{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

set2-f5

# set2-f5 - we now want to know the temporal evolution of the...

This preview shows page 1. Sign up to view the full content.

Astro 405/505, fall semester 2005 Homework, 2nd set, return before Friday, September 30, 4pm. Don’t forget to give your name. Problem 3: Radiation spectra under LTE A supernova remnant has an angular diameter θ = 4 . 3 arcmin and a flux a 100 MHz of F 100 = 1 . 6 · 10 - 19 erg / cm 2 / s / Hz Assume the emission is thermal and emitted under LTE conditions. a) What would be the temperature of the radiation material, if the emission were optically thick? (This is called the brightness temperature) b) At what frequency would the remnant have its radiation maximum, if the emission were optically thick? c) Given the above, what can you say about the temperature of the radiating material? Problem 4: Time-dependent line profiles Let us as in class consider the optically thin line profile resulting from material that is expelled in a supernova explosion. In contrast to the time-independent treatment that we used in class,
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: we now want to know the temporal evolution of the line pro±le. Assume all particles have the same velocity P ( v ) = δ ( v-v ) , have been expelled isotropically at the same location and time ( t = 0 ). a) Suppose a particle emits at time t . At what time would be observe the emission? Assume the distance between observer and supernova, d , very much larger that any distance the radiating particle may reasonably propagate. Can you use an approximation to simplify the time relation, so it is linear in t ? b) Assuming the particles decay exponentially after instantaneous injection as would be±t a radioactive particle ( P ( t ) = exp(-t/t ) Θ( t ) ), calculate the time-dependent line pro±le. Explain the evolution of the derived pro±le qualitatively....
View Full Document

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern