A wealth of molecules in an extreme galaxy

Feb 21, 2011
A Hubble image of the galaxy Arp 220, the brightest object in our local universe. A team using the Submillimeter Array studied the gas component of this galaxy, and concluded that bursts of star formation power its dramatic energetics. Credit: NASA and Hubble

(PhysOrg.com) -- Arp 220 is the closest galaxy to the Milly Way with an extreme luminosity, defined as being more than about 300 times that of our own galaxy. Some dramatic galaxies have values of luminosity ten times brighter still. Astronomers are still piecing together the reasons for these huge energy outputs, while sorting out why our own galaxy is so modest.

The two primary suspects for the energetics are bursts of that produce many hot , and processes associated with accretion of material onto a at a galaxy's nucleus. Arp 220 is the closest example, and one of the best places to probe these scenarios.

A team of astronomers including SAO astronomer Jun-Hui Zhao have used the Submillimeter Array (SMA) to obtain the first unbiased galaxy survey of molecular and atomic lines using a telescope array. They covered a complete, large wavelength interval in the millimeter regime that is accessible through Earth's atmosphere. The team reports finding seventy-three spectral features from fifteen molecular species in this survey band. A remarkable 28% of the total flux from this galaxy in this band is emitted by these molecules. The SMA also obtains images of the galaxy at each of the many wavelengths.

The results are consistent with Arp 220's being driven primarily by star-formation. The chemistry of the galaxy derived from the observations also leads to this conclusion, with species normally enhanced by star formation clearly detected. Moreover, it appears one such burst of activity is currently underway. The team estimates, for this extreme galaxy, that several million regions of activity are localized within a relatively small volume (a few thousand light-years) around the nucleus. The new results are an important improvement in our understanding of what powers extreme , and how they differ from the Milky Way.

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User comments : 7

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jsn3604
3 / 5 (2) Feb 21, 2011
Where's the "Milly Way?"
Physmet
5 / 5 (1) Feb 21, 2011
jsn3604, Milliways is the restaurant at the end of the universe...
Telekinetic
2.3 / 5 (3) Feb 21, 2011
It's named after the fraudulent lip-synching duo Milli Vanilli. You see, crime DOES pay.
Tuxford
1 / 5 (4) Feb 22, 2011
The central core region is likely in the active state, ejecting new matter and energy from the non-black black hole. Just another example which flips cosmology models on their heads. Why struggle to fit accretion models? If the shoe fits... Go ahead. Ignore the obvious. Simple to do. Remain safe, uncurious. Just say no! The religious do it every day!
tflahive
not rated yet Feb 22, 2011
What are the "fifteen molecular species"?
Modernmystic
1 / 5 (1) Feb 22, 2011
The central core region is likely in the active state, ejecting new matter and energy from the non-black black hole. Just another example which flips cosmology models on their heads. Why struggle to fit accretion models? If the shoe fits... Go ahead. Ignore the obvious. Simple to do. Remain safe, uncurious. Just say no! The religious do it every day!


So there's a viable theory that violates the first law of thermodynamics? Is there a shred of proof of it?
yyz
5 / 5 (3) Feb 22, 2011
"What are the "fifteen molecular species"?"

Table 6 of the paper by Martin et al lists the "73 features identified from 15 molecular species and 6 isotopologues":

h
ttp://arxiv.org/PS_cache/arxiv/pdf/1012/1012.3753v2.pdf

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