RINGO3 - A 3 channel, rapid response polarimeter for the Liverpool Telescope

RINGO3 - 用于利物浦望远镜的 3 通道快速响应旋光计

• 批准号: ST/J000914/1
• 负责人: Iain Allan Steele
• 金额: $ 9.06万
• 依托单位: Liverpool John Moores University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2012
• 资助国家: 英国
• 起止时间: 2012 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FJ000914%2F1
• 关键词: RINGO3; channel; rapid; response; polarimeter

GRBs form when the core of a massive star collapses or two neutron stars merge together. The resulting explosions are the brightest events in the universe, vastly outshining entire galaxies containing hundreds of billions of stars. The energy output is believed to be largely concentrated in a jet however, rather than spread out in all directions. A GRB event is detected if the Earth happens to lie within the beam direction of its jet.The jet contains rapidly moving electrons which will spiral around magnetic field lines. This causes them to emit light due to the synchrotron radiation process. This emitted light will be polarized (i.e. the electromagnetic waves will be vibrating in a preferred direction related to the direction of the magnetic field lines). By measuring the polarization (using a Polaroid similar to that used in sunglasses) we can therefore determine the strength and geometry of the magnetic fields.This is important because it may be that the magnetic field is what powers the jet. Alternatively the magnetic field may be generated by the shock when the jet hits the surrounding medium. So far we have built a series of polarimeters (RINGO and RINGO2) to investigate this by measuring the polarization of optical light from GRBs at a certain single wavelength. The instruments are mounted on the Liverpool Telescope, which is a fully robotic (i.e. unmanned) telescope on La Palma which reacts to triggers from satellites such as the NASA SWIFT mission. The satellites monitor the sky for Gamma Ray Bursts, and automatically notify ground based followup facilities such as the Liverpool Telescope if they detect one. The LT can then automatically react to slew to the coordinates it has been sent by the satellite and start taking data within 3 minutes. This has had great success, with the first ever detections of early time optical polarization being made. In addition the first measurements of the change in optical polarization from a GRB as the jet expands have recently been obtained.We are now applying for funds to build RINGO3. This will be a multi-colour instrument that can observe simultaneously at three wavelengths. By doing so we will be able to unambiguously identify where in the burst the polarized emission is coming from. This will allow us to distinguish between three possibilities:1. Magnetic instabilities generated in the shock front giving rise to independent ordered magnetic field patches (the polarised radiation would come from the non-perfect cancellation of the polarizationfrom a large number of these patches each of which was randomly oriented). 2. Another situation that could give rise to polarised light from a GRB is if the observer's line of sight lies along the edge of the jet. In this case the magnetic fields parallel and perpendicular to the shock front could have different strengths, producing a polarised signal.3. Large-scale magnetic fields present throughout the relativistic outflow, originating from the inside the "central engine" driving the explosion and accelerating and collimating the jet.RINGO3 will also allow us to use GRBs to carry out tests of new theories of gravity which predict an energy dependance of the speed of light. This would cause rotation of the polarization of thelight from the GRB by different amounts at different wavelengths.Finally RINGO3 will be a common-user instrument on the telescope, used for polarization monitoring of many other objects including asteroids (where is can help determine the surface texture and composition), X-ray binaries and Blazars (which like GRBs also contain jets of unknown origin).

当一颗大质量星星的核心坍缩或两颗中子星合并在一起时，伽马射线暴就形成了。由此产生的爆炸是宇宙中最明亮的事件，大大超过了包含数千亿颗恒星的整个星系。然而，能量输出被认为主要集中在射流中，而不是分散在各个方向。如果地球恰好位于其喷流的射束方向内，就可以探测到伽玛暴事件。喷流中含有快速运动的电子，这些电子将围绕磁力线螺旋运动。这使得它们由于同步辐射过程而发光。该发射的光将被偏振（即电磁波将在与磁场线的方向相关的优选方向上振动）。通过测量偏振（使用类似于太阳镜中使用的偏振片），我们可以确定磁场的强度和几何形状。这很重要，因为磁场可能是喷射的动力。或者，磁场可以由射流撞击周围介质时的冲击产生。到目前为止，我们已经建立了一系列的偏振仪（RINGO和RINGO 2）来研究这一点，通过测量在某一单一波长的伽玛暴的光学光的偏振。这些仪器安装在利物浦望远镜上，这是一个完全自动化（即无人驾驶）的望远镜，位于拉帕尔马，对来自美国宇航局SWIFT使命等卫星的触发作出反应。这些卫星监测天空中的伽马射线暴，并自动通知地面后续设施，如利物浦望远镜，如果他们发现一个。然后，LT可以自动做出反应，将其转换到卫星发送的坐标，并在3分钟内开始获取数据。这已经取得了巨大的成功，第一次探测到早期的光学偏振。此外，最近还首次测量了伽玛暴在喷流膨胀时光学偏振的变化。我们现在正在申请建造RINGO 3的资金。这将是一个多色仪器，可以同时观察三个波长。通过这样做，我们将能够明确地识别偏振发射来自脉冲群的何处。这将使我们能够区分三种可能性：1。在激波阵面中产生的磁不稳定性产生了独立的有序磁场块（极化辐射来自于大量这些块的非完美抵消，每个块都是随机取向的）。2.另一种可能引起伽玛射线暴偏振光的情况是观察者的视线沿着喷流的边缘。在这种情况下，平行和垂直于冲击波阵面的磁场可能具有不同的强度，从而产生极化信号。大规模的磁场存在于整个相对论流出物中，起源于驱动爆炸的“中央引擎”内部，并加速和准直喷射。RINGO 3还将使我们能够使用GRB来进行新的引力理论的测试，该理论预测光速的能量依赖性。最后，RINGO 3将成为望远镜上的一个普通用户仪器，用于对许多其他物体进行偏振监测，包括小行星（它可以帮助确定表面结构和成分），X射线双星和Blazar（像GRB一样也包含未知来源的喷流）。

项目成果

RINGO3: a multi-colour fast response polarimeter

• DOI: 10.1117/12.927000
• 发表时间: 2012-09
• 作者: D. Arnold;I. Steele;S. Bates;C. Mottram;R. Smith

Calibration of the Liverpool Telescope RINGO3 polarimeter

• DOI: 10.1093/mnras/stw309
• 发表时间: 2016-02
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: A. Słowikowska;K. Krzeszowski;M. Zejmo;P. Reig;Iain Steele Janusz Gil Institute of Astronomy;University Research;Technology University of Crete;Physics Institute;Liverpool John Moores University

The RINGO2 and DIPOL optical polarization catalogue of blazars

耀变体的 RINGO2 和 DIPOL 光学偏振目录

• DOI: 10.1093/mnras/stw1770
• 发表时间: 2016
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: Jermak H

LIMITS ON OPTICAL POLARIZATION DURING THE PROMPT PHASE OF GRB 140430A

• DOI: 10.1088/0004-637x/813/1/1
• 发表时间: 2015-09
• 期刊: The Astrophysical Journal
• 作者: D. Kopač;C. Mundell;C. Mundell;J. Japelj;D. Arnold;I. Steele;C. Guidorzi;S. Dichiara;S. Kobayashi;A. Gomboc;R. Harrison;G. Lamb;A. Melandri;Robert J. Smith;F. Virgili;A. Castro-Tirado;A. Castro-Tirado;J. Gorosabel;A. Jarvinen;R. Sánchez-Ramírez;S. Oates;Martin Jelínek

PHENOMENOLOGY OF REVERSE-SHOCK EMISSION IN THE OPTICAL AFTERGLOWS OF GAMMA-RAY BURSTS

• DOI: 10.1088/0004-637x/785/2/84
• 发表时间: 2014-04-20
• 期刊: ASTROPHYSICAL JOURNAL
• 影响因子: 4.9
• 作者: Japelj, J.;Kopac, D.;Gomboc, A.
• 通讯作者: Gomboc, A.