Secrets Of W49A –
17 December, 2013

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Follow us: – Astronomers using the Smithsonian’s Submillimeter Array (SMA), have been able to provide the first clear view of W49A, an active site of star formation that shines 100 times brighter than the Orion nebula.


The region is so obscured by dust that very little visible or infrared light escapes.


The SMA showed that central 30 light-years of W49A is several hundred times denser than the average molecular cloud in the Milky Way. In total, the nebula contains about 1 million suns’ worth of gas, mostly molecular hydrogen.




This image from the Smithsonian’s Submillimeter Array maps the projected density of molecular gas in the central 30 light years of W49A. Brighter colors mark denser regions. The brightest region at the image center is less than three light-years across, yet it contains about 50,000 suns’ worth of molecular gas. Roberto Galván-Madrid (ESO), Hauyu Baobab Liu (ASIAA, Taiwan), Tzu-Cheng Peng (ESO)




It operates at frequencies from 180 GHz to 700 GHz, the 6m dishes may be arranged into configurations with baselines as long as 509m, producing a synthesized beam of sub-arcsecond width. Each element can observe with two receivers simultaneously, with 2 GHz bandwidth each.
“We were amazed by all the features we saw in the SMA images,” says lead author Roberto Galván-Madrid, who conducted this research at the Harvard-Smithsonian Center for Astrophysics (CfA) and the European Southern Observatory (ESO).




W49A is located about 36,000 light-years from Earth, on the opposite side of the Milky Way.It’s a place of vigorous star formation seen in so-called “starburst” galaxies, where stars form 100 times faster than in our galaxy. The gaseous filaments in W49A form three big streamers, which funnel star-building material inward at speeds of about 4,500 miles per hour (2 km/sec).

The heart of W49A holds a giant yet surprisingly compact star cluster that might remain intact for billions of years.



About 100,000 stars already exist within a space only 10 light-years on a side. In contrast, fewer than 10 stars lie within 10 light-years of our Sun.


In a few million years, the giant star cluster in W49A will be almost as crowded as a globular cluster.




See also:
Tough Alien Worlds Found In Rich And Dense Star Cluster


Powerful ALMA Finds Star Forming Galaxies In The Early Universe


Earliest Vigorous Bursts Of Star Formation


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