THESIS IDENTIFICATION.

You should have initiated the search for an advisor and a thesis topic 
as soon as possible after passing the Qualifying Exam at the beginning 
of the Second year.  

It is a basic rule of our graduate program that a student entering 
the Third year must have identified an advisor who is willing to 
supervise her/him through the candidacy and presumably then the thesis. 
Students who are unable to satisfy this requirement can not continue 
in our program. 

PHD CANDIDACY.

All students are expected to appear for their Candidacy Exam in Winter 
or Spring quarter of the Third year, and must do so by the end of 
Summer quarter without petitioning for re-enrollment. The student, working in 
consultation with a faculty advisor, proposes a specific area of research 
to be undertaken as his/her PhD thesis program. The student is 
expected to be adequately versed in the chosen area of research and to 
have undertaken sufficient research to assess that the proposed research 
is viable and can be finished within 2-3 years.

Experience has shown that a minimum of six months of prepatory work and 
research is necessary to define a thesis project. Accordingly, we strongly 
recommend that students start focussing on thesis development research 
by Spring quarter of the Second year, maturing the effort over 
the Summer quarter and into the Third year.

The committee for the candidacy exam is appointed by the Astronomy 
Option Rep, with strong guidance from the student and the advisor. 
In other words, you choose and I approve, subject to your choices
meeting the distribution requirements.
For further guidance on the candidacy committee composition 
and the exam content and procedures, please see
http://www.astro.caltech.edu/~lah/option/cand.html  

Enrolling in a Fourth year without being admitted to candidacy requires 
a petition to the Caltech Graduate Studies Office for extended registration 
in the PhD program.  See https://gradoffice.caltech.edu/forms-petitions

COURSE WORK.

All students beyond the Second year are required to take Ay 141abc,
in addition to the course credit for research that is received via Ay 142. 
You need a minimum of 36 units to be registered as a student at Caltech.