Starburst Galaxies

Contents

Introduction

Starbust galaxies are either young or rejuvenated galaxies, with a star formation activity significantly larger than in our own Milky Way. These galaxies typically contain very luminous X-ray sources, including the Ultra-luminous X-ray sources (ULXs) that may harbor massive black holes.

A nearby example of starburst galaxy is M82, which hosts a number of variable ULXs; the most luminous of these ULXs reaches a peak luminosity in the range of 1041 erg s-1 and is the best and most discussed candidate for a black hole of mass higher than 100 solar masses. Hot X-ray emitting interstellar matter is also found in starburst galaxies. In M82 this hot gas appears to be escaping the nuclear region as a wind, visible above and below the stellar disk of this galaxy. Galaxy interaction or merging is frequently the trigger of a starburst episode.

A starburst galaxy is a galaxy experiencing a period of intense star forming activity. The burst occurs over a region a few thousand light years in diameter. The most popular theory for the cause of a starburst is that it is triggered by a close encounter or collision with another galaxy. This collision sends shock waves rushing through the galaxy. These shock waves push on giant clouds of gas and dust, causing them to collapse and form a few hundred stars. The massive stars use up their fuel quickly and explode as supernovas, which produce more shock waves and more star formation. In this way, a chain reaction of star formation and supernovas can sweep through the central region of a galaxy, where most of the gas is located. When most of the gas is used up or blown away by the explosions, the starburst ends.

External Links

• Chandra Observatory - Harvard.
• Chandra Observatory - NASA.
• "Great Observatories Present Rainbow of a Galaxy" - (An animation) M82 is shown in all its wavelength glory. Dissolving from Chandra X-ray Observatory images of three X-ray energy bands to images in three bands of the infrared spectrum taken by the Spitzer Space Telescope, and ending with the Hubble Space Telescope's visible- and near-infrared-light image. The three observatories' images were composited to reveal the galaxy's stars, as well as gas and dust features.  NASA/JPL Photo Journal Animation PIA08093.
• "Starburst Galaxies" - Chandra Observatory, Harvard.

Preview Image

"M82: Images From Space Telescopes Produce Stunning View of Starburst Galaxy" - Images from three of NASA's Great Observatories were combined to create this spectacular, multiwavelength view of the starburst galaxy M82. Optical light from stars (yellow-green/Hubble Space Telescope) shows the disk of a modest-sized, apparently normal galaxy.  Credit: X-ray: NASA/CXC/JHU/D.Strickland; Optical: NASA/ESA/STScI/AURA/The Hubble Heritage Team; IR: NASA/JPL-Caltech/Univ. of AZ/C. Engelbracht.  See also the animation "Great Observatories Present Rainbow of a Galaxy" (Source: Harvard-Smithsonian Center for Astrophysics/NASA by SAO.)