astronomy

Swift J1644+57

Swift J1644+57 is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Swift J1644+57 rather than just read about it. In short: Swift J164449.3+573451, initially referred to as GRB 110328A, and sometimes abbreviated to Sw J1644+57, was a tidal disruption event (TDE), the destruction of a star by a supermassive black hole. It was first detected by the Swift Gamma-Ray Burst Mission on March 28, 2011.

Key takeaways

Swift J1644+57 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Swift J1644+57 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Swift J1644+57 from memory before moving on to harder problems.

Reference excerpt

Swift J164449.3+573451, initially referred to as GRB 110328A, and sometimes abbreviated to Sw J1644+57, was a tidal disruption event (TDE), the destruction of a star by a supermassive black hole. It was first detected by the Swift Gamma-Ray Burst Mission on March 28, 2011. The event occurred in the center of a small galaxy in the Draco constellation, about 3.8 billion light-years away. It was the first confirmed jetted tidal disruption event and is the most luminous and energetic TDE recorded.

Relativistic jet Swift J1644+57 occurred when a star wandered too close to the central supermassive black hole in the galaxy, and was gravitationally torn apart, forming an accretion disk from stellar material. When this occurred, an astrophysical jet was launched with material traveling at relativistic speeds, near the speed of light. The beam of radiation from one of these jets pointed directly toward Earth, enhancing the apparent brightness. Swift J1644+57 was observed by many telescopes across the electromagnetic spectrum. γ- and X-rays were detected due to jet plasma physics from the relativistic jet, with repetitive dimming and softening of the X-rays due to precession within the warped disk. The jets drive shocks into the surrounding interstellar medium, resulting in a radio to infrared afterglow. Observed linear polarization of the infrared radiation was consistent with synchrotron emission from the afterglow shock. Continuous monitoring at radio and X-ray wavelengths indicated that after roughly 600 days (1.5 years), the relativistic jet shut off. This time likely corresponds with when the mass accretion from the stellar debris passed under the Eddington rate, at which point the jet was no longer fueled. Since then, the outflow has become non-relativistic in speed, and emission is consistent with that of a shock wave that continues to expand into the surrounding material. As of 2021, the event is no longer detectable in X-rays but is still radio bright, and it is anticipated radio emission from Swift J1644+57 will be observable for several decades as emission continues to slowly fade.

Host galaxy and progenitor Detection of the relativistically expanding afterglow confirmed the identity of the host galaxy. Optical emission lines imply that the host is not an active galactic nucleus (AGN), but a starburst galaxy of HII galaxy classification. The supermassive black hole at the center of the galaxy is estimated to be more than 7 million solar masses (M☉). Timing considerations suggest that the tidally disrupted star was possibly a white dwarf and not a regular main sequence star. When the relativistic jet turned off, given the mass of astronomers calculated the amount of mass needed to fuel the jet for the Swift J1644+57 black hole as ~0.15 M☉, which is consistent with a solar mass star.

See also Supermassive black hole Tidal force

References

Illustrations

Worked examples

Example 1 — a first encounter with Swift J1644+57

Start with the simplest possible case. Write down what Swift J1644+57 claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Swift J1644+57 before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Swift J1644+57 ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Swift J1644+57

In research: Swift J1644+57 appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Swift J1644+57 in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Swift J1644+57 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 2011, Draco (constellation), Long-duration gamma-ray bursts, so understanding it makes those chapters shorter.
In everyday life: Look for Swift J1644+57 outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Swift J1644+57 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Swift J1644+57 means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Swift J1644+57 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Swift J1644+57 in simple terms?

Why does Swift J1644+57 matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Swift J1644+57?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Swift J1644+57.