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Astr212 Galaxy Projects, Spring 2007

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NGC 4214, MJ Block

NGC 4214

The galaxy pictured above is NGC 4214. It is an irregular galaxy. Unlike ellipticals which have an oval or circular shape, irregular galaxies have a box-like shape. Irregular galaxies also have no spiral arms (unlike spiral galaxies). NGC 4214 is approximately 13 million light years away from us and has a diameter of about 9300 light years.

In the image above, we see lots of interstellar gas and dust surrounding a few knots of star formation. The blue in this image indicates newly-formed, high-mass stars. There are many low-mass stars in NGC 4214 as well, but it has a lot of glowing gas around these new star clusters.


UIT. Principle astronomers: Kuchinski, et. al.

This is a picture of NGC 4214 in the ultraviolet wavelength. Ultraviolet shows star formation well because new, young stars emit a lot of blue light. This is depicted by the black in the center of the image. There is a lot of star formation occurring in this galaxy in both the core and in a few knots on the outer edges of the galaxy.

NGC4214 Hubble Space TelescopeHubble Space Telescope. Principle Astronomers: MacKenty, et. all.

This is another picture of NGC 4214, but this picture is a composite of pictures in six different wavelengths. The wavelengths are Infrared, R, H alpha, V, O III, and U. The infrared and the red filters indicate the high-mass stars (the dark red and orange-red in the photograph). The H alpha emission lines indicate ionized Hydrogen gas, which in this photograph is the yellow. New stars form, ionizing the Hydrogen gas surrounding the clusters. The O III emission lines indicate oxygen gas in the galaxy, which is blue in this photograph. We see this in the very center of the galaxy where it is too hot for the Hydrogen to recombine. But these even hotter stars allow Oxygen to combine. In the center of the galaxy, hundreds of massive blue stars are being formed, each with a brightness more than 10,000 times brighter than the sun. In the U filter, we can see the high-mass stars (which in this photograph are the very blue specks).

NGC 4214 Light Profile

This is the light profile for NGC 4214. This shows us how bright the galaxy is as we move out from the center into the outer edges of the galaxy. An important thing to note about NGC 4214's light profile is that it has no bulge as normal galaxies do. If it had a bulge, the data points would increase greatly near the y-axis. As it is, the galaxy follows the same function from the center of the galaxy to the edge. The pink line in the center of the navy blue data points is the line of best fit for the data. This line can be described by the equation y = (-4.28+/.06)x + (9.20 +/-.05). The scale length found for NGC 4214 is 0.234 +/-.003 kpc along its major axis and 0.148 +/- .002 kpc along the minor axis. Since NGC 4214 is an irregular galaxy, the inclination cannot be computed from the major and minor axes. Since spiral galaxies studied by others in Astr212 have a scale length ranging from 0.6-1.8 kpc, it is obvious that NGC 4214 is a small irregular galaxy.

Tarantula Nebula
Anglo-Austrailian Observatory. Principle Astronomer: David Malin.

The picture above is of a nebula in the Large Magellanic Cloud called the Tarantula Nebula. The Tarantula Nebula is a nearby irregular galaxy that is similar to NGC 4214 and behaves similarly to the center of star formation as well. By comparing the linear diameter of the star formation region in the Tarantula Nebula to the center of star formation in NGC 4214, we can begin to grasp the size of NGC 4214. The linear diameter of the star formation of NGC 4214 is 380 Light years while the linear diameter of the star formation in the Tarantula Nebula is 720 Light years. This tells us that the Tarantula Nebula is twice as large as the central nebula in NGC 4214.

NGC 4214 is classified as a IAM(s)m galaxy. The "I" stands for an irregular galaxy. The "AB" means that NGC 4214 may have an ovally distorted bar. Essentially, this means that the galaxy does not have a clear, distinct bar, but it does not have no bar either. The "(s)" means that the spiral arms start from the center of the galaxy. The "m" in the classification means that the galaxy has very little structure (or disk), but it is more coherent than an "Ir" galaxy.

All images were taken with the Calvin-Rehoboth Robotic telescope. Data were reduced in Maxim®. Raw images were calibrated with dark, bias, and flat images. Once the images were calibrated, median combine was used to combine all of the images taken in a filter into a single image. In order to make a single color image, the color combine process was used. For these data the color numbers were red 0.5, green 1, and blue 8. The Gamma stretch process was used to eliminate background light in the images as well. The gamma value used in these data was 0.35.

References:
NASA and The Hubble Heritage Team (STScI/AURA). "Fireworks of Star Formation Light Up A Galaxy." Hubblesite. <http://hubblesite.org/newscenter/archive/releases/2000/01/image/a/l>.

This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

Frommert, Hartmut and Kronberg, Christine. "NGC 2070." Students for the Exploration and Development of Space. <http://www.seds.org/MESSIER/xtra/ngc/n2070.html>

Right Ascension (J2000) 12:15:59
Declination (J2000) 36:17:22
Filters used blue(B), green(V), red(R), and clear(C)
Exposure time per filter 300 seconds in all filters
Number of Exposures

10 in B, 4 in V, 3 in R, 7 in C

Dates observed
  • February 21, 2007 (BC)
  • February 26, 2007 (BVRC)
  • March 13, 2007 (BVRC)