加拿大氢强度测绘实验旁瓣探测射电暴的通量密度校准
Flux Density Calibration of Radio Bursts Detected in the Sidelobes of the Canadian Hydrogen Intensity Mapping Experiment
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中文总结 AI 辅助
本研究提出CHIME/FRB旁瓣探测射电暴的通量密度校准方法，覆盖宽赤纬和时角范围，校准不确定性为20%至42%。
中文摘要 AI 辅助
加拿大氢强度测绘实验/快速射电暴（CHIME/FRB）仪器是一项瞬变天体物理暴发巡天，正在发现快速射电暴（FRB）、脉冲星和长周期瞬变源。作为一台中天望远镜，该巡天在子午线2度范围内最为灵敏；然而，CHIME/FRB能够探测到其地平线处明亮的 astrophysical 暴发，灵敏度为其峰值灵敏度的10^-2至10^-3。在本研究中，我们详细介绍了针对在CHIME旁瓣中探测到的这些暴发的通量密度校准程序，涵盖通道化电压（基带）和强度数据。我们通过将基带数据波束成形指向旁瓣中明亮、稳定的源，比较同一天体物理瞬变源的基带和强度通量密度校准，以及对中天稳定源进行强度通量密度校准，来验证并估计校准不确定性。我们能够对赤纬跨度从-12度到+59度、时角达30度的源进行通量密度校准，并且对于接近金牛座A（蟹状星云，赤纬约+22度）赤纬的源，时角可达90度。我们得出结论，CHIME旁瓣中瞬变源的通量密度校准不确定性范围为20%至42%，具体取决于所使用的数据和暴发的时角。
英文摘要
The Canadian Hydrogen Intensity Mapping Experiment/Fast Radio Burst (CHIME/FRB) instrument is a transient astrophysical burst survey that is discovering FRBs, pulsars, and long-period transients. As a transit telescope, the survey is most sensitive within 2 degrees of the meridian; however, CHIME/FRB can detect bright astrophysical bursts out to its horizon, at 10^-2 to 10^-3 of its peak sensitivity. In this study, we detail the flux density calibration procedure for these bursts detected in the CHIME sidelobes for both channelized voltage (baseband) and intensity data. We validate and estimate the calibration uncertainties by beamforming baseband data towards bright, steady sources in the sidelobes, comparing baseband and intensity flux density calibrations of the same astrophysical transients, and calibrating intensity flux densities for transiting steady sources. We are able to calibrate flux densities for declinations spanning -12 degrees to +59 degrees out to hour angles of 30 degrees, and out to 90 degrees in hour angle for declinations near that of Taurus A (Crab Nebula, declination of about +22 degrees). We conclude that uncertainties in the flux density calibration for transients in the CHIME sidelobes range from 20% to 42%, depending on the data used and the hour angle of the burst.
发表机构
- York University（约克大学）
- ASTRON, Netherlands Institute for Radio Astronomy（荷兰射电天文研究所）
- UvA（阿姆斯特丹大学）
- MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology（麻省理工学院卡弗里天体物理与空间研究研究所）
- Department of Physics, Massachusetts Institute of Technology（麻省理工学院物理学系）
- Laboratoire d’Astrophysique de Marseille, Aix-Marseille Univ.（马赛天体物理实验室，艾克斯-马赛大学）
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