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NGC 3953 (M109 Group)
Taylor Mulder

NGC 3953

NGC 3953 is a barred spiral galaxy located in the constellation of Ursa Major and is a member of the M109 group (Wikipedia). There have been two observed supernovae within NGC 3953. These supernovae are recorded as SN 2001dp and SN 2006bp. As indicated in the recorded names, these were observed in 2001 and 2006 respectively. If focus is directed to the right of the galaxy approximately halfway between the galaxy and the edge of the picture, another galaxy can be seen. This galaxy is PGC 2412642. Another galaxy observed in this picture is to the bottom left of the galaxy, approximately between the three stars. This galaxy is PGC 213900.

As can be seen in the picture shown above, the center of the galaxy appears to be yellow in color. This yellowing is a direct result of the age of the stars that are located there. The stars in the center of the galaxy are all older stars and emit more yellow light than younger starts which would appear blue in nature. This indicates that the center does not have a large amount of star formation occurring as few young stars are prominent. Another feature of the center of the galaxy is a bar structure. Less visible in this picture, but a closer view would reveal this bar. This is common in spiral galaxies, appearing in approximately two thirds of all spiral galaxies the Milky Way included (Wikipedia). These structures are hypothesized to be stellar nurseries (Wikipedia).

The distance to NGC 3953 is estimated to be 16.75 Mpc (Ned). We find a major axis maximum angular size of 381 arcseconds which corresponds to a linear size of 101000 ly. We find a minor axis maximum angular size of 183 arcseconds which corresponds to a linear size of 48600 ly. Using these measured distances, the inclination of the galaxy can be calculated. The equation used is Θ = arccos(Minor Axis/Major Axis). This calculation gives an inclination of 1.07 radians or 61.2 degrees.

The image seen above is the combination of many shots as well as calibration through bias, dark, flat field and cosmic ray reduction techniques. Bias, dark and flat field steps all involve taking additional photos at set conditions and then combining into master calibration images which are then applied to the final data image. The bias calibration image is needed because the sensors used to take the images are not perfect and have defects. It offsets these imperfections by taking an instantaneous picture with no light. The dark calibration image is needed because as temperature changes, the sensor can change how its images are taken. The dark set offsets these temperature fluctuations by taking dark images throughout the image taking process. The flat field calibration images are needed to correct for any dust or other obstacles that could alter the light received by the sensor. These images are taken by placing a uniformly colored object in front the the telescope. Lastly, the cosmic ray reduction is used to eliminate any small but drastic fluctuations in the image. These can occur from cosmic rays hitting the sensor with large amounts of energy.

References:

NED, "NGC 3953"

Wikipedia, "NGC 3953".

Right Ascension (J2000) 11:53:48.92
Declination (J2000) +53:19:36.38
Filters used B (Blue), C (Clear), R (Red), V (Green)
Exposure time per filter B, V, C, and R (300s x 6)
Image dimension 899x592 pixels; 19.8x13.0 arc minutes
Date/time observed March 13, 2017, 12:05 UT

 

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