2025ApJ...990L..49D

We present the discovery of a 421 s long period transient using the CHIME telescope, CHIME J0630+25. The source is localized to R.A. = 06:30:38.4 $\pm 1^{\prime} $ decl. = 25:26:23 $\pm 1^{\prime} $ using voltage data acquired with the CHIME baseband system. A timing analysis shows that a model including a glitch is preferred over a nonglitch model with dF/F = 1.3 × 10^–6, consistent with other glitching neutron stars. The timing model suggests a surface magnetic field of ∼1.5 × 10¹⁵ G and a characteristic age of ∼1.28 × 10⁶ yr. A separate line of evidence to support a strong local magnetic field is an abnormally high rotation measure of RM = -347.8(6) rad m^–2 relative to CHIME J0630+25's modest dispersion measure of 22(1) pc cm^–2, implying a dense local magneto-ionic structure. As a result, we believe that CHIME J0630+25 is a magnetized, slowly spinning, isolated neutron star. This marks CHIME J0630+25 as the longest period neutron star and the second-longest period neutron star with an inferred magnetar-like field. Based on dispersion measure models and comparison with pulsars with distance measurements, CHIME J0630+25 is located at a nearby distance of 170${}_{-100}^{+310}$ pc (95.4%), making it an ideal candidate for follow-up studies.