Gamma Ray Bursts: what percentage do we observe on earth ?

given the theory of Gamma Ray Bursts and the idea that we only see a
small percentage on earth what is that percentage ?

if we observed GRBs from a distant galaxy would we see the same
results ?

blackboab writes:

given the theory of Gamma Ray Bursts and the idea that we only see a
small percentage on earth what is that percentage ?

If you are referring to beaming, I believe the beaming ratio is in the
neighborhood of 500:1 (Frail et al 2001). Of course, there are many
bursts which are too faint to be detectable by today's instruments.

if we observed GRBs from a distant galaxy would we see the same
results ?

It's not clear what you mean by "the same results." It's reasonable
to suppose that the universe is largely isotropic and homogeneous, so
a similar distribution of bursts would be observed today by the same
instrumentation in another galaxy.

CM

On Jan 4, 12:11 pm, Craig Markwardt
wrote:
blackboab writes:
given the theory of Gamma Ray Bursts and the idea that we only see a
small percentage on earth what is that percentage ?

If you are referring to beaming, I believe the beaming ratio is in the
neighborhood of 500:1 (Frail et al 2001). Of course, there are many
bursts which are too faint to be detectable by today's instruments.

if we observed GRBs from a distant galaxy would we see the same
results ?

It's not clear what you mean by "the same results." It's reasonable
to suppose that the universe is largely isotropic and homogeneous, so
a similar distribution of bursts would be observed today by the same
instrumentation in another galaxy.

thats what i meant. so there are approximately 500 times as many GRBs
as we can observe here on earth ?

blackboab writes:

On Jan 4, 12:11 pm, Craig Markwardt
wrote:
blackboab writes:
given the theory of Gamma Ray Bursts and the idea that we only see a
small percentage on earth what is that percentage ?

If you are referring to beaming, I believe the beaming ratio is in the
neighborhood of 500:1 (Frail et al 2001). Of course, there are many
bursts which are too faint to be detectable by today's instruments.

if we observed GRBs from a distant galaxy would we see the same
results ?

It's not clear what you mean by "the same results." It's reasonable
to suppose that the universe is largely isotropic and homogeneous, so
a similar distribution of bursts would be observed today by the same
instrumentation in another galaxy.

thats what i meant. so there are approximately 500 times as many GRBs
as we can observe here on earth ?

Hmmm, that's not quite what I wrote. The 500:1 ratio would mean that
we miss 499 out of 500 GRB explosions because of beaming.

And if one considers the *entire universe*, there are surely far more
than 500x the number GRB explosions than we can observe at Earth, but
just too far away (and faint) to detect.

CM

On Jan 6, 5:15 am, Craig Markwardt
wrote:
blackboab writes:
On Jan 4, 12:11 pm, Craig Markwardt
wrote:
blackboab writes:
given the theory of Gamma Ray Bursts and the idea that we only see a
small percentage on earth what is that percentage ?

If you are referring to beaming, I believe the beaming ratio is in the
neighborhood of 500:1 (Frail et al 2001). Of course, there are many
bursts which are too faint to be detectable by today's instruments.

if we observed GRBs from a distant galaxy would we see the same
results ?

It's not clear what you mean by "the same results." It's reasonable
to suppose that the universe is largely isotropic and homogeneous, so
a similar distribution of bursts would be observed today by the same
instrumentation in another galaxy.

thats what i meant. so there are approximately 500 times as many GRBs
as we can observe here on earth ?

Hmmm, that's not quite what I wrote. The 500:1 ratio would mean that
we miss 499 out of 500 GRB explosions because of beaming.

And if one considers the *entire universe*, there are surely far more
than 500x the number GRB explosions than we can observe at Earth, but
just too far away (and faint) to detect.

CM

ok. thats what i imagined the theory (beaming) was pointing to.

does the beaming theory not actually make the number of GRBs in the
universe implausibly high ?

blackboab writes:
On Jan 6, 5:15 am, Craig Markwardt
wrote:
....
Hmmm, that's not quite what I wrote. The 500:1 ratio would mean that
we miss 499 out of 500 GRB explosions because of beaming.

And if one considers the *entire universe*, there are surely far more
than 500x the number GRB explosions than we can observe at Earth, but
just too far away (and faint) to detect.

CM

ok. thats what i imagined the theory (beaming) was pointing to.

does the beaming theory not actually make the number of GRBs in the
universe implausibly high ?

If beaming is correct, it would certainly mean that there are many
more GRBs that we can't see. Whether this total GRB rate is
"implausible" is more difficult to say, because first we have to
assert that we know about the progenitors and how they form.

Assuming the GRBs come from high mass stars ("hypernova") and neutron
star mergers, I don't think there is a huge discrepancy between the
progenitor production rate and the observed GRB rate. However, the
uncertainties are also large.

CM