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arXiv · 2503.06668

Optical photon-counting observation of the Crab pulsar with Kanata telescope using prototype IMONY

Takeshi Nakamori·Kazuaki Hashiyama·Rin Sato·Masayoshi Shoji·Anju Sato·Eiji Ono·Yuga Ouchi·Tatsuya Nakaoka·Koji S. Kawabata·Toshio Terasawa·Hiroaki Misawa·Fuminori Tsuchiya·Kazuhiro Takefuji·Yasuhiro Murata·Dai Takei·Kazuki Ueno·Hiroshi Akitaya
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Abstract

We have developed an optical photon-counting imaging system, IMONY, as an instrument for short-scale time-domain astronomy. In this study, we utilized a Geiger avalanche photodiode array with a $4\times 4$ pixel configuration, with each pixel measuring \SI{100}{\micro m}. We developed a dedicated analog frontend board and constructed a data acquisition system with an FPGA to time-stamp each photon with a time resolution of \SI{100}{\ns}. We mounted a prototype model of the system on the 1.5-m Kanata telescope, intending to observe the Crab pulsar and conduct joint observations with Iitate and Usuda radio telescopes in Japan. We successfully demonstrated that IMONY could image the Crab pulsar as an expected point source and acquire the well-known pulse shape. We found that the time lag between the optical and radio main pulses was $304\pm$\SI{35}{\mu s}, consistent with previous studies.

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Takeshi Nakamori, Kazuaki Hashiyama, Rin Sato, Masayoshi Shoji, Anju Sato, Eiji Ono, Yuga Ouchi, Tatsuya Nakaoka, Koji S. Kawabata, Toshio Terasawa, Hiroaki Misawa, Fuminori Tsuchiya, Kazuhiro Takefuji, Yasuhiro Murata, Dai Takei, Kazuki Ueno, Hiroshi Akitaya. 2025-03-09. Optical photon-counting observation of the Crab pulsar with Kanata telescope using prototype IMONY. https://doi.org/10.1093/pasj%2Fpsaf009

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