ASTR 505/511: Observational Cosmology

Course instructor: Jon Willis (jwillis@uvic.ca, Elliot 109, Tel. 7704)

This is a short handout to provide details of the following topics:

1. Course outline.

2. Assessment plan.

3. Recommended reading.

4.Office hours.

1. Course Outline

i) "Classical" tests of the world model (e.g. FRW metric) via

observational programmes designed to test the redshift distance and

redshift volume relations (for example). Discussion of the reasons for

failure - small and local samples, evolution within objects considered

standard candles.

ii) The triumph of theory. The prediction and observation of the CMB and

relic baryon fractions. Discussion of the theoretical and observational

techniques involved.

iv) The history of dark matter - from Fritz Zwicky to the present day. I

will describe the initial observations that indicated a serious

discrepancy between observed light and inferred matter in the Universe. I

will follow this observationally driven field through major developments

up until the present day using observations of gravitational lenses, large

scale structure and X-ray clusters (to name a few).

v) Mathematical cosmology. The late 1960s and early 1970s witnessed a

revolution in our approach to describing the Universe. New mathematical

expressions were developed to link observations to theoretical

descriptions of the Universe. Foremost among these were the concepts of

correlation, luminosity and density field functions. Underlying them all

is the belief that the distribution of properties of extragalactic sources

retains the imprint of the initial conditions. I will describe the

execution of observational programmes to determine these functions to

greater precision with the passing years and describe their successes and

drawbacks.

vi) Observational bias and the birth of galaxy evolution. Not all

astronomers would agree with the statement that the study of galaxy

evolution arose from the realisation in the 1960s and 1970s that

galaxies were not good cosmological probes - however, it remains a

useful historical introduction to the field. The problem was that

galaxies evolved. Therefore much early effort was spent attempting to

correct for the evolution of galaxies in order to improve the

cosmological tests. The 1980s saw the birth of galaxy evolution as a

mature field and the realisation that galaxies are not linear or

unbiased tracers of mass in the Universe. I will describe examples of

the problem yet will not delve too deeply into galaxy evolution

(depends upon course timing).

vii) Precision cosmology. Much of what we knew about the Universe before

1995 (say) was based upon fairly imprecise data that fortunately pointed

us in roughly the right direction. However the last decade has seen the

advent of a number of dedicated cosmological tests based upon specific and

(hopefully) well understood extragalactic sources (in the sense that they

minimise the previously discussed observational biases). Examples of these

tests include satellite CMB observations, HST key projects, the search for

high redshift supernovae, large redshift surveys, and large surveys for

clusters of galaxies. However, the most significant breakthrough has been

the realisation that the above observations each test different

combinations of cosmological parameters that, when combined, generate

orthogonal (or nearly orthogonal) constraints. The resulting precision to

which cosmological parameters can be constrained has placed our knowledge

of the Universe on a much firmer footing.

viii) Full circle. One of the most talked about parameters in cosmology is

Lambda - Einstein's cosmological constant. What is it's effect upon the

evolving Universe? I will describe the combination of observations that

point to the existence of Lambda. I will discuss how more complex

observational tests are currently being executed to constrain the nature

of Lambda via the equation of state. I will then discuss the "concordance

cosmology" or standard model. What is it and why should you believe it?

One of the most important lessons learned from the history of science is

that, as soon as everyone starts agreeing upon a broad scientific view of

the Universe, someone else comes along and demonstrates that we have been

getting it wrong all along. Where might we be fooling ourselves?}

General points: as the course develops I will make more detailed decisions

regarding breadth versus depth. Specifically, I want to cover certain

areas of the course in more mathematical depth than others, e.g. the FRW

metric and the behaviour of the evolving Universe, the CMB and the baryon

budget, the growth of structure from the Press-Schechter formalism, the

correlation function and its calculation in practice, luminosity function

estimators and orthogonal tests of cosmological parameters.

I have left out a couple of points that may or may not make it into the

course, specifically the role of AGN and restrictions placed upon our view

of the Universe via available instrumentation.

2. Assessment plan.

i) Numerical/computational assignment on cosmology relations.

ii) Data assignment on determination of cosmological parameters.

iii) Computational project on LF determination and galaxy evolution.

iv) Essay assignment on dark matter and energy in the Universe.

v) Oral presentation of selected scientific papers.

vi) Final exam.

3. Recommended reading.

There currently exists no single textbook that provides

suitable coverage of all the material covered in the

course. Throughout the course I will provide photocopied handouts taken

from selected textbooks and important scientific papers. In addition

to this material, the following books may provide informative

additional reading:

i) Peebles: Physical Cosmology (excellent general textbook).

ii) Gunn, Longair and Rees: Observational Cosmology, 1978 Saas-Fe

conference proceedings (good description of basic cosmological

ideas, some sections are rather dated).

iii) Rees: Perspectives in Astrophysical Cosmology (though not

employed directly in the course, this book provides excellent

additional reading).

iv) Peacock: Cosmological Physics (a modern cosmology textbook

but the presentation of some of the material can render it somewhat

impenetrable).

v) Weinberg: The First Three Minutes (excellent reading

material for early Universe physics).

vi) Berry: Principles of Cosmology and Gravitation (a good

introductory text for cosmology and GR).

4. Office Hours.

Monday 2--4pm

Tuesday 3.30-5pm

Wednesday 2--4pm

Thursday 2--4pm