Development of Faster and More Accurate Supernova Localization at Super-Kamiokande
Abstract
The next nearby core-collapse supernova (SN) promises to yield a treasure of scientific information through multi-messenger astronomy. Early observations of the shock breakout (SBO) emissions are especially critical to understand the SN explosive mechanism as well as the properties of the progenitor star. Neutrino observatories are able to provide an early alert of a SN before the arrival of the SBO radiation. Super-Kamiokande (SK) has the unique capability to independently reconstruct an accurate SN pointing direction as part of its real-time monitoring system, ``SNWATCH.'' Recent upgrades to SK by adding gadolinium (Gd) to the detection volume have been accompanied by efforts to improve the speed and accuracy of SN direction reconstruction. A new, novel HEALPix-based approach (``HP-Fitter'') can calculate the SN direction from the reconstructed burst event directions in less than one second. As well, the previous maximum-likelihood direction fitter (``ML-Fitter'') was upgraded by incorporating event information from Gd neutron-capture as well as using the HP-Fitter for the initial fit parameters and from code refactoring and optimization. The improved ML-Fitter has better angular resolution but direction reconstruction time is (sec). Together with improvements in burst detection and event reconstruction times, SNWATCH is now able to generate an SN alert with pointing information in about 90 seconds. These upgrades have been implemented at SK and integrated into a new automated system to provide GCN notices.
Cite
@article{arxiv.2604.07702,
title = {Development of Faster and More Accurate Supernova Localization at Super-Kamiokande},
author = {K. Abe and Y. Asaoka and M. Harada and Y. Hayato and K. Hiraide and K. Hosokawa and T. H. Hung and K. Ieki and M. Ikeda and J. Kameda and Y. Kanemura and Y. Kataoka and S. Miki and S. Mine and M. Miura and S. Moriyama and K. Nakagiri and M. Nakahata and S. Nakayama and Y. Noguchi and G. Pronost and K. Sato and H. Sekiya and K. Shimizu and R. Shinoda and M. Shiozawa and Y. Suzuki and A. Takeda and Y. Takemoto and H. Tanaka and T. Yano and S. Chen and Y. Itow and T. Kajita and R. Nishijima and K. Okumura and T. Tashiro and T. Tomiya and X. Wang and P. Fernandez and L. Labarga and D. Samudio and B. Zaldivar and C. Yanagisawa and B. Jargowsky and E. Kearns and J. Mirabito and L. Wan and T. Wester and B. W. Pointon and J. Bian and B. Cortez and N. J. Griskevich and Y. Jiang and M. B. Smy and H. W. Sobel and V. Takhistov and A. Yankelevich and J. Hill and M. C. Jang and S. H. Lee and D. H. Moon and R. G. Park and B. S. Yang and B. Bodur and K. Scholberg and C. W. Walter and A. Beauchêne and O. Drapier and A. Ershova and M. Ferey and E. Le Blévec and Th. A. Mueller and P. Paganini and C. Quach and R. Rogly and T. Nakamura and J. S. Jang and R. P. Litchfield and L. N. Machado and F. J. P. Soler and J. G. Learned and K. Choi and N. Iovine and S. Cao and L. H. V. Anthony and D. Martin and N. W. Prouse and M. Scott and Y. Uchida and V. Berardi and N. F. Calabria and M. G. Catanesi and N. Ospina and E. Radicioni and A. Langella and G. De Rosa and G. Collazuol and M. Feltre and M. Mattiazzi and L. Ludovici and M. Gonin and L. Périssé and B. Quilain and S. Horiuchi and A. Kawabata and M. Kobayashi and Y. M. Liu and Y. Maekawa and Y. Nishimura and R. Okazaki and R. Akutsu and M. Friend and T. Hasegawa and Y. Hino and T. Ishida and T. Kobayashi and M. Jakkapu and T. Matsubara and T. Nakadaira and K. Nakamura and Y. Oyama and A. Portocarrero Yrey and K. Sakashita and T. Sekiguchi and T. Tsukamoto and N. Bhuiyan and G. T. Burton and F. Di Lodovico and J. Gao and A. Goldsack and T. Katori and R. Kralik and N. Latham and J. Migenda and R. M. Ramsden and S. Zsoldos and H. Ito and T. Sone and A. T. Suzuki and Y. Takagi and Y. Takeuchi and S. Wada and H. Zhong and J. Feng and L. Feng and S. Han and J. Hikida and J. R. Hu and Z. Hu and M. Kawaue and T. Kikawa and T. Nakaya and T. V. Ngoc and R. A. Wendell and K. Yasutome and S. J. Jenkins and N. McCauley and P. Mehta and A. Tarrant and M. Fanì and M. J. Wilking and Z. Xie and Y. Fukuda and H. Menjo and Y. Yoshioka and J. Lagoda and M. Mandal and J. Zalipska and M. Mori and M. Jia and J. Jiang and W. Shi and K. Hamaguchi and H. Ishino and Y. Koshio and F. Nakanishi and S. Sakai and T. Tada and T. Tano and T. Ishizuka and G. Barr and D. Barrow and L. Cook and S. Samani and D. Wark and A. Holin and F. Nova and S. Jung and J. Y. Yang and J. Yoo and J. E. P. Fannon and L. Kneale and M. Malek and J. M. McElwee and T. Peacock and P. Stowell and M. D. Thiesse and L. F. Thompson and S. T. Wilson and H. Okazawa and S. M. Lakshmi and E. Kwon and M. W. Lee and J. W. Seo and I. Yu and Y. Ashida and A. K. Ichikawa and K. D. Nakamura and S. Tairafune and S. Abe and A. Eguchi and S. Goto and S. Kodama and Y. Kong and H. Hayasaki and Y. Masaki and Y. Mizuno and T. Muro and Y. Nakajima and N. Taniuchi and E. Watanabe and M. Yokoyama and P. de Perio and S. Fujita and C. Jesús-Valls and K. Martens and Ll. Marti and A. D. Santos and K. M. Tsui and M. R. Vagins and J. Xia and S. Izumiyama and M. Kuze and R. Matsumoto and K. Terada and R. Asaka and M. Ishitsuka and M. Shinoki and M. Sugo and M. Wako and K. Yamauchi and T. Yoshida and Y. Nakano and F. Cormier and R. Gaur and V. Gousy-Leblanc and M. Hartz and A. Konaka and X. Li and B. R. Smithers and S. Chen and Y. Wu and B. D. Xu and A. Q. Zhang and B. Zhang and H. Adhikary and M. Girgus and P. Govindaraj and M. Posiadala-Zezula and Y. S. Prabhu and S. B. Boyd and R. Edwards and D. Hadley and M. Nicholson and M. O'Flaherty and B. Richards and A. Ali and B. Jamieson and S. Amanai and C. Bronner and D. Horiguchi and A. Minamino and Y. Sasaki and R. Shibayama and R. Shimamura},
journal= {arXiv preprint arXiv:2604.07702},
year = {2026}
}