SGR 1935+2154

SGR 1935+2154
Name	SGR 1935+2154
Epoch	J2000
Type	Magnetar
Discovered	2014

SGR 1935+2154 is a Galactic object identified as a magnetar that produced X-ray bursts and a notable radio burst. It is associated with transient high-energy emission and studied by observatories across the electromagnetic spectrum. The source sits in the plane of the Milky Way and has been monitored by a range of instruments and missions.

Discovery and Naming

The source was first reported following detections by the Neil Gehrels Swift Observatory, Fermi Gamma-ray Space Telescope, and INTEGRAL teams in 2014, with initial X-ray activity prompting identification as a soft gamma repeater comparable to historical sources such as SGR 1806−20 and SGR 1900+14. Cataloguing followed conventions used by the International Astronomical Union and high-energy archives maintained by NASA and the European Space Agency, aligning the designation with the object's coordinates used by the Chandra X-ray Observatory and the XMM-Newton Science Operations Centre. Subsequent alerts and circulars from the Gamma-ray Coordinates Network and notices from the Astronomer's Telegram solidified its observational record alongside reports from the Rossi X-ray Timing Explorer archival searches and the MAXI team.

Properties and Classification

Observations with the NuSTAR observatory, Chandra X-ray Observatory, and XMM-Newton established a spin period and period derivative consistent with magnetar classification, comparable to parameters measured for 1E 2259+586 and 4U 0142+61. Timing and spectral fits used models developed in studies of AXP 1E 1048.1−5937 and incorporated methods from the High Energy Astrophysics Science Archive Research Center and researchers affiliated with institutions such as the Harvard-Smithsonian Center for Astrophysics and the Max Planck Institute for Extraterrestrial Physics. Derived surface dipole magnetic field strengths and characteristic ages invoke frameworks applied to PSR J1846−0258 and CXOU J164710.2−455216, while luminosity estimates referenced distances inferred from comparisons to Westerhout 49 and spiral arm models used by the Reid et al. maser distance consortium.

Burst Activity and Radio Emission

The source exhibited burst activity detected by the Fermi Gamma-ray Burst Monitor, Swift BAT, and Konus-Wind, with temporal and spectral properties analyzed alongside bursts from SGR 1806−20 and SGR 0526−66. In 2020 it produced a millisecond-duration radio burst contemporaneous with an X-ray flash, an event compared to extragalactic fast radio burst detections reported by teams using the Canadian Hydrogen Intensity Mapping Experiment and the Parkes Observatory. Radio follow-up involved facilities such as the CHIME/FRB collaboration, the European VLBI Network, and the Karl G. Jansky Very Large Array, drawing parallels with radio-loud magnetars like XTE J1810−197 and PSR J1622−4950. Multi-instrument timing linked the burst phenomenology to models developed in papers from groups at the California Institute of Technology, University of Manchester, and Swinburne University of Technology.

Association with Supernova Remnant G57.2+0.8

The positional coincidence with the supernova remnant designated G57.2+0.8 prompted studies by teams experienced with remnants such as Cassiopeia A and Puppis A, using radio maps from the Very Large Array and infrared data from the Spitzer Space Telescope. Morphological and distance analyses applied methods used in investigations of SNR CTB 109 and SNR G327.1−1.1, with debates paralleling those seen in associations between PSR B1757−24 and SNR G5.4−1.2. Researchers affiliated with the National Radio Astronomy Observatory, the Institute of Space and Astronautical Science, and university groups including University of Cambridge and University of Tokyo assessed age and energetics in the context of explosion models from teams at the Max Planck Institute for Astrophysics and the Los Alamos National Laboratory.

Multiwavelength Observations and Monitoring

Long-term monitoring campaigns included X-ray timing by NICER and XMM-Newton, gamma-ray monitoring by Fermi LAT, radio imaging by the European VLBI Network, and optical/infrared searches leveraging instruments on the Subaru Telescope and Gran Telescopio Canarias. Comparative multiwavelength strategies mirrored programs targeting Vela Pulsar, Crab Nebula, and magnetar follow-ups coordinated through the International Astronomical Union working groups and the Transient Name Server. Data reduction and archiving involved pipelines developed by teams at the Space Telescope Science Institute and the Astrophysics Data System, while coordinated campaigns included contributions from the Chinese Academy of Sciences and the National Astronomical Observatories of Japan.

Theoretical Interpretations and Magnetar Models

Theoretical work interpreting the source invoked magnetar frameworks advanced by researchers such as Robert Duncan and Christopher Thompson, building on models applied to magnetar giant flares and persistent emission seen in objects like 4U 0142+61. Scenarios for radio burst generation drew on mechanisms discussed in papers by groups at Princeton University, MIT, and Columbia University, linking to plasma physics studies from the Max Planck Institute for Plasma Physics and numerical simulations developed by teams at the Simons Foundation and Lawrence Berkeley National Laboratory. Discussions of crustal failure, magnetic reconnection, and pair cascade processes referenced comparative analyses of gamma-ray bursts and theoretical work produced in collaboration with the Kavli Institute for Theoretical Physics and the Perimeter Institute.

Category:Magnetars Category:Galactic sources