Yet another oldest Supernova ever

Yousuf Khan

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Jul 9, 2009, 11:55:10 PM7/9/09

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I'm getting a little confused by these announcements. Today they
announced that they have discovered the oldest and farthest supernova
ever, at nearly 11 billion light-years. But just a few weeks back,
didn't they announce the oldest, farthest Gamma-Ray Burst, which would
also be a type of supernova. And the GRB was farther away still, at over
13 billion light-years.

Most Distant Supernovae Found
""The ones that we've detected happened about 11 billion years ago, so
you're getting close already," said lead author Jeff Cooke, an
astronomer at the University of California, Irvine. "
http://news.nationalgeographic.com/news/2009/07/090708-most-distant-supernova.html

The previous announcement, about the oldest GRB they found was in this
thread:

sci.astro | Google Groups
http://groups.google.com/group/sci.astro/tree/browse_frm/thread/3dabd93a42530b1f/04dd3c5a0e5f737d?rnum=1&q=bbbl67+OR+yjkhan+oldest+supernova&_done=%2Fgroup%2Fsci.astro%2Fbrowse_frm%2Fthread%2F3dabd93a42530b1f%2F15d7f6cc530c0a56%3Fq%3Dbbbl67%2BOR%2Byjkhan%2Boldest%2Bsupernova%26#doc_04dd3c5a0e5f737d

Yousuf Khan

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Jul 10, 2009, 12:00:53 AM7/10/09

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Sam Wormley

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Jul 10, 2009, 12:15:23 AM7/10/09

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So did you sort out to your satisfaction the details and differences
between these observations?

Yousuf Khan

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Jul 10, 2009, 12:44:18 AM7/10/09

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Sam Wormley wrote:
> So did you sort out to your satisfaction the details and differences
> between these observations?
>

No, enlighten me.

Yousuf Khan

HardySpicer

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Jul 10, 2009, 1:53:32 AM7/10/09

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On Jul 9, 9:00 pm, Yousuf Khan <bbb...@yahoo.com> wrote:
> I'm getting a little confused by these announcements. Today they
> announced that they have discovered the oldest and farthest supernova
> ever, at nearly 11 billion light-years. But just a few weeks back,
> didn't they announce the oldest, farthest Gamma-Ray Burst, which would
> also be a type of supernova. And the GRB was farther away still, at over
> 13 billion light-years.
>
> Most Distant Supernovae Found
> ""The ones that we've detected happened about 11 billion years ago, so
> you're getting close already," said lead author Jeff Cooke, an

> astronomer at the University of California, Irvine. "http://news.nationalgeographic.com/news/2009/07/090708-most-distant-s...

>
> The previous announcement, about the oldest GRB they found was in this
> thread:
>

> sci.astro | Google Groupshttp://groups.google.com/group/sci.astro/tree/browse_frm/thread/3dabd...
>
> Yousuf Khan

It's a bit like religion.

Hardy

Sam Wormley

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Jul 10, 2009, 10:48:28 AM7/10/09

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http://www.skyandtelescope.com/community/skyblog/newsblog/50249452.html

Yousuf Khan

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Jul 10, 2009, 1:18:05 PM7/10/09

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This is just another article about the same story I previously posted in
this thread. What I was asking about was if people had previously
discovered GRB's at 13 billion light-years already, then why are these
people saying that these supernova at around 11 billion light-years are
the farthest out yet? 13 billion beats 11 billion doesn't it?

Yousuf Khan

dlzc

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Jul 10, 2009, 3:15:23 PM7/10/09

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Dear Yousuf Khan:

Not all GRBs are supernovae. More correctly, a supernova has to have
other characteristics, including a certain duration / luminosity
relationship.

David A. Smith

YKhan

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Jul 10, 2009, 3:58:30 PM7/10/09

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On Jul 10, 3:15 pm, dlzc <dl...@cox.net> wrote:
> Not all GRBs are supernovae. More correctly, a supernova has to have
> other characteristics, including a certain duration / luminosity
> relationship.

I think in this case, they did identify this GRB as a supernova. I
guess the other possibilities for GRBs are Active Galactic Nucleii.
AGN's are usually long-duration, while supernovas are short duration
GRBs.

Sam Wormley

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Jul 10, 2009, 4:07:01 PM7/10/09

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Have you considered that the GRB might result from something
other than a supernova explosion. Did you compare the energy
levels?

Sam Wormley

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Jul 10, 2009, 4:08:40 PM7/10/09

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...or merging black holes.

Steve Willner

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Jul 10, 2009, 6:37:52 PM7/10/09

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In article <4a56bcf4$1...@news.bnb-lp.com>,

Yousuf Khan <bbb...@yahoo.com> writes:
> didn't they announce the oldest, farthest Gamma-Ray Burst, which would
> also be a type of supernova. And the GRB was farther away still, at over
> 13 billion light-years.

I think the difference -- as you indicate in a later message -- is
that GRBs are not known to be supernovae.

A difference that is of considerable practical interest is that
intrinsic luminosities of GRBs are not known even crudely. That
makes cosmological tests using GRBs impossible. Mind you, I'm not
sure luminosities for Type IIn SNe are known well enough to do
cosmology, but at least there's some hope for those.

--
Steve Willner Phone 617-495-7123 swil...@cfa.harvard.edu
Cambridge, MA 02138 USA
(Please email your reply if you want to be sure I see it; include a
valid Reply-To address to receive an acknowledgement. Commercial
email may be sent to your ISP.)

BradGuth

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Jul 10, 2009, 8:13:59 PM7/10/09

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On Jul 10, 3:37 pm, will...@cfa.harvard.edu (Steve Willner) wrote:
> In article <4a56bcf...@news.bnb-lp.com>,

> Yousuf Khan <bbb...@yahoo.com> writes:
>
> > didn't they announce the oldest, farthest Gamma-Ray Burst, which would
> > also be a type of supernova. And the GRB was farther away still, at over
> > 13 billion light-years.
>
> I think the difference -- as you indicate in a later message -- is
> that GRBs are not known to be supernovae.
>
> A difference that is of considerable practical interest is that
> intrinsic luminosities of GRBs are not known even crudely. That
> makes cosmological tests using GRBs impossible. Mind you, I'm not
> sure luminosities for Type IIn SNe are known well enough to do
> cosmology, but at least there's some hope for those.
>
> --

> Steve Willner Phone 617-495-7123 swill...@cfa.harvard.edu

> Cambridge, MA 02138 USA
> (Please email your reply if you want to be sure I see it; include a
> valid Reply-To address to receive an acknowledgement. Commercial
> email may be sent to your ISP.)

Each new and improved telescope (terrestrial or orbital) will discover
older and further away objects or cosmic events. So what?

What about all the stuff that's nearby and could directly affect us?
(obviously it's not getting 0.1% of the public funded action)

~ BG

BradGuth

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Jul 10, 2009, 8:15:55 PM7/10/09

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What do you expect from a parrot like Sam Wormley?

~ BG

BradGuth

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Jul 10, 2009, 8:17:26 PM7/10/09

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And those level differences are?

~ BG

Eric Gisse

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Jul 10, 2009, 11:23:30 PM7/10/09

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On Jul 10, 12:07 pm, Sam Wormley <sworml...@mchsi.com> wrote:
[...]

>
> Have you considered that the GRB might result from something
> other than a supernova explosion. Did you compare the energy
> levels?

It is very likely that GRBs are the product of a supernova, we just
don't know for sure yet.

Yousuf Khan

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Jul 11, 2009, 1:43:38 AM7/11/09

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Steve Willner wrote:
> In article <4a56bcf4$1...@news.bnb-lp.com>,
> Yousuf Khan <bbb...@yahoo.com> writes:
>> didn't they announce the oldest, farthest Gamma-Ray Burst, which would
>> also be a type of supernova. And the GRB was farther away still, at over
>> 13 billion light-years.
>
> I think the difference -- as you indicate in a later message -- is
> that GRBs are not known to be supernovae.
>
> A difference that is of considerable practical interest is that
> intrinsic luminosities of GRBs are not known even crudely. That
> makes cosmological tests using GRBs impossible. Mind you, I'm not
> sure luminosities for Type IIn SNe are known well enough to do
> cosmology, but at least there's some hope for those.
>

Well, some GRB's are thought to be the result of supernovas that have
their axes pointed directly toward us by chance. Not all supernovas have
their explosion axes pointed toward us, that's why we don't see them all
as GRB's.

Yousuf Khan

YKhan

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Jul 12, 2009, 2:13:12 AM7/12/09

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On Jul 10, 4:08 pm, Sam Wormley <sworml...@mchsi.com> wrote:
> > I think in this case, they did identify this GRB as a supernova. I
> > guess the other possibilities for GRBs are Active Galactic Nucleii.
> > AGN's are usually long-duration, while supernovas are short duration
> > GRBs.
>
> ...or merging black holes.

But I think a merging black hole or neutron star would produce very
short duration gamma rays, a few seconds at most.

Yousuf Khan

Sam Wormley

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Jul 12, 2009, 10:08:55 PM7/12/09

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http://imagine.gsfc.nasa.gov/docs/science/know_l1/bursts.html
followed by

http://imagine.gsfc.nasa.gov/docs/science/know_l1/grbs_duration.html
followed by

http://imagine.gsfc.nasa.gov/docs/science/know_l1/grbs_explosion.html
followed by

http://imagine.gsfc.nasa.gov/docs/science/know_l1/grbs_mysteries.html

Yousuf Khan

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Jul 13, 2009, 1:33:33 PM7/13/09

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Sam Wormley wrote:
>> But I think a merging black hole or neutron star would produce very
>> short duration gamma rays, a few seconds at most.
>>
>> Yousuf Khan
>
>
> http://imagine.gsfc.nasa.gov/docs/science/know_l1/bursts.html
> followed by
>
> http://imagine.gsfc.nasa.gov/docs/science/know_l1/grbs_duration.html
> followed by
>
> http://imagine.gsfc.nasa.gov/docs/science/know_l1/grbs_explosion.html
> followed by
>
> http://imagine.gsfc.nasa.gov/docs/science/know_l1/grbs_explosion.html
> followed by
>
> http://imagine.gsfc.nasa.gov/docs/science/know_l1/grbs_mysteries.html

So according to your link, the dividing line between long GRB's and
short GRB's is 1 or 2 seconds. If it's a long GRB, then it's likely a
supernova, otherwise it's a black hole/neutron star merger.

According to emails exchanges between NASA experts, the duration is
about 1.1 to 1.3 seconds in duration, which leads them to believe it's
closer to a long burst, thus of supernova origins.

"When converted to the rest frame, the T90 values (10.3 � 1.1 sec,
Swift/BAT 15-350 keV, Palmer et al., GCN 9204) and (12 sec, Fermi/GBM
8-1000 keV, Kienlin, GCN Circ. 9229) transform to 1.1 � 0.1 sec and 1.3
sec, respectively. However, one must be careful in comparing these
numbers to the BATSE short-hard burst divide (Kouveliotou et al., ApJ
413, L101, 1993). The BATSE duration distribution is in the observer
frame. With a typical redshift of z = 1-2 for BATSE bursts, the dividing
line between long and short in the rest frame is 0.7 to 1.0 seconds.
Thus this burst is on the boundary and toward the long side. "
http://gcn.gsfc.nasa.gov/other/090423.gcn3

Sam Wormley

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Jul 13, 2009, 1:51:29 PM7/13/09

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My point is that the astrophysics community has not come to any
final conclusions concerning all the GRB observations, and I wanted
you to be aware of some of the arguments and continuing mysteries.