ASTR 605
Interstellar Medium
New Mexico State University
MW 2:30-3:55
Biology Annex 102 (BX 102)
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INSTRUCTOR INFORMATION
Professor
Dr. Chris Churchill
Office hours: T & Th 12:30-1:30
Office: Rm 206 ASTR (Bldg 55)
Phone: 646-1913
Email: "cwc"
COURSE MOTIVATION
The ISM plays a crucial role in astrophysics because of its
intermediate role between stellar and galactic scales. The ISM is
also responsible for extinction and reddening, the decreasing light
intensity and shift in the dominant observable wavelengths of light
from a star or galaxy.The ISM is usually far from thermodynamic
equilibrium. Collisions establish a Maxwell-Boltzmann distribution of
velocities, and the 'temperature' normally used to describe
interstellar gas is the 'kinetic temperature', which describes the
temperature the particles would have for a Maxwell-Boltzmann velocity
distribution in thermodynamic equilibrium.
The ISM can be characterized by the following
Components:
(1) Molecular clouds,
(2) Cold Neutral Medium (CNM),
(3) Warm Neutral Medium (WNM),
(4) Warm Ionized Medium (WIM),
(5) H II regions,
(6) Coronal gas,
and (7) Hot Ionized Medium (HIM).
The gas is heated and cooled. Heating mechanisms include:
(1) low-energy cosmic rays,
(2) Photoelectric heating in grains,
(3) Photoionization,
(4) X-ray heating,
(5) Chemical heating,
and (6) Grain-gas heating.
Cooling mechanisms include:
(1) Fine structure cooling, and (2) Cooling by permitted lines.
In this course we will study these components and mechanisms. As
astronomers, we collect photons (we are passive observers). To
understand stars and galaxies we need to know how the ISM works
physically, how photons are generated and absorbed, and how our
vantage point as observers is convolved with these processes such that
they result in the distribution of photons we observe. Most all
physics of the ISM is learned via spectroscopy. However, we need to
know how these processes also affect images.
COURSE SPECIFICS
CREDIT/GRADING
Attendance of the lectures is mandatory. In summary, the
following will be counted for credit. Two required
mid-term exams (15% each). Weekly homework assignments (50%). A
cumulative final exam (20%). See the below chart:
-
Midterm exam 1 = 15%
-
Midterm exam 2 = 15%
-
Homework = 50%
-
Cumulative final exam = 20%
LECTURES
The lectures are designed to parallel the reading material and to
expand on the reading material. They will be very helpful for being
prepared to do the homework assignments. Discussions will be an
important part of the lectures. You are encouraged to ask questions
during the lectures!
READING
There will be weekly assigned
reading. Some of the reading will be from books (see below), and some
will be from my notes or notes "borrowed" from others (especially Rene
Walterbos). Reading will be necessary for you to be able to do well
on the exams and complete the homework assignments. Often the reading
material will be handed out to you; but if not, the books will be made
available in the ASTRO building library (only 1 copy of each). You
are encourage to purchase some of the books for yourself, since they
will be useful throughout your research and teaching career.
Books:
-
Interpreting Astronomical Spectra, by David Emerson (1997, Wiley & Sons) You can pick up a copy at amazon.com for ~$100.
-
The Interstellar Medium, by James Lequeux (2005, Springer). You can pick up a copy at amazon.com
for ~$85-95.
-
Physics of the Galaxy and Interstellar Matter, by H. Scheffler & H. Elsasser (1988, Springer-Verlag). You can pick up a copy at amazon.com for ~$19-55.
-
The Physics of the Interstellar Medium, by J.E. Dyson & D.A. Williams (1980, IOP). You can pick up a copy at amazon.com for ~$55-60.
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Astrophysics Of Gaseous Nebulae And Active Galactic Nuclei, by D..E. Osterbrock & G.J. Ferland (2005, University Science Books). You can pick up a copy at amazon.com for ~$70-80.
EXAMS
There will be two midterm exams covering the material discussed in
class, homework assignments, and reading. There is also a required cumulative
final exam. You must take all exams to pass the class.
MAKE-UP EXAM POLICIES: No make-up exams will be given except in cases
of: (1) a medical emergency documented by an official physician's
note; (2) official University business documented by an official from
the University; or (3) death in your family with official
documentation. The format of the makeup exam will be
at the discretion of the instructor. YOU MUST CONTACT ME BY EMAIL OR
PHONE MESSAGE NO LATER THAN THE DAY OF THE EXAM FOR THESE POLICY TO
HOLD.
HOMEWORK ASSIGNMENTS
There will be weekly or sometimes bi-weekly homework assignments.
HOME WORK FORMAT POLICIES: All homework is to be
handed in on 8.5x11 in paper with no tears or perforations on the
edges (not torn from notebooks). Write only on ONE SIDE of the paper.
Your full name, the assignment
number, and the assignment due date are to be printed on the
upper right hand corner. Work is "final", that is, no scratch work
and/or scratched out work, and the problems are to be presented in
numerical order. Multiple papers are to
be stapled together in the upper left hand corner.
HOMEWORK COLLABORATION (AVOIDING PLAGIARISM): You may collaborate
with other classmates for studying the questions and developing
understanding for the solutions to the homework questions.
But, it is an absolute rule that to receive credit for the homework,
you individually must write the answer in your own words on your
own. This is a clear policy and will not be compromised.
Individuals who are judged to be copying (or being copied from!),
either fully or partially will be contacted directly- the situation
will be discussed and documented with signatures. For the first
infraction, the student(s) will receive no credit. For all subsequent
infractions, the student(s) will receive no credit and the offense may
result in disciplinary action. Don't copy others' work; don't let
others copy your work. [We have had some problems in the past.]
HOME WORK LATE POLICY: Homework should be handed in at the beginning
of class on the due date. Unless you have made mutually agreed upon
(confirmed) PRIOR arrangements (at least 48 hours in advance- not the
day of class), homework is late if not handed in by the end of class
on the due date. Homework can be handed in only in one installment
(no partial sets). If there is no prior communication about handing
in the homework past the due date, the unexcused late homework will be
docked 10% per day to maximum of 50%.
OFFICE HOURS
You are encouraged to come to the
professor's scheduled office hours for help with the course
material. However, the professor has open door policy.
COMMUNICATION AND DAMAGE CONTROL
Direct and honest communication with your professor will always
serve your interest best. If you have personal issues that affect
your performance and/or attendance, the responsible thing is to
communicate these as soon as possible. Informing the professor ahead
of time that you will be missing class is effective communication.
ADVICE FOR DAMAGE CONTROL. It is strongly advised that you to KEEP ALL
WORK WITH GRADES MARKED ON THEM for backup proof in the case of
mistakes in record keeping. Besides, they will help for studying for
the exams.
COURSE HOMEPAGE
A home page will be continually
updated for this course, and its address is the following:
http://astronomy.nmsu.edu/cwc/Teaching/ASTR605/.
ACADEMIC INTEGRITY
All New Mexico State University policies regarding ethics and
honorable behavior apply to this course (and they are taken very
seriously). For details, please see the NMSU Student Code of Conduct
at
http://www.nmsu.edu/~vpsa/SCOC/misconduct.html. Plagiarism will
not be tolerated. PLAGIARISM includes, but is not necessarily limited
to, "submitting examinations, themes, reports, drawings, laboratory
notes, undocumented quotations, computer-processed materials, or other
material as one's own work when such work has been prepared by another
person or copied from another person." Both intentional and
unintentional plagiarism is considered academic misconduct. The NMSU
Student Code of
Conduct will be applied as policy in this course.