Stellar Exclamation

Credit: X-ray NASA/CXC/IfA/D.Sanders et al; Opti­cal NASA/STScI/NRAO/A.Evans et al

Col­lid­ing galax­ies form an excla­ma­tion point in this com­pos­ite image from NASA’s Chan­dra and Hub­ble telescopes.

Explore the image of VV 340, or Arp 302. What shapes and pat­terns do you see in pair of galax­ies? Leave a note below.

Although the two spi­ral galax­ies are in the begin­ning stages of inter­ac­tion, they are des­tined to merge far in the future. Sci­en­tists study these galax­ies with many sen­sors. Chan­dra X-ray Obser­va­tory data is shown in pur­ple. infrared light is picked up by Spitzer Space Tele­scope. And vis­i­ble light in the form of red, green and blue light is com­bined with light from the other sen­sors to make this image. One thing of inter­est to sci­en­tists is the bright infrared glow from VV 340. Astronomers call these kinds of objects Lumi­nous Infrared Galax­ies or LIRGs. Astronomers do not know why these galax­ies emit so much infrared radi­a­tion. Infrared is a part of the spec­trum of light with a slightly longer wave­length as vis­i­ble light. We feel infrared radi­a­tion as heat. One pos­si­bil­ity shown in the Chan­dra obser­va­tions is that a grow­ing super­mas­sive black hole pow­ers the galaxy at the top. While only a small amount of infrared light is given off by a black hole, black holes do give off ultra­vi­o­let light.

VV 340 is found about 450 mil­lion light-years from Earth toward the con­stel­la­tion of Boötes, the Watcher of the Bear. In Greek mythol­ogy Boötes guards over both the great bear Ursa Major and Ursa Minor. The con­stel­la­tion con­tains the third bright­est star in the night sky, the red star Arcturus.