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: http://www.mso.anu.edu.au/pfrancis/roleplay/html_dir/firstlight/node27.html
Дата изменения: Unknown Дата индексирования: Tue Oct 2 15:14:03 2012 Кодировка: Поисковые слова: star |
Your main research interests concern dust.
From your offices, high in a tower block in South Kensington, London, you have long been leading a crusade for dust. One of your main pleasures in life is going to conferences, and asking the question `have you considered dust obscuration?' after every talk by an optical astronomer, and watching their embarrassed evasions. The universe is full of dust! Whenever stars form, dust is produced. Just look at the Milky Way any clear night (not that you can see it through all the streetlights and fog from your offices). The dust clouds are obvious. The whole field of star formation studies relies on using radio or infra-red telescopes to peer deep inside giant molecular clouds.
Wherever massive amounts of stars are forming locally, they form in dust clouds. Just look at any starburst galaxy: they are the most luminous objects in the local universe, but they are so dusty that the optical astronomers never even noticed them until the infra-red astronomers pointed them out!
The history of astronomy is a long saga of optical astronomers ignoring dust, and being horribly wrong in consequence. Those fools never seem to learn: they just keep on pretending that visible light gives the true picture, when it is abundantly, overwhelmingly clear that most of the interesting pieces of the universe are hidden by dust.
Now, those optical idiots are at it again. They are busy studying new-born galaxies using optical telescopes: ie. looking at the rest-frame UV emission from galaxies. If there is any dust at all in the early universe, it will completely stuff them up. They are probably missing all the most active star formation regions in the universe: thousands if galaxies are probably forming out there, and the optical astronomers will never know.
You have found a number of clues suggesting that there are some dusty star-burst galaxies in the early universe. The most famous example is IRAS10214, an extremely dusty, molecule-rich violently star-forming galaxy, which is a gravitational lens as well.
More recently, the ISO (Infrared Space Observatory) satellite, despite it's ghastly French detectors, discovered a large population of mysterious things in the high redshift universe that emit lots of far-IR emission. The DIRBE (Diffuse Infrared Background Experiment) detector on the COBE satellite has also recently picked up a diffuse background glow of far-IR light, above and beyond the cosmic microwave background. This is probably the integrated light of billions of dusty high-redshift starburst galaxies.