My Scientific Research

Supernova Photometric Analysis


Let me tell you a little about my research. I analyzed data from Van Vleck Observatory's observations of Supernova 1994ae (sn1994ae). This type Ia supernova occured in the galaxy NGC3370. Type Ia supernovae are being studied for use as "standard candles" in determining extragalactic distances as well as to obtain a value for the Hubble constant. After host galaxy subtraction has taken place, one can perform photometry on the supernova images. Once photometry has been performed, one creates light and color curves to describe how the supernova fades with time and how it's color changes (reddening).


Let me show you pictorally the galaxy subtraction process. The image below is of the supernova (the bright spot left of center), its galaxy (the big bright area to the left of it), and some comparison stars (the three stars on the lower right).

Below, a surface plot of the area around the supernova shows the relative effect the galaxy is having on this particular supernova. As you can see, there isn't much effect here! To really be sure though, one needs to perform the galaxy subtraction. (The big hump in the middle is ALL the supernova)

Let's see what the subtraction process yields. Below is the galaxy without the supernova. It was taken about a year after the supernova had faded below the observatory's 24Inch Cassegrain detection threshold.

Once the two images that are going to be subtracted are matched in seeing conditions and scaled to stellar brightness (things astronomers know about that I won't trouble you with), galaxy subtraction can be performed. This next image is a supernova and galaxy frame with the background (galaxy and comparison stars) subtracted out of it. The lower right comparison star is likely a binary system, therefore it did not subtract perfectly.

Now, let's see below for another surface plot of the supernova region once the galaxy subtraction has taken place.

One can observe that some smoothing out of the far edge behind the supernova (the direction that the galaxy is in) has taken place. However, a conclusion is that the background galaxy played a very small role in the luminosity of this supernova. Below is a better view to make the comparison. The top plot is of the unsubtracted image, the bottom is of the subtracted.

More to come as I will soon condense both my undergraduate and graduate research onto this page.