Syllabus
Scope and Spirit of the Course
ASTRO-497 is a lecture course on astrophysical radiation processes for advanced astronomy undergraduates. Upon successful completion of this course, the students will:
have a firm grasp of the basic physics underlying astrophysical radiation processes, including the relevant aspects of special relativity, atomic physics, and statistical mechanics,
be able to calculate the radiative power emitted by a variety of astrophysical plasmas and describe the properties of the emerging spectra,
be able to infer many of the properties of the source based on the properties of the emitted radiation and estimate the cooling rate and cooling time of the plasma.
The topics will be covered at a fairly advanced level and substantial background will be needed. The course will emphasize analytic calculations of the radiative processes at work in astrophysical nebulae and hot plasmas. Homework assignments will be an integral part of the course and an important means by which the students will learn the basic principles of radiation processes and how to apply these principles to astrophysical nebulae and plasmas.
Textbooks and Summary of Topics Covered in This Course
There is no required textbook for this course. The material is drawn primarily but not exclusively from the textbooks below; but keep in mind that the course content is defined by what is presented in class, not by the textbooks. These books have been placed on reserve in the Physical and Mathematical Sciences Library (PAMS library, 201 Davey Lab).
Spitzer: “Physical Processes in the Interstellar Medium,” by Lyman Spitzer Jr. (1978, reprinted in 2004 by Wiley, paperback). Call Number: QB790.S67 1998.
O&F (2nd Edn) or Osterbrock (1st Edn): “Astrophysics of Gaseous Nebulae and Active Galactic Nuclei,” by D. E. Osterbrock & G. J. Ferland (2nd Edition, 2006, or 1st Edition 1989 by Osterbrock only without Ferland), University Science Books, Call Number: QB855.55.O88 2006.
R&L: “Radiative Processes in Astrophysics,” by G. Rybicki & A. P. Lightman (1979, Wiley) Call Number: QB461.R88 2004.
GG: “Radiative Processes in High-Energy Astrophysics,” by G. Ghisellini (2013, Springer). Call Number: QB461.R88 2004. This book is also available electronically. You will be asked to log in with your PSU credentials to access it.
The following are useful but more advanced textbooks. We will refer to them selectively.
Shu: “The Physics of Astrophysics, Vol 1: Radiation” by F. Shu (1991, University Science Books). Call Number: QB461.S58 1991 v.1.
Padmanabhan: “Theoretical Astrophysics, Vol 1: Astrophysical Processes” by T. Padmanabhan (2000, Cambridge University Press). Call Number: QB461.P33 2000 v.1. This book is also available electronically. You will be asked to log in with your PSU credentials to access it.
The first quarter of the course covers much of the background that is necessary in order to develop the theory of radiation processes. That includes basic physics, such as special relativity, and statistical mechanics. Included is also an introduction to the radiative transfer equation and the consequence of thermodynamic equilibrium in astrophysical plasmas. The second quarter of the course covers continuum radiation processes, most of which are applicable to very hot astrophysical plasmas and some additional. The second half of the course covers line emission and absorption from collisionally excited or photoionized plasmas and includes some additional background on atomic physics and statistical mechanics. A detailed list of topics is given in a separate page of this web site (see navigation bar). The relevant sections of the above textbooks where those topics are discussed are also given. Appendix A should be regarded as a wish list because some topics will be covered in more depth than others and topics near the end of this list will only be covered to the extent that time permits.
Expected Background
Since PHYS-237 is a pre-requisite course, students should be very familiar with the following topics (a) elementary quantum mechanics, specifically the discrete energy levels of atoms, (b) elementary statistical mechanics of Fermions and Bosons, (c) the basic properties of the Planck function and blackbody radiation, (d) basic particle kinematics and mechanics in special relativity. Students should also be able to solve simple differential equations and be familiar with the solutions of the well-known differential equations of mathematical physics (e.g., the wave equation and the Schroedinger equation).
Class Web Site and Canvas Page
On this web site you will find the material that is in the printed syllabus (see this page, the homework page, and the policies page) plus a calendar of important events for this semester and any additional materials that may be needed for some of the assignments. The calendar will be updated regularly to indicate the due dates of assignments and other relevant events.
Canvas will be used as a way of communicating and distributing documents and other materials. The Canvas site for this course includes a copy of the syllabus and the course packet as well as links to the external web site above. Additional notes, slides, homework solutions, etc., will be posted on Canvas. Canvas is also the means by which homework assignments are to be submitted by the students.
Course Materials
The following materials are distributed in print at the beginning of the semester. Copies in PDF format can be found on the Canvas web site for the course. There may be additions to these materials over the course of the semester.
Syllabus: The printed syllabus contains the information included in this web site.
Course Packet: This packet contains materials that supplement the lectures. You should bring it with you to tests so that you can consult it. It may be supplemented by additional pages distributed later in the semester. It consists of the following parts.
Data and Formulae.– Physical and astronomical constants and mathematical and physical formulae that are relevant to this course (the units are appropriate for the conventions adopted in this course). If you need any of these constants, you should use the values given in the course packet not look them up somewhere else. The collection of formulae is very extensive and spans all the topics covered in this course.
Tutorials, Note Sets, and Reference Material.– Several detailed note sets to supplement topics covered in class (e.g., detailed derivations), data on atomic processes, etc.
Illustrations.– Figures used in class to supplement the lecture material. Some of these figures encode a great deal of essential information. It is important to learn how to read these figures and extract the relevant information from them.
Problem Set Packet: Exercises that will be assigned during the semester. Some of the exercises will be turned in for credit and others will be used for practice. This set may be supplemented by other problems distributed later.
Assessed Work and Basis for Grades
The assessed work for this course consists of regularly assigned homework and three tests (there is no final exam). The final grade is based on a weighted combination of scores from the above (25% for each test, 25% for all homeworks combined). The final, letter grades will be assigned after considering the complete record of performance of each student and they will follow these rules:
A final, average score of... is guaranteed a grade of...
50% or higher D or better
60% or higher C or better
90% or higher A– or better
The dates of the tests are:
Test 1: Thursday, February 9, 2023
Test 2: Thursday, March 16, 2023 (week after spring break)
Test 3: Thursday, April 20, 2023 (penultimate week of classes)
If the university is closed because bad weather (or any other reason) on the day of a scheduled test, the test will be given during the immediately following class period, unless other istructions are issued.
The tests will be given in the regular classroom (unless announced otherwise) during regular class time. Each test will examine the material covered in class since the previous test as well as essential background and relevant material from earlier in the course.
The printed course packet, without the homework problems and their solutions, is allowed in the tests. You are also allowed to add your own annotations and explanations on the pages of the course packet. However, additional notes that you take during class, books or copies of pages from books, homework problems or earlier tests, and their solutions are not allowed. Calculators are allowed, but other electronic devices, such as phones, tablets, or laptops are not allowed (even if you intend to use them only as calculators).
As a rule, no makeup tests will be given. Exceptions may be granted if a student missed the regularly scheduled test because of a serious medical or family emergency or because of university business. It will be up to the instructor to approve the request for a makeup test. Students requesting a makeup test are expected to be cooperative and forthcoming with information and evidence to support their request (for example, a letter from the university or from a doctor). If a makeup test is approved, its content will likely be different from that of the regular test. The date and time of the makeup test will be set by the instructor after consultation with the student(s). Make-up tests will be given after the regular test, not before, and must be completed before the time of the next regularly scheduled test or the end of the semester in the case of the last test).
Homeworks will be assigned every week or every other week and their due date and time will be announced at that time. Typically, the due date will be one week after the assignment is issued. By the deadline, students are expected to upload their homework answers on Canvas. The answers for each homework should be submitted as a single, self-contained PDF file; they can be written by hand and then scanned or photographed (e.g., using Microsoft Lens or Adobe Scan), or they can be written on a tablet and exported to PDF, or they can be typed (or they can be produced by some other method that creates a PDF file). A PDF resolution of 200–300 dpi (dots per inch) is prefered because it results in readable text and files that are not too big to be unwieldy. At any rate, it is the responsibility of the students to make sure that the files they upload are readable and can be manipulated by Canvas without problems.
The official solutions will be distributed through Canvas right after the deadline. This policy implies that there can be no extensions to the homework deadline (nor can homeworks be made up).
Detailed instructions and advice on how to solve homework problems and how to present the solutions are given in Appendix B of this syllabus. The importance of homeworks should not be underestimated, since they serve as essential practice for the type of problems that will appear on the test. In other words the homeworks are an extension of instruction; they will contain examples that are useful for understanding the material and they will also cover some topics that follow naturally from the lectures but are not covered explicitly or in great detail in the lectures themselves.
The Cardinal Rule
All students are responsible for knowing and following all the rules and regulations for this course as set forth in the syllabus. Not knowing the rules is not an excuse for not following them. In case of any ambiguity, the instructor is the final arbiter. Students are also responsible for knowing what is announced in class.