Analyzing Light: Starburst Galaxy M82

Spectra and images
Full Story

Starburst Galaxy M82 Interactive

Rising brightness vs. wavelength graph with peaks and dips
Rising brightness vs. wavelength graph with small peaks
Flat brightness vs. wavelength graph showing 5 sharp peaks
Rising brightness vs. wavelength graph with peaks & wide dip
Falling brightness vs. wavelength graph with sharp peaks
Loading images...

The spectrum of light emitted by galaxy M82 reveals a variety of materials with different temperatures.

The X-ray spectrum shows hot gas with atoms whose electrons have been stripped off by powerful supernova explosions.

The visible spectrum shows elements in warm gas heated by young stars and thrown out from the central starburst region.

The mid-infrared spectrum shows that the warm dust carried away from the central region is rich with hydrocarbons and silicates.

The far-infrared spectrum shows nitrogen and carbon monoxide in the cold gas and dust throughout the galaxy.


A Story Of Analyzing Light: Starburst Galaxy M82

We can analyze light from galaxy M82 to understand what it is made of and how it formed.

Almost everything we know about M82, a spiral galaxy roughly 12 million light-years away, comes from studying the different forms of light—including infrared, visible, and X-ray light—that it gives off. By analyzing this light, we can map the structure of the galaxy and its surrounding environment, determine what different parts of the galaxy are made of, and estimate how hot various materials are. There are two main ways to study the light from celestial objects like M82: images and spectra.

Images of M82 are like photographs. They allow us to see what the galaxy looks like in different wavelengths: how bright it is in different types of light; how the brightness varies over space; and how different parts of the galaxy relate to each other.

The spectra of M82 give us other details. Spectra show us small differences in the brightness of very specific colors (wavelengths) that human eyes cannot discern on their own. These differences in brightness give us information about the galaxy that the image does not show. The pattern of peaks and valleys provides evidence for specific elements and compounds in their particular environments: Different atoms, molecules, and ions shine in very specific wavelengths, and some materials block certain wavelengths of light. The spectrum can also give us clues about temperature and the events—like galaxy collisions and supernova explosions—that formed different materials and structures in the galaxy.

Quick Facts: Starburst Galaxy M82

Also known as: Messier 82, The Cigar Galaxy, NGC 3034

Type of object: Starburst galaxy, spiral galaxy

Distance from Earth: 12 million light-years away

Location in the sky: Ursa Major Constellation

Location in the universe: Outside the Milky Way

Size: 37,000 light-years across

Did you know: The mixture of hot, warm, and cold gas and dust scattered throughout M82 is a result of a collision with a neighboring galaxy, which caused an intense burst of star formation and star death.

Explore More About Analyzing Light

Find out more with these additional resources from NASA’s Universe of Learning

Credits: Starburst Galaxy M82

Multi-wavelength image (mid-infrared, visible, X-ray): NASA, ESA, A. Pagan (STScI)

Multi-wavelength spectrum based on R. C. Kennicutt, et al. 2003, PASP, 115, 928-952 (Figure 1)

Pull-out of X-ray spectrum from the Chandra X-ray Observatory: Laura Lopez

X-ray light image from the Chandra X-ray Observatory: NASA

X-ray spectrum from the Chandra X-ray Observatory: Laura Lopez

Visible light image from the Hubble Space Telescope: NASA, ESA

Visible light spectrum from the Hubble Space Telescope based on L. J. Smith, et al. 2006, MNRAS, 370, 1, 513-527 (Figure 6)

Mid-infrared image from the Spitzer Space Telescope: NASA

Mid-infrared spectrum from the Spitzer Space Telescope based on P. Beirão, et al. 2008, ApJ, 676, 304-316 (Figure 4)

Far-infrared image from the Herschel Space Telescope: ESA

Far-infrared spectrum from the Herschel Space Telescope based on P. Panuzzo, et al. 2010, A&A, 518, L37 (Figure 1)

Subject-matter expertise provided by Dr. Laura Lopez

Produced by the Space Telescope Science Institute’s Office of Public Outreach