set2-06 - emission regions along a line of sight. Region 1...

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Astro 346, Spring Semester 2006 Homework, 2nd set, return before Friday, February 10, 2pm. Don’t forget to give your name. Problem 1: Radiation transport (13 P) a) A gas can emit continuum emission and lines. How does the optical depth at the frequency of a line compare with the optical depth at neighboring frequencies? b) Sketch the emission spectrum of thermal gas as a function of the optical depths for lines and continuum (in the limits much smaller or much larger than unity). Always draw a Planckian for comparison. How many diFerent cases would you distinguish? c) Suppose we see two homogeneous
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Unformatted text preview: emission regions along a line of sight. Region 1 in the background has a high optical depth, τ 1 À 1 , and temperature T 1 . Region 2 is in the foreground and has the optical depth τ 2 and temperature T 2 . Repeat the exercise of part b) by varying τ 2 , now also discriminating the two cases T 2 À T 1 and T 2 ¿ T 1 . Again draw Planckians for comparison. Problem 2: Energy transport by radiation (7 P) Do problem 5.11 in the textbook. Explicitly write down the calculation and explain your arguments in a few lines of text, whenever it says argue, verify, or compute....
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This note was uploaded on 02/29/2012 for the course PHYS 227 taught by Professor Rabe during the Fall '08 term at Rutgers.

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