An old galaxy at z=7.1

On Wednesday, March 4, 2015 at 2:56:17 PM UTC-5, wlandsman wrote:

There are many possible clear and definitive tests but here's a simple
one -- find any object that has an origin more than 13.8 billion years
ago. This could be a globular cluster in our Galaxy more than 13.8
billion years old, or a galaxy at z = 7.5 that is more than 700
million years old.


If this z=11 galaxy candidate holds up, would that be a problem for the conventional early expansion period models?

For latest paper on this object see: http://arxiv.org/abs/1502.05681

Le 04/03/2015 15:51, Martin Hardcastle a ecrit :
So why do you think that's relevant? What calculation have you done
that suggests that the*gas to dust ratio* should be different in a
young galaxy and the MW?

Mr Hardcastle:

A few lines above I said:

quote from my post
1) Dust production in galaxies is a cumulative process. The older the
galaxy, the more dust it has. This is because supernova explosions
produce the dust, as has been recently found.
end quote

Now, would you please answer to this instead of asking the questions I
have already answered?

Since dust is produced in supernova explosions, the longer a galaxy
lives, the more dust it has. This is also confirmed by the article I cited:

quote
Instead of a young, dust-poor galaxy, these measurements suggest an
evolved system. Finally, the deep upper limit on the C III]
1909Angstroms line, of 4 Angstroms restframe equivalent width is
unusual for line-emitting galaxies at these redshifts.

Based on galaxies at lower redshift, we might expect an equivalent width
as high as 30 Amstrongs for this star-formation rate for a young galaxy.

And while the lack of Ly-alpha emission in this galaxy could be
explained by IGM absorption, the absence of C III] emission cannot, and
is consistent with a more evolved galaxy.
end quote

AN EVOLVED SYSTEM within the "reionization" age according to BB theory.

Now please explain me this:

If the "dark ages" lasted 550 million years, as the Planck satellite
data suggest, how can we have an EVOLVED dusty galaxy 150 million years
later?

The data is relatively new. See
http://www.mpg.de/8950872/planck-star-formation (Feb 9th 2015)
That URL is the Max Planck institute in Germany. This is not "some web
site". It is the official web site of the Max Planck Institut that has
*some* insight into the data of the Max Planck Satellite, I suppose...

They refer to MANY scientific papers, and that is the problem, I can't
tell you which. But I am sure this will be no problem for professionals
really.


You say:

quote from Mr Hardcastle's message
Not really -- the number of stars that have died to make the dust will
be a pretty small fraction of the total mass. Look up the concepts of
'initial mass function' and 'main sequence lifetime of stars'. This is
all elementary first-year astronomy that it's really useful to know
before setting up as a cosmologist!
end quote

Thanks for the hint but I am NOT a cosmologist, I have a PhD in
biochemistry so I won't be a cosmologist any time soon :-)

But coming back to the discussion.

The 'initial mass function' just tells us essentially that there will be
less numbers of massive stars and more smaller stars. But I thought that
this would not apply to the very first stars/galaxies since all of them
should be very massive and die quickly to make all the dust and metals
necessary to explain the metallicity of the early galaxies that is observed!


You continue with this:
quote
Prove to me from first principles that that gas to dust ratio cannot
possibly be achieved in 1-3 hundred Myr and I'll agree you have a point
end quote

In the article we have this:
quote
This gives a dust-to-gas mass ratio of about 17 x 10 -3. And while the
uncertainty on the gas and dust masses is large -- approximately 0.5 dex,
dominated by the scatter in the Schmidt-Kennicutt law and the unknown
dust temperature, where the two values are linked through
the SFR -- the dust-to-gas mass ratio is nevertheless high for this
redshift, between a half and a few times the Milky Way value
end quote

The problem is not that I have to prove you that this dust to gas ratio
is impossible (obviously it is not since it is observed!). The problem
is for you to explain HOW this galaxy can achive in 150 million years
what the milky way needed 12 0000 million years to achieve!!!

Even if we take the lower figure (half the ratio of the MW) it would be
still 6000 million years, supposing a linear accumulation function.

You say:
quote
Again -- describing this galaxy as 'fully developed' is nonsense
end quote

In the cited paper we have:
quote
Instead of a young, dust-poor galaxy, these measurements suggest an
evolved system.
end quote

OK?
It is not me (again). It is the authors of that paper.

Mr Hardcastle:
Even if the tone of my messages is polemic, I thank you for your
answers, and I hope I did not upset you (and the other professionals
here) with my rumblings.

jacob

[Mod. note: non-ASCII characters removed again -- mjh]

In article ,
jacob navia wrote:
A few lines above I said:

quote from my post
1) Dust production in galaxies is a cumulative process. The older the
galaxy, the more dust it has. This is because supernova explosions
produce the dust, as has been recently found.
end quote

Now, would you please answer to this instead of asking the questions I
have already answered?

Since dust is produced in supernova explosions, the longer a galaxy
lives, the more dust it has.

Yes, we might expect the dust mass of a galaxy to increase with time
along with everything else (dust is not exclusively produced in
supernova explosions, but that doesn't really matter in this context).
But as I already said, this galaxy has very little dust, just as it
has very little gas and very few stars: so what's your point?

This is also confirmed by the article I cited:
AN EVOLVED SYSTEM within the "reionization" age according to BB theory.

Evolved in the sense that there has already been a generation of stars
that's gone off the main sequence and created dust. Do you know the
main-sequence lifetime of the most massive stars? No? It's a few
million years. (It might be less in the very early universe.) So a
young galaxy can be 'evolved' in this sense.

Now please explain me this:

If the "dark ages" lasted 550 million years, as the Planck satellite
data suggest, how can we have an EVOLVED dusty galaxy 150 million years
later?

No problem at all, see above.

The data is relatively new. See
http://www.mpg.de/8950872/planck-star-formation (Feb 9th 2015)
That URL is the Max Planck institute in Germany. This is not "some web
site". It is the official web site of the Max Planck Institut that has
*some* insight into the data of the Max Planck Satellite, I suppose...

There's no relationship between the two bodies other than that they
have the same name and, as I said, I'm not going to waste time
analysing material aimed at journalists. Whatever timescale you take,
it is clear that there is plenty of time for the stars that are
observed to form, as I already said.

The 'initial mass function' just tells us essentially that there will be
less numbers of massive stars and more smaller stars. But I thought that
this would not apply to the very first stars/galaxies since all of them
should be very massive and die quickly to make all the dust and metals
necessary to explain the metallicity of the early galaxies that is observed!

Not necessarily. The dust mass they quote is a few per cent of the
stellar mass. Most stars that have formed since the start of star
formation are still there in the galaxy.

In the article we have this:
quote
This gives a dust-to-gas mass ratio of about 17 x 10 -3. And while the
uncertainty on the gas and dust masses is large -- approximately 0.5 dex,
dominated by the scatter in the Schmidt-Kennicutt law and the unknown
dust temperature, where the two values are linked through
the SFR -- the dust-to-gas mass ratio is nevertheless high for this
redshift, between a half and a few times the Milky Way value
end quote

The problem is not that I have to prove you that this dust to gas ratio
is impossible (obviously it is not since it is observed!). The problem
is for you to explain HOW this galaxy can achive in 150 million years
what the milky way needed 12 0000 million years to achieve!!!

Like I said before. It's the dust to gas RATIO that is comparable to
the Milky Way value. Not the total mass of dust, the RATIO between the MASS
OF DUST and the MASS OF GAS.

There is no reason why you should expect this RATIO to evolve in a
simple linear way with age because it depends not just on the MASS OF
DUST but also on the MASS OF GAS, and BOTH OF THOSE CHANGE WITH TIME.
(Gas is accreted by gravity and depleted by star formation. Dust is
created, but also destroyed, in stellar processes.)

In 150 million years there is time for many generations of massive
stars to form, evolve off the main sequence and die, creating dust.

You need to do detailed modelling of the star formation processes in
the galaxy to claim that the observed dust mass -- the gas to dust
ratio is really not particularly relevant -- can't be generated in the
time available since the start of star formation. You have not done this.

You say:
quote
Again -- describing this galaxy as 'fully developed' is nonsense
end quote

In the cited paper we have:
quote
Instead of a young, dust-poor galaxy, these measurements suggest an
evolved system.
end quote

OK?
It is not me (again). It is the authors of that paper.

They say 'evolved' -- by which they mean 'there is some dust'. You say
'fully developed' -- which is nonsense. Do you see the difference?

Martin
--
Martin Hardcastle
School of Physics, Astronomy and Mathematics, University of Hertfordshire, UK
Please replace the xxx.xxx.xxx in the header with herts.ac.uk to mail me

On Thursday, March 5, 2015 at 2:39:30 AM UTC-5, Robert L. Oldershaw wrote:

If this z=11 galaxy candidate holds up, would that be a problem for the conventional early expansion period models?


Why would that be a problem? Astronomers are investing billiions of
dollars in the James Webb Space Telescope to obtain the ability to
detect galaxies with a redshift down to z = 14, in order to search for
the first galaxies. This will likely be one of the first galaxies to
be observed spectroscopically with JWST. Of course, one expects -- as
observed with millions of other galaxies -- that its spectroscopically
derived age will be consistent with the upper limit from its redshift.

A more troublesome fact for BB theory is the report of the Planck satellite:
(http://physicsworld.com/cws/article/...smic-dark-ages)

One important point not apparent in this popular articles is that
galaxies can be forming long before the start of reionization (end of
the dark ages).

For example, Djorgovski (
http://www.astro.caltech.edu/~george...lFormReion.pdf )
report the WMAP results -- "Hinshaw et al (2012) report tau = 0.084 +/-
0.013 consistent with an instantaneous reionization at z = 10.3 +/- 1.1!
But also consistent with an extended reionization from z ~ 20 -- 25 to
z ~ 6 (more realistic)!"

Also see,
http://en.wikipedia.org/wiki/Reioniz...d_polarization

"The parameter usually quoted here is tau, the "optical depth to
reionization," or alternatively, z_re, the redshift of reionization,
assuming it was an instantaneous event. While this is unlikely to be
physical, since reionization was very likely not instantaneous, zre
provides an estimate of the mean redshift of reionization."

[Mod. note: non-ASCII characters fixed up -- mjh]

On Thursday, March 5, 2015 at 2:09:29 PM UTC-5, wlandsman wrote:

For example, Djorgovski (
http://www.astro.caltech.edu/~george...lFormReion.pdf )
report the WMAP results -- "Hinshaw et al (2012) report tau = 0.084 +/-
0.013 consistent with an instantaneous reionization at z = 10.3 +/- 1.1!
But also consistent with an extended reionization from z ~ 20 -- 25 to
z ~ 6 (more realistic)!"


Could the 13.8 Gyr estimate be adjusted if that is required by new data?

Le 04/03/2015 20:55, wlandsman a écrit :
There are many possible clear and definitive tests but here's a simple
one -- find any object that has an origin more than 13.8 billion years
ago.

Take a pair of binoculars, and look into the constellation of Libra.
There, you can see HD 140283, that lies 190.1 light-years away. Its age
was before estimated to 16 billion years. Now, NASA has brought that
down into 14.5 billion. Further tweaking by the astronomers will surely
bring that star into the desired range :-)

http://www.nasa.gov/mission_pages/hu.../hd140283.html

If we take your argument further, if you see an object that is X years
old with an universe thatis only Y years old (YX) that disproves BB
theory too.

We are seeing now a dusty galaxy that must have formed in only 150
million years can you imagine?

We are seeing a billion solar masses quasar at 12.8 billion years, i.e.
when the universe was only 900 million years old. But those are just
HINTS that point (since a long time) towards the same conclusion.

The first results of ALMA (this dusty galaxy) at age of the Universe of
700 million is another example and it is the FIRST object that ALMA has
seen. ALMA is quite new, and many similar results will come this year.


The new MUSE instrument at ESO is also pretty incredible. It can see
objects in the HDF South that Hubble did not see at all, AND taking
their spectra!

I think it will be that instrument that will bring the big bang to explode.

Le 05/03/2015 20:09, wlandsman a écrit :
One important point not apparent in this popular articles is that
galaxies can be forming long before the start of reionization (end of
the dark ages).

Surely not VERY long before since we would crash into the big bang then. :-)

This ridiculous time scales (a few hundred million years to build a
dusty galaxy) will be compressed even further with the two new
instruments that are going to be used this year:

ALMA and MUSE. MUSE can take the spectrum of extremely faint galaxies
and is even more sensitive than Hubble.

This year promises to be quite interesting. Keep tuned!

jacob

In article , "Robert L.
Oldershaw" writes:

For example, Djorgovski (
http://www.astro.caltech.edu/~george...lFormReion.pdf )
report the WMAP results -- "Hinshaw et al (2012) report tau = 0.084 +/-
0.013 consistent with an instantaneous reionization at z = 10.3 +/- 1.1!
But also consistent with an extended reionization from z ~ 20 -- 25 to
z ~ 6 (more realistic)!"


Could the 13.8 Gyr estimate be adjusted if that is required by new data?

That's not the way science works. One can't just arbitrarily adjust
estimates. What we have now is an estimate of the age of the universe,
based on the values of the Hubble constant, Omega, and lambda. Each of
these has error bars. Do the maths, and you come up with a value for
the age of the universe---13.8 Gyr or whatever---and an associated error
bar. If new data comes along which indicates that the age is more or
less than the current best-fit value, then, yes, the best-fit value can
be adjusted, because we are incorporating new information---but only as
long as the new value is not too far away from the old value, say, not
more than 4 sigma away. If the new data indicates an age which is, say,
10 sigma away from the old best-fit value, then one would probably
conclude that the new data are wrong (because the old value is backed up
by several independent lines of evidence).

In other words, if someone finds evidence that the universe is, say,
14.5 Gyr old, then there is no problem. (Of course, any new value would
also have its own error bar.) If the error bars overlap, one would
expect the values to converge as measurements become better. On the
other hand, convincing evidence that the universe is, say, 20 Gy old
would require more than just adjusting the estimate.

In article , jacob navia
writes:

Take a pair of binoculars, and look into the constellation of Libra.
There, you can see HD 140283, that lies 190.1 light-years away. Its age
was before estimated to 16 billion years. Now, NASA has brought that
down into 14.5 billion. Further tweaking by the astronomers will surely
bring that star into the desired range :-)

NASA has not "brought that down". Rather, estimates are improved with
time. That's why people continue to study objects which have been
studied before.

Columbus underestimated the circumference of the Earth. We now know
that he was wrong (and that people long before him had the right value).

In article , jacob navia
writes:

This ridiculous time scales (a few hundred million years to build a
dusty galaxy) will be compressed even further with the two new
instruments that are going to be used this year:

You keep claiming that a few hundred million years is too short, without
any quantitative evidence. A few hundred million years is a long time.
Massive stars have a lifetime of just a few million years.

Also, keep in mind that there are many, many galaxies in the universe.
Look at enough, and you'll find some statistical flukes, just like there
are a few people on Earth taller than 220 cm or whatever. However, if
your claim is true, then one should expect to find many more galaxies
such as the one being discussed here.