Large, Bright Galaxy at z ~ 11

http://arxiv.org/abs/1603.00461

Oesch et al

Some Commentary: However, the discovery also raises many new questions
as the existence of such a bright and large galaxy is not predicted by
theory. "It's amazing that a galaxy so massive existed only 200
million to 300 million years after the very first stars started to
form. It takes really fast growth, producing stars at a huge rate, to
have formed a galaxy that is a billion solar masses so soon," explains
Garth Illingworth of the University of California, Santa Cruz. (From
Science Daily 3/3/16)

RLO http://ww3.amherst.edu/~rloldershaw

In article , "Robert L.
Oldershaw" writes:

Some Commentary: However, the discovery also raises many new questions
as the existence of such a bright and large galaxy is not predicted by
theory. "It's amazing that a galaxy so massive existed only 200
million to 300 million years after the very first stars started to
form. It takes really fast growth, producing stars at a huge rate, to
have formed a galaxy that is a billion solar masses so soon," explains
Garth Illingworth of the University of California, Santa Cruz. (From
Science Daily 3/3/16)

Since s.a.r contributor is a co-author, I'm sure he will comment. :-)

Maybe he can counter the argument that the big bang didn't happen, or
that this proves the fractal structure of the universe.

On Saturday, March 5, 2016 at 4:29:59 AM UTC-5, Phillip Helbig (undress to reply) wrote:

Since s.a.r contributor is a co-author, I'm sure he will comment. :-)

Maybe he can counter the argument that the big bang didn't happen, or
that this proves the fractal structure of the universe.

Are you claiming that I argue "that the big bang didn't happen, or
that this proves the fractal..."?

If so I regret to inform you that your claim is completely false. If
you had made a slightest bit of effort to learn what it is I do
specifically propose, and we have been arguing about for over a
decade, it would be impossible to make such a false accusation.

Could you please candidly explain yourself on this comment?

[Mod. note: further comments in this thread should be of general
interest or taken to private e-mail -- mjh]

RLO http://www3.amherst.edu/~rloldershaw

http://arxiv.org/abs/1603.00461

In article ,
"Robert L. Oldershaw" writes:
the existence of such a bright and large galaxy is not predicted by
theory.

Neither is its absence predicted by theory. There is no theory that
predicts high-z galaxy luminosity functions. Or low-z galaxy
luminosity functions, for that matter.

People who are interested should read the preprint (or eventually the
paper, which is accepted but not published quite yet) to understand
the uncertainties in the derived parameters. The redshift seems
secure to me, but the stellar mass and star formation rate depend on
assumptions. As an example, the longest wavelength observation at
4.5 microns corresponds to a rest-frame (i.e., emitted) wavelength of
375 nm, which is not an ideal indicator of stellar mass.

What we really need is a proper survey to _measure_ the luminosity
function at z = 11. That could be done with a properly instrumented
1.5-m telescope at L2. Last year Japan (JAXA) rejected a proposal
for such a mission. A similar mission may be proposed to ESA later
this year, but even if accepted, it probably wouldn't fly until
2027-2029. There seems to be no suitable funding opportunity at NASA:
the mission is too expensive to fit in the Explorer category but too
specialized to qualify as a Flagship mission. Some of us would like
to see a new funding line for "Probe-class missions," but it will
probably take a Decadal Survey recommendation to establish one.

--
Help keep our newsgroup healthy; please don't feed the trolls.
Steve Willner Phone 617-495-7123
Cambridge, MA 02138 USA

On Tuesday, March 8, 2016 at 3:16:42 AM UTC-5, Steve Willner wrote:

http://arxiv.org/abs/1603.00461

Neither is its absence predicted by theory. There is no theory that
predicts high-z galaxy luminosity functions. Or low-z galaxy
luminosity functions, for that matter.

People who are interested should read the preprint (or eventually the
paper, which is accepted but not published quite yet) to understand
the uncertainties in the derived parameters. The redshift seems
secure to me, but the stellar mass and star formation rate depend on
assumptions. As an example, the longest wavelength observation at
4.5 microns corresponds to a rest-frame (i.e., emitted) wavelength of
375 nm, which is not an ideal indicator of stellar mass.

What we really need is a proper survey to _measure_ the luminosity
function at z = 11. That could be done with a properly instrumented
1.5-m telescope at L2. Last year Japan (JAXA) rejected a proposal
for such a mission. A similar mission may be proposed to ESA later
this year, but even if accepted, it probably wouldn't fly until
2027-2029. There seems to be no suitable funding opportunity at NASA:
the mission is too expensive to fit in the Explorer category but too
specialized to qualify as a Flagship mission. Some of us would like
to see a new funding line for "Probe-class missions," but it will
probably take a Decadal Survey recommendation to establish one.


Also what we need are fully general relativistic modeling to supersede
crude toy models that use the Newtonian approximations.

For hints that this work is in progress, see:
https://www.sciencedaily.com/release...0307112935.htm

RLO http://www3.amherst.edu/~rloldershaw
Keep science and our newsgroups healthy - question authority and hand-waving

Robert L. Oldershaw wrote:
Also what we need are fully general relativistic modeling to supersede
crude toy models that use the Newtonian approximations.

For hints that this work is in progress, see:
https://www.sciencedaily.com/release...0307112935.htm

See also

Sabino Matarrese
"Computational cosmology: A general relativistic approach"
Nature Physics
(2016)
http://dx.doi.org/10.1038/nphys3706

It's unclear to me whether this commentary is open-access or behind
the usual Nature paywall.

--
-- "Jonathan Thornburg [remove -animal to reply]"
Dept of Astronomy & IUCSS, Indiana University, Bloomington, Indiana, USA
"There was of course no way of knowing whether you were being watched
at any given moment. How often, or on what system, the Thought Police
plugged in on any individual wire was guesswork. It was even conceivable
that they watched everybody all the time." -- George Orwell, "1984"

In article , "Robert L.
Oldershaw" writes:

Also what we need are fully general relativistic modeling to supersede
crude toy models that use the Newtonian approximations.

Yes, GR is more correct than Newtonian theory. However, one has to make
many approximations. In many cases, Newtonian theory is good enough,
since relativistic effects or small and/or cancel out.

Note that "toy model" does not apply here. The term "toy model" has a
specific meaning: a model which is as simple as possible in order to
illustrate a certain point, with no claim to being realistic in general,
even approximately. It is not a term for any approximate model, nor for
any which you don't like.

On Wednesday, March 9, 2016 at 3:18:06 AM UTC-5, Phillip Helbig (undress to reply) wrote:
In article , "Robert L.
Oldershaw"

Also what we need are fully general relativistic modeling to supersede
crude toy models that use the Newtonian approximations.

Yes, GR is more correct than Newtonian theory. However, one has to make
many approximations. In many cases, Newtonian theory is good enough,
since relativistic effects or small and/or cancel out.

Note that "toy model" does not apply here. The term "toy model" has a
specific meaning: a model which is as simple as possible in order to
illustrate a certain point, with no claim to being realistic in general,
even approximately. It is not a term for any approximate model, nor for
any which you don't like.
----------------------------

Well, both the quark model and the the Big Bang model started out as
toy models and then they were developed and refined until they are now
considered well-established mature theories/models. Having been taught
as near fact to generations of students, they are regarded "the way
nature works".

We could waste considerable time and effort arguing about whether we
have sufficient evidence to say that no further fundamental
modification to these models is required, so let's skip that and agree
to disagree on that issue.

But a question I will ask is how, exactly do we get from toy model to
mature model. Was and is Newtonian gravitation a toy model of
gravitation?

To paraphrase Shakespere again: Is it possible that "a toy by any
other name is still a toy", until it gets superseded by a better toy
model?

RLO http://www3.amherst.edu/~rloldershaw

In article , "Robert L.
Oldershaw" writes:

Also what we need are fully general relativistic modeling to supersede
crude toy models that use the Newtonian approximations.

Note that "toy model" does not apply here. The term "toy model" has a
specific meaning: a model which is as simple as possible in order to
illustrate a certain point, with no claim to being realistic in general,
even approximately. It is not a term for any approximate model, nor for
any which you don't like.
----------------------------

Well, both the quark model and the the Big Bang model started out as
toy models and then they were developed and refined until they are now
considered well-established mature theories/models.

True. However, LCDM is not a "toy model", as you claimed.

Was and is Newtonian gravitation a toy model of
gravitation?

No. It is an approximation.