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Blobrana


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RE: Galactic gas
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Discovering a New Stage in the Galactic Lifecycle

On its own, dust seems fairly unremarkable. However, by observing the clouds of gas and dust within a galaxy, astronomers can determine important information about the history of star formation and the evolution of galaxies. Now thanks to the unprecedented sensitivity of the telescope at the Atacama Large Millimeter Array (ALMA) in Chile, a Caltech-led team has been able to observe the dust contents of galaxies as seen just 1 billion years after the Big Bang - a time period known as redshift 5-6. These are the earliest average-sized galaxies to ever be directly observed and characterised in this way.
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Blobrana


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Neutral atomic hydrogen gas
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Title: Gas reservoirs and star formation in a forming galaxy cluster at z=0.2
Authors: Yara L. Jaffé, Bianca M. Poggianti, M. A. W. Verheijen, Boris Z. Deshev, Jacqueline H. van Gorkom

We present first results from the Blind Ultra Deep HI Environmental Survey (BUDHIES) of the Westerbork Synthesis Radio Telescope (WSRT). Our survey is the first direct imaging study of neutral atomic hydrogen gas in galaxies at a redshift where evolutionary processes begin to show. In this letter we investigate star formation, HI-content, and galaxy morphology, as a function of environment in Abell 2192 (at z=0.1876). Using a 3-dimensional visualisation technique, we find that Abell 2192 is a cluster in the process of forming, with significant substructure in it. We distinguish 4 structures that are separated in redshift and/or space. The richest structure is the baby cluster itself, with a core of elliptical galaxies that coincides with (weak) X-ray emission, almost no HI-detections, and suppressed star formation. Surrounding the cluster, we find a compact group where galaxies pre-process before falling into the cluster, and a scattered population of "field-like" galaxies showing more star formation and HI-detections. This cluster proves to be an excellent laboratory to understand the fate of the HI gas in the framework of galaxy evolution. We clearly see that the HI gas and the star formation correlate with morphology and environment at z=0.2. In particular, the fraction of HI-detections is significantly affected by the environment. The effect starts to kick in in low mass groups that pre-process the galaxies before they enter the cluster. Our results suggest that by the time the group galaxies fall into the cluster, they are already devoid of HI.

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Blobrana


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Stars may be running out of molecular gas

Australian scientists gazing billions of years back in time with powerful radio telescopes on Monday warned that the universe's lights - the stars - were quite literally running out of gas.
Robert Braun, astronomy and space chief at Australia's government science agency CSIRO, said about one-third of the molecular gas vital for the formation of new stars had been used up and the skies were slowly dimming.
Braun's team mapped the light densities of galaxies about five billion light years from Earth and compared them with today's "local universe" to see how much gas they contained and rates at which new stars were born.
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Blobrana


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Raging storms sweep away galactic gas

ESA's Herschel infrared space observatory has detected raging winds of molecular gas streaming away from galaxies. Suspected for years, these outflows may have the power to strip galaxies of gas and halt star formation in its tracks.
 The winds that Herschel has detected are extraordinary. The fastest is blowing at a speed of more than 1000 km/s, or about 10 000 times faster than the wind in a terrestrial hurricane.
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