SDSS-III and the Cosmic Web

Posted in The Universe and Stuff with tags , , , , , on January 12, 2011 by telescoper

It’s typical, isn’t it? You wait weeks for an interesting astronomical result to blog about and then two come along together…

Another international conference I’m not at is the 217th Meeting of the American Astronomical Society in the fine city of Seattle, which yesterday saw the release of some wonderful things produced by SDSS-III, the third incarnation of the Sloan Digital Sky Survey. There’s a nice article about it in the Guardian, followed by the usual bizarre selection of comments from the public.

I particularly liked the following picture of the cosmic web of galaxies, clusters and filaments that pervades the Universe on scales of hundreds of millions of lightyears, although it looks to me like a poor quality imitation of a Jackson Pollock action painting:

The above image contains about 500 million galaxies, which represents an enormous advance in the quest to map the local structure of the Universe in as much detail as possible. It will also improve still further the precision with which cosmologists can analyse the statistical properties of the pattern of galaxy clustering.

The above represents only a part (about one third) of the overall survey; the following graphic shows how much of the sky has been mapped. It also represents only the imaging data, not the spectroscopic information and other information which is needed to analyse the galaxy distribution in full detail.

There’s also a short video zooming out from one galaxy to the whole Shebang.

The universe is a big place.


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First Science from Planck

Posted in The Universe and Stuff with tags , , , , , , , , , on January 11, 2011 by telescoper

It’s been quite a long wait for results to emerge from the Planck satellite, which was launched in May 2009, but today the first science results have at last been released. These aren’t to do with the cosmological aspects of the mission – those will have to wait another two years – but things we cosmologists tend to think of as “foregrounds”, although they are of great astrophysical interest in themselves.

For an overview, with lots of pretty pictures,  see the European Space Agency’s Planck site and the UK Planck outreach site; you can also watch this morning’s press briefing in full here.

A repository of all 25 science papers can be found here and there’ll no doubt be a deluge of them on the arXiv tomorrow.

A few of my Cardiff colleagues are currently in Paris living it up at the junket working hard at the serious scientific conference at which these results are being discussed. I, on the other hand, not being one of the in-crowd, am back here in Cardiff, only have a short window in between meetings, project vivas and postgraduate lectures  to comment on the new data. I’m also sure there’ll be a huge amount of interest in the professional media and in the blogosphere for some time to come. I’ll therefore just mention a couple of things that struck me immediately as I went quickly through the papers while I was eating my sandwich; the following was cobbled together from the associated ESA press release.

The first concerns the so-called  ‘anomalous microwave emission’ (aka Foreground X) , which is a diffuse glow most strongly associated with the dense, dusty regions of our Galaxy. Its origin has been a puzzle for decades, but data collected by Planck seem to confirm the theory that it comes from rapidly spinning dust grains. Identifying the source of this emission will help Planck scientists remove foreground contamination which much greater precision, enabling them to construct much cleaner maps of the cosmic microwave background and thus, among other things, perhaps clarify the nature of the various apparent anomalies present in current cosmological data sets.

Here’s a nice composite image of a region of anomalous emission, alongside individual maps derived from low-frequency radio observations as well as two of the Planck channels (left).

Credits: ESA/Planck Collaboration

The colour composite of the Rho Ophiuchus molecular cloud highlights the correlation between the anomalous microwave emission, most likely due to miniature spinning dust grains observed at 30 GHz (shown here in red), and the thermal dust emission, observed at 857 GHz (shown here in green). The complex structure of knots and filaments, visible in this cloud of gas and dust, represents striking evidence for the ongoing processes of star formation. The composite image (right) is based on three individual maps (left) taken at 0.4 GHz from Haslam et al. (1982) and at 30 GHz and 857 GHz by Planck, respectively. The size of the image is about 5 degrees on a side, which is about 10 times the apparent diameter of the full Moon.

The second of the many other exciting results presented today that I wanted to mention is a release of new data on clusters of galaxies – the largest structures in the Universe, each containing hundreds or even thousands of galaxies. Owing to the Sunyaev-Zel’dovich Effect these show up in the Planck data as compact regions of lower temperature in the cosmic microwave background. By surveying the whole sky, Planck stands the best chance of finding the most massive examples of these clusters. They are rare and their number is a sensitive probe of the kind of Universe we live in, how fast it is expanding, and how much matter it contains.

Credits: ESA/Planck Collaboration; XMM-Newton image: ESA

This image shows one of the newly discovered superclusters of galaxies, PLCK G214.6+37.0, detected by Planck and confirmed by XMM-Newton. This is the first supercluster to be discovered through its Sunyaev-Zel’dovich effect. The effect is the name for the cluster’s silhouette against the cosmic microwave background radiation. Combined with other observations, the Sunyaev-Zel’dovich effect allows astronomers to measure properties such as the temperature and density of the cluster’s hot gas where the galaxies are embedded. The right panel shows the X-ray image of the supercluster obtained with XMM-Newton, which reveals that three galaxy clusters comprise this supercluster. The bright orange blob in the left panel shows the Sunyaev-Zel’dovich image of the supercluster, obtained by Planck. The X-ray contours are also superimposed on the Planck image.

UPDATES: For other early perspectives on the early release results, see the blogs of Andrew Jaffe and Stuart Lowe; as usual, Jonathan Amos has done a very quick and well-written news piece for the BBC.


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Extraordinary Rendition

Posted in Music, Opera with tags , , , , on January 10, 2011 by telescoper

BBC Radio 3 is now well into its celebration of the Genius of Mozart, which involves playing every note he wrote over 12 days. I’m a devout admirer of Mozart, but I’m not sure that uninterrupted diet like this is actually a good idea. It is in danger of doing something that I wouldn’t previously have thought possible – making me bored of Mozart.

I’m a firm believer that you should just an artist, composer, musician (or scientist, for that matter) by his or her best work and by that reckoning Mozart is among the greatest of them all. But I have to say among the glorious masterpieces there’s also quite a lot of quite dull stuff. Take the symphonies, for example. Mozart wrote his First Symphony when he was only 8 years old. That fact on its own makes the work worth listening to. However, in my humble opinion, you can fast forward through at least twenty of the following compositions before finding one that’s really worth listening to, and even further before you find the really brilliant ones.

I’m not saying that the lesser works of Mozart shouldn’t be played. In a balanced programme, contrasted with works by other composers, they are interesting to listen to. It’s good to hear the rarely performed works from time to time, if only to understand why they are rarely performed. However, with only Mozart on offer day after day the effect is only to lessen the impact of the great works by surrounding them with hour after hour of lower quality music. I don’t think the BBC has done the Mozart legacy any favours by revealing that he actually wrote too much music, a lot of it not particularly good.

After that, I’m about to duck back down below the parapet but before I do, I thought I’d make my contribution to the ongoing Mozartfest with a piece from my favourite Mozart opera, The Magic Flute, in a version that’s itself very rarely heard. Fortunately. This is what Florence Foster Jenkins – the opera singer to end all opera singers – did with Der Hölle Rache kocht in meinem Herzen. For some reason Sony admits to owning the copyright of this, so you’ll have to click through to Youtube to hear it in its full glory.


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In a Mood

Posted in Jazz with tags , , , on January 9, 2011 by telescoper

Back to work tomorrow, and I’ve got quite a lot to sort out before we start back so I’ll be in the office this afternoon. No time for anything of any great consequence, therefore, so I thought I’d post this bit of music which some of you might find amusing and/or enjoyable.

I think I’ve written on this blog before that mathematical theorems and physical laws often have the wrong name associated with them. So it is with famous tunes. I’m in the mood to point this one out. The following track, called Tar Paper Stomp, was recorded by Wingy Manone and his Orchestra in 1930. The tune features a well-known riff that formed the basis of a much more famous and commercially successful recording made in 1939. In fact Glen Miller‘s hit was a second-order copy; he got the theme from a tune called Hot and Anxious recorded by Fletcher Henderson‘s Orchestra in 1931. There’s some debate who actually wrote it first – Fletcher Henderson’s brother Horace claimed to have done so – but Wingy Manone did receive an out-of-court cash settlement in return for not pursuing a copyright claim.

Anyway, in case you were wondering “Wingy” Manone’s nickname derived from the fact that he lost his right arm when he was run over by a streetcar as a child. Thereafter he wore a prosthetic limb, hence the name. It sounds a bit cruel, but he didn’t seem to object. In fact he was an extrovert showman, singer, comedian and all-round entertainer as well as a fine trumpeter. It can’t be that easy to play the trumpet with only one working hand – he seems to have used his prosthetic arm just for support, fingering the valves and holding the horn with his left. His style was firmly rooted in Dixieland; it may be a bit rough around the edges, occasionally downright raucous, but he certainly could play with a lot of gusto – his solo on this track is hugely enjoyable. In fact, I think this track makes Glen Miller’s In the Mood sound like a wet weekend in Stevenage.

I don’t have a personnel listing for this recording, but the tenor saxophonist sounds to me a lot like Bud Freeman. Although Benny Goodman played with Manone’s band around 1930 the clarinettist doesn’t sound like him to me. Could it have been Frank Teschmacher?


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Mock Examination

Posted in Bute Park on January 8, 2011 by telescoper

Regular readers (both of them) will know I’m Professor of Theoretical Astrophysics at Cardiff University. With the undergraduate mid-year exam period coming up shortly, I was thinking of posting something to help the students with their revision of my specialist topic. Based on an appropriate syllabus for this subject inferred from rigorous study of the content of this blog, a friend of mine (who should remain nameless, but is called Anton) suggested the following examination questions.

Feel free to suggest others through the comments box!

CARDIFF UNIVERSITY FINAL YEAR EXAMINATION IN PHYSICS

Option: Theoretical Astrophysics.

Time allowed: 2 hours.

Answer all questions, in full. No credit will be given for partial answers, numerical or grammatical errors, spelling mistakes or any other variety of underachievement.

1. “England’s victorious Ashes series in 2005 was more meritorious than retaining the Ashes in 2010/11.” Discuss.

2. Was Charlie Parker a greater saxophonist than Miles Davis was a trumpeter?

3. Compose a 15 × 15 cryptic crossword using only astrophysical terms.

4. You hear that Bute Park is to be turned into an airport. Write a model letter of complaint to Cardiff City Council.

5. Discuss the influence of Mahler’s awareness of his own mortality on his later Lieder.

6. You have 10 minutes on Google to find a US TV soap star lookalike for Prof. Coles. (Marks will be awarded automatically by a Bayesian image comparison routine.)

7. Compose a Pindarian ode protesting about governmental priorities in science funding.


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Ashes Victory

Posted in Cricket, Poetry with tags , , , , , on January 7, 2011 by telescoper

Well, there you have it. England’s cricketers finally won the final Test of the Ashes series in Sydney by an innings and 83 runs, to win the series outright. It has been a wonderful performance by the England team down under which has warmed the cold English (and Welsh) winter.

Commiserations to Australian cricket fans. Their team just wasn’t as good as England, with bat or ball. They have a lot of rebuilding to do, but you can be sure they’ll be back challenging for the Ashes again before long.

I thought I’d put up a poem to celebrate. This one is called The Game and was written by John Groves. It represents an idyllic view of what many English crickets fans surely regard as the match of any season – the Lord’s Test – which we can now look forward to with relish in the summer. However, I chose this poem for this occasion primarily because of the final couplet which takes us far beyond the boundaries of St John’s Wood.

A painter’s sky over Lord’s.
A gentle zephyr, blowing without brace,
The crowd engaged in all that joy affords
And England batting with admired grace.
The sun ablaze, an unforgiving pitch,
A bowler with a patriotic itch,
A ticking scoreboard and a close-run thing,
A resolute gull, high on a drowsy wing.

Though one team triumph, victory’s all the same:
The winner is the beauty of the game.


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Epiphany

Posted in Cricket, Football, Literature with tags , , , on January 6, 2011 by telescoper

So here we are then, it’s “officially” the last day of Christmas.

Last night was Twelfth Night, traditionally marked by an evening of festive merrymaking. And so it came to pass, as I sat with a cup of Ovaltine watching TV highlight’s of the third day’s play in the final Ashes Test in Sydney followed by Match of the Day, featuring coverage of Newcastle’s 5-0 thrashing of West Ham.

Today, 6th January, is Epiphany which traditionally marks the arrival of the three Magi and the presentation of their gifts to the baby Jesus. As far as I’m aware there’s no actual evidence that this actually happened on January 6th, but there you go. It’s a tradition nevertheless. In fact, I seem to remember that the Magi only appear in one of the four gospels (Matthew) and it doesn’t even specify that there were three of them..

Here in the United Kingdom, January 6th is when the holiday season really finishes, when Christmas trees and decorations come down, and when we’re allowed at last to stop eating Turkey curries. Some years ago I discovered that in other countries Epiphany is actually observed rather differently and is in fact one of the main events of the Christmas period. I only discovered this when I tried to arrange a meeting with Spanish and Italian representatives of an EU Network I was involved with on January 6th, only to be greeted with howls of protest. It actually makes sense, though, as presumably the exchanging of gifts at Christmas is supposed to commemorate the visit of the Magi. Why not, therefore, do it at Epiphany?

All this reminded me of the following (very famous) poem, called The Journey of the Magi , by T.S Eliot. I’m all out of gold, frankenstein and myrrh (whatever that is) – and I’m not a particularly wise man anyway – so I’ll offer this in lieu of a gift.

‘A cold coming we had of it,
Just the worst time of the year
For a journey, and such a journey:
The ways deep and the weather sharp,
The very dead of winter.’
And the camels galled, sore-footed, refractory,
Lying down in the melting snow.
There were times we regretted
The summer palaces on slopes, the terraces,
And the silken girls bringing sherbet.

Then the camel men cursing and grumbling
And running away, and wanting their liquor and women,
And the night-fires going out, and the lack of shelters,
And the cities hostile and the towns unfriendly
And the villages dirty and charging high prices:
A hard time we had of it.
At the end we preferred to travel all night,
Sleeping in snatches,
With the voices singing in our ears, saying
That this was all folly.

Then at dawn we came down to a temperate valley,
Wet, below the snow line, smelling of vegetation;
With a running stream and a water-mill beating the darkness,
And three trees on the low sky,
And an old white horse galloped in away in the meadow.
Then we came to a tavern with vine-leaves over the lintel,
Six hands at an open door dicing for pieces of silver,
And feet kicking the empty wine-skins.
But there was no imformation, and so we continued
And arrived at evening, not a moment too soon
Finding the place; it was (you may say) satisfactory.

All this was a long time ago, I remember,
And I would do it again, but set down
This set down
This: were we led all that way for
Birth or Death? There was a Birth, certainly,
We had evidence and no doubt. I had seen birth and death,
But had thought they were different; this Birth was
Hard and bitter agony for us, like Death, our death.
We returned to our places, these Kingdoms,
But no longer at ease here, in the old dispensation,
With an alien people clutching their gods.
I should be glad of another death.


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Herschel Views Andromeda (via The Herschel Space Observatory)

Posted in The Universe and Stuff with tags , , , , on January 6, 2011 by telescoper

An amazing composite image of M31 in Andromeda using both infra-red and X-rays was recently obtained using Herschel and XMM space observatories. It featured in the BBC Stargazing Live programme earlier this week and I’m told that, typically for astronomy, the inspiration behind it was … beer.

Herschel Views Andromeda We've been sitting on this image since just before Christmas so that it could be unveiled during the BBC Stargazing Live show last night, but I've been aching to get this onto the blog ever since I saw it. This is a Herschel image of our nearest neighbour galaxy, the Andromeda galaxy, also known as M31, along with comparison images at other wavelengths. [/captio … Read More

via The Herschel Space Observatory


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My Fellow Pagans …

Posted in The Universe and Stuff with tags , , on January 5, 2011 by telescoper

I was reminded yesterday of the following clipping, which I found in The Times, in 1999, just before the total eclipse that was visible from parts of the United Kingdom in that year. It was a feature about the concerns raised by certain residents of Cornwall about the possible effects of the sudden influx of visitors on the local community. Here is a scan  of a big chunk of the story, which you probably can’t read…

.and here is a blow-up of the section shown in the red box, which places cosmologists in rather strange company:

This makes it clear what journalists on this rag think about cosmology! In protest, I wrote a letter to the The Times saying that, as a cosmologist, I thought this piece was very insulting … to Druids.

They didn’t publish it.


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Einstein and the Eclipse

Posted in Biographical, The Universe and Stuff with tags , , , , , , , on January 4, 2011 by telescoper

Following on from my previous post, I thought you might be interested in this. It’s the last programme in a series called Six Experiments that Changed the World which was presented by the late Ken Campbell. It was made for Channel 4 and first broadcast in 2000. It’s in two parts. If you watch the second one, you might see someone you recognize…


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