2025AJ....170..145C

We present first-light deep Hα imaging taken with the Nanshan 1 m wide-field telescope on the local galaxy NGC 4258, alongside archival data from Hubble Space telescope (HST), Westerbork Synthesis Radio Telescope, and The Dark Energy Camera Legacy Survey. The Hα image shows ongoing star formation not only inside the galaxy but also in an H I cloud in the eastern H I tail, which is roughly 16 kpc away from the main galaxy. The HST images reveal several ultrablue compact objects (F555W - F814W < -0.5 mag, FWHM ∼ 0$\mathop{.}\limits^{\unicode{x02033}}$2) in the Hα bright region, aligned with the H I tail, suggesting the presence of young open cluster candidate in the H I tail. Our results suggest that wide field Hα imaging is a valuable tool for investigating recent star formation in the extended regions of NGC 4258. Furthermore, the star formation in diffuse H I tails could highlight an potential aspect of galaxy stellar halo formation, warranting further investigation of the impact of star formation in halos on galaxy evolution.