Gamma Ray Burst in 2022 is Brightest of all Time

[brockrwood]

I see that this forum has been expanded in scope a bit include space-related topics as well as rocketry-related topics. Yay!

https://www.sciencealert.com/astronomers-witness-the-brightest-space-explosion-ever-seen

 

[Hobie1dog]

2.4 Billion light years away, and One light-year is about 6 trillion miles so it doesn't seem possible for them to determine 2.4 BILLION light years away.

 

[Antares JS]

2.4 Billion light years away, and One light-year is about 6 trillion miles so it doesn't seem possible for them to determine 2.4 BILLION light years away.

A type 1a supernova occurs when a white dwarf pulls enough matter off a companion star to reach a certain critical mass (I think it's about 1.4 solar masses or so). Because this mass is so consistent, it means that type 1a supernovae are all basically identical. This allows them to be used as a "standard candle." When a type 1a supernova is detected in a distant galaxy, its exact luminosity can be measured and used to determine exactly how far away that galaxy is.

For stars in the Milky Way, we can use parallax measurements taken six months apart, when the Earth is on opposite sides of the sun, but for distant galaxies, that parallax is too small to measure and the type 1a supernova standard candle is used.

This gamma ray burst presumably took place in a galaxy whose distance was known via this approach.

 

[Funkworks]

Every bright star and galaxy is mostly made up of hydrogen. But hydrogen emits and absorbs light at very specific (electro-magnetic frequencies or colors), which together make up a pattern.

Here's the pattern ...
1. ... when hydrogen is in a stationary container, as measured in a lab.
2. ... when hydrogen is that of a nearby star moving away.
3. ... when hydrogen is that of a galaxy moving away faster.
4. ... when hydrogen is that of a galaxy moving away even faster.
5. ... when hydrogen is that of a quasar, moving away even faster.



It's the same pattern in all cases, and therefore hydrogen, except that the pattern is shifted to the right when the star is moving away fast.

In space, galaxies that are moving away faster are also further away, and the relationships between shift, speed and distance are known. So once an amount of shift (redshift) is known, so is the speed and distance of the star or galaxy made up of that hydrogen.

 

[brockrwood]

So, if we can only detect gamma ray bursts when they are aimed almost directly at us, and since we have only had the instruments to detect them for, say, 70 years, and since we have detected them for that 70 years, gamma ray bursts (supernovae leading to a neutron star or black hole) must happen very frequently. Is that logic sound?

 

[Funkworks]

So, if we can only detect gamma ray bursts when they are aimed almost directly at us, and since we have only had the instruments to detect them for, say, 70 years, and since we have detected them for that 70 years, gamma ray bursts (supernovae leading to a neutron star or black hole) must happen very frequently. Is that logic sound?

I'm sure occurences can be quantified, but qualifying them as "very frequently" sounds arbitrary. Frequent compared to what? Do we mean "within the local group?, "within the Virgo supercluster?", "within the observable universe", beyond? Over what time interval? One Earth year? Within the 1st billion years? In the last millions years? It sounds to me like something someone should have estimated by now, but I don't know who.