Chris Lintott’s Universe

It’s difficult, as someone who uses telescopes which work in the sub-mm – effectively short-wave radio – it’s difficult not to be jealous of optical astronomers, many of whom are busy in the exhibit hall giving out beautiful posters of their latest hits. Instead, we end up often with spectra, or at best with a picture like this, obtained by the state of the art SCUBA camera on the JCMT.

View from the JCMT's SCUBA camera

I remember SCUBA-guru Rob Ivison’s description of the field on the Sky at Night as ‘blobology’ which hits the nail on the head. When these blobs were first discovered a decade or so ago, no-one knew what they were.

Worse, this simple question turns out to be harder to answer than you might think because the resolution in the sub-mm is so poor. When we look at a sub-mm image, we’re looking at a blurred view of the Universe. If you pointed a big optical telescope at the blob in the image above, the odds are that you’d see many separate galaxies within the one blob. Which of them is responsible for the blob? We wouldn’t know. Rather than jump straight to the optical, therefore, astronomers look deep in longer wavelength radio. Anything we see in the radio is then assumed to correspond to the sub-mm blob, and we’ll have a precise enough position to go chasing the thing with optical telescopes, allowing us to measure the distance.

This technique works for about half the sources, and the orthodox conclusion is that these are rapidly star-forming massive galaxies, the likely precursors of today’s old red and dead ellipticals. What about the other half? My assumption had always been that these were much like the others, but were radio quiet or otherwise difficult to pin down.

In a talk by Kartik Sheth of Caltech here at the American Astronomical Society meeting this morning, I realised I might have to rethink. Sheth’s group used the CARMA array to look directly at one sub-mm galaxy which hadn’t been matched with a counterpart.

The CARMA mm array.

They were able to sidestep the need for radio, and go directly to Hubble data which covered the field.

The Antennae Galaxies

To their surprise, the system was much nearer than other sub-mm galaxies. The best analogue seems to be a merging system, rather like the well-known Antennae which are pictured above. Is this a one-off? Are other nearby galaxies lurking among the distant blobs SCUBA sees? We’ll need, it seems much more data before we can say for sure.

Those of you who didn’t spend the last few days up a mountain may have noticed that it’s no longer 2008, and is in fact 2009. Hopefully, it’s equally obvious that 2009 is the International Year of Astronomy, as designated by the United Nations.

IYA is a big deal; whatever you’ve heard already is almost certainly only the surface. Many of my friends and colleagues have been working incredibly hard over the last year and more to bring the joys of astronomy to everyone on the planet. I’m sitting in my first press conference of the American Astronomical Society conference in Long Beach, California which is detailing some of the things that are going on ahead of the formal launch of IYA tomorrow night.

One date for your diary – or rather set of dates – is April 2-5th which is set to be the 100 hours of astronomy. Roughly 100 observatories around the world will be coordinating webcasts so that as night falls around the globe you’ll be able to listen in on the work that professional astronomers are doing – if it isn’t cloudy, of course.

In the meantime, cyberspace has been well and truly taken over. I insist you all immediately go and subscribe to 365 Days of Astronomy, the podcast that will give you your daily dose of astronomical content each and every day throughout IYA. As the first episode said, 365 Days of Astronomy is a nutritional part of your breakfast (or lunch, or dinner). Given that you’re reading this, then the Carnival of Space is the only guide that you need. If you’re a Second Life person, then the Second Astronomy island will be officially opened tomorrow. Oh, and a little project called Galaxy Zoo is a tiny part of IYA too…

There are plenty of IYA websites, too : here are efforts mentioned in the press conference from NASA, the Astronomical Society of the Pacific (who are targeting astronomical societies) and the US national site. And let’s not forget the UK’s own contributions. There’s also the Portal to the Universe which will be a one-stop shop for blogs, press releases and just about everything else.

Happy New International Year of Astronomy. Have a good one.

Talks to astronomical societies are almost invariably – and rather pleasurably – followed by a trip to the pub. There, the conversation usually touches on my luck in visiting some of the world’s great observing sites. I’m still getting stick, for example, for the evening in Chile when we were on the hill next to the Very Large Telescope which is now home to the European survey telescope, Vista. I confidently declared to camera – through chattering teeth – that it was 2am, and time for bed. It was freezing, I was tired and we were filming early the next day, but apparently wasting such good skies is sacrilege.

I walk away from these conversations realising how lucky I am. But as I’ve written each column for the Times over the last year, describing a city dweller’s sky, I’ve begun to realise that part of the joy of being an amateur astronomer (and I’m definitely still that, too) lies in simply noticing the sky. How many of London’s 8 million people noticed Venus in the evening sky in the past week, knew what it was and saw how its position changed from night to night? Not many.

I’m transcribing this from a notebook I was scribbling in some 10 km above the Earth’s surface, flying home from my share of the observing run described on the Galaxy Zoo blog. (Don’t ever fly Iberia, by the way – it’s been rather eventful). The observing was conducted almost entirely under cloud, but now, out of the window, my notebook records one of the most beautiful sunrises I have ever seen.

The horizon is a perfect rainbow; red at the bottom, and then passing through the sequence of colours, their boundaries distinct and yet not sharp. At the top, indigo and violet appear as separate colours, and above them, about ten degrees above the horizon, is the deep black of the still-night sky. That will soon vanish, but for now it’s sparkling with jewels, with Antares and the rest of Scorpius hanging there.

I was the only person on the entire flight, as far as I could see, paying any attention to the view from the window. That’s why this year – the International Year of Astronomy (more about which on Monday) – my resolution is to long just a little less to be back under the starlit skies of the Atacama, and to make sure that I – and anyone I talk to – doesn’t miss the glory of the sky above them, wherever they are.

Happy New Year.