Institute for Computational Cosmology

ICC News Summer Science RAS Awards

Research Overview of ICC research themes

Ogden@10 10th Anniversary of the ICC

COSMA V New installation of Cosmology Machine

July 2013

Cosmology in Crisis: What is the matter?

Astronomy Picture of the Day 12th October 2012

Discover the cosmos! Each day a different image or

photograph of our fascinating universe is featured, along

with a brief explanation written by a professional

astronomer.

Pan-STARRS and Nebulae

Image Credit: PS1 Science Consortium

Processing: Nigel Metcalfe, Peter Draper (Durham Univ.),

Gene Magnier (IfA Hawaii)

Explanation: A single field from the world's most

powerful survey instrument captures this spectacular

skyview. Looking toward Sagittarius, the scene spans

nearly 3 degrees or six times the width of the Full Moon.

At bottom, upper right, and lower left it covers the Lagoon

Nebula (M8), the Trifid Nebula (M20), and NGC 6559, in

the crowded, dusty starfields of the central Milky Way.

The adopted color scheme shows dust reddened starlight

in red hues and normally red emission from hydrogen

atoms in green. Built and operated by the Pan-STARRS

project, the instrument featured a 1.4 gigapixel (billion

pixel) digital camera and telescope. Pan-STARRS, the

Panoramic Survey Telescope & Rapid Response

System, is intended to scan the skies for potentially

dangerous near-earth asteroids and comets, exploring

the Universe with a unique high resolution, wide field

view.

http://apod.nasa.gov/apod/ap121012.html (NASA APOD)

ICC NEWS July 2013 icc.dur.ac.uk

Written and designed by: Carlton Baugh

Image, text credits: Mark Lovell, Till Sawala, Richard Bower, Virgo

Consortium, Durham University, IBM, Baojiu Li, ITN News, Euclid

Consortium, Royal Astronomical Society.

“Durham University plays a starring role in computational cosmology”

Case Study reproduced with permission from IBM Systems and

Technology.

Institute for Computational Cosmology. All rights reserved.

ICC NEWS

“The Ogden Centre is a

world-class centre for

research into the

fundamental mysteries

of modern science, from

the properties of the

smallest elementary

particles to the structure

of our Universe as a

whole…”

- Prof Carlos Frenk, ICC Director

In This Issue ICC news

Research at the ICC

Ogden@10

Cosmology Machine

A PhD at the ICC

The Ogden Centre and the Cosmology Machine

Welcome to the first ICC news! To coincide with the Royal Society’s Summer Science Exhibition in July 2013, we

are delighted to release the first ever issue of the Institute for Computational

Cosmology Newsletter. The past year has been very busy, with events ranging

from the 10th Anniversary of the Ogden Centre for Fundamental Physics to the

latest installation of the Cosmology Machine supercomputer. ICC News brings you

up to date with all the recent activity at the ICC and explains our research and

outreach.

What is the ICC? The Institute for Computational Cosmology (ICC) is a leading international centre

for research into the origin and evolution of the Universe based at Durham

University. We address some of the most fundamental questions in science: What

were the first objects in the Universe? How do galaxies form? What is the nature

of the dark matter and dark energy? Where does the large-scale structure of the

universe come from? What is the fate of the Universe?

The ICC is housed in the Ogden Centre for Fundamental Physics, named after the

benefactor businessman and Durham physics graduate Professor Sir Peter

Ogden. The Ogden Centre is also home to the Institute for Particle Physics

Phenomenology (IPPP).

Institute for Computational Cosmology Newsletter July 2013

ICC at Summer Science 2013 The Royal Society’s annual Summer Science Exhibition showcases the most

exciting cutting-edge science and technology research. The Exhibition is the

Society's main public event of the year and is open to members of the general

public as well as students and teachers, scientists, policymakers and the media.

Cosmology in Crisis: What is the Matter? The ICC, along with collaborators from the Virgo Consortium and Nick Holliman’s

Visualisation Lab, was awarded a place at Summer Science 2013 to present our

latest research into the identity of the dark matter, which is generally thought to be

a “cold”, weakly interacting elementary particle. ICC researchers, working with the

Virgo Consortium, have created computer simulations to model how dwarf

galaxies formed, testing their assumptions about the nature of the dark matter.

The team found that the final results of these simulations did not at all match what

we observe. The models showed many more small galaxies in a wide halo around

the Milky Way, whereas in reality there are fewer, larger dwarf galaxies.

So what does this mean for dark matter? One possible explanation is that Cold Dark Matter (CDM) does not exist, and the

predictions of the standard model relating to it are false.

Instead of "cold" dark matter that formed within the first one millionth of a second

after the Big Bang, the Universe may instead be filled with warm dark matter

(WDM). The WDM would have formed later, up to minutes after the Big Bang, and

is described as "warm" as the particles would be lighter and more energetic.

When simulations of galaxy formation are run with WDM instead of CDM, the halo

of dwarf galaxies has the same structure as we observe. Perhaps we need to

change our ideas about dark matter at a fundamental level.

Awards for ICC staff BIERMANN LECTURER Prof Carlos Frenk

The Biermann lectures bring world-class theoretical and computational astrophysicists to Garching.

This year's Biermann lecturer

is Prof. Carlos Frenk, who has worked closely with scientists at the Max-Planck-Institute for Astrophysics for almost two decades, trying to understand the evolution of cosmic structure.

RAS FOWLER AWARD Dr Mark Swinbank

For developing new techniques to study high redshift galaxies, for example coupling integral field spectrographs with adaptive optics and

spatial magnification from gravitational lensing to gain extra detail of these distant objects.

RAS WINTON CAPITAL AWARD Dr Baojiu Li

Baojiu Li is a world leader in the field of explanations of the accelerating expansion of the universe that are alternatives to the standard LCDM model.

A galactic halo simulated with cold dark matter (left) and warm dark matter (right)

Recreating the Universe with the Cosmology Machine

"We have a world-

leading research base in

the UK, thanks to

excellent institutions like

Durham. Today’s visit

has provided an insight

into the range of exciting

projects at the

university.”

- David Willetts, Minister of State for Universities and Science

The Rt. Hon. David Willetts (left) , Carlos Frenk (centre) and Simon Pendlebury (IBM; right)

David Willetts visits Durham The Minister of State for Universities and Science, David Willetts, visited Durham

University to see research projects made possible by government and private

investment. He also unveiled a new £3.7 million supercomputer.

The computer, which is one of the most powerful in the country, is being used to

run simulations of the Big Bang, the birth of the universe, through to the present

day. Scientists at the Institute of Computational Cosmology (ICC) hope it will

explain how the universe works.

Professor Carlos Frenk, Director of the ICC said: "Modern scientific research, from

recreating the evolution of the universe to designing life-saving drugs, relies

heavily on supercomputing - the ``new mathematics'.' The machine opened today

by the Minister of State is one of the most powerful in the UK and will be wholly

dedicated to science." (Reproduced from ITN North East News)

Euclid Mission ICC researchers joined 400 scientists and

engineers from across Europe and the USA at

the recent Euclid Consortium meeting held in

Leiden.

Euclid is a Medium-class mission of the

European Space Agency which aims to

measure the properties of dark energy.

Although Euclid is scheduled for launch in

2019, there is still a huge amount of work to do

beforehand, and Durham is helping to lead the

way!

ICC RESEARCH

The flagship of Durham Galaxy formation simulations is the EAGLE project. It builds

on two of our earlier simulations of the universe : the GIMIC simulation (carried out

at the ICC, Crain et al. 2009) and OWLS (carried out in collaboration with

astronomers at Leiden University, Schaye et al 2010). These simulations showed

that it was possible to incorporate the main processes of galaxy formation into a

computer simulations, and that it was possible to simultaneously achieve sufficient

resolution to create realistic-looking galaxies and to model a sufficiently large

cosmological volume that the results were representative of the universe as a whole.

The EAGLE (Evolution of Galaxies and their Environment) simulations push the

ideas presented in GIMIC and OWLS to the next level.

This image, measuring 50 Mpc across, shows the formation

of a cluster of galaxies in the Eagle simulation. The colours

show gas at different temperatures from cold 10 000 K (blue),

warm (100,000 K, green) to hot (>1,000,000 K) gas. The main

structure is created by the gravitational skeleton of dark

matter. Galaxies form a knots in these filaments heating the

surrounding gas and creating the fluffy appearance. The

large, hot bubbles are created by feedback from black holes

in the largest galaxies.

“The simulations make a

remarkably realistic virtual

universe. We believe that they

are unique in the accuracy

with which they describe the

universe around us…”

- Prof Richard Bower

BUILDING A UNIVERSE OF GALAXIES

REDESIGNING GRAVITY “Understanding gravity is one of the

frontiers of physics. Although

Einstein’s theory of general relativity

has been tested to high accuracy, the

tests have so far been restricted to

rather small scales, such as the solar

system. To apply this theory on

cosmological scales is a remarkable

extrapolation of what is known”

- Dr Baojiu Li

The images show the density fields (top panels) in

different modified gravity models, called f(R) gravity.

The models approach standard gravity moving from

left to right. The bottoms panels show the

Newtonian potential Φ in the same simulations. The

middle panels show the scalaron field which

governs the modification to gravity.

GALACTIC ARCHEOLOGY Simulations have been carried out to predict which satellite haloes in the

Aquarius simulations of Milky Way mass halos (shown here in purple)

will host dwarf galaxies. Some of these satellites are pulled apart by tidal

forces as they orbit inside the Milky-Way like dark haloes. This image

shows (in blue and yellow) the 'debris' of these shredded galaxies, visible

in faint clouds and huge 'ghostly' streams. Streams and clouds like these

have already been seen around the Milky Way, and our simulations

predict that many more are waiting to be discovered. The properties of

these streams are a test of the 'lost' population of satellite galaxies, which

might not be the same as those that still survive.

“The work of Durham University ranks at #22 among the 140 institutions comprising the top 1% in

the field of Space Science. Durham's current record in this field includes 1,278 papers cited a to-

tal of 48,057 times between January 1, 2000 and October 31, 2010. “

—Essential Science Indicators from Thomson Reuters

A census of where the baryons are at the present day shows that only a very small fraction is in stars, cold gas that

can be detected in absorption or emission, or hot gas in clusters that emits X-rays, meaning that most of it must be in

some yet undetected form. Hydrodynamical simulations like the one above show that indeed at the present day the

majority of baryons is in a relatively low-density warm-hot phase, called the WHIM. Such low-density ionised gas is

very difficult to detect. The image shows the results of one such numerical simulation, in which we compute how

strongly the WHIM radiates in Oxygen-VI — the colours show the intensity of the line emission. This UV-emission line

traces the filamentary structure of the large-scale matter distribution. We have investigated the surface brightness for

a large number of UV and X-ray emission lines, and also qualified how uncertainties in the modelling affect our

results. These results can be used to design future space missions that will look for the missing baryons.

GAS BETWEEN GALAXIES

LIGHTING UP THE DARK MATTER Modelling the formation and evolution of galaxies is one of the toughest

challenges in astrophysics as it requires many nonlinear processes to be

followed, such as star formation and heating by AGN, which operate over vast

ranges of length, time and mass scales. At the ICC, we pursue complementary

routes to study how galaxies are made, which can be divided into gas dynamics

simulations and semi-analytical modelling:

The ICC is one of the pioneers of the semi-analytical approach to modelling

galaxy formation. The current semi-analytical code, GALFORM, makes an ab

initio prediction of the star formation, merger and chemical enrichment histories of

galaxies. GALFORM is implemented in high-resolution, large-volume N-body

simulations of the hierarchical clustering of the dark matter, to predict the spatial

distribution of galaxies. Such calculations are used to build mock catalogues for

galaxy surveys such as Pan-STARRS and Euclid.

The images show the distribution of dark matter (top) in the Millennium Simulation

and the location of the galaxies, (bottom panel) as predicted by GALFORM.

http://www.youtube.com/watch?v=w4im7cDkRZg&feature=player_embedded

Contact Us

Postal address: Institute for Computational Cosmology, Ogden Centre for Fundamental Physics, Department of Physics, Durham University, Science Laboratories, South Road, Durham, DH1 3LE. UK.

The next generation The ICC has an outstanding track record of training young researchers,

offering access to world leading expertise and state of the art resources.

Students and postdocs work in a collaborative and supportive

environment.

Durham provides the opportunity to participate in international

collaborations. In addition to the Virgo Consortium for Cosmological

Simulations, the ICC plays leading roles in international surveys,

including Pan-STARRS, Herschel, GAMA, SCUBA-II and Euclid. We are

also the coordinating node of two Marie-Curie funded training programs,

CosmoComp and LACEGAL.

Studying for a PhD at the ICC

The postgraduate student body at the ICC is truly international (with

representatives from China, Crete, Portugal, Ireland, Chile, Mexico,

USA, Germany, Switzerland and, of course, the UK).

Around half of the places we offer are supported by STFC-funded PhD

studentships: the remainder are funded by a range of different sources

(e.g. ERC, non-UK government).

Students undertake full-time cutting edge astronomical research, in

addition to our post-graduate lecture courses in their first year.

The STFC-funded PhD studentships cover course fees and living

expenses for 3.5 years. Applicants are required to have, or expected to

gain, at least a 2.1 in an integrated MPhys or a pass in a Masters degree

or a 1st class in a Bachelors degree, in physics, astrophysics or

mathematics.

Further details and information about how to apply can be found at:

http://icc.dur.ac.uk/index.php?content=Postgraduate/Postgraduate