The dark nemesis of galaxy formation: why hot haloes trigger black hole growth and bring star formation to an end

I’ve just submitted a new paper to MNRAS, the professional journal of astronomy… its all about black holes and how they bring star formation in galaxies to an end, creating two distinct galaxy types and making the Universe look the way it is. Far from being exotic predictions of Einsteins General Relativity, it seems that black holes play a fundamental role in shaping the observable universe.

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Here’s the paper’s abstract, click to get a link to the paper… Continue reading The dark nemesis of galaxy formation: why hot haloes trigger black hole growth and bring star formation to an end

What does Cosmology have to do with Formula One?

bbc web pageIt’s great – a while ago I had the opportunity to teach a course on Physics and Motorsport. It was a great way of uniting two of my passions.

Now this is taking a new direction, and I’ve been contributing to a BBC article on technology in Formula One. “Would Formula One be more thrilling without cutting edge tech”.

I love the broad span of physics. Both Cosmology and Formula One are a matter of understanding, of seeing through complicated equations to the principles that underly them,  of developing an intuition about how things – in this case, cars and galaxies – will behave under extreme conditions.

 

Re-live the Durham 2015 Lumiere

 

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Ross Ashton has just sent me the “official” video of the World Machine installation from Durham Lumiere 2015. If you missed out, now you can relive the experience. If you want to recreate the amazing atmosphere, you’ll need about 200,000 friends and some huge speakers to carry the depth of John Del’Nero/Isobella Waller-Brige’s amazing sound track. Giles Gasper suggests that for the complete experience,  you’ll also need a bucket of water to pour over your head while you watch… it poured with rain.

Hopefully we can bring the real thing to a dark night near you. Let me know if you have a 12th Century Cathedral that I can borrow.

LDSS at the Las Campanas Observatory

It’s amazing. I’m at the Las Campanas Observatory, using the LDSS (low Dispersion Survey) spectrograph. A triumph of North East engineering, she was built in Durham University in 1991 by a team of “real” engineers,  including John Webster. It was one of the first instruments to allow astronomer to survey the distant Universe and to see galaxies when the Universe was only a fraction of its present age.

In 2001, John and I moved LDSS to its new home at the incredible 6.5m Magellan Clay telescope. The instrument has evolved for strength to strength, using its solid engineering as a plot form for the latest technological developments in optics and, most recently, its CCD detector. LDSS is still at the leading edge of cosmology.

Now, here I am looking for some of the faintest galaxies in the Universe. Our new ‘Deep Depletion’ detector lets us find galaxies at even higher redshift, and clever electronics allow us to detect lower mass galaxies than ever before, revealing the secrets of how galaxies, and the nuclear elements they contain (such as the carbon and oxygen that we are made of) have been created over the history of time.

 

The World Machine at Lumiere

The World Machine is a daring new art work for Durham Lumiere 2015.

Over the past year I’ve been putting together a study comparing understanding of the Cosmos in Ancient Greece with its understanding in Medieval times and today. It’s been great to see many of these ideas inspire the “World Machine” and major art project for the Durham 2015 Lumiere. Its been a great pleasure to work with Carlos Frenk (Institute for Computational Cosmology) and Giles Gasper (Ordered Universe Project), together with a whole team of young people, on this project. Our role has been to supply many of the images and movies that underly the artwork. The World Machine is a major collaboration between our Art and History teams, projection artist Ross Ashton, sound designer John del’Nero, and composer Isobel Waller-Bridge.

 

 

EAGLE takes off

The first EAGLE paper is now available on the astro-ph archive. It will tell you everything you wanted to know about the project (and more probably more!).  Most importantly, it sets out the project philosophy and shows just how much the simulated universe looks like the real one.

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This plot counts the numbers of galaxies of different masses. It compares the main Eagle simulation (the dark blue line) to previous work (the other lines) and observational data (the fray points)… you’re meant to see that EAGLE fits the data really well – it captures both the flat part (similar numbers of galaxies with masses to our Milky Way galaxy and with mass 10 times smaller), and the exponential break at higher masses (galaxies much larger than our own are incredibly rare). EAGLE is a huge step forward compared to previous work. There are many more comparisons like this in the paper.

Here’s the paper’s abstract…. Continue reading EAGLE takes off

Cosmic Own Goal

gas imageOne of the very exciting things about the Eagle project is that it is possible to pick out interesting objects, and then re-simulate the volume around them at higher resolution giving a much better view of what’s going on and letting us find even the smallest galaxies.

So what are the smallest galaxies? Surely galaxies can be as small as you want? Well – no. There’s a limit to the smallest size of galaxies, and Till Sawala has just written an exciting paper demonstrating why.

The science paper is available here…  http://arxiv.org/abs/1406.6362

but we’ve also issued a press realease with some very cool pictures. The full pictures are here… http://star-www.dur.ac.uk/~till/

Here’s the story ….

Continue reading Cosmic Own Goal

EAGLE in the News

Images from our EAGLE simulations appeared on the BBC’s Newsnight program last night. Journalist Rebecca Morelle used them to explain the concept of Dark Matter: the exotic and invisible matter that makes up most of the mass of the Universe. The images contrast the universe as we see it (from looking at starlight) to the way it would appear if it were possible to see the Dark Matter.

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Follow the on-line story at the BBC’s news website.

If you would like to explore more of the Universe, download our app “Cosmic Universe” from the apple store.