Quote:
On 2002-01-17 08:47, Donnie B. wrote:
Thanks, Dr. D. I should have realized we weren't talking about a rotating object (necessarily).
|
Well, the underlying object is very likely
rotating, but the *emission* that we *see*
as a GRB is coming from far away from that
object (at least 10^15 cm), and would not be
rotating.
Quote:
|
Perhaps this is a bit too arcane for my understanding, but what's the current thinking on why the GRB forms a beam? Or is that question still being debated?
|
Oh, very hotly. One idea, which I heard
about through Andrew MacFayden and Stan
Woosley, is the following: if the GRB
progenitor is a collapsing massive star
(akin to a supernova; and there have been
GRBs linked with supernovae), then you
would expect that material in the star's
mantle would tend to fall into the core
more easily along the poles, since there
wouldn't be a centrifugal barrier to overcome.
The density along the poles would therefore
be much less than in the torus around the
equator, so when the explosion (of whatever
origin) happens deep down in the center, it
will be more likely to spew stuff out the
poles because there's less resistence than
there would be along the equator where all
the junk is in the way.
That's one idea being explored.
Yours,
Don Smith