查斯卡等人。使用射电干涉仪观察并定位了 FRB。宿主星系的视线恰好穿过更近的前景星系的外围。通过分析快速射电暴的传播，作者对前景星系外围气体的密度和磁化强度进行了限制。该技术为使用背景类星体的现有方法提供了补充信息。科学，本期第 14 页。 231 穿过前景星系外围的快速射电暴限制了气体密度和磁化强度。当今的星系被冷却且丰富的晕气体包围，晕气体延伸数百千秒差距。这种晕气体被认为是可用于为未来恒星形成提供燃料的主要物质库，但很难获得对其质量和物理性质的直接限制。我们报告检测到快速射电爆发（FRB 181112），其定位精度为弧秒，穿过前景星系的光晕。爆发分析表明晕气体具有较低的净磁化强度和湍流。我们的结果表明，巨大的星系晕中主要存在扩散气体，即使是那些拥有活跃超大质量黑洞的星系晕，这与之前的一些结果相反。
Probing a galaxy halo with a radio burst Fast radio bursts (FRBs) are millisecond flashes of radio emission from distant galaxies. It has only recently become possible to locate single bursts precisely enough to determine the host galaxy. Prochaska et al. have observed and localized a FRB using a radio interferometer. The line of sight to the host galaxy coincidentally passes through the outskirts of a closer foreground galaxy. By analyzing the propagation of the FRB, the authors put constraints on the density and magnetization of gas in the outskirts of the foreground galaxy. The technique provides complementary information to existing methods using background quasars. Science, this issue p. 231 A fast radio burst passing through the outskirts of a foreground galaxy constrains the gas density and magnetization. Present-day galaxies are surrounded by cool and enriched halo gas extending for hundreds of kiloparsecs. This halo gas is thought to be the dominant reservoir of material available to fuel future star formation, but direct constraints on its mass and physical properties have been difficult to obtain. We report the detection of a fast radio burst (FRB 181112), localized with arcsecond precision, that passes through the halo of a foreground galaxy. Analysis of the burst shows that the halo gas has low net magnetization and turbulence. Our results imply predominantly diffuse gas in massive galactic halos, even those hosting active supermassive black holes, contrary to some previous results.