Tracking the photospheric horizontal velocity field with shallow U-net models Jiajia Liu, Quan Xie, Cheng Zhong, Yudong Ye, Yimin Wang, Kaifan Ji and Yuming Wang A&A, 698 (2025) A263 Published online: 20 June 2025 DOI: 10.1051/0004-6361/202453627