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Messier 49

John-Marc Eshelman

Eshelman-M49-RGB

Introduction:

Messier 49 (NGC 4472) is an E4 type elliptical galaxy in the Virgo cluster. It was first discovered by Charles Messier on February 19, 1771. The galaxy is 52.8 million light years away. M49 is the brightest member of the Virgo cluster, and while it will not be able to be seen by the naked eye, it should be able to be seen with binoculars as a small bright spot. The galaxy was the first member of the Virgo cluster to be discovered. It's a massive galaxy with the bright core being between 14.5 and 17.3 thousand Ly across. The full extent of the galaxy is about 800,000 Ly across, eight times the width of our Milky Way galaxy.

A calculation was done for the size of the bright center of the galaxy, it was found how many pixels across the center was and then this value was changed first to arcsec and finally to Light-years. The center was found to be 17.3 kLy in width.
The image above is very yellow because the stars in this galaxy are quite old. Elliptical galaxies seem to have very few young stars and star forming nebulae. The light we see is due to the stars and dust that make up the galaxy. Image was created using a combination of blue, clear, red, and visible light filters. When these were stacked and aligned a false color was added to the image to mirror what would be seen with your eye.


Image Processing:

Graph of log(intensity) vs 0.25R

Above is a Graph of log(intensity) vs R^(1/4). This graph is based off of the de Vaucouleaurs profile, a function that generally describes elliptical galaxies. The fit slope is theoretically 1 and this fit slope is 1.047, very close to what it should be.

Below is an X-ray image of M49 from NASA's Chandra X-ray Observatory. The image shows clouds of hot gas around the center of the galaxy. This much hot gas would usually signify the formation of new stars yet that is not what we see. Astronomers hope to use images like this to explain why elliptical galaxies, like this one, contain so few young stars. This image is interesting to overlay on the visual light image of the galaxy. Because of the galaxy's dust cloud we cannot see the center with visual light. X-ray light, on the other hand, allows us to peek in a little more and see what's happening on the inside of the galaxy.

Eshelman-M49-RGB

References:

"Elliptical Galaxies: Chandra Helps Explain "Red and Dead Galaxies"." Chandra X-rayObservatory. NASA, 2014. Web. 13 May 2015. <http://chandra.harvard.edu/photo/2014/coldgas/>.

Messier Seds. N.p., 27 June 1999. Google. Web. 13 May 2015. <http://messier.seds.org/more/m049_more.html>.

 

Right Ascension (J2000) 12:30:05
Declination (J2000) +07:58:09
Filters used B (Blue), C (Clear), R (Red), V (Green)
Exposure time per filter B (300s x 16), C (60s x 3, R (240s x 3), and )V (300s x 5)
Image dimension 305x295 pixels; 6.0x5.8 arcminutes
Date/time observed March 21, 2015, 07:44 UT

 

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