Redshift Seven

June 29, 2011

I am very happy today to report a triumph for UKIDSS, for Dan Mortlock and Steve Warren, and for UKIRT  : the first quasar to break the redshift seven barrier. You can read the Mortlock et al Nature paper, the STFC story, the Gemini version, or the ESO version. And Telescoper has already splashed it too ! The science is best in the Gemini version, but the ESO has wonderfully gaudy animations….

When we were designing UKIDSS back in 1998-2001, SDSS was doing its thing and the redshift record climbed from 5ish to 6.3. The secret was finding i-band dropouts, as the famous forest cuts out nearly all light shortward of Lyman alpha. However this can’t work past z=6.4 as you get no visible light at all. Bring on the massive IR survey please… This was Steve Warren’s big push, along with the importance of the new Y-band, so we could tell the difference between high-z quasars and T-dwarfs. Finding these swines though is the classic needle in a haystack problem, with millions of fake candidates to weed out. Dan Mortlock has worked long hard and patiently, along with Steve Warren, Bram Venemans, Richard McMahon and others. Team UKIDSS were starting to get worried, as we were succesfully finding more 6ish quasars, but nothing past the magic 6.4… then suddenly bang – redshift 7.085.

Apart from breaking records, the new quasar is important in two ways. First, the Ly-alpha line is eaten away even redward of the peak, implying a small “near-zone” size, and so the best evidence so far for a significant neutral fraction near the quasar. Second, it has an estimated mass of two billion solar masses at just 770 million years after the Big Bang. It is generally thought that the very first stars, and so the first seed black holes, won’t be there until about z=25; then any such seed should not be able to grow by accretion to two billion solar masses until at least 900 million years…

Quasar near-zone

Artists impression of ionised bubble formed around quasar ULASJ1120+0641

Anyhoo. Although ESO and Gemini are getting lots of excellent PR, I think this is a triumph for UKIRT . Not dead yet, squire. In fact, how do we get more of these beasties, and push on to redshift 8 ? Survey the rest of the Northern Hemisphere, thats how. Another four years will do. (OK, VISTA helps too…).

Other thoughts. The Infra-red is cool. Big public surveys work. And for such massive surveys, properly processed and archived data is crucial. The whole thing would have been impossible without the selfless work of the teams at CASU and WFAU. Thank you guys.

Get your own data at the WSA ! DR9 coming your way soon.


Education, Education, Education : Cost, Cost, Cost

June 28, 2011

Whats the word I am looking for ? Chutzpah ? Brass Neck ? Arrogance ? Yet again, the coalition government are launching into an extra-ordinarily radical reform agenda with no mandate whatsoever. I refer of course to the appearance of David Willetts this morning on the Today programme, trailing the HE White Paper that isn’t even out yet. You can listen to the interview here, and read summaries from the Guardian and the THE; and here is the opposition response from, John Denham.  The pitch is (i) More power to the student with the money ! (ii) More competition please ! (iii) More concentration on teaching quality !  (iv) More information so students can decide !

Some concrete ideas seem to be (i) Remove the quota on places. (ii) Universities must publish information on employment outcomes of degrees (iii) Universities must publish data on contact hours. (iv) Universities must account for how they use fees. (v) Courses that employers don’t like should be scrapped.

Why is this happening ? Whats broke that needs fixing ? Well partly its the good old “profit motive fixes everything”, but mostly its about COSTS. Government wants large fraction of people to have HE. But can’t afford this from public purse. So get universities to charge the customer. But this is impossible for most families  unless big loans are available, so government has to cough up in first instance. Mega cash flow problem unless universities bring in full fees a little bit slower please. Ooops. Everybody wants to charge 9000 NOW. Ok. Only option is force some universities to get cheaper. Drive them into competition and let some go to the wall unless they develop cut price versions.

I am not sure I am totally against more university competition. But please don’t believe any of the bollocks about improving student experience etc. Its exactly the opposite. The whole thing only adds up if some universities are dirt cheap, and offer an experience to match. OK, so this is a real option. Lets be open minded. But lets call a pig a pig.

If you are upset enough, you can sign a no confidence petition here.

Oh .. and .. anybody know what will happen in Scotland ?


Austerity bites in Utrecht

June 27, 2011

As you may have heard, the University of Utrecht has taken the extraordinary decision to completely shut down its Astronomical Institute SIU  by 2014. You can read about in a blog post written last week by Sarah Kendrew, and there is also a press statement  issued by the SIU. This is the scariest astro-disaster since the INAF panic. Utrecht is a significant fraction of Dutch astronomy; it is one out of five universities in the NOVA alliance , although of course a significant fraction of Dutch astronomy also goes on at two big NWO  labs, ASTRON  and SRON , as well as the ESA establishment ESTEC.

Some of the comments on Sarah’s post suggest that Dutch astronomers are not planning a protest campaign, because they don’t want to rock the boat in the upcoming NOVA review, and I have had similar comments by email from at least one Dutch ex-pat colleague. This may be a mistake. The “Science is Vital” campaign made a genuine difference here in the UK. You have to have a genuine case, but you also want to make sure you are not labelled as the patsy. If they change their minds about protesting, lets get our pens and keyboards ready…

The University of Utrecht is facing a horrible problem of course – 20% cuts. Like much of the rest of Europe, the Dutch – yes, even those softy liberal dope smoking Dutch – have decided that the age of austerity is upon us, and that the only way to get back the money we gave to the banks is to cut it from public services – from the armed services, from arts and culture, from everything. There have been some protests, eg over university cuts and arts cuts, but there is also a feeling that there is a puzzling absence of coherent mass protest against such drastic wholesale cuts , as explored in this RNW video piece.

The dutch deficit is pretty similar to ours – an accumulated debt thats about 75% of GDP, and a running annual deficit of 10% of GDP. You can see the UK statistics on an official government website, or loook at an interesting private analysis  here  put together by conservative writer Christopher Chantrill . To put this in perspective, France has reached about 100% of GDP, Italy 130%, and Greece 166%. So are we in a historically unprecedented debt-saddled epoch ? Nope. As the figure below, taken from Christopher Chantrill’s site, shows, debt as a fraction of GDP has been larger than 75% in the UK for the majority of the last few hundred years.

So where does the moral panic come from ? And why is it currently so obvious to everybody  in Europe that what we require is to cut spending, as opposed to (a) increasing taxes or (b) growing GDP by investing in economic activity ?

Well… I am not a knee-jerk Keynesian. These issues are practical, not philosophical. But it is puzzling that every government in Europe suddenly believes in austerity. As scientists we should care, both because we should believe in evidenec-based policy rather than ideological strife, and because science is the epitome of the case for investment for growth – over fifty years, not fifty weeks.

Evolution of UK national debt over history

Evolution of UK national debt over history, from Christopher Chantrill's UK public spending website


Dark Matter heats up

June 13, 2011

As we all know, the non-existence of pancakes tells us that Dark Matter must be cold, not hot. This is why D, E, F, and W can now pay off their mortgages. (Back in them days, I dimly recall George telling me that he had trained his toddler to say “CDM Daddy !”). Here I refer not to the temperature of the mysterious particles, but to the temperature of the almost equally mysterious debate. Two rather fascinating but controversial results have come out in the last few weeks. They cannot both be right. Of course they could both be wrong. But if either one is right, its really really really important.

First up is a paper on arXiv by Hernandez, Jimenez and Allen. They examine the relative proper motions of very wide binaries from a new SDSS sample of such beasts, and find that, just like the rotation of galaxies and the random motions in clusters, they are moving faster than they ought to be, and in pretty much the same acceleration regime as those other examples. Its all baryons here squire, so dark matter ain’t the answer. This is the most interesting evidence yet for a modified law of gravity. Over at Cosmic Variance, Sean Carroll already wrote a short  post. There is as ever an interesting comment stream, but mostly a bit off base I think. Sean already made the key point : on the face of it, this is a crucial result, but statistical analyses of this kind can have systematic biases you just haven’t thought of yet. You can place a bet this will go away somehow. But then again thats what I thought when I first heard of the supernova acceleration results…

The Hernandez paper is a tad proselytising for my taste, which leaves me a little uncomfortable. Here is a quote from the opening :

Direct detectionof the elusive (illusive?) dark matter particles, in spite of decades of extensive and dedicated searches, remains lacking.

Ah … but maybe it doesn’t ! This week the CoGENT team posted a paper on arXiv confirming their claim from last year of direct detection of dark matter particles, and showing that the detection rate shows an annual modulation – just like those DAMA claims that everybody else has poured scorn on for a decade. In fact, their confidence contours for the mass and cross-section of the DM particles seems to be nicely consistent with DAMA, showing a rather light particle which will make many theorists uncomfortable. However – the much bigger CDMS and XENON experiments claim to have already ruled out this region of parameter space. The situation is summarised in the plots below, which I have taken from an independent paper analysing the CoGENT data, by Hooper and Kelso. The Hooper and Kelso paper appeared on arXiv THREE DAYS after the Aalseth paper. No slouches these guys. I have to confess I found the Hooper and Kelso paper a bit easier to understand.

Hooper-Kelso Figs 6-7

Figs 6 and 7 from Hooper and Kelso paper, comparing CoGENt and DAMA constraints (on left) and CoGENT, CDMS, and XENON constraints (on right)

The CoGENT team are being fairly cautious. They don’t claim they have a proved detection of DM, but rather a signal which is consistent with the predictions of DM. Removing the backgrounds and systematic effects from these experiments is very tricky, which is why most people will still be sceptical, even with CoGENT and DAMA agreeing. Of course the XENON and CDMS guys could get it wrong too. Either CoGENT and DAMA are reading too much into the inkblots, or CDMS and XENON are throwing the baby out with the bathwater. Improved metaphor contributions welcome.

I know Alex Murphy sometimes reads this blog so I am hoping he will give us the lowdown. Which is right ? Result A, Result B, or neither ?

Finally, a wee sociological note. None of these papers have been refereed yet. But the world might already have decided by then. Over at Cosmic Variance there was a string of people saying either “well, this is wrong because..” or “Hem. My theory about the dinosaurs, by Anne Elk. Hem.”


You don’t know me

June 9, 2011

In case my last post seemed to line me up with the trendy young things, against my stick-in-the-mud colleagues, here is a corrective. I am pleased to announce a return to grumpy old pedant mode.

People call me Andy. Everybody knows this. However, in this semi-intelligent computerised world, I find myself increasingly obliged to type my name in boxes as “Andrew” because it will then be the same as it is in other official forms, and no confusion will ensue. As a result of course I get letters from companies starting “Dear Andrew”, or get phoned by people I don’t know who call me “Andrew”. Well, we can all have opinions about the correct mode of address in various social circumstances, but for me there is this extra irksome twist. Anybody who calls me Andrew is acting like they know me but they transparently don’t. Its not my name. Only my mother  calls me Andrew. And only when she’s cross. And she’s dead, so thats not often.

Yesterday I  got an email from a central university administrator who I didn’t know that started “Dear Andrew”. I am afraid I ranted about this somewhat in a return email. I apologised for being a bit of a prat, but I still did it. She replied vary graciously and and now she calls me Andy, so maybe its ok – but it shows its a difficult thing to get right as social rules evolve. Even nice people are unsure of themselves. Anyhoo, what I said was that usually people who know me write “Andy – ” and people who don’t write “Dear Professor Lawrence, …”. In the latter case I nearly always sign my reply email “andy lawrence” which then gives them permission to call me Andy. I guess this tells me that I am at the same time both informal but and rule-bound.

I find this a very confusing matter so will be interested to hear what others think. I know that the change we are witnessing is largely driven by a long term decline of formality and pomposity and class structure in society, all of which erosion I thoroughly approve of. And at a personal level, it comes from a desire to signal friendliness, or in the case of commercial contacts, to simulate such friendliness. So I think the niggling is to do with power and respect. Somehow names still do have power. When someone uses your first name without your permission, its like an adult speaking to a child. Its patronising.

Anyway. Better do some work now.


Social and anti-social astronomers

June 7, 2011

Its exam time. Don’t we love it. Students and Staff alike. We do ours a little earlier than most, so my marking is all done and we are in the middle of exam boards. Its a multi-stage process these days, with separate special circumstances committees, pre-boards, and stage-1 course boards, before the official final exam board. The latter then largely homologates the recommendations of these earlier committees. Probably more efficient than it used to be, but even more bureaucratic. So we all look forward to the small amount of socialisation that goes with the process – the annual exam board dinner !

So there we were last night, at Blonde. By the way, I recommend you don’t Google “Blonde, Edinburgh” unless you have safe search switched on. Or on the other hand… anyway. It was a fairly usual mix. Gossiping about George and Carlos and the Gruber Prize, bitching about absent members of staff, and as the wine flowed on, bitching about present members of staff. But there was also an interesting conversation about Blogs and Twitter.

Nearly everybody present was a Luddite and thought blogs and tweeting were onanistic and time wasting. A polite exception was made for my blog, and Peter’s, on account of they were (at least sometimes) a useful community conversation forum. Myself and @wikimir and @paula_wilkie were the only Tweeters. To everybody else, Twitter seemed even more clearly bizarrely pointless. People thought the idea of @WETI was funny, but that was seen as a joke on Tweeting. I was challenged to describe a real use of Twitter. About the best I could come up with was that Paul Crowther knew everything first, and that if you followed him on Twitter, you would know everything second. The response to this was “whats the hurry ?”

Then this morning I became aware of an interesting new attempt to make Twitter useful – the Astronomy Journal Club, set up by Emma Rigby, Matt Burleigh, and Emily Baldwin. I learned about it first in Sarah Kendrew’s blog post here. Its all brand new, so who knows if its going to work, but why not give it a go ?