Skip to Navigation | Skip to Content

Astronomical Observatory: Cool Images

Astr212 Galaxy Projects, Spring 2007

Previous imageUp to Astr212 IndexNext image

Messier 95 (NGC 3351), Steve DeMaagd

Messier 90

Fig. 1: Messier 95

The beautiful image above is of the Messier 95 barred spiral galaxy. A galaxy is a gravitationally bound system containing stars and a spiral galaxy is one that has basic characteristics like a center bulge, surrounded by a disk and halo. Roughly two thirds of spiral galaxies contain bars which fuel star birth at their centers. The Messier 95 is in the constellation Leo and roughly 38 million light years away from Earth with a diameter of 12.8 kilo parsecs. It was first seen by Pierre Mechain in 1781 and cataloged by Charles Messier 4 days later. This galaxy was one of the galaxies viewed by the Hubble Space Telescope in order to determine the Hubble constant.

This galaxy has a hint of light blue color. It has a bar which is the reason that it has many hot, young stars and also many new forming stars. The intense light in the center and bar is because of the production of stars at the center and in the bar because the gas flows from the spiral bars into the center. It is an SB(r)b which means that is is a Spiral Barred with spiral arms that start from the ring and also a medium size bulge with semi-loose arms.

M95 Light Profile - Bar

Fig. 2: Light Profile graph along the Bar

This graph displays the relationship between radius and brightness. It is a line profile that passes directly through the bar of the galaxy. As you can see the closer you get to the center of the galaxy the brighter the luminosity will become. I have added a trend line that will help to characterize the surface brightness compared to radius. The scale length of this galaxy is 0.71 +/- 0.01 kilo parsecs and is smaller than most spiral galaxies. The inclination of my galaxy is 53 degrees. The inclination of a galaxy is the angle measured between the disk and the perpindicular to our line of sight and this is measured because the apparent shape of the galaxy is varied. The bar line profile shows that the Messier 95 galaxy has a weak bar because it has a exponential fit rather than a more flat fit.

M95 Light Profile - Major Axis

Fig. 3:Light Profile graph along the Major Axis

M95 Light Profile Minor Axis

Fig. 4: Light Profile graph along the Minor Axis

The two graphs shown above are additional light profiles I have made on the M95 galaxy. Figure 3 is the major axis and Figure 4 is the minor axis. The major axis plateaus between the a radius of 1 and 2 kpc. It plateaus at this distance because of the bar at the center which the major axis is partly going through. The minor axis however does not pass through the ring and that is why the curve has a more exponential shape. The scale length for the Major Axis is 0.011 kilo parsecs while the scale length for the Minor Axis is 0.016 kilo parsecs.

M95 Near Infrared

Fig. 5: Near Infrared image

Taken from NED database <>

This image was taken with the 2MASS1.3m telescope

In this near infrared picture we are able to see the F, K, M, stars. This shows there are many of these types of stars and what is most interesting is that we are able to see the bulge which indicates these types of stars. We can also see emission of material at roughly 2000 k.

M95 Ultraviolet

Fig. 6: Ultraviolet non-optical image

This image was taken with the Galex telescope

This image in the ultraviolet shows hotter stars. This shows that there are many young stars being developed in this galaxy, it is showing many more stars than in the near infrared which means there are many young and old stars in the Messier 95 galaxy.

Data Reduction

In order to get a good image of the Messier 95 galaxy I first formed a calibration group of the Bias, Darks, and Flat images. I calibrated this group and then removed bleeding of my image. Next I aligned the images using the 2 brightest stars nearest to my galaxy. I then aligned the different filters. When I used the color combine i found that the best set up for my galaxy would be 29 in blue, 4 in green, and 2 in red. This was best for my galaxy because it gives it a nice light blue color. I adjusted the gamma value to .3 for my galaxy and then cropped the image.


1. A. Garcia. "Messier 95." <>

2. Frommert, Hartmut "Barred Spiral Galaxies." <>

3. Elmgreen. Galaxies and Galactic Structure. Prentice Hall, 23, 97

4. Kronberg, Christine "Messier 95." Observations and Descriptions <>


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.


Right Ascension (J2000) 10:42:57.7
Declination (J2000) +11:42:14
Filters used blue(B), green(V), red(R), and clear(C)
Exposure time per filter 12x300 s in B, 4x180s in C, 2x300 s in R 4x300 s in V
Date observed

March 13, 2007 (C), (B), (R), and (V)






Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Nulla ut nibh.


Lorem ipsum dolor sitamet, consectetuer adipiscing elit. Nulla ut nibh.