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#11
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Beyond IDCS J1426.5+3508
In article , jacob navia
writes: Note that paradigm changes are painful but I hope people proposing a new one won't have the problems of Galileo... A man does not attain the status of Galileo merely because he is persecuted; he must also be right. ---Stephen Jay Gould 1) We have a really MASSIVE cluster at 10 GY from here (3.7 from the supposed "bang"). Right. Note that the lensing confirms the big mass of that cluster. Right. How can such a monster cluster evolve in just 3.7 GY? A galaxy merger takes like 1GY, and the central galaxy must have done some to acquire its size. You are making a common error: rejecting an entire paradigm because of problems with details. Yes, if such details persist, then it might indicate a real problem. However, structure formation is very difficult to model compared with cosmological tests which lead to the currently accepted "standard model". The center of the arc is the central cluster galaxy. The arc is the background galaxy at higher redshift. It isn't in the lensing cluster. Its position with respect to the lensing cluster is also not at the center. The arc is at the edge of the cluster (as seen on the sky). You misunderstood the abstract. 2) The lensing implies that there is a BIG galaxy much farther away, No. It implies only that there is a galaxy farther away. (It appears bug because of the magnification due to the lensing effect). The question is how likely it is to have a galaxy at this redshift, not its size. so much farther away that it is lensed by the cluster. Then, several questions are raised: How come that there are so many big galaxies behind that cluster that we see a lensing effect? Galaxies should be smaller approaching the supposed "bang"! But no, there are so many big ones that we see a lensed one. Again, I think you misunderstand. The lensing effect magnifies the size of the galaxy (and, since it conserves surface brightness, also makes it brighter.) |
#12
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Posting in ASCII
In article , jacob navia
writes: I apologize for those problems but I can't help it. I am using an Apple Macintosh system (OS X) and the whole system is Unicode. All software including the mail client, text editor, web browser etc is all Unicode (16 bits chars) and there is no way for me to see which characters aren't ASCII since I haven't any software that doesn't accept UTF8 (not even the vi editor!) There are various ways to represent Unicode, UTF8 etc. A common one is to have it correspond to ASCII if the characters in question are ASCII. So, as long as you stick to ASCII characters, your post should show up OK. [Mod. note: for those people who don't know the ASCII character set, a good rule is to avoid any accented characters, any non-Roman letters, and any 'smart quotes'. Letters A-Z and a-z, numbers and basic punctuation only, please. This is particularly important when cutting and pasting from a web source. I'm posting this to make other people aware of the issue -- mjh] If you follow Martin's advice, things should be OK. Here is the ASCII character set: +------------------------------------------+ | 0 1 2 3 4 5 6 7 | +---+--------------------------------------+ | 0 | NUL DLE SP 0 @ P ` p | | 1 | SOH DC1 ! 1 A Q a q | | 2 | STX DC2 " 2 B R b r | | 3 | ETX DC3 # 3 C S c s | | 4 | EOT DC4 $ 4 D T d t | | 5 | ENQ NAK % 5 E U e u | | 6 | ACK SYN & 6 F V f v | | 7 | BEL ETB ' 7 G W g w | | 8 | BS CAN ( 8 H X h x | | 9 | HT EM ) 9 I Y i y | | A | LF SUB * : J Z j z | | B | VT ESC + ; K [ k { | | C | FF FS , L \ l | | | D | CR GS - = M ] m } | | E | SO RS . N ^ n ~ | | F | SI US / ? O _ o DEL | +---+--------------------------------------+ The numbers at the top and at the side are combined to give the hexadecimal number of the character. Thus, the "!" character has value 21 in hex, or 33 in decimal. Values 20 through 7E should be OK, i.e. all but the first two columns and the DEL at the lower right. So, anything which looks like something in the 6 rightmost columns should be OK. (The first two columns and DEL are non-printable characters.) |
#13
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Beyond IDCS J1426.5+3508
In article , jacob navia
writes: 1) A cluster of 2.6 x 10^14 M0 in 3.7 GY is nothing special. From the observation, we can conclude that such a cluster exists. Without further information, we can't say whether or not it is special. The paper mentions that it is expected to be rare (which doesn't mean it cannot exist). You seem to say "either it is nothing special, or it cannot exist". There is another possibility: it can exist, but be special. Do not try to conclude more than the observations give you. (A biologist, a physicist and a mathematician were travelling on a train in Scotland. The biologist looks out the window, sees a black sheep and says "Sheep are black in Scotland." The physicist looks out the window and says "Some sheep are black in Scotland." The mathematician doesn't need to look out the window and says "There is at least one sheep in Scotland, which is black on at least one side.") All those galaxies (and the massive central galaxy) merged and concentrated in record time. It is not only galaxy formation but also cluster formation that must be reviewed Right. to fit the bang. Unjustified extrapolation. Again, you claim that problems in structure formation calls into question the existence of the big bang. What about another possibility: the big bang exists, but structure formation is a bit different than what current thinking implies? Considering the amount of other evidence for the big bang, this seems to be the most likely alternative, especially considering the fact that there are known problems with the details of structure formation. 2) The fact that we see a lensed galaxy implies that there is a wide field of BIG galaxies behind that galaxy cluster. Why BIG? That is nothing surprising you say. It is just that fully formed BIG galaxies appear immediately after the supposed bang 3.7 billion years is not "immediate". Our galaxy formation theories are wrong, not the bang. Wrong in detail, probably. But that's not surprising. |
#14
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Beyond IDCS J1426.5+3508
In article , Steve Willner
writes: The two relevant preprints seems to be the ones at http://arxiv.org/abs/1205.3788 http://arxiv.org/abs/1205.3787 In article , jacob navia writes: 1) A cluster of 2.6 x 10^14 M0 in 3.7 GY is nothing special. More like 4 to 5E14 Msun at z=1.75. There shouldn't be many such clusters in the sky, but there should be a few. If a lot more are discovered, something is going to have to change, but it will take more than a single object to force changes. One needs to interpret such rare objects properly. See recent work by Ian Harrison and Peter Coles on extreme-value statistics in cosmology: http://telescoper.wordpress.com/2011...-the-universe/ There is a real problem, however, with the 775 nm magnitude of the lensed source. Even with lensing, it's too bright for the population of known z3 objects. It's going to be very interesting to see how this plays out. Yes. It might be improbable. However, improbable does not mean impossible. How probable is it that the Moon and the Sun have the same angular size? Doesn't this low probability question the entire big-bang paradigm? :-) |
#15
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Beyond IDCS J1426.5+3508
In article , "Richard D. Saam"
writes: How about framing the question in terms of a more defined Supernovae Type 1a standard candle condition. Use the distance modulus equation: m-M = 5 log(d) - 5 then d = 10^((m-M)/5 - 1) From Supernovae compilation http://supernova.lbl.gov/Union/figur....1_mu_vs_z.txt the current maximum Type 1A redshift 2003dy z = 1.34 m-M = 45.0675055813 d = 10^((m-M)/5 - 1) = 1.03E+08 parsec or 3.18E+26 cm I haven't checked the actual numbers, but OK so far. This is about 2.5 percent of the present universe First, note that the distance involved is the luminosity distance. There is little point in expressing this in terms of the radius of the universe. assuming expansion from the Big Bang at the speed of light c/H = 1.30E+28 cm Not sure what you mean here. The speed of light is not a limiting factor for the expansion of the universe. If z=1.34, then the universe is 2.34 times larger now than when the light was emitted. This is independent of the cosmological model. So why does type 1A 2003dy standard candle redshift (z=1.34) represent a condition within ~2.5% of the Big Bang with its z in the thousands and probably much greater? I do not understand this. What does the "z in the thousands" mean? |
#16
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Beyond IDCS J1426.5+3508
On 7/1/2012 9:59 AM, Phillip Helbig---undress to reply wrote:
In article , Steve Willner jacob navia writes: ... 1) A cluster of 2.6 x 10^14 M0 in 3.7 GY is nothing special. More like 4 to 5E14 Msun at z=1.75. There shouldn't be many such clusters in the sky, but there should be a few. If a lot more are discovered, something is going to have to change, but it will take more than a single object to force changes. One needs to interpret such rare objects properly. See recent work by Ian Harrison and Peter Coles on extreme-value statistics in cosmology: http://telescoper.wordpress.com/2011...-the-universe/ OK, in Fig. 1 there, 4 to 5E14 Msun at this redshift seems to be right at the expected largest mass seen. Excellent fit! There is a real problem, however, with the 775 nm magnitude of the lensed source. Even with lensing, it's too bright for the population of known z3 objects. It's going to be very interesting to see how this plays out. Yes. It might be improbable. Do we also have statistical expectation curves for this? Like the one above, but for any luminous object at this higher z, and then combined with the probability of it being lensed? A somewhat complicated combination of probability distributions seems to be needed here, apparently shown in Fig. 3 in the preprint: http://arxiv.org/abs/1205.3788 The figure seems to show quite some uncertainty (the two curves plotted are quite different) but does lead to the conclusion at the end of the paper, that this was an improbable observation! Do I understand correctly that everyone agrees with that? -- Jos |
#17
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Beyond IDCS J1426.5+3508
In article , Jos Bergervoet
writes: Do we also have statistical expectation curves for this? Like the one above, but for any luminous object at this higher z, and then combined with the probability of it being lensed? A somewhat complicated combination of probability distributions seems to be needed here, apparently shown in Fig. 3 in the preprint: http://arxiv.org/abs/1205.3788 In order to calculate the probability, one needs to know the number of galaxies at this redshift. However, one needs the number at the luminosity of the UNLENSED source. So, divide the observed luminosity of the arc by the magnification (which depends on the lens model, but the ballpark figure should be Ok) to get the unlensed luminosity. How well are these numbers known? (One also has to take into account that the area is also increased by the lens effect; normally one observes the number of objects of a certain luminosity at a certain redshift per area of sky.) |
#18
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Beyond IDCS J1426.5+3508
On 7/1/2012 2:01 PM, Phillip Helbig---undress to reply wrote:
In article , Jos Bergervoet writes: Do we also have statistical expectation curves for this? Like the one above, but for any luminous object at this higher z, and then combined with the probability of it being lensed? A somewhat complicated combination of probability distributions seems to be needed here, apparently shown in Fig. 3 in the preprint: http://arxiv.org/abs/1205.3788 In order to calculate the probability, one needs to know the number of galaxies at this redshift. However, one needs the number at the luminosity of the UNLENSED source. But that seems to be a much simpler question. Their reference Coe et al. (2006) seems to be their source for it. Anyhow, if even that kind of basic information is uncertain, there is not much chance to reach a valid conclusion.. So, divide the observed luminosity of the arc by the magnification (which depends on the lens model, but the ballpark figure should be Ok) to get the unlensed luminosity. How well are these numbers known? Hmm.. If you don't question the lens model, and also not the unlensed source distribution, there is no problem, is there? (One also has to take into account that the area is also increased by the lens effect; normally one observes the number of objects of a certain luminosity at a certain redshift per area of sky.) So by magnification, the lensing cluster is looking at a very small area, reducing the chance something is lensed. But this I would expect to be part of the lens model, which cannot be wrong unless GR is wrong! (I would expect that GR simply *is* the lens model, it is surprising that this is made an issue..) [Mod. note: the lens model includes the mass distribution of the lens -- mjh] -- Jos |
#19
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Beyond IDCS J1426.5+3508
In article , Jos Bergervoet
writes: In order to calculate the probability, one needs to know the number of galaxies at this redshift. However, one needs the number at the luminosity of the UNLENSED source. But that seems to be a much simpler question. Their reference Coe et al. (2006) seems to be their source for it. I'm not up-to-date on galaxy luminosity functions. However, a redshift of 3 is quite large for such things, especially allowing for the fact that the unlensed luminosity is less. However, I would have thought that, especially at this high (for ordinary galaxies) redshift, there would be something more recent than 2006. In any case, such numbers will have error bars. Hmm.. If you don't question the lens model, and also not the unlensed source distribution, there is no problem, is there? No, but both have error bars. (One also has to take into account that the area is also increased by the lens effect; normally one observes the number of objects of a certain luminosity at a certain redshift per area of sky.) So by magnification, the lensing cluster is looking at a very small area, reducing the chance something is lensed. But this I would expect to be part of the lens model, which cannot be wrong unless GR is wrong! (I would expect that GR simply *is* the lens model, it is surprising that this is made an issue..) [Mod. note: the lens model includes the mass distribution of the lens -- mjh] Martin is right. In fact, by "lens model", I (and essentially everyone working in gravitational lensing) mean "the mass distribution of the lens". I was referring to the effect of the magnification on the luminosity function. (There are two competing effects: magnification makes things brighter, thus more likely to be observed, while it also means a smaller area of sky is observed, which means things are less likely to be observed. Which wins out depends on how steep the luminosity function is.) |
#20
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Beyond IDCS J1426.5+3508
On Sun, 01 Jul 12, Phillip Helbig wrote:
How probable is it that the Moon and the Sun have the same angular size? Possibly close to 1, due to the anthropic principle: such a moon may have been needed to give the Earth tectonic and rotational stability across epochs, else we wouldn't have evolved to be discussing it. |
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