SN2003CG
Got an e-mail 3/24/03 from AAVSO HQ regarding this super-nova which had just been discovered in the core area of the galaxy NGC-3169. That evening was just about as perfect as it ever gets here in Rockville, so, I added it to my list of other things to image.
Two things:
1) It is amazing to me that anyone was ever able to actually detect this one since it occurred close to the core of the galaxy (the brightest part). You can't really even see it in the main image. Maybe as a little bulge, but really folks.
2) It must be early in the life of the object.
This image contains 4 sub images.
1) The main large image showing the environment around the super-nova
2) a really processed down insert showing the bulge a bit better
3) A star map of the area showing the location of the SN against NGC 3169
4) a 3-d light curve plot of the core of the galaxy. The large spike is the galaxy core, while the small spike to the right is the SN.
I processed the plot using a reticle shown by the purple circle on the large image. This stuff is very new and late breaking. The image was taken around 1030pm, and the image processing took place on the morning of the 25th. I imaged using the V filter of the Johnsons Cousins set.
I have extracted measurements of the supernova by subtracting the light from the galaxy in the immediate region of the SN, and compared the delta to that produced by comparison stars on the CCD frame with the SN, and have estimated the brightness in V, where V is the V band of the Johnson-Cousins standard filter. This is the standard filter bandpass of this standard set that most closely approximates human visual response. Note that most CCD cameras respond more heavily to light in the red and near IR regions, while human vision responds most strongly to light from the yellow-green region. The measurements can be found in the descriptions for each of the plots below.
Steve
I was able to measure the SN against the background of the galaxy and compare that delta against a 14.4V magnitude star adn a 15.5V magnitude star. I estimate the magnitude of the supernova in V band light at 15.3V.
The plot that follows was taken from an image taken at 10:20pm on 3/25/03. Note the relative increase in the size of the supernova indicated on the plot. The change represents a tremendous increase in luminocity. In both images, the amount of energy represented for this single star is a significant percentage of the amount of energy output by the billions of suns that make up the luminous mass of this galaxy. The 3/25/03 image begins to more clearly show the luminous bulge of the SN. The scale appears to be different between the two images, but the key to the plots is the relative height of the two spikes in each plot. Note: The image was taken using the V filter.
I was able to measure the SN against the background of the galaxy and compare that delta against a 14.4V magnitude star adn a 15.5V magnitude star. I estimate the magnitude of the supernova in V band light at 15.1V.
The plot that follows appears to show a definite dimming in the light from the SN relative to the light output of the galaxy. The third plot was taken from an image taken on 3/27/03 at about 10:30pm. Again, the image was taken using the V filter. I was able to measure the SN against the background of the galaxy and compare that delta against a 14.4V magnitude star adn a 15.5V magnitude star. I estimate the magnitude of the supernova in V band light at 15.3V.
The plot that follows was taken on 3/31/03 about 10:30pm and shows an increased luminocity over the image taken on 3/27/03. I was able to measure the SN against the background of the galaxy and compare that delta against a 14.4V magnitude star adn a 14.9V magnitude star. I estimate the magnitude of the supernova in V band light at 14.6V.
And finally the last image below taken on 4/14.2003 shows the galaxy almost back to normal. I extracted a measurement of this bump by subtracting the light from the galaxy in the region of the SN, and compared the delta to that produced by a magnitude 14.9V and a magnitude 15.5V star on the CCD frame with the SN, and estimate the brightness at 15.1V.
The data collected from the above observations have been summarized in the chart shown below. Remember that the larger the magnitude, the dimmer the object. As the supernova unfolded, it apparently brightened, then dimmed a bit then brightened substantially as indicated by the data point taken at 4/1. Unfortunately due to weather, we don't know what happened after 4/1 up to 4/13, except to say that at 4/13, the SN was observed to be dimmer than 15th magnitude(V).
