Thursday, November 08, 2012

CMB anisotropy, 13 years later

Sean wrote a wonderful post about the recent measurement of the anisotropies in the cosmic microwave background from the South Pole Telescope. I am so impressed by the data. To give you a visual impression on just how dramatically the measurements have improved, I've dug out an old plot from 1999. (Note the square root in the vertical axis though.)

Fig1: CMB power spectrum, 1999, data from Python (star) and Viper (box). Image source.
Fig 2: CMB power spectrum, 2012, data from WMAP7 and SPT.  Image source.
For more information about the CMB anisotropies, please refer to this or this earlier post.

13 comments:

Amara said...

I must read that paper more carefully (if I can), but what I'm most interested in, is if the non-Gaussianity detected previously has disappeared. I read in this paper of an 8 sigma detection of Gaussianity, so I hope I understand their context. I know that a detection of an intrinsic non-Gaussianity would be evidence for a departure from standard inflationary theories, highlight important secondary sources of non-Gaussianity or highlight the presence of spurious signals due to foregrounds or systematic effects. And such an intrinsic non-Gaussianity has previously been detected (1, 2, 3, 4, 5, 6, 7).

(1) McEwen, J., Hobson, M., Lasenby, A., and Mortlock, D. A high-significance detec- tion of non-Gaussianity in the Wilkinson Microwave Anisotropy Probe 1-yr data using directional spherical wavelets. Monthly Notices of the Royal Astronomical Society, 359(8):1583–1596, June 2005.

(2) McEwen, J. D., Hobson, M. P., Lasenby, A. N., and Mortlock, D. J. A high- significance detection of non-gaussianity in the WMAP 3-yr data using directional spherical wavelets. Monthly Notices of the Royal Astronomical Society, 371:L50– L54, Sep 2006.

(3) Vielva, P., Martınez-Gonz ́alez, E., Barreiro, R. B., Sanz, J. L., and Cay ́on, L. Detection of non-Gaussianity in the Wilkinson Microwave Anisotropy Probe first- year data using spherical wavelets. Astrophysical Journal, 609(1):22–34, July 2004.

(4) Cayon, L., Jin, J., and Treaster, A. Higher Criticism statistic: detecting and identifying non-Gaussianity in the WMAP first-year data. Monthly Notices of the Royal Astronomical Society, 362:826–832, 2005.

(5) Cruz, M., Cayon, L., Mart ́ınez-Gonz ́alez, E., Vielva, P., and Jin, J. The Non- Gaussian Cold Spot in the 3 Year Wilkinson Microwave Anisotopy Probe Data. Astrophysical Journal, 655:11–20, January 2007.

(6) Mukherjee, P. and Wang, Y. Wavelets and Wilkinson Microwave Anisotropy Probe Non-Gaussianity. Astrophysical Journal, 613:51–60, September 2004.

(7) Cruz, M., Mart ́ınez-Gonz ́alez, E., Vielva, P., and Cayon, L. Detection of a non- Gaussian spot in WMAP. Monthly Notices of the Royal Astronomical Society, 356:29–40, January 2005.

Plato Hagel said...

Hi Bee,

It is nice to see the progressions as they have lead Sean Carroll in his cosmic view of the universe.

Refining our views according to the measures going on with "backdrops" and decay chains allow us to see the universe "in every now" with much greater depth then we can ever have appreciated. And to think this is all around us in the universe now. Of course one is looking for these driving factors of expression. are they being sustained on our describing the universe geometrically.

Best,

Plato Hagel said...

Just to help drive home the point about clarity of thinking a corollary example might help here?:)

Picture Perfect: Hubble's New Improved Optics Probe the Core of a Distant Galaxy

As you can see when perception is greatly enhanced, "the picture taking" changes how far we can actually see into what is happening all around. Sean was very methodical in his work.

ghonada said...

Hi Bee, this is truly amazing.

Phil Warnell said...

Hi Bee,

Thanks for the heads up regarding Sean’s post. It’s nice to see when theory and observation fit so well even though there are many that wouldn’t mind finding an anomaly here and there . One thing for certain things have gone a long way since Arno Penzias and Robert Wilson were looking for pigeon dropping to have its signal explained.


Best,

Phil

Zephir said...

These fluctuations follows from nested dodecahedron geometry of hypersphere packing, as described with root vector system of Lie group. I presume, the similar tail will be revealed soon for AdS/CFT dual Higgs boson resonance.

N said...

Droppings that made history :)

Eric said...

Hi Plato,

"It is nice to see the progressions as they have lead Sean Carroll in his cosmic view of the universe"

Yes, Sean seems to be an intellectually honest physicist. While he doesn't come right out and say the probability of the universe acting a certain way has changed from his original predisposition, ( take the title of his blog as a hint), it's clear he has moved with the evidence. Kudos to him for that.

Plato Hagel said...

Hi Eric,

That change your taking about was in regard to his old website(Preposterous Universe) and the move to Discovery, while I was talking about what was leading him in respect of his research. I think that has been consistent in my view.

Incompatible Arrows, I: Martin Amis
Incompatible Arrows, II: Kurt Vonnegut
Incompatible Arrows, III: Lewis Carroll
Incompatible Arrows, IV: F. Scott Fitzgerald



Tagging along over the years you learn things as I have learn things from Bee and others in the scientific trade.

Best,

Eric said...

Well, you are right that he still has an interest in the direction and progression of time. What I was really talking about was his well documented interest in the multiverse that he used to post a lot of articles about. That seems to have trailed off. I think it corresponds to the ever more well documented evidence of an accelerating, but always less accelerating universe, as time progresses. That has definite mathematical implication for the whole idea of bubble universes.

Best,

Plato Hagel said...
This comment has been removed by the author.
Plato Hagel said...

.....and just to add, the that his original blog site(Preposterous Universe) is being made use of under a new format here.

Again Eric, one does not disassociate all that has been mathematically developed in order to please some group that rejects and have multivariate approach. So rejection is high against a targeted value, against the theoretical development, as a just as responsible of developing theory and moving toward phenomenological approach.

So one having a focus is always looking at the latest research and development to see that they have worked in concert with this desire of proof and responsibility. Not to support the bias, but of actual evidence that can be ascertained.

From my perspective such variance in the photon travel does imply that I would not dissociate a stance taken by some groups in science to say that they are somehow acting irresponsible. That is all part of the growth in science.

Plato Hagel said...

Also Eric the links given are more then just about time.

Ways in which one is limited by the subject of entropy and aspects of the motivations behind Dark matter and dark energy as an overall expression in the dynamics of the universe "as Omega."

The idea that one is limited by this time line and requires further insight into this development is a move to understand the decay chain. I believe that this is developing beside Sean's perspective as it must.

There is a value underlying universe as an administrative of a false vacuum, so how does the universe express itself from? So one may say such supersymmetry has a basis that underlies all materialist notion right down to the notion of energy as particulate expressions and that the development of asymmetrical realizations, are indeed particulate constructions.

As well, by picking a time line, one proposes as some do of this idea of a cyclical nature between two points. So how would this be proofed? As an ultimate expression of the universe?

In my opinion it is a Superset of ideas that are part and parcel of that expression under the constraints of entropy yet the beginning goes before the point at which cosmology wishes to start. The have a difficulty with that. And so do a lot of people.

Best,