Syllabus for PHYS
581-002/480 Advanced Topics: Observational Cosmology
Instructor: Dinesh
Loomba
This
class is a full 3 credit course and can serve as a
A4XX elective for undergraduates.
Meeting
times:
The class will meet on Monday and Wednesday from 9:30-11:00 in Rm 5.
Office
Hours:
M 3-4PM, T 10-11AM, or please request an appointment.
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)
Website(s):
NED IPAC Level 5:
https://ned.ipac.caltech.edu/level5/
(click
on Cosmology link)
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.
What
I will require of students:
The
final grade will consist of equal contributions from the following three
things:
a)
Homeworks 40%.
Approximately 6-8 homework sets over the semester.
b)
A midterm exam 30%
c)
Final Project 30%. A final project involving a term paper. I will require that
students to 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 noted!
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.
HOMEWORKS:
HW1: Due in class on Wednesday Sept 21st. Solution is here.
A beautiful introduction to observational tests by Allan Sandage in NED IPAC Level 5:
http://ned.ipac.caltech.edu/level5/Sept01/Sandage/frames.html
Another that is more up to date by Sanders:
http://ned.ipac.caltech.edu/level5/Sept03/Sanders/frames.html
Some news on Isotropy bounds of the universe, hot off the press:
http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.117.131302
HW2: Due in class on Wednesday Sept 28th. Solution is here.
Olbers Paradox by Ed Harrison in Physics Today:
http://scitation.aip.org/content/aip/magazine/physicstoday/article/27/2/10.1063/1.3128443
HW3: Due in class on Wednesday October 12th. Solution is here.
HW4: Due in class on Friday November 11th.