Euclid: 快速数据发布 (Q1) -- 强射电星系中的光学热斑
Euclid: Quick Data Release (Q1) -- Optical hotspots in powerful radio galaxies
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中文总结 AI 辅助
本研究结合LOFAR与Euclid Q1数据，识别77个强射电星系热斑，发现7%-15%有光学对应体，并首次探测到红移1.6的最高红移光学热斑，为高能粒子加速统计研究奠定基础。
中文摘要 AI 辅助
强射电星系的热斑是高能粒子加速的场所，但射电观测为我们提供的关于其产生的电子能量分布的信息有限，这影响了我们对其物理和能量学的整体理解。射电星系热斑的光学同步辐射对应体，能够探测高能电子，已为人所知多年，但仅在少数被选为射电波段非常明亮的源中进行了研究。通过将低频阵列（LOFAR）的观测与Euclid Q1数据发布在Euclid深场北区的数据相结合，我们识别出77个具有热斑的强射电星系，并表明其中一小部分但显著的比例（7%--15%）可能探测到了其热斑的红外和光学对应体。在我们最清晰的案例中，热斑的谱能量分布与粒子加速至能量高达（但不超过）1 TeV的假设一致，该假设基于场强接近均分；而未探测到的热斑要么未达到如此高的电子能量，要么必须具有非常不同的电子能量谱或显著低于均分的磁场强度。两个新的候选光学热斑被清晰探测到，与高分辨率LOFAR数据匹配；其中一个尤为引人注目，因为它既是迄今已知红移最高的光学热斑（$z \approx 1.6$），也是重启源内瓣热斑的首次光学探测。我们讨论了利用完整的宽场Euclid巡天，特别是与LOFAR的国际基线相结合，开展大规模热斑研究的方法，这将首次实现对热斑中高能粒子加速的统计分析。
英文摘要
The hotspots of powerful radio galaxies are the sites of high-energy particle acceleration, but radio observations give us limited information on the electron energy distributions that they generate, which affects our overall understanding of their physics and energetics. Optical synchrotron counterparts to radio galaxy hotspots, which probe high electron energies, have been known for many years, but have only been studied in a small number of objects selected as being very bright in the radio. By combining Low-Frequency Array (LOFAR) observations with the Euclid Q1 data release in the Euclid Deep Field North, we identify 77 powerful radio galaxies with hotspots and show that a small but significant fraction of them, 7--15\%, may have detected infrared and optical counterparts to their hotspots. The hotspot spectral energy distributions in our clearest cases are consistent with particle acceleration up to (but not beyond) 1\,TeV in energy on the assumption of field strengths close to equipartition, whereas non-detected hotspots either do not reach such high electron energies or would have to have very different electron energy spectra or significantly sub-equipartition magnetic field strengths. Two new candidate optical hotspots are clearly detected matching high-resolution LOFAR data; one is remarkable as both the highest-redshift optical hotspot known to date ($z \approx 1.6$) and also the first optical detection of the hotspot of the inner lobe of a restarting source. We discuss approaches to performing a large-scale study of hotspots with the full wide-area Euclid surveys, particularly when combined with the international baselines of LOFAR, enabling for the first time a statistical analysis of high-energy particle acceleration in hotspots.
发表机构
- University of Hertfordshire（赫特福德大学）
- INAF-Osservatorio Astronomico di Padova（意大利国家天体物理研究所帕多瓦天文台）
- INAF, Istituto di Radioastronomia（意大利国家天体物理研究所射电天文研究所）
- INAF-Istituto di Astrofisica e Planetologia Spaziali（意大利国家天体物理研究所天体物理学与行星科学研究所）
- Durham University（杜伦大学）
- Leiden University（莱顿大学）
- Roma Tre University（罗马三大）
- INAF-Osservatorio Astronomico di Roma（意大利国家天体物理研究所罗马天文台）
- University of Oslo（奥斯陆大学）
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