33 votes

Why are there no gamma-ray bursts detected in our galaxy?

All models of gamma-ray bursts involve extremely energetic phenomena: particular types of supernovae, the coalescence of binary compact objects, strong magnetar flares, or tidal disruption events. It ...
  • 34.2k
18 votes
Accepted

"Who saw" the binary neutron star merger first? What was the sequence of events? (GRB/GW170817)

The initial Fermi trigger can be found here, and the following sequence of alerts that were sent out by the LIGO Scientific Collaboration/Virgo Collaboration (LVC) and various electromagnetic ...
17 votes
Accepted

If GRB 080319B happened next to nearest star: Proxima Centauri, what effect would that have had on us?

Faster than light's answer is fine if the gamma ray burst is "pointing" towards us. The emission from rapidly moving material in a GRB is thought to be beamed in the direction of that motion,...
  • 120k
14 votes
Accepted

Why can there be several seconds of lag between a binary neutron star merger and the emission of gamma rays from the same area?

The paper (section 5.1) discusses three possibilities in the context of a relativistic fireball model, where some of the kinetic energy in relativistic jets of material emerging from the explosion is ...
  • 120k
11 votes

If GRB 080319B happened next to nearest star: Proxima Centauri, what effect would that have had on us?

Short answer: We're screwed. Long answer: Using the inverse square law, the apparent magnitude of the GRB would be about -36.51, which is about 8091 times brighter than the Sun. That's amazing, but no ...
9 votes
Accepted

Quasars and Gamma Ray Bursts

I think you may be mixing up "Energy" and "Power" a little here. Power is the rate of Energy output per time. If Power is the speed, then Energy is the distance travelled. Quasars look like stars, ...
  • 93.6k
8 votes

Why is the number of Long Gamma Ray Burst (LGRB) event occurrences greater than the number of Short Gamma Ray Burst (SGRB) event occurrences?

Long and short GRBs are thought to arise from different types of event, involving different types of star. Therefore the question you should be asking is why are their event rates so similar?! Long ...
  • 120k
7 votes
Accepted

If getting shined on by a gamma ray is an extinction level event how do we detect them?

The danger from gamma-ray bursts (GRBs) is the potential to reduce atmospheric ozone drastically, allowing harmful ultraviolet radiation to pass through the atmosphere and make life on Earth much more ...
  • 34.2k
6 votes
Accepted

What does it mean for something to be optically thick to pair production?

In astrophysics, being "optically thick" means that light (and it is applied to photons of any frequency, not just visible light) cannot travel across or out of a body (which may be the ...
  • 120k
5 votes
Accepted

What do the acronyms in "AT 2017 gfo" mean?

You are correct. The AT is short for Astronomical Transient. The follows the year and an arbitary sequence of letters to uniquely identify the event, which is assigned by the Transient Name Server ...
  • 93.6k
5 votes
Accepted

Should we fear Wolf-Rayet WR-104?

Should we fear Wolf-Rayet WR-104? Not really. What you should fear more is getting hit by a bolt of lightning from a storm that is 477 miles (768 kilometers) away. This actually happened fairly ...
  • 28.7k
4 votes

Should we fear Wolf-Rayet WR-104?

WR104 seems to be pointed away from us at an angle of about 30 to 40 degrees, and likely won’t do a gamma ray burst when it goes supernova. The dust is lit up in a spiral pattern and it is carried ...
4 votes
Accepted

Do mixed type remnant collisions produce anything interesting?

WD+NS collision cannot leave nothing behind. Gravitational mass defect of NS is ~10% of its rest mass -- thus whatever energy released in the collision cannot disrupt the NS. The energy released is ...
4 votes

What are the Gamma rays and Cosmic rays effects on humans and equipments?

First of all *not to consider me a conspiracy theorist(, but isn't landing on the moon a questionable issue? Only to conspiracy theorists. To everyone else, no, it's not a questionable issue. My ...
  • 28.7k
4 votes
Accepted

How likely and severe is the threat of a gamma ray burst to earth?

I'll address WR104 first. The National Geographic article calls it a "potential threat." Yet that potential may be low. There are a slew of articles quoting astronomer Grant Hill on the ...
  • 34.2k
3 votes

What is the shape and size of a gamma ray burst?

When "shape" is used in the context of gamma-ray bursts, it is typically used to refer to the jets emitted on opposite ends of an axis through the source. These jets contain huge amounts of energy, ...
  • 34.2k
3 votes
Accepted

Should we expect clues from a gamma ray burst causing massive extinctions on Earth?

A gamma ray burst could cause an extinction event. There is no evidence that this has ever happened to the Earth. Gamma ray bursts are rare events, we don't know exactly how rare, but to cause a mass ...
  • 93.6k
3 votes
Accepted

How does the Gamma Ray Burst that occurred when 2 black holes merged compare to other GRB's?

The interpretation you suggest in the second paragraph is incorrect. It is understandable, since there is a debate in the literature - different papers come to potentially contradicting conclusions. ...
3 votes

Energy Source for Gamma Rays from Merging Neutron Stars

Not Nuclear fusion; There is also a huge amount of nuclear fusion that creates heavy elements from all the iron there is in neutron star: they in fact are not only made of neutrons. But as said in ...
  • 1,402
2 votes
Accepted

Is there a way to know how the magnetic field was at the very beginning of our universe?

Is there a way to know how the magnetic field was at the very beginning of our universe? I don't know of one. But then again I think there was no magnetic field at all at the very beginning of the ...
2 votes

What is the difference between $E_\gamma$ and $E_{\gamma,iso}$ in gamma ray bursts?

I will answer with what I now believe to be the correct answer. We see some gamma-ray burst emission hit our satellite which carries an amount of energy $E_{obs}$. If we say the burst was emitted ...
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2 votes

Should we fear Wolf-Rayet WR-104?

With basis on the limited information available, we can try to get some crude estimates for an adverse outcome. From the Wikipedia article: Recent studies suggest these effects pose a "highly ...
  • 895
2 votes
Accepted

What does the word "compact" mean in astronomy/astrophysics?

Compact stars are stars of great density; stellar remnants in which the fermion constituents have become degenerate. i.e. white dwarfs and neutron stars (though sometimes black holes would be included)...
  • 120k
1 vote

Extent of knowledge of potential future gamma ray bursts

Although not being an expert on the field, I found a multitude of studies dealing with events which may be used as indicator that a GBR is about to happen somewhere. Research on GBR precusor events ...
  • 5,334
1 vote

Where can I look up assigned origins of gamma ray bursts events? (GRBs)

I found a database that contains all GRBs from April 1991-August 1991. However, it has 1637 registered GRBs so it would probably be enough for your purposes. Here is the link-Goddard Space Center GRB ...
1 vote
Accepted

Gamma ray detection for SETI. How far away could we detect an alien nuclear powered rocket?

It's unclear if nuclear energy would be a choice propulsion for a space faring civilization. It's possible, but it's not the only option. That said, if it was the method of choice, it's not at all ...
  • 22.9k
1 vote

Is there any possible connection between Gamma Ray Burst and Fast Radio Bursts?

There is a tentative detection of a GRB simultaneously with an FRB, DeLaunay et al 2016. If it is true, it would mean that at least some FRBs have the same origin as some GRBs. Theoretically many ...
1 vote

Could a pair of binary black holes form within a star?

I doubt two black holes could form within a single star, but they might form from a contact binary. That's a pair of stars so close that they touch and share a single atmosphere. For the stars that ...
  • 762
1 vote

How do we know an event is a gamma-ray burst?

Yes, on the right track where the energy produced in a supernova can indicate if it was a LGRB or SGRB. An indicative tools stems from the light curves of the remnants, both the afterglow brightness ...

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