# Reading my first Astrophys paper

• ZachWeiner

#### ZachWeiner

I'm getting a little stuck on terminology, but most of it can be looked up in wikipedia. However, there's one term I'm having trouble with.

The paper is for a model of micrometeorites entering the atmosphere. It says:

"Entry velocities ranged between 11.2 and 72 km/sec following a v^-5,394 velocity distribution,"

What is a "a v^-5,394 velocity distribution" ?

That just means that the distribution of micrometeorite velocities between 11.2 and 72 km/s looks like the plot of v^{-5394}.

i.e. - it falls off really steeply as velocity increases.

Okay, that makes sense. Any idea how I could convince MatLab to make such a matrix for me :)

Ah, what they're describing in the paper isn't a matrix, it's best viewed as a probability density function.

If you wanted to display it as a probability distribution, you would just plot v^{-5394}, but would need to multiply it by a normalization constant. That constant (using latex formating) will be 1 / (\int_11.2^72 v^{-5394}). That is to say, 1 over the integral of v^{-5394} from 11.2 km/s to 72 km/s.

Do you need a matrix for some other reason?