Cooray et al - A Possible Solution to IR/X-ray Correlation?

On Saturday, October 27, 2012 4:41:01 PM UTC-4, Martin Hardcastle wrote:
In article ,

Most importantly, the ARCADE-2 results need to be verified by follow-up
experiments, and hopefully refined and/or expanded so as to provide more
diagnostic evidence.

Agreed.

-------------------------------------------

Thanks again Martin.

The ARCADE-2 results are very provocative, but still allow too much flexibility in modeling. Some models put on arxiv.org are at least as speculative as anything I have proposed regarding ARCADE-2. Hopefully, future research on the radio background will provide clearer clues relating to this interesting result. Is it real, and if so are the generating sources local or very distant?

RLO
DSR

In article , "Richard D. Saam"
writes:

On 10/25/12 12:16 PM, Phillip Helbig---undress to reply wrote:
(Note, by the way, that by
far the majority of photons in the universe are in the CMB.)

The current CMB density is

sigma*Tb^4*4/c^3 = 4.67E-34 g/cc
which is about four orders of magnitude
below current rho_c at 9.57E-30 g/cc.

Right.

Since ~95 percent of rho_c physical content is unknown
an opening is apparent to diverse explanatory theories
including the photonic nature of rho_c.

[Mod. note: no it's not: we know it's not photons at any waveband
currently visible to us -- mjh]

Right. Just to be clear: the majority of the photons IN TERMS OF
NUMBERS is in the CMB, not the majority of the mass-energy density of
the universe, which is about 27% matter (baryonic and non-baryonic,
light and dark, known and unknown) and 73% in the cosmological
constant (or something similar but more complicated, though all current
observations are compatible with the traditional cosmological constant),
the amount in radiation being negligible.

We also know that there is not a large unaccounted source of photons.
As I said, most known photons are from the CMB. There can't be any
large hidden contribution, since the expansion history of the universe
(and hence things like the magnitude-redshift relation) would be
different in a radiation-dominated universe.

On 10/28/12 6:07 AM, Phillip Helbig---undress to reply wrote:

Right. Just to be clear: the majority of the photons IN TERMS OF
NUMBERS is in the CMB, not the majority of the mass-energy density of
the universe, which is about 27% matter (baryonic and non-baryonic,
light and dark, known and unknown) and 73% in the cosmological
constant (or something similar but more complicated, though all current
observations are compatible with the traditional cosmological constant),
the amount in radiation being negligible.

We also know that there is not a large unaccounted source of photons.
As I said, most known photons are from the CMB. There can't be any
large hidden contribution, since the expansion history of the universe
(and hence things like the magnitude-redshift relation) would be
different in a radiation-dominated universe.

let the radiation CMB density component be
sigma*Tb^4*4/c^3 = rho_b = 4.67E-34 g/cc (present value at Tb = 2.73K)
and mass density component
(3/8pi)*H^2/G = rho_c = 9.57E-30 g/cc (present value)

rho_b scales as (1+z)^4
and
rho_c scales as (1+z)^3

Looking back,
the mass dominated universe transitions
into radiation dominated universe at:
Tb = 37,200 K z= 13,600 age = 8,600 years
rho_b = rho_c = 1.62E-17 g/cc

At this point before the first light at z=1,100 and Tb = 3,000,
is the 73% cosmological constant and 23% dark matter maintained?

RDS

On Sunday, October 28, 2012 2:42:53 AM UTC-4, Robert L. Oldershaw wrote:


I would like to make a second attempt at stimulating a discussion of the main theme of this thread.

If Cappelluti et al are correct about the X-ray/IR cross-correlation, and if Cooray et al are correct that the CIB is generated by stars in the DM halos of galaxies, is it possible that DM halos also have a substantial population of low-luminosity X-ray sources that can only (so far) be detected by their collective X-ray output.

A. What is the range of integrated total X-ray output (in ergs/sec) for galaxies? What is an average value?

B. If the DM halo X-ray sources had luminosities of 10^26 to 10^31 ergs/sec, how many sources would be needed to produce a typical galaxy's total X-ray output?

Thanks for any help on these questions.

Robert L. Oldershaw
Discrete Scale Relativity
http://www3.amherst.edu/~rloldershaw

On 10/28/2012 12:07 PM, Phillip Helbig---undress to reply wrote:
In article , "Richard D. Saam"
...
Since ~95 percent of rho_c physical content is unknown
an opening is apparent to diverse explanatory theories
including the photonic nature of rho_c.

[Mod. note: no it's not: we know it's not photons at any waveband
currently visible to us -- mjh]

Right. Just to be clear: the majority of the photons IN TERMS OF
NUMBERS is in the CMB,

Can we be sure that there aren't even larger
numbers at extremely low frequencies? Wouldn't
slowly varying strong magnetic fields require
an enormous amount of photons?

--
Jos

In article , "Richard D. Saam"
writes:

let the radiation CMB density component be
sigma*Tb^4*4/c^3 = rho_b = 4.67E-34 g/cc (present value at Tb = 2.73K)
and mass density component
(3/8pi)*H^2/G = rho_c = 9.57E-30 g/cc (present value)

rho_b scales as (1+z)^4
and
rho_c scales as (1+z)^3

Right.

Looking back,
the mass dominated universe transitions
into radiation dominated universe at:
Tb = 37,200 K z= 13,600 age = 8,600 years

Right. So for all practical purposes in conventional astronomy and
cosmology (e.g. m-z relation, gravitational lensing etc), the radiation
can be neglected.

rho_b = rho_c = 1.62E-17 g/cc

At this point before the first light at z=1,100 and Tb = 3,000,
is the 73% cosmological constant and 23% dark matter maintained?

No. Here, for all practical purposes, Omega=1 and lambda=0. All
non-empty big-bang models start out arbitrarily close to the Einstein-de
Sitter model. In general, lambda and Omega change with time.

Omega := \frac{8\pi G \rho}{3H^2}

lambda := \frac{Lambda}{3H^2}

where Lambda is constant in time. So, (in general) both vary in time
since (in general) H varies with time. In addition, Omega varies since
\rho drops as the universe expands. The reason for this is the
different dependence of lambda and Omega on z.

Check out http://www.jb.man.ac.uk/~jpl/cosmo/f....html#solution for
an interactive visualization of how lambda and Omega change with time.
For the theoretical basis (but with an older notation) check out:

@ARTICLE {RStabellSRefsdal66a,
AUTHOR = "Rolf Stabell and Sjur Refsdal",
TITLE = "Classification of general relativistic
world models",
JOURNAL = MNRAS,
YEAR = "1966",
VOLUME = "132",
NUMBER = "3",
PAGES = "379",
}

I've said many times that if one reads just one paper in cosmology, this
should be it.

In article , Jos Bergervoet
writes:

Can we be sure that there aren't even larger
numbers at extremely low frequencies? Wouldn't
slowly varying strong magnetic fields require
an enormous amount of photons?

Interesting point. I admit that I normally don't think of, say,
metre-wave radiation being photons, but of course it is. (What I mean
is that the typical radio receiver is not a photon-counting device.)
So, to answer your question, I don't know.

What is true, though, is that most of the energy in radiation comes from
CMB photons.

[Mod. note: for observational constraints on the low-frequency radio
background, see the summary in Section 4 of
http://iopscience.iop.org/0004-637X/...9883.text.html
-- mjh]

On Monday, October 29, 2012 1:39:08 PM UTC-4, Robert L. Oldershaw wrote:

I would like to make a second attempt at stimulating a discussion of the main theme of this thread.

--------------------------------------------------

I may be talking mainly to myself, but perhaps there are one or two readers out there in the ether who would be interested in a rough answer to the questions I posed in my 10/29 post.

A typical total X-ray luminosity for a normal (non-AGN) galaxy would be roughly 10^40 ergs/sec, with a range of 10^38 to 10^42 ergs/sec.

I looked up the predicted X-ray luminosities for Discrete Scale Relativity's major dark matter candidates and the values were 10^26 ergs/sec and 10^27 ergs/sec for the discrete masses of 0.145 and 0.580 solar masses.

Making a initial rough and tentative calculation:

10^40 divided by 10^26 = 10^14 stellar-mass black holes, i.e., 100 trillion! That is decreased by a factor of 10 if 10^27 ergs/sec is a more accurate average X-ray luminosity.

Bottom line: Stellar-mass black holes generating X-rays via low-level accretion processes might well be an excellent candidate for the galactic dark matter. The isolated ones would be low-luminosity emitters and the interacting ones (LMXRBs + HMXRBs) could be much stronger emitters.

Are there problems in my reasoning and/or analysis?

Do we have a new and promising explanation for the galactic DM?

Robert L. Oldershaw
Discrete Scale Relativity
http://www3.amherst.edu/~rloldershaw

On Tuesday, October 30, 2012 11:08:16 AM UTC-5, Robert L. Oldershaw wrote:
On Monday, October 29, 2012 1:39:08 PM UTC-4, Robert L. Oldershaw wrote:



I would like to make a second attempt at stimulating a discussion of the main theme of this thread.



--------------------------------------------------



I may be talking mainly to myself, but perhaps there are one or two readers out there in the ether who would be interested in a rough answer to the questions I posed in my 10/29 post.


This is why you are talking to yourself, Robert. You writing stuff like this:


Are there problems in my reasoning and/or analysis?

Why, you ask for some reason?

http://groups.google.com/group/sci.a...a?dmode=source

IT DOES NOT WORK. YOU HAVE BEEN TOLD WHY IT DOES NOT WORK.

Your theory is DEAD. It has been dead for years. The accretion aspect is wrong as per the above, the actual existence of the objects is wrong as per LITERALLY EVERY MICROLENSING SURVEY EVER PERFORMED.

You have NO ARGUMENT against this. Not one. Zilch. Zero.

This was your response to the above: "We are going to have to agree to disagree on the mass issue. I am unwilling to concede that any evidence currently available, including all available microlensing observations, rule out my prediction that virtually all of the dark matter mass is in the form of ultracompacts with masses of 8 x 10^-5, 0.145 and 0.580 solar masses."

This is why you hardly get any responses anymore. You ignore them.

The ultracompacts do not exist. It is as simple as that. I can prove they do not exist while you cannot prove that they do, and I'm baffled as to why you refuse to accept it.

Why don't you take the time to explain exactly why you don't accept the microlensing surveys? Please do us the favor of elaborating beyond "Mike Hawkins says something I find useful."

In article ,
Robert L. Oldershaw wrote:
Are there problems in my reasoning and/or analysis?

Yes: three. Firstly, a population of compact objects as the major
explanation for the dark matter is ruled out by microlensing
observations, as you know very well. Second, the luminosities you
'predict' -- and I use the scare-quotes because you have not told us
how you do this calculation -- imply accretion rates that are way
higher than anything that's plausible for isolated objects in the halo
of this or any other galaxy. Eric has given you the link to the
calculation I did in the summer; you should be able to plug in the
numbers for the black hole masses you propose to check this. And
third, you're missing the fact that the dominant contribution to X-ray
luminosity is known: X-ray binaries in the case of low-mass galaxies,
hot gas at the virial temperature at larger masses. X-ray telescopes
can resolve a substantial fraction of the XRB population in nearby
galaxies, so we know pretty well how much this contributes (see e.g.
http://adsabs.harvard.edu/abs/2011A%26A...534A..55S for M31, or
various papers by my colleagues on Centaurus A), and of course it
is relatively easy to study individual XRB in the MW. Lest you think that
the XRB actually are the sub-solar mass BH population, it may be worth
adding that where masses of the compact components of XRB are known,
as they often are in the Milky Way, they are much higher than the
masses you're talking about; their luminosities are ~ 10 orders of
magnitude higher than the luminosities you're talking about; they are
distributed locally like stars, not like dark matter; and there are,
of course, many, many fewer of them than would be required to make up
the dark matter. Putting points (2) and (3) together, I would suggest
that even if your putative black hole population existed, and all the
evidence is that it does not, the X-ray properties of galaxies would
be expected to tell us nothing about it, since it would be expected to
contribute negligibly to the X-ray emission of galaxies, which comes
from other sources.

Martin
--
Martin Hardcastle
School of Physics, Astronomy and Mathematics, University of Hertfordshire, UK