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An Old quasar in a Young Universe?

  1. Sep 9, 2005 #1

    Garth

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    An Old quasar in a Young Universe?
    On the arXiv today:Age of High Redshift Objects - a Litmus Test for the Dark Energy Models The Abstract:
    (Italics mine)
    Just for the record, in the SCC scenario, in the Einstein conformal frame with constant atomic proper masses, the age of the universe at z = 3.91 is 2.8 Gyrs. The authors quote their eprint Cosmological Constraints on a Power Law Universe . Abstract.
    Here we go again?

    Garth
     
    Last edited: Sep 9, 2005
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  3. Sep 9, 2005 #2

    turbo

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    If we believe that redshift is caused by cosmological expansion, we will continually run into these problems. Many decades ago, it was firmly established that Sirius B had an intrinsic redshift due to its density and strong gravitational field. This is a dwarf star, boys and girls! Quasars are often said by standard model adherents to be powered by black holes with a billion times as much mass, yet these same people deride Arp, the Burbidges, and others who say that quasars can have intrinsic redshift. Where's the logic? Quasars are not as distant, as massive, as energetic, or as old as is commonly believed.
     
  4. Sep 9, 2005 #3

    Garth

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    The age problem is not that severe, and the error bars on the observed quasars age determination have not been published. These are crucial in determining whether the standard model has a problem.
    Quasars do have gravitational red shift on top of their cosmological red shift, however if all the red shift was a local gravitational effect then
    i. It would be smeared out and
    ii. it would not be 'contaminated' by the Lyman Alpha forests that lie between the quasar and us.

    Garth
     
  5. Sep 9, 2005 #4

    SpaceTiger

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    For anyone interested in a reasonable analysis of this system, see Hasinger, Schartel, and Komossa 2002. You'll note that they're not fool enough to try to disprove the cosmological model based on that one measurement (which makes a lot of assumptions). In fact, the last sentence of their paper says:

    Perhaps we should have a thread reviewing why it's important to have large samples when performing this kind of measurement...
     
  6. Sep 9, 2005 #5

    Garth

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    Well if there was just one example that was precisely determined to have an age older than the model universe at the time, would that not present a falsification of the model? Of course the more the merrier....

    I found it puzzling that that paper (thank you for the link I had missed that one so far) adopts
    a little passe for 2002??

    That E-dS universe only gave an age of 1 Gyr at z = 3.91, whereas including DE to accelerate the universe, (yes, DE 'acceleration' is significant even in the early deceleration epoch when the LCDM ages are considerably more than the E-dS equivalent) yields an age of around 1.6 Gyr. Still not enough for the 2.1 Gyr originally reported, but more than Hasinger, Schartel, and Komossa report for "an expected delay of ~1 Gyr until Fe/O reaches solar value". The crucial question is: “How robust is the quoted 2.1 Gyr age for the quasar APM 08279+5255?”

    Garth
     
  7. Sep 9, 2005 #6

    SpaceTiger

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    Do you understand how the Fe/O determination of age works? Do you really think that qualifies as a "precise" measurement? We have no "precise" ways of measuring the ages of distant quasars or galaxies.


    If your only claim about cosmological models is:

    then it doesn't matter all that much which model you assume in your analysis.

    Overall, I think this measurement is really uninteresting, mainly because there are so many possible sources of error. Given that the original observers were unwilling to make any strong statements about cosmology based on their measurements, it was, at best, reckless of Jain & Dev 2005 to claim the following based on them:

    That on top of the fact that they performed their entire analysis without once considering the observational errors makes me hope that this does not make it past the referees.
     
  8. Sep 9, 2005 #7

    Garth

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    That wasn't an answer to my question, however, of course I realise that this measurement is not precise, as I posted in #3 above,
    So the question is how big are those error bars? The fact that Jain and Dev do not quote them, or give a reference for their age of 2.1 Gyrs is very unsatisfactory and I agree with you that the paper is uncomplete and should not pass peer review without it - I would not let it go as it is.

    However given that they felt able to publish on the arXiv led me to raise this as a question to be discussed in this thread - others may have references to this age even if I do not.
    A lot of cosmological parameters are dependent on h or h2. If you take a value h=0.5 when it is generally accepted that it is h=0.71 then h2 is going to be only half its accepted value and, other things being equal, cosmological ages are going to be twice their 'real' value. I just was surprised they took this value of h and wondered why.


    Garth
     
  9. Sep 9, 2005 #8

    SpaceTiger

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    Of course a "precise" measurement of an age that was discordant with LCDM would be a falsification. That should go without saying, but in practice, precise measurements are extremely hard to come by.


    I dunno, it's a good question. The point of my referencing that paper was only to demonstrate the uncertainty of the age measurement. I'm not concerned about their choice of cosmology because they made no bold claims about it.

    What I would find interesting is an analysis of a large sample of quasars using this method. If, upon doing this, they still found discordant ages, then it would imply something interesting was going on, either in the cosmology, the star formation history, or our understanding of supernovae at high redshift.
     
  10. Sep 10, 2005 #9

    Chronos

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    I read the paper and found no serious challenges to mainstream models, nor did the authors, so far as I saw. I did see additional constraints on other models.
     
  11. Sep 10, 2005 #10

    Garth

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    Which paper are you referring to?
    Certainly that is true with SpaceTiger's link Hasinger, Schartel, and Komossa 2002.
    However, my link in the OP was to the eprint by Jain and Dev, in which they say
    Then there certainly is a challenge to the mainstream model, even when the parameters are pushed to their acceptable limits.

    The question of whether the eprint poses a serious challenge depends on how robust their quasar age of 2.1 Gyrs. is; that is what are the error bars of their estimation. If they are only +/- 0.1 Gyr. then the mainstream model is in trouble, if they are =/- 0.5 Gyr then it is not. The age of the universe at z = 3.91 with Omega_m = 0.23 and Omega_vac = 0.78 being 1.75 Gyr. (Ned Wright's calculator).

    Garth
     
    Last edited: Sep 10, 2005
  12. Sep 10, 2005 #11

    Garth

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    Okay, the problem has just deepened! Searching for papers on quasar APM 08279+5255 I find: Cosmological implications of APM 08279+5255, an old quasar at z= 3.91 Alcaniz J.S.; Lima J.A.S.; Cunha J.V, Monthly Notices of the Royal Astronomical Society, Volume 340, Number 4, April 2003, pp. L39-L42(1)
    (emphasis mine)

    So it looks as if Jain and Dev we quoting the lower end of that age range, with a possible error of -0.1 Gyr. Is not the standard model looking shaky?
    Garth
     
    Last edited: Sep 10, 2005
  13. Sep 11, 2005 #12

    Garth

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    And again here
    Dr Norbert Schartel
    European Space Agency
    Spain
    Tel: 34 91 8131 184
    Fax: 34 91 8131 139
    E-mail: norbert.schartelesa.int

    Dr Fred Jansen
    European Space Agency
    The Netherlands
    Tel: +31 71 565 4426
    E-mail: fred.jansenesa.int

    Prof. Guenther Hasinger
    Max-Planck-Institut f|r extraterrestrische Physik
    Germany
    Tel: +49 89 30000 3402
    Fax: +49 89 30000 3569
    E-mail: ghasingermpe.mpg.de

    (emphasis mine)
    They give an alternative explanation for the high Iron content:
    But at least that idea (if there is no laboratory physics to verify it) would make another good 'epicycle' don't you think?

    So, how far are we from falsification of the mainstream model?

    Just a thought, Garth.
     
    Last edited: Sep 11, 2005
  14. Sep 11, 2005 #13

    Garth

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    Have a look at quasar APM 08279+5255 spectrum:here showing the Iron K edge absorbed by the massive amount (3 x solar) of iron in the outflowing clouds from the quasar at z = 3.91.

    Garth
     
    Last edited: Sep 11, 2005
  15. Sep 11, 2005 #14

    SpaceTiger

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    Show me a statistical prevalence of this effect in a larger sample of quasars and I'll be interested. One quasar with an unusual chemical composition just doesn't cut it.
     
  16. Sep 12, 2005 #15

    Garth

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    The First XMM-Newton spectrum of a high redshift quasar - PKS 0537 ,
    z = 3.104, (Oct 2000).
    Restless quasar activity: from BeppoSAX to Chandra and XMM-Newton
    z > 4, (2004)
    (Emphasis mine)
    Although the ages of these quasars at those high red shifts have not been determined, or at least published, they do have substantial iron abundance at an early cosmological age, therefore it does seem that there may indeed be a “statistical prevalence of this effect”.

    SpaceTiger, are you interested?

    Garth
     
    Last edited: Sep 12, 2005
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