对椭圆星系中磁星产生的快速射电暴的定向搜寻
A targeted search for fast radio bursts from magnetars in elliptical galaxies
- West Virginia University（西弗吉尼亚大学）
- National Centre for Radio Astrophysics, Tata Institute of Fundamental Research（国家射电天文中心，塔塔基础研究院）
- Morgantown High School（摩根敦高中）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究对5个本地大质量椭圆星系开展FRB定向搜寻，发现FRB 20240817A为背景事件，还识别出一组低显著性重复脉冲，设定了椭圆星系内单个磁星FRB源的本征暴率上限，揭示动力学星团内磁星形成效率低于预期。
AI中文摘要：
受相关预测的启发——与附近巨椭圆星系相关的球状星团是探测磁星产生的快速射电暴（FRB）的理想环境，我们报告了对5个本地大质量椭圆星系开展的高灵敏度定向搜寻结果。我们利用GREENBURST单脉冲搜寻管道，以及绿岸望远镜（GBT）的VEGAS后端，对每个目标环境开展了L波段（1.4 GHz）的FRB巡天。我们在M49（NGC 4472）方向发现了FRB 20240817A，其脉冲宽度为15 ms，信噪比为13，色散量（DM）为983 cm⁻³ pc。尽管贝叶斯空间关联框架最初将M49标记为其宿主，但仔细核算银河系、室女星际介质以及M49热气体晕的前景电子柱贡献（合计约300-400 cm⁻³ pc）后，强烈否定了二者存在物理关联。我们得出结论，FRB 20240817A是一个背景事件。我们还在M49方向识别出一组重复出现的低显著性脉冲，共3个，其色散量为150-160 cm⁻³ pc，符合物理上的合理范围。结合每个目标观测到的延展球状星团分布占比，由于未发现明确的宿主定位暴，我们对这些系统内单个活跃源的本征暴率设定了联合上限R₀ < 0.028 hr⁻¹（M49的综合率上限为<1.0 hr⁻¹），该结果降低了此前的上限，表明动力学星团内的磁星形成效率低于此前假设。
英文摘要：
Motivated by predictions that globular clusters associated with nearby giant elliptical galaxies are prime environments for detecting fast radio bursts (FRBs) from magnetars, we report on a targeted high-sensitivity search across five local massive elliptical galaxies. We utilized the GREENBURST single-pulse search pipeline and the VEGAS backend on the Green Bank Telescope (GBT) to conduct an L-band (1.4 GHz) survey for FRBs in each target environment. We discovered FRB 20240817A in the direction of M49 (NGC 4472) which has a pulse width of 15 ms, a signal-to-noise ratio of 13, and a dispersion measure (DM) of $983~\rm{cm}^{-3}$ pc. Although a Bayesian spatial association framework initially flags M49 as the host, carefully accounting for the foreground electron column contributions from the Milky Way and both the Virgo intracluster medium and M49's hot gaseous halo ($\sim300-400~\rm{cm}^{-3}$ pc combined) strongly disfavours a physical connection. We conclude that FRB 20240817A is a background event. We also identified a repeating cluster of three low-significance pulses from the direction of M49 at a physically plausible DM of $150-160~\rm{cm}^{-3}$ pc. Accounting for the fraction of each target's extended globular cluster distribution observed, the absence of unambiguous, host-localized bursts allows us to place a joint upper limit on the intrinsic burst rate of a single active source within these systems of $R_0 < 0.028~\rm{hr}^{-1}$ (and an integrated rate limit of $<1.0$~hr$^{-1}$ for M49), lowering previous upper limits and suggesting that magnetar formation within dynamical clusters is less efficient than previously assumed.
