SGR 1935+2154
What is SGR 1935+2154?
Neutron stars & pulsars· Distance ~30,000 ly. The magnetar that on 28 April 2020 produced the first fast radio burst ever caught inside our galaxy — decisive evidence that magnetars are behind at least some FRBs, a mystery that had lasted years. It lies in the galactic disk toward Vulpecula.
📍 Visible from where you are right now — computed in your browser
bearing · altitude · rise time · best time tonight
Where SGR 1935+2154 is in your sky right now: https://nowsky.org/solar/sky?sel=sgr 1935 — location and time set automatically, no login.
Its place in the sky
A magnetar, in the direction of Vulpecula.
Spin, distance, discovery
| Type | magnetar, source of the first fast radio burst seen inside our galaxy |
|---|---|
| Spin period | 3.24 s |
| Distance | ~30,000 ly (estimates vary widely) |
| Discovered | 2014 by the Swift satellite; FRB 200428 on 28 April 2020 |
Figures are representative approximations. Source: compiled from NASA and IAU public data.
Discovery and name
In April 2020 it fired a fast radio burst — the first FRB tied to a magnetar.
Frequently asked
- What kind of object is SGR 1935+2154?
- magnetar, source of the first fast radio burst seen inside our galaxy.
- How long is the orbital period of SGR 1935+2154?
- 3.24 s.
- How far is SGR 1935+2154 from Earth?
- ~30,000 ly (estimates vary widely).
- When was SGR 1935+2154 discovered?
- 2014 by the Swift satellite; FRB 200428 on 28 April 2020.
- Where in the sky is SGR 1935+2154?
- In the direction of Vulpecula.
- Where is SGR 1935+2154 in the sky right now?
- Open the sky view for your location and time and it shows the position in the sky right now.
The anti-glitch of 2022 — bursts that followed a sudden slowdown
A pulsar glitch is a sudden speed-up of rotation, but in October 2020 SGR 1935+2154 did the opposite: its spin slowed abruptly within hours, and three days later the magnetar emitted radio bursts again. Data from NASA's NICER and NuSTAR covering the interval were published in 2023, the first case in which an anti-glitch and radio bursts followed one another in time.
The interpretation is that a strong wind of plasma blew off the star's surface, draining rotational energy, and reshaped the magnetosphere in a way that opened a path for radio bursts to escape — a clue linking the mechanism by which magnetars produce fast radio bursts. This star 30,000 light-years away in Vulpecula has been watched continuously since its galactic fast radio burst of 2020, and it is the only specimen in which such events can be seen recurring from the same star.
The neutron star in depth
SGR 1935+2154 is a magnetar in the galactic disk toward Vulpecula, at an estimated distance of about 30,000 light-years. It spins every 3.24 seconds with a field of order 10¹⁴ gauss, and NASA's Swift satellite first caught it in 2014 through a short X-ray burst. It sits inside the supernova remnant G57.2+0.8, so it is thought to be the core of a star that exploded a few thousand years ago.
On 28 April 2020 it emitted FRB 200428, a powerful radio flash lasting about a millisecond, caught simultaneously by Canada's CHIME and the STARE2 array in the United States. An X-ray burst was seen at the same moment, providing the first proof that magnetars produce at least some fast radio bursts — a phenomenon whose origin had been a mystery since its discovery in 2007. The burst was thousands of times weaker than FRBs from other galaxies, but seeing one inside the Milky Way finally pinned down a source.
Vulpecula is a dim constellation beneath Cygnus in the summer Milky Way, neighbor to the first pulsar, PSR B1919+21. Select SGR 1935+2154 in the Sky view and it marks the direction hidden behind thick interstellar dust. It will never be visible in light, but looking up at the summer Milky Way overhead, remember that somewhere in it lies the star that solved one of the sky's riddles.
Related
Figures are representative approximations. Simulated positions use J2000 mean elements.