Syllabus for PHYS 480-002/581-004 Advanced Topics: Observational Cosmology

Instructor: Dinesh Loomba

 

 

This class is a full 3 credit course and can serve as a A480 elective for undergraduates.

 

Meeting times: The class will meet on T, Th from 12:30-1:45 in Rm 5.

 

Office Hours: Wednesdays 9:30 – 10:30AM in room 131.

 

Book(s): None required but below is a list of books which I will use as references for my lectures.  

- The Early Universe by Kolb and Turner

- Physical Cosmology by Peebles

- Galaxy Formation by Longair

- Modern Cosmology by Dodelson

- Theoretical Astrophysics I, II, II, a 3 volume set by Padmanabhan

- Structure Formation in the Universe by Padmanabhan

- Cosmological Physics by Peacock

- Cosmology by Steven Weinberg

- Cosmology by Ryden (an undergrad text)

 

Prequirements:

 

            Undergrads: The following courses will help

                        301 (Thermo), 366 (Math Methods), 405 (E&M), and 491 (QM)

Graduate Students: none but I'm assuming you are at or above the level of the courses listed above.

 

Cosmology is a subject that requires a wide knowledge of physics and math, so it is difficult to specify pre-requisites in terms of specific courses.  A senior undergraduate or beginning graduate student should have sufficient knowledge (or be willing to do some self study) to take this course.  

 

Preliminary outline of the course:

 

The course will be divided into roughly 5 parts:

 

I)              The Robertson-Friedman-Walker Model of the universe.  We will begin by postulating that the Universe is isotropic and homogeneous.  This will lead us to the Robertson-Walker metric which we will use to constrain both the geometry and, at low redshift, the dynamics of the Universe.  Next we will write down the solutions to Einstein's General Relativity which fully describe the dynamics of a homogeneous and isotropic Universe.  We will examine these solutions (the Friedman Equations) and consider the various allowable cosmological world models which can result.  Possible tests of which of these models is our Universe will be discussed.

II)            Big Bang Nucleosynthesis (BBN).  This is generally touted as one of the great successes of Big Bang cosmology (it is one of the 3 "pillar" on which the theory stands).  We will describe the epoch in the early universe when protons and neutrons are made into deuterium, the 2 isotopes of helium, and some lithium 7.  We will see how the abundances of these various elements depend on one parameter, the present matter density in baryons (i.e., protons, neutrons), within the assumptions of BBN.  We will compare the predicted abundances with data and find constraints on the baryon density.

III)          Cosmic Microwave Background Radiation (CMB).  This is the other "pillar" on which the Big Bang stands.  We will discuss, at various levels of detail, the physics of the CMB epoch.  The properties of the CMB (temperature, anisotropies, etc) are one of the most precisely measured quantities of the early universe.  We will discuss what constraints the measurements place BOTH on what comes later in time - structure formation - as well as what took place earlier, e.g., inflation.  We will also see that the CMB data now provide independent constraints on the baryon density and show that these are consistent with the BBN prediction.

IV)           Structure formation.  During this part we will attempt to connect the early universe constraints from the CMB, BBN, inflation, etc, with what we observe today: galaxies, clusters of galaxies, superclusters, etc. 

V)             Special Topics.  These might include: dark matter; gravitational lensing; Sunyaev-Zeldovich effect; and possibly topics of the very early universe such as bariogenesis, phase-transitions, inflation; and others.  This part provides me a buffer in case parts I-IV require more time.  This part also provides the students a chance to have input on what they'd like to hear (tell me soon!).

 

As noted above, this is a rough list of topics.  We can spend more time on a few of these if there's interest, or include others not on the list.

 

Grade:

 

The final grade will consist of the following three things:

 

a) Homeworks 40%.  Approximately 6-8 homework sets over the semester. 

 

b) A midterm exam 25%

 

c) Final Project 35%.  A final project involving a term paper. I will ask that students meet with me to discuss the topic of their term paper and to turn in a brief outline.  Depending on time and number of students enrolled in the course, I may devote several lectures to short talks given by students on their final paper topic.

 

I could be convinced of a final project in theoretical cosmology; however, I would urge you to pick something that has observational consequences (i.e., it should be a testable theory) and, if you go this route, it better be good!

 

Besides the three official contributions to your grade listed above, the following will help you but not hurt you:

 

d) During class I may suggest a problem for extra credit.

 

e) Oftentimes questions will be raised during class-time that I won't answer to everyone's satisfaction.  Students who, by whatever means, return with additional information that sheds light on the subject will be duly rewarded!

 

f) Students are strongly encouraged to ask questions, express skepticism, start discussions, and in general actively participate in the course.  If there is a single motto to follow in this course, it is that there are no "dumb" questions!  If you don't ask, you won't learn so please don't be shy.

 

 

NOTES:

 

6Feb_18 – Notes on geometry/curvature

Plots from Longair and Kolb& Turner shown in class and referenced in above notes

 

Matter Dominated – Notes for Matter Dominated universe; r(z), D, and tests using standard ruler (angular diameter), standard candles (flux-luminosity), and number counts

 

Lambda cosmologies – Notes on lambda cosmologies

 

Also, please read the following review papers on lambda cosmologies:

1)   The Cosmological Constant, Carroll, Press, Turner, Annual Reviews of Astronomy & Astrophysics. 1992. 30:499-542

2)    Scale factors R(t) and critical values of the cosmological constant in Friedmann universes, Felten, Isaacman, Review of Modern Physics. 1986. 58:689-698

 

 

HOMEWORKS:

 

HW 1, Due Feb 6 IN CLASS

Solutions HW1sol_a and HW1sol_b

 

HW 2, Due Feb 15 IN CLASS

Solutions HW2_sol

 

HW 3, Due Feb 27 IN CLASS

Solutions HW3_sol

 

MIDTERM will be a take home, handed out on March 20^th and will be due March 27^th IN CLASS – NOTHING LATE WILL BE ACCEPTED!

 

HW 4, Due Apr 17^th IN CLASS