Swift J164449.3+573451, initially referred to as GRB 110328A, and sometimes abbreviated to Sw J1644+57, was a tidal disruption event, 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 Draco is a constellation in the far northern sky. Its name is Latin for dragon. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations today. The north pole of the e ...

, about 3.8 billion light-years away. Studied by dozens of telescopes, it is one of the most puzzling cosmic blasts of high-energy radiation ever observed when it comes to brightness, variability and durability. It probably occurred when a star wandered too close to the central black hole in the galaxy, and was gravitationally torn apart and swallowed by it. Timing considerations suggest that the tidally disrupted star was a

white dwarf A white dwarf is a stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very dense: its mass is comparable to the Sun's, while its volume is comparable to the Earth's. A white dwarf's faint luminosity comes fro ...

and not a regular

main sequence In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Her ...

star. Debris now encircles the black hole in an

accretion disk An accretion disk is a structure (often a circumstellar disk) formed by diffuse material in orbital motion around a massive central body. The central body is typically a star. Friction, uneven irradiance, magnetohydrodynamic effects, and other fo ...

, which launches bipolar jets at near the

speed of light The speed of light in vacuum, commonly denoted , is a universal physical constant that is important in many areas of physics. The speed of light is exactly equal to ). According to the special theory of relativity, is the upper limit ...

. Jet plasma emits the γ- and

X-ray An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...

s. The beam of radiation from one of these jets points directly toward Earth, enhancing the apparent brightness. Repetitive dimming and softening of the X-rays implies that the jet temporarily tilts away from us, due to precession of the warped disk. The jets drive shocks into the surrounding interstellar medium, resulting in a

radio Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmit ...

infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...

afterglow. Detection of the relativistically expanding afterglow confirmed the identity of the host galaxy. Observed linear polarization of the infrared radiation is consistent with

synchrotron emission Synchrotron radiation (also known as magnetobremsstrahlung radiation) is the electromagnetic radiation emitted when relativistic charged particles are subject to an acceleration perpendicular to their velocity (). It is produced artificially in ...

from the afterglow shock. "This is truly different from any explosive event we have seen before," said

Joshua Bloom Joshua Simon Bloom (born June 8, 1974 in Washington, D.C.) is an American astrophysicist, chair and professor of astronomy at the University of California, Berkeley, and was the CTO and co-founder of the machine-learning companwise.io(acquired b ...

of the

University of California The University of California (UC) is a public land-grant research university system in the U.S. state of California. The system is composed of the campuses at Berkeley, Davis, Irvine, Los Angeles, Merced, Riverside, San Diego, San Francisco, ...

Berkeley Berkeley most often refers to: *Berkeley, California, a city in the United States **University of California, Berkeley, a public university in Berkeley, California * George Berkeley (1685–1753), Anglo-Irish philosopher Berkeley may also refer ...

, the lead author of the study published in the June 2011 issue of ''

Science Science is a systematic endeavor that builds and organizes knowledge in the form of testable explanations and predictions about the universe. Science may be as old as the human species, and some of the earliest archeological evidence for ...

''.

References

{{DEFAULTSORT:GRB 110328A 20110328 Draco (constellation) 110328A March 2011 events

See also

References