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Thread: Big Bang's afterglow fails intergalactic 'shadow' test

  1. #1

    Big Bang's afterglow fails intergalactic 'shadow' test

    The apparent absence of shadows where shadows were expected to be is raising new questions about the faint glow of microwave radiation once hailed as proof that the universe was created by a "Big Bang."

    In a finding sure to cause controversy, scientists at University of Alabama Huntsville found a lack of evidence of shadows from "nearby" clusters of galaxies using new, highly accurate measurements of the cosmic microwave background.
    Source

  2. #2
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    Interesting. Anyone have the arXiv link to Lieu's paper in Astrophysical Journal?
    Forming opinions as we speak

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  4. #4
    Title: Are the WMAP angular magnification measurements consistent with an inhomogeneous critical density Universe?
    Authors: Richard Lieu and Jonathan P.D. Mittaz

    The propagation of light through a Universe of (a) isothermal mass spheres amidst (b) a homogeneous matter component, is considered. We demonstrate by an analytical proof that as long as a small light bundle passes through sufficient number of (a) at various impact parameters - a criterion of great importance - its average convergence will exactly compensate the divergence within (b). The net effect on the light is statistically the same as if all the matter in (a) is ‘fully homogenised’. When applying the above ideas towards understanding the angular size of the primary acoustic peaks of the microwave background, however, caution is needed. The reason is that most (by mass) of (a) are in galaxies - their full mass profiles are not sampled by passing light - at least the inner 20 kpc regions of these systems are missed by the majority of rays, while the rest of the rays would map back to unresolvable but magnified, randomly located spots to compensate for the loss in angular size. Therefore, a scanning pair of WMAP beams finds most frequently that the largest temperature difference occurs when each beam is placed at diametrically opposite points of the Dyer-Roeder collapsed sections. This is the mode magnification, which corresponds to the acoustic peaks, and is less than the mean (or the homogeneous pre-clumping angular size). Since space was seen to be Euclidean without taking the said adjustment into account, the true density of the Universe should be supercritical. Our analysis gives Ωm = 0.278 ±0.040 and ΩΛ = 0.782 ±?0.040.

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  5. #5
    Title: The Sunyaev-Zel'dovich effect in a sample of 31 clusters - a comparison between the X-ray predicted and WMAP observed CMB temperature decrement
    Authors: Richard Lieu, Jonathan P.D. Mittaz, Shuang-Nan Zhang

    The WMAP Q, V, and W band radial profiles of temperature deviation of the cosmic microwave background (CMB) were constructed for a sample of 31 randomly selected nearby clusters of galaxies in directions of Galactic latitude |b| > 30°. The profiles were compared in detail with the expected CMB Sunyaev-Zel'dovich effect (SZE) caused by these clusters, with the hot gas properties of each cluster inferred observationally by applying gas temperatures as measured by ASCA to isothermal β models of the ROSAT X-ray surface brightness profiles, and with the WMAP point spread function fully taken into consideration. After co-adding the 31 cluster field, it appears that WMAP detected the SZE in all three bands. Quantitatively, however, the observed SZE only accounts for about 1/4 of the expected decrement. The discrepancy represents too much unexplained extra flux: in the W band, the detected SZE corresponds on average to 5.6 times less X-ray gas mass within a 10 arcmin radius than the mass value given by the ROSAT β model. We examined critically how the X-ray prediction of the SZE may depend on our uncertainties in the density and temperature of the hot intracluster plasma, and emission by cluster radio sources. Although our comparison between the detected and expected SZE levels is subject to a margin of error, the fact remains that the average observed SZE depth and profile are consistent with those of the primary CMB anisotropy, i.e. in principle the average WMAP temperature decrement among the 31 rich clusters is too shallow to accommodate any extra effect like the SZE. A unique aspect of this SZE investigation is that because all the data being analysed are in the public domain, our work is readily open to the scrutiny of others.

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    IIRC, we discussed at least the second paper once before, in a thread in the ATM section.

    Basically, Lieu et al. have at least one mistake in their approach, and are also trying to use the WMAP data for something it was neither intended for nor expected to be sensitive enough to test properly.

    If anyone's interested, I'll see if I can dig up a critique or three.

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    Quote Originally Posted by Nereid View Post
    If anyone's interested, I'll see if I can dig up a critique or three.
    Yes thanks, I'm interested.
    Forming opinions as we speak

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    Quote Originally Posted by Nereid View Post
    IIRC, we discussed at least the second paper once before, in a thread in the ATM section.

    Basically, Lieu et al. have at least one mistake in their approach, and are also trying to use the WMAP data for something it was neither intended for nor expected to be sensitive enough to test properly.

    If anyone's interested, I'll see if I can dig up a critique or three.
    Sure, maybe we should even ask Fraser to interview Lieu and maybe he (Lieu) wants to comment on your critique(s). This preprint was a year old, and the publication is this month, maybe something happened in between and has strengthened the observations?
    Cheers.

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    There's a more basic problem-- when I add, I get a total energy density of 1.06 with two errors of .04. Generally you might add these errors in quadrature, yielding a combined error of almost .06. In short, their results are statistically consistent with a critical energy density. Not a headline there.

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    Quote Originally Posted by Blob View Post
    Is that the Trifid nebula they're using to represent a galaxy cluster in the illustration?

  11. #11
    Hum,
    looks like it.

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    Just over a year ago Lieu and Dr. Jonathan Mittaz, a UAH research associate, published results of a study using WMAP data to look for evidence of "lensing" effects which should have been seen (but weren't) if the microwave background was a Big Bang remnant. Lieu, Mittaz and Shuang-Nan Zhang, UAH, "The Sunyaev-Zel'dovich effect in a sample of 31 clusters: A comparison between the X-ray predicted and WMAP observed decrement," Astrophysical Journal, Sept. 1, 2006, Vol. 648, No. 1, p. 176
    And this was also at the bottom of page here.

    http://www.moondaily.com/reports/Big..._Test_999.html

  13. #13
    It is not worth to make such a hype about this observation.
    The same author has presented a conventionel explanation for the anomalous
    Sunyaev-Zel'dovich effect. See please :http://arxiv.org/abs/astro-ph/0607304

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    Astrophysical Journal, Sept. 1, 2006, Vol. 648, No. 1, p. 176


    astro-ph/0607304
    From: Richard Lieu [view email]
    Date: Thu, 13 Jul 2006 19:46:43 GMT (10kb)

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    Quote Originally Posted by Nereid View Post
    IIRC, we discussed at least the second paper once before, in a thread in the ATM section.

    Basically, Lieu et al. have at least one mistake in their approach, and are also trying to use the WMAP data for something it was neither intended for nor expected to be sensitive enough to test properly.

    If anyone's interested, I'll see if I can dig up a critique or three.
    I'd be interested in seeing that critique.

  16. #16
    Quote Originally Posted by RussT View Post
    Astrophysical Journal, Sept. 1, 2006, Vol. 648, No. 1, p. 176


    astro-ph/0607304
    From: Richard Lieu [view email]
    Date: Thu, 13 Jul 2006 19:46:43 GMT (10kb)

    Dear RussT, I`m not sure what you wanted to express with your thread.Did you believe that the arxiv paper I qouted is not as actual as the Astrophysical Journal paper from Sept. 1, then you are wrong. It takes a long time until a paper is accept by the AJ..Usually it takes over half a year and more. So the arxiv article http://arxiv.org/abs/astro-ph/0607304 (arxiv is a pre-print server ) is much more up to date than the AJ article. Sorry for any spelling mistake-I`m not an american

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    Quote Originally Posted by VanderL View Post
    Sure, maybe we should even ask Fraser to interview Lieu and maybe he (Lieu) wants to comment on your critique(s). This preprint was a year old, and the publication is this month, maybe something happened in between and has strengthened the observations?
    Cheers.
    Yes, indeed a great deal happened between the preprint* we discussed elsewhere in BAUT (the discussion starts about half-way down the page) and the one that's now up on ArXiV (v6).

    In particular, section 5 has been greatly expanded (and renamed; formerly "Interpretation, revisiting the question of the cosmological origin of the CMB", now "Interpretation") - a new phrase, right at the end of the (v6) paper is telling: "We are grateful to an anoymous referee for comments and critique of this work."

    Much of the expanded section 5 is devoted to the points raised by the critique earlier (and elsewhere) in BAUT (of course, Lieu et al. go into far more detail than we did, in BAUT).

    That the v6 paper is far more nuanced than the breathless UAH PR cited in the OP should come as no surprise; that Lieu et al. seem to have found something interesting about the SZE, in the WMAP data (or, if you prefer, something interesting about the WMAP data), is clear; that their work can be summarised as "Big Bang's afterglow fails intergalactic 'shadow' test" is pure hype and marketing fluff.

    In fact, the v6 paper explicitly says: "The SZE has already been detected in a large number of high-redshift clusters using interferometric techniques of higher resolution than the WMAP data" (there's more).

    Can the latest draft still be faulted, on grounds of poor technique, or inadequate coverage of relevant issues? I don't have any views one way or the other, right now.

    *v2, I think.

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    Quote Originally Posted by inflaton View Post
    Dear RussT, I`m not sure what you wanted to express with your thread.Did you believe that the arxiv paper I qouted is not as actual as the Astrophysical Journal paper from Sept. 1, then you are wrong. It takes a long time until a paper is accept by the AJ..Usually it takes over half a year and more. So the arxiv article http://arxiv.org/abs/astro-ph/0607304 (arxiv is a pre-print server ) is much more up to date than the AJ article. Sorry for any spelling mistake-I`m not an american
    Yes, I noticed the dates.

    Thanks for the clarification.

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    Quote Originally Posted by Nereid View Post
    Yes, indeed a great deal happened between the preprint* we discussed elsewhere in BAUT (the discussion starts about half-way down the page) and the one that's now up on ArXiV (v6).

    In particular, section 5 has been greatly expanded (and renamed; formerly "Interpretation, revisiting the question of the cosmological origin of the CMB", now "Interpretation") - a new phrase, right at the end of the (v6) paper is telling: "We are grateful to an anoymous referee for comments and critique of this work."

    Much of the expanded section 5 is devoted to the points raised by the critique earlier (and elsewhere) in BAUT (of course, Lieu et al. go into far more detail than we did, in BAUT).

    That the v6 paper is far more nuanced than the breathless UAH PR cited in the OP should come as no surprise; that Lieu et al. seem to have found something interesting about the SZE, in the WMAP data (or, if you prefer, something interesting about the WMAP data), is clear; that their work can be summarised as "Big Bang's afterglow fails intergalactic 'shadow' test" is pure hype and marketing fluff.

    In fact, the v6 paper explicitly says: "The SZE has already been detected in a large number of high-redshift clusters using interferometric techniques of higher resolution than the WMAP data" (there's more).

    Can the latest draft still be faulted, on grounds of poor technique, or inadequate coverage of relevant issues? I don't have any views one way or the other, right now.

    *v2, I think.

    It seems Lieu and his group are quite busy exploring all the possible applications of the WMAP data: this recent paper calculates the expected time delay from primordial density perturbation in the spectrum of the WMAP data and compares these to the actual time delay observed:

    A test was performed to find out if time delay observations of the multiple images of two strongly lensed quasars reflect the theoretical expectation based upon the 2dFGRS/WMAP1 spectrum P(k) of primordial density perturbation. Our estimate of the expected time delay anisotropy is expressed as a simple analytical formula, which when applied to the (observationally non-verifiable) scenario of the CMB resulted in a typical amplitude on par with the calculation of Hu and Cooray (2001). Our prediction is in substantial disagreement with the temporal (light curve) alignment of the two quasars, in that the observed delay is ∼350 times, or five standard deviations, smaller. The probability of this discrepancy being a chance coincidence is completely negligible. Previous investigators only considered the relatively minor effect, on the light arrival times, of the lensing mass itself. If the additional disturbance on the light paths by nonlinear density growths, viz. the galaxies and clusters, are also included with the prediction, the gulf between the standard model and observations will further widen.
    My interpretation is that this paper could also be regarded as an indication that possibly something is wrong with the redshift=distance assumption, just like the SZE paper, where some galaxy clusters do, and some galaxy clusters don't show the expected effects.

    Cheers.

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    I think Lieu's conclusions are overly speculative in this paper. A criticism which, IMO, can be applied to some of his other papers, e.g. :

    Time delay observations of the lensed quasars SDSS J1004+4112 and HE0435-1223: are they consistent with the 2dFGRS/WMAP1 primordial density fluctuation?
    http://arxiv.org/abs/astro-ph/0608587

    On the absence of gravitational lensing of the cosmic microwave background
    http://arxiv.org/abs/astro-ph/0412276

    Are the WMAP angular magnification measurements consistent with an inhomogeneous critical density Universe?
    http://arxiv.org/abs/astro-ph/0409048

  21. 2006-Sep-09, 08:45 AM
    Reason
    religious spam

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    Quote Originally Posted by Thanatos View Post
    I think Lieu's conclusions are overly speculative in this paper. A criticism which, IMO, can be applied to some of his other papers, e.g. :

    Time delay observations of the lensed quasars SDSS J1004+4112 and HE0435-1223: are they consistent with the 2dFGRS/WMAP1 primordial density fluctuation?
    http://arxiv.org/abs/astro-ph/0608587

    On the absence of gravitational lensing of the cosmic microwave background
    http://arxiv.org/abs/astro-ph/0412276

    Are the WMAP angular magnification measurements consistent with an inhomogeneous critical density Universe?
    http://arxiv.org/abs/astro-ph/0409048

    Why do you consider them "overly speculative"? It could also mean that you might be "overly confident" in Big Bang theory and it's afterglow.

    Cheers.

  23. #22
    Hum,
    i noticed that forum member Peter Wilson had posted a thread to a MSNBC article that is surprising good, and describes the above scientific papers in an easy to read type way.

    But Spergel says he seriously doubts the conclusions reached by Lieu's team are correct for a number of reasons. First, WMAP, one of the instruments used by Lieu's team, is not the best instrument for detecting the shadow effect, Spergel said. The shadow effect "occurs on small angular scales predominately, while WMAP is designed to look at large scales across the sky," he said.
    Afshordi, the Harvard astrophysicist, suggested that a more likely explanation for Lieu's findings is that there is something about galaxy clusters scientists don't yet understand.
    http://msnbc.msn.com/id/14785762/

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    Further from the MSNBC article linked to:

    Lieu counters that WMAP's resolution might be a problem for far away galaxy clusters, but points out that the clusters he examined were relatively close by, and certainly close enough for WMAP to see a shadow effect if it existed.

    "The WMAP's resolution is not an excuse here," Lieu said.

    Afshordi, the Harvard astrophysicist, suggested that a more likely explanation for Lieu's findings is that there is something about galaxy clusters scientists don't yet understand.

    "I think that even if Lieu were correct, it would teach us about clusters rather than the Big Bang theory," Afshordi said in a telephone interview. "Clusters are complicated things and there's still a lot to learn about them."

    Lieu concedes this is a possibility. "That I do buy," he said. "I myself am not at this point prepared to accept that the CMB is noncosmological and that there was no Big Bang. That would be doomsday."

    Lieu said that one unlikely, but possible explanation is that the galaxy clusters he examined are unusually strong emitters of radio waves, which could have prevented the shadows from being seen.

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    Quote Originally Posted by ngeo View Post
    Further from the MSNBC article linked to:

    Lieu counters that WMAP's resolution might be a problem for far away galaxy clusters, but points out that the clusters he examined were relatively close by, and certainly close enough for WMAP to see a shadow effect if it existed.

    "The WMAP's resolution is not an excuse here," Lieu said.

    Afshordi, the Harvard astrophysicist, suggested that a more likely explanation for Lieu's findings is that there is something about galaxy clusters scientists don't yet understand.

    "I think that even if Lieu were correct, it would teach us about clusters rather than the Big Bang theory," Afshordi said in a telephone interview. "Clusters are complicated things and there's still a lot to learn about them."

    Lieu concedes this is a possibility. "That I do buy," he said. "I myself am not at this point prepared to accept that the CMB is noncosmological and that there was no Big Bang. That would be doomsday."

    Lieu said that one unlikely, but possible explanation is that the galaxy clusters he examined are unusually strong emitters of radio waves, which could have prevented the shadows from being seen.
    This is great stuff, astronomers discussing the method and the implications of a finding in a way that can be followed by non-experts too. I think they have gotten it right that the data "teach us about clusters".

    There are a number of possibilities, one of which is that the redshifts of the clusters are not good distance indicators (as per Arp), this could explain why the SZ effect is too small for many of them.

    Cheers.

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    And there are innumerable other possible explanations that have not been proven wrong by all the error bars. I think Lieu is distancing himself from his failed collaboration with Cooperstock. I also think he is going about it in the right way - by acknowledging the weaknesses and proposing reasonable alternatives. That is the mark of a good scientist.

  27. #26
    Quote Originally Posted by Squink View Post
    Is that the Trifid nebula they're using to represent a galaxy cluster in the illustration?
    It's the Cocoon (IC 5146).

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    Quote Originally Posted by Wolverine View Post
    It's the Cocoon (IC 5146).
    Ahh, good! That's a better fit. Still, an actual galactic cluster like this would have been a better choice.

  29. #28
    Dear Sir,

    Did you ever think that there was no big bang. Universe created at all places at the same time.
    if big bang, where is the center of the universe, please explain the isotropic nature of universe in case of big bang.
    Spherical, dounut, Sadle, flate universe model could not able to explain the symetrical universe in case of big bang. I accept the big bang model of universe but sometimes it seems to me that universe must has different model. As quantum flactuation cause the big band at the time zero.
    So the point is that if fluctuation in energy, means events were occuring before big bang. So we can not say time Zero at big bang.
    By defination time is between two events.

    Please explain with thanks.

    S. Waqar

    e-mail: intersoft@wol.net.pk

    S.Waqar

  30. #29

    Thumbs down

    waiting

  31. #30
    Quote Originally Posted by swaqar View Post
    waiting
    You waited two whole minutes for an answer? We're not fast enough for you? Sorry.

    Welcome to BAUT.

    But, you might have to wait hours or even a day or two for the answer you're seeking. First a willing person -- not me -- must encounter your question, then think about an answer, maybe do a little research, and then write up a response.

    Oh, and if you want to raise the probability of generic questions being answered -- still not within minutes, but on the order of hours -- you might want to post them in the Questions and Answers Forum, rather than placing them as comments within existing topics.
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