The relationship between the formation of galaxies and large-scale structures
Lead Research Organisation:
University of Sussex
Department Name: Sch of Mathematical & Physical Sciences
Abstract
When we look up at the night sky, we see that galaxies seem to be arranged in a particular way. One might expect that galaxies would be distributed randomly, much as grains of sand would if you threw a handful across the floor, but instead, they seem to trace elegant structures; galaxy clusters are connected to each other by long filaments, interspersed with large voids, where few or no galaxies are seen. The reason why galaxies are arranged this way is deeply mysterious; we know that, when the Universe was very young, it was a very smooth, even place, so how did the Universe go from being homogeneous and smooth just after the Big Bang to the clumpy, clustered, irregularly structured Universe we see today? A second problem, concerns how bright and active we see galaxies to be. Nearby galaxies are quiet, placid things where not an awful lot happens; at most a few stars are born and a few die each year. For galaxies a long long way away, things are completely different; they are much more violent - forming hundreds, if not thousands of new stars each year - and are many hundreds of times brighter than local galaxies. Furthermore, these distant galaxies seem to be colliding with each other much more frequently than galaxies nearby us, and it is suspected that these galaxy collisions are in some way responsible for their huge star formation rates. The central puzzle remains though; why is the Universe nearby to us such a quiet, unassuming place, while the distant Universe is so violent and active? In recent years, astronomers have started to suspect that the answer to both these questions may lie in the same place, namely the mysterious and poorly understood `dark' matter. Dark matter is so called because it has the singularly disobliging tendency not to emit any light at all, at any wavelength, which makes it impossible to see with conventional telescopes. If however we look at the way stars move in galaxies, we can see that there must be an awful lot of dark matter in these galaxies (something like ten times the mass of visible matter), as we can see the dark matter pulling the stars around. We might suspect that this dark matter may have something to do with how galaxies are distributed on the sky, simply because there's so much of it. We might also expect that galaxies should trace the dark matter, with more galaxies occurring in regions of more dark matter and vice versa, because dark matter is comprised, in part, of the gas and dust from which stars are formed. So, if we want to work out why galaxies trace the structures they do, or how galaxies are formed, we must work out how galaxies trace the underlying dark matter, and how this dark matter affects galaxy formation. This is one of the most important problems in astronomy today, as it literally underpins everything we see. A series of new telescopes hold the promise of a revolution in our understanding of how galaxies, and clusters and filaments, form. The goal of the fellowship will be to combine data from these new facilities with the latest computer models and simulations, to make great strides in our understanding of galaxy and structure formation. Work using optical data will focus on how the stars in very distant galaxies are assembled. Does it happen gradually or all at once? When during the history of the Universe do most stars in galaxies form? What parts of the Universe will eventually become the densest galaxy clusters we see nearby us, and which will become large, empty voids? Work in the infrared on the other hand will focus on galaxies with huge bursts of star formation - these are thought to be the formation events of some of the biggest galaxies in the Universe. By studying how these distant infrared bright galaxies are grouped on the sky, and exactly how the star formation within them is occurring, I will relate how and when they form to the dark matter that surrounds them.
People |
ORCID iD |
Duncan Farrah (Principal Investigator / Fellow) |
Publications
Amblard A
(2011)
Submillimetre galaxies reside in dark matter haloes with masses greater than 3 × 1011 solar masses
in Nature
Austermann J
(2010)
AzTEC half square degree survey of the SHADES fields â?? I. Maps, catalogues and source counts
in Monthly Notices of the Royal Astronomical Society
Bernard-Salas J
(2009)
A SPITZER HIGH-RESOLUTION MID-INFRARED SPECTRAL ATLAS OF STARBURST GALAXIES
in The Astrophysical Journal Supplement Series
Clements D
(2009)
RESOLVED DUST EMISSION IN A QUASAR AT z = 3.65
in The Astrophysical Journal
Cooray A
(2010)
HerMES: Halo occupation number and bias properties of dusty galaxies from angular clustering measurements
in Astronomy and Astrophysics
Coppin K
(2010)
MID-INFRARED SPECTROSCOPY OF CANDIDATE ACTIVE GALACTIC NUCLEI-DOMINATED SUBMILLIMETER GALAXIES
in The Astrophysical Journal
Eales S
(2010)
First results from HerMES on the evolution of the submillimetre luminosity function
in Astronomy and Astrophysics
Elbaz D
(2010)
Herschel unveils a puzzling uniformity of distant dusty galaxies
in Astronomy and Astrophysics
Farrah D
(2009)
MID-INFRARED SPECTROSCOPY OF OPTICALLY FAINT EXTRAGALACTIC 70 µM SOURCES
in The Astrophysical Journal
Farrah D
(2009)
AN EVOLUTIONARY PARADIGM FOR DUSTY ACTIVE GALAXIES AT LOW REDSHIFT
in The Astrophysical Journal
Farrah D
(2010)
THE EXTRAORDINARY MID-INFRARED SPECTRAL PROPERTIES OF FeLoBAL QUASARS
in The Astrophysical Journal
Finoguenov A
(2010)
X-ray groups and clusters of galaxies in the Subaru-XMM Deep Field
in Monthly Notices of the Royal Astronomical Society
Fiolet N
(2009)
Multi-wavelength properties of Spitzer selected starbursts at z ~ 2
in Astronomy & Astrophysics
Fiolet N
(2010)
Mid-infrared spectroscopy of Spitzer -selected ultra-luminous starbursts at z ~ 2
in Astronomy & Astrophysics
Garn T
(2010)
Obscured star formation at z = 0.84 with HiZELS: the relationship between star formation rate and Ha or ultraviolet dust extinction
in Monthly Notices of the Royal Astronomical Society
Hatziminaoglou E
(2010)
HerMES: Far infrared properties of known AGN in the HerMES fields
in Astronomy and Astrophysics
Hernán-Caballero A
(2009)
Mid-infrared spectroscopy of infrared-luminous galaxies at z ~ 0.5-3
in Monthly Notices of the Royal Astronomical Society
Hwang H
(2010)
Evolution of dust temperature of galaxies through cosmic time as seen by Herschel? Evolution of dust temperature of galaxies
in Monthly Notices of the Royal Astronomical Society
Ivison R
(2010)
The far-infrared/radio correlation as probed by Herschel
in Astronomy and Astrophysics
Khan S
(2009)
ON THE NATURE OF THE FIRST GALAXIES SELECTED AT 350 µm
in The Astrophysical Journal
Kovács A
(2010)
FAR-INFRARED PROPERTIES OF SPITZER -SELECTED LUMINOUS STARBURSTS
in The Astrophysical Journal
Lonsdale C
(2009)
MAMBO 1.2 mm OBSERVATIONS OF LUMINOUS STARBURSTS AT z ~ 2 IN THE SWIRE FIELDS
in The Astrophysical Journal
Magdis G
(2010)
Herschel reveals a Tdust-unbiased selection of z~ 2 ultraluminous infrared galaxies Herschel observations of z ~ 2 ULIRGs
in Monthly Notices of the Royal Astronomical Society
Oliver S
(2010)
Specific star formation and the relation to stellar mass from 0 < z < 2 as seen in the far-infrared at 70 and 160 µ m
in Monthly Notices of the Royal Astronomical Society
Ono Y
(2010)
STELLAR POPULATIONS OF Lya EMITTERS AT z ~ 6-7: CONSTRAINTS ON THE ESCAPE FRACTION OF IONIZING PHOTONS FROM GALAXY BUILDING BLOCKS
in The Astrophysical Journal
Ono Y
(2010)
Stellar populations of Lya emitters at z = 3-4 based on deep large area surveys in the Subaru-SXDS/UKIDSS-UDS Field
in Monthly Notices of the Royal Astronomical Society
Ouchi M
(2009)
DISCOVERY OF A GIANT Lya EMITTER NEAR THE REIONIZATION EPOCH
in The Astrophysical Journal
Papovich C
(2010)
A SPITZER -SELECTED GALAXY CLUSTER AT z = 1.62
in The Astrophysical Journal
Roseboom I
(2009)
SPITZER IRS OBSERVATIONS OF k+a GALAXIES: A LINK BETWEEN POLYCYCLIC AROMATIC HYDROCARBON EMISSION PROPERTIES AND ACTIVE GALACTIC NUCLEUS FEEDBACK?
in The Astrophysical Journal
Roseboom I
(2010)
The Herschel Multi-Tiered Extragalactic Survey: source extraction and cross-identifications in confusion-dominated SPIRE images Multiwavelength identifications for HerMES
in Monthly Notices of the Royal Astronomical Society
Rowan-Robinson M
(2010)
Cold dust and young starbursts: spectral energy distributions of Herschel SPIRE sources from the HerMES survey? Cold dust and young starbursts
in Monthly Notices of the Royal Astronomical Society
Serjeant S
(2010)
The AGN fraction of submm-selected galaxies and contributions to the submm/mm-wave extragalactic background light
in Astronomy and Astrophysics
Spoon H
(2009)
HIGH-VELOCITY NEON LINE EMISSION FROM THE ULIRG IRAS F00183-7111: REVEALING THE OPTICALLY OBSCURED BASE OF A NUCLEAR OUTFLOW
in The Astrophysical Journal
Tran K
(2010)
REVERSAL OF FORTUNE: CONFIRMATION OF AN INCREASING STAR FORMATION-DENSITY RELATION IN A CLUSTER AT z = 1.62
in The Astrophysical Journal
Trichas M
(2010)
Spectroscopic identifications of SWIRE sources in ELAIS-N1 ELAIS-N1 optical spectroscopy
in Monthly Notices of the Royal Astronomical Society
Vaccari M
(2010)
The HerMES SPIRE submillimeter local luminosity function
in Astronomy and Astrophysics
Wang L
(2011)
Principal component analysis of the Spitzer IRS spectra of ultraluminous infrared galaxies PCA of the Spitzer IRS spectra of ULIRGs
in Monthly Notices of the Royal Astronomical Society