Galactic Luminosity Profile Fitting Using SDSS Data

Posted on: 2014-04-09 00:31:34 by dankatz

For many purposes it is useful to have a functional form which describes the distribution of light observed from a distant galaxy. Traditionally the Sersic profile
$latex I(x) \propto e^{-x^{1/n}}$
where $latex I(x)$ stands for the luminosity, in arbitrary units, of the galaxy at a distance $latex x$ from its center and $latex n$ is a free parameter which must be fit to each galaxy. The quantity $latex x=r/r_0$ is used because it incorporates in a natural way the characteristic length scale of the galaxy, also known as its half-light radius, $latex r_0$. The half-light radius is defined as the radius of the circle which contains half...

Lesson 3: Sound

Posted on: 2014-02-07 22:23:11 by jennyau

This past week, I've been able to introduce the concept of sound to students in Mr. Vera's Geometry class. We started the class off with a DO NOW where they graphed five data points and labeled their graph on the x-axis and y-axis. Most of the students were out of practice, so this was a good refresher. This DO NOW exercise was important because during my lesson, the students had to take live data and plot on a graph and analyze it.
After the DO NOW, I asked the class what they know about sound. Then I asked them how does sound travel. The power point had a good visual moving figure of air particles moving from an oscillating drum. I ex...