The Fast Radio Burst-emitting magnetar SGR 1935+2154 -- proper motion and variability from long-term Hubble Space Telescope monitoring

Abstract

We present deep Hubble Space Telescope near-infrared (NIR) observations of the magnetar SGR 1935+2154 from June 2021, approximately 6 years after the first HST observations, a year after the discovery of fast radio burst like emission from the source, and in a period of exceptional high frequency activity. Although not directly taken during a bursting period the counterpart is a factor of ~1.5 to 2.5 brighter than seen at previous epochs with F140W(AB) = $24.65\pm 0.02$ mag. We do not detect significant variations of the NIR counterpart within the course of any one orbit (i.e. on minutes-hour timescales), and contemporaneous X-ray observations show SGR 1935+2154 to be at the quiescent level. With a time baseline of 6 years from the first identification of the counter-part we place stringent limits on the proper motion of the source, with a measured proper motion of $\mu =3.1\pm 1.5$ mas/yr. The direction of proper motion indicates an origin of SGR 1935+2154 very close to the geometric centre of SNR G57.2+08, further strengthening their association. At an adopted distance of $6.6\pm 0.7$ kpc, the corresponding tangential space velocity is ${\nu }_T=97\pm 48$ km/s (corrected for differential Galactic rotation and peculiar Solar motion), although its formal statistical determination may be compromised owing to few epochs of observation. The current velocity estimate places it at the low end of the kick distribution for pulsars, and makes it among the lowest known magnetar kicks. When collating the few-magnetar kick constraints available, we find full consistency between the magnetar kick distribution and the much larger pulsar kick sample

Accepted for publication in ApJ

References in corpus (21)

• Binary interaction dominates the evolution of massive stars
• An online repository of Swift/XRT light curves of GRBs
• Long gamma-ray bursts and core-collapse supernovae have different environments
• Corona of Magnetars
• INTEGRAL discovery of a burst with associated radio emission from the magnetar SGR 1935+2154
• A Debris Disk Around An Isolated Young Neutron Star
• Magnetar-like Emission from the Young Pulsar in Kes 75
• Characterizing the FRB host galaxy population and its connection to transients in the local and extragalactic Universe
• Hunting for open clusters in \textit{Gaia} DR2: $582$ new OCs in the Galactic disc
• The observed velocity distribution of young pulsars
• The Explosion of Helium Stars Evolved With Mass Loss
• Radio continuum and polarization study of SNR G57.2+0.8 associated with magnetar SGR1935+2154
• Identification of a Local Sample of Gamma-Ray Bursts Consistent with a Magnetar Giant Flare Origin
• X-ray and Near-IR Variability of the Anomalous X-ray Pulsar 1E 1048.1-5937: From Quiescence Back to Activity
• On the Distance of SGR 1935+2154 Associated with FRB 200428 and Hosted in SNR G57.2+0.8
• Constraints on millisecond magnetars as the engines of prompt emission in gamma-ray bursts
• Updated radio $\Sigma -D$ relation for Galactic supernova remnants
• Multi-frequency observations of SGR J1935+2154
• On the maximum luminosities of normal stripped-envelope supernovae -- brighter than explosion models allow
• The Galactic neutron star population I - an extragalactic view of the Milky Way and the implications for fast radio bursts
• High-energy gamma-ray emission from SNR G57.2+0.8 hosting SGR J1935+2154