Cosmology/Glasgow exam technique

Along with a large fraction of the UK astronomical community, I am at the National Astronomy Meeting (NAM2010) in Glasgow. Just imagine a well placed bomb. Could be like the Manchester United Plane Crash all over again.

Two fabulous plenary talks this morning from George Esthathiou and Rosie Wyse. Plack has completed its first survey, but George is not allowed to show us the CMB maps yet. We have to wait until October 2012. (Southwood was in the audience, so he had to behave…) But he did give us a taster – Galactic cold dust map, made by combining Planck and IRAS.  Rosie Wyse showed us all sorts of fascinating stellar population data reflecting the merger history of the Milky Way and other nearby galaxies, as expected in the standard CDM cosmology. But she also showed two worrying things. The thick disc is thought to be made by mergers stirring up an older thin disc. But the stars in the thick disc are really old, suggesting the thick disc of the Milky Way has not been affected by mergers since about redshift two. The second niggle was that the distribution of abundances is consistent with the stellar initial mass function being constant through cosmic history – whereas the galaxy formation simulators desperately want early star formation to be high-mass biased. Hmmm.

Brain spinning, I wandered across the corridor to the Hunterian Museum. This has one of my favourite pieces of Glasgow History – the Blackstone Chair. From mediaeval times until the 19th century, this is how Glasgow students were examined. When you were ready, you sat on a special chair surrounded by Profs. They fired questions at you for twenty minutes, with the sand running out just behind your head. Then some flunky stamped a pole on the ground and you were done.

We gotta bring this back.

16 Responses to Cosmology/Glasgow exam technique

  1. That would certainly be one way of reducing the size of the UK astronomy community without making anyone redundant (a bomb, that is, not the chair)…

  2. Nick Cross says:

    This would indeed be helpful to STFC, and they would have many fewer complaints. Maybe we shouldn’t suggest this: it may give them ideas.

  3. Michael Merrifield says:

    I wouldn’t get too brain-spun Andy: perhaps the thick disk is just the old tail of a disk population heated by secular processes, and there is some other nob that needs twisting in the semi-analytic models that previously suggested a bizarre top-heavy IMF.

    • andyxl says:

      Mike, you disappoint me. Can we not decide whether semi-analytic LCDM models are or are not the best way we have at the moment of predicting a wide range of physical parameters based purely on inputting a wide range of physical parameters ?

  4. “Now I will run from the room” – John Womersley – think he’s escaping before the bomb goes off and kills us all!

  5. andyxl says:

    Lunch time conversation : X suggested that if George had shown real Planck data Southwood would have had to shoot him immediately. Y suggested that actually we would all have been in danger. The doors would have locked and gas would have started seeping into the room …

    • Mark McCaughrean says:

      I realise I’m treading a fine line if I try and take a serious stance on this jocularity, Andy, but I’ll take the risk.

      Within ESA and in discussion with the Planck consortia, we’re having a long hard think about how to address the understandable desire from astronomers (outside Planck) and the public alike to see the Planck all-sky CMB data sooner rather than later, without undermining the agreed Science Management Plan, which obviously gives first crack at the data to the consortia.

      Keep in mind that some fraction of the new (beyond WMAP) science can in principle be gleaned fairly readily even from a JPEG version of the all-sky CMB image, as long as it hasn’t been degraded to WMAP resolution (which would miss the point slightly). After all, a couple of papers appeared in astro-ph soon after the First Light Survey data were press-released last year, despite their only covering 14% of the sky. Yes, they were probably poor papers and no, they probably weren’t submitted to journals, but the point stands.

      Also, it’s a difficult job getting the CMB out from underneath the galactic emission: the beautiful and complex structure in the recently released Planck HFI+IRAS image of the galactic plane demonstrates that quite clearly. Even though the first all-sky survey is now complete, I don’t think it’s right to do a hack job on trying to extract the CMB in a hurry, just to get a picture out a.s.a.p., a picture that people outside the teams who’ve worked for years on the mission may be able to exploit. So, yes, it may be quite some time yet before you see the final CMB data (and no, I haven’t seen them yet either 🙂

      However, in all fairness to David Southwood, he has been on the side of pushing to get stuff out early, employing the rhetorical question of “What would NASA do?” to suggest we should get something out immediately when foot-draggers like me counsel a more cautionary approach. (Of course, the irony is that NASA didn’t release anything at all for 19 months after WMAP was launched, so …)

      Anyway, I understand that the Planck Science Team and our Project Scientist are thinking along the lines of a high-frequency all-sky map showing the galactic foreground in May or so, perhaps with the CMB actually deliberately (even if crudely) removed, if possible.

      If so, I’ll be pushing for it to also contain a hidden steganographic twiddle, so that when you Fourier transform the image, the power spectrum reads “Max Tegmark woz ‘ere”.

  6. Rob Ivison says:

    given the relative sizes of the consortia, i bet 10x more folk have seen the Planck images than the PACS data in GOODS. i’ve written a paper using them (the latter, before someone cuts my throat from ear to ear), but i haven’t seen the image. i sent them my code, then they sent me the results of running it. the weirder science gets, the more i love it…

  7. telescoper says:

    The exam system you describe is not dissimilar to the (current) Italian one, except I think they use an Albanian rather than a Pole.

  8. andyxl says:

    I do miss Mrs Trellis.

  9. Mrs Trellis says:

    Dear Alastair,

    I agree with Nick.

    Yours sincerely,

    Mrs Trellis

  10. ian smail says:

    SNAM would seem more appropriate in the light of the make-up of the SOC (note, not the LOC). The membership is: Glasgow (4), Edinburgh (4) and 2 people from as far away as St Andrews…

  11. andyxl says:

    Ian – certainly a serious mistake. There should have been somebody from Durham. Obviously we will be drawing the border slightly south of Durham after the war.

  12. ian smail says:

    no one further south in England (ie most of it) knows where the border is anyway – they probably think its at Scotch corner. so we could just move the “Welcome to Scotland” sign there, if it means we can apply for SUPA funds?

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