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Messier 102 (NGC 5866)
Theron Tjapkes

NGC 5866

In the Draco constellation lies NGC 5866 often referred to as the Spindle Galaxy (not to be confused with NGC 3115 which often goes by the same name). The galaxy is widely considered to be Messier 102 but it isn’t entirely certain. Other galaxies such as the Pinwheel Galaxy(M101) match the description recorded by Charles Messier in his catalog. NGC 5866 is similar in mass to our own Milky Way Galaxy, however it takes about 30 percent less time for light to travel the width of the galaxy. NGC 5866 is classified as a S0 or lenticular galaxy which is a cross between an elliptical galaxy(no spiral structure) and spiral galaxy(disk shaped). Lenticular galaxies often have a large amount of dust in their disks, which is one of the most defining features of NGC 5866. The galaxy was likely first discovered by Pierre Méchain in 1781, Charles Messier added it to his catalog shortly after.

NGC 5866 appears yellow with a stronger yellow color in the center of the galaxy indicating an older stellar population. As you look further from the center you can see the color turn to white meaning an increase in blue light which indicates that there is a greater amount of young stars the further from the center of the galaxy. NGC 5866 is categorized as a lenticular galaxy which tend to have little to no new star formation. Observing the image we can see that this is the case as the color would be a more blue color if this were the case. The distance to NGC 5866 is approximately 12.250 mega parsecs or about 40 million light years. With the small angle formula and the distance to the galaxy, we can calculate the width of the galaxy which comes to 59627 light years.

A surface brightness profile shows how the brightness of the galaxy decreases as the distance from the center of the galaxy increases. This is done by taking the brightness values across the galaxies' width:

I plotted the brightness values using de Vaucouleurs Law, an equation used to describe the brightness. To linearize the equation I took the log of both sides which resulted in this result:

From the results it can be observed that as the distance from the center of the galaxy increases the brightness decreases in a linear fashion. There is a spike in brightness towards the end of the data but this is due to a star situated at the edge of the galaxy.

To get the final image, each filter(Clear, Red, Green, and Blue) had to be calibrated, to do this I created a master flat, bias and dark frame. Starting with the flat image, I calibrated each of the filters, followed by the bias and dark frames. This removes imperfections in the final image caused by dead pixels, wear on the sensor, cosmic rays, etc. Now that each of the four filters were calibrated, the next step is to combine them into a color image. In order to create an accurate color image, each filter needs to be adjusted correctly otherwise the final image may come out favoring a particular color. The final image above was produced using the following color settings:

Input/Output Red Green Blue
Red 1 0 0
Green 0 1.5 0
Blue 0 0 6

References:

Frommert, Hartmut. "Messier 102." seds.org , SEDS, 4 Apr. 2006, messier.seds.org/m/m102d.html. Accessed 28 Apr. 2017.

Nemiroff, Robert, and Jerry Bonnell. "Edge-On Galaxy NGC 5866." Astronomy Picture of the Day, NASA, 12 June 2006, https://apod.nasa.gov/apod/ap060612.html. Accessed 28 Apr. 2017.

Fromert, Hartmut, and Christine Kronberg. "Messier 102." seds.org, SEDS, 7 May 2013, messier.seds.org/m/m102.html. Accessed 28 Apr. 2017.

Right Ascension (J2000) 15:06:29
Declination (J2000) +55:45:48
Filters used B (Blue), C (Clear), R (Red), V (Green)
Exposure time per filter C, B (300s x 8); V, R(300s x 4)
Image dimension 800x600 pixels; 17.6x13.2 arcminutes
Date/time observed March 13, 2017, 7:03 UT

 

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