APOD: X-Ray Rings Around a Gamma Ray Burst (2022 Oct 17)

[APOD Robot]

X-Ray Rings Around a Gamma Ray Burst

Explanation: Why would x-ray rings appear around a gamma-ray burst? The surprising answer has little to do with the explosion itself but rather with light reflected off areas of dust-laden gas in our own Milky Way Galaxy. GRB 221009A was a tremendous explosion -- a very bright gamma-ray burst (GRB) that occurred far across the universe with radiation just arriving in our Solar System last week. Since GRBs can also emit copious amounts of x-rays, a bright flash of x-rays arrived nearly simultaneously with the gamma-radiation. In this case, the X-rays also bounced off regions high in dust right here in our Milky Way Galaxy, creating the unusual reflections. The greater the angle between reflecting Milky Way dust and the GRB, the greater the radius of the X-ray rings, and, typically, the longer it takes for these light-echoes to arrive.

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[Ann]

X-Ray Rings Around a Gamma Ray Burst. Image Credit: NASA Swift Obs.; Data: B. Cenko (NASA's GSFC), A. Beardmore (U. Leicester) et al.; Processing: J. Miller (U. Michigan)

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Click to play embedded YouTube video.

A video of black and white paintings turned up in my Youtube flow yesterday, and I watched it for a bit until I got tired of all the black-and-whiteness.

Anyway, I think there is a similarity between the painting and the X-ray rings in the APOD!

Ann

[AVAO]

X-Ray Rings Around a Gamma Ray Burst

Explanation: Why would x-ray rings appear around a gamma-ray burst? The surprising answer has little to do with the explosion itself but rather with light reflected off areas of dust-laden gas in our own Milky Way Galaxy. GRB 221009A was a tremendous explosion -- a very bright gamma-ray burst (GRB) that occurred far across the universe with radiation just arriving in our Solar System last week. Since GRBs can also emit copious amounts of x-rays, a bright flash of x-rays arrived nearly simultaneously with the gamma-radiation. In this case, the X-rays also bounced off regions high in dust right here in our Milky Way Galaxy, creating the unusual reflections. The greater the angle between reflecting Milky Way dust and the GRB, the greater the radius of the X-ray rings, and, typically, the longer it takes for these light-echoes to arrive.

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This Day in APOD

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...hmmm. So I see a massive old star in a distant galaxy imploding into a black hole within 10 hours, accidentally firing its natal jets right in our direction 1.9 billion years ago...

"The signal, originating from the direction of the constellation Sagitta, had traveled an estimated 1.9 billion years to reach Earth. Astronomers think it represents the birth cry of a new black hole, one that formed in the heart of a massive star collapsing under its own weight. In these circumstances, a nascent black hole drives powerful jets of particles traveling near the speed of light. The jets pierce through the star, emitting X-rays and gamma rays as they stream into space. "
https://www.nasa.gov/feature/goddard/20 ... smic-blast

This sequence constructed from Fermi Large Area Telescope data reveals the sky in gamma rays centered on the location of GRB 221009A. Each frame shows gamma rays with energies greater than 100 million electron volts (MeV), where brighter colors indicate a stronger gamma-ray signal. In total, they represent more than 10 hours of observations. The glow from the midplane of our Milky Way galaxy appears as a wide diagonal band. The image is about 20 degrees across.


Credit: NASA/DOE/Fermi LAT Collaboration


Images taken in visible light by Swift’s Ultraviolet/Optical Telescope show how the afterglow of GRB 221009A (circled) faded over the course of about 10 hours. The explosion appeared in the constellation Sagitta and occurred 1.9 billion years ago. The image is about 4 arcminutes across.


Credit: NASA/Swift/B. Cenko

Swift’s X-Ray Telescope captured the afterglow of GRB 221009A about an hour after it was first detected. The bright rings form as a result of X-rays scattered from otherwise unobservable dust layers within our galaxy that lie in the direction of the burst.


Credits: Credit: NASA/Swift/A. Beardmore (University of Leicester)

Compare with: X-Ray Rings Expand from Gamma Ray Burst GRB 031203

https://apod.nasa.gov/apod/ap040130.html

[Mario]

Why a ring? Is there a preferred angle of reflection, like for ice crystals in the atmosphere reflecting sunlight, and why?

[orin stepanek]

Image X-Ray Rings Around a Gamma Ray Burst

Explanation: Why would x-ray rings appear around a gamma-ray burst? The surprising answer has little to do with the explosion itself but rather with light reflected off areas of dust-laden gas in our own Milky Way Galaxy. GRB 221009A was a tremendous explosion -- a very bright gamma-ray burst (GRB) that occurred far across the universe with radiation just arriving in our Solar System last week. Since GRBs can also emit copious amounts of x-rays, a bright flash of x-rays arrived nearly simultaneously with the gamma-radiation. In this case, the X-rays also bounced off regions high in dust right here in our Milky Way Galaxy, creating the unusual reflections. The greater the angle between reflecting Milky Way dust and the GRB, the greater the radius of the X-ray rings, and, typically, the longer it takes for these light-echoes to arrive.

If GBR comes almost same time as X-Rays; than they must be
associated with each other? JMHO

Reminds me of an old fashioned doily! What caused the split at
right side of photo?

[DL MARTIN]

To AVAO: Thanks for putting things into a temporal context. It animates distance.

[starsurfer]

Bruce Banner would approve of this APOD.

[VictorBorun]

How far is the dust that makes a light echo (or an X rays echo) ring to grow up to a radius of 7.5 arc min in an hour after the flash?

Well, the source is distant (1.9 billion ly), so let us take the flash wave front for a plane.
There is a rectangular triangle Observer, the Centre of the ring, a Point in the ring, and we know that OC is 1 light hour shorter than OP and that CP is 7.5 arc min wide looking from O.
So the distance to the dust is OP = (OP—OC)/(1—cos O) = 1 light hour / (1 — cos 7.5 arc min) = 1 light hour • 420199 = 48 light years

[longtry]

Why a ring? Is there a preferred angle of reflection, like for ice crystals in the atmosphere reflecting sunlight, and why?

Echoing these questions, I have the same. Could anyone provide a sketch from a point of view far from Earth? Does the intervening gas look like a veil? From my understanding of Einstein rings, if the mechanisms are similar then this veil must be positioned really "accurately" in space for us to see a circle like this, no?