* Astronomy

This composite image of the nearby starburst galaxy M82 shows Chandra X-ray Observatory data in blue, optical data from the Hubble Space Telescope in green and orange, and infrared data from the Spitzer Space Telescope in red. The pullout is a Chandra image that shows the central region of the galaxy and contains two bright X-ray sources -- identified in a labeled version -- of special interest.

Source

Mystery object in Starburst Galaxy M82 possible micro-quasar

Radio astronomers at the University of Manchester's Jodrell Bank Observatory have discovered a strange new object in a nearby galaxy. The object, which appeared very suddenly in radio wavelengths and shows no signs of going away, does not appear to be like anything that has been seen in the Milky Way. Dr Tom Muxlow will present the discovery at the National Astronomy Meeting in Glasgow on Wednesday 14th April.
The galaxy, known as M82, is 10 million light years away and is a stellar production line churning out new stars at a prodigious rate. However, many of these stars die quickly in huge explosions, with a new supernova explosion occurring every 20 to 30 years.
Read more

NEWFIRM Discovery of Warm Molecular Hydrogen in the Wind of M82
Using NEWFIRM on the Mayall 4-meter telescope at Kitt Peak, Veilleux, Rupke and Swaters have reported the discovery of warm H2 gas in the prototypical galactic wind of M82. They report filaments extending above and below the disk, roughly coincident with the location of the galactic wind in this galaxy. The warm H2 material is not found to be a dynamically important component of the outflow: however, a comparison between the H2 emission and the distribution of the CO emission reveals that most of the features seen in CO are detected in H2 but not the converse. Deep H2 2.12 m observations such as these represent a promising new method to study the elusive but potentially important molecular component of galactic winds. In the accompanying figure the new data are compared with published H- and PAH emission images (left) and H2-to-PAH emission ratio map in the brightest filaments.

Source

Title: M82 as a Galaxy: Morphology and Stellar Content of the Disk and Halo
Authors: Y. Divakara Mayya (1), Luis Carrasco (1) ((1) INAOE, Mexico)

For decades, the nuclear starburst has taken all the limelight in M82 with very little discussion on M82 as a galaxy. The situation is changing over the last decade, with the publication of some important results on the morphology and stellar content of its disk and halo. In this review, we discuss these recent findings in the framework of M82 as a galaxy. It is known for almost half a century that M82 as a galaxy doesn't follow the trends expected for normal galaxies that had prompted the morphologists to introduce a separate morphological type under the name Irr II or amorphous. It is now being understood that the main reasons behind its apparently distinct morphological appearance are its peculiar star formation history, radial distribution of gas density and the form of the rotation curve. The disk formed almost all of its stars through a burst mode around 500 Myr ago, with the disk star formation completely quenched around 100 Myr ago. The fossil record of the disk-wide burst lies in the form of hundreds of compact star clusters, similar in mass to that of the globular clusters in the Milky Way, but an order of magnitude younger. The present star formation is restricted entirely to the central 500 pc zone, that contains more than 200 young compact star clusters. The disk contains a non-star-forming spiral arm, hidden from the optical view by a combination of extinction and high inclination to the line of sight. The halo of M82 is also unusual in its stellar content, with evidence for star formation, albeit at low levels, occurring continuously for over a gigayear. We carefully examine each of the observed abnormality to investigate the overall effect of interaction on the evolution of M82.

Read more  (551kb, PDF)