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Observing time

One of the best bits about research astronomy is getting to play with some pretty cool telescopes. It's not simple though. Telescope time is expensive and scarce, if you want to use a telescope you have to justify your plan to a panel of other researchers. This means writing a proposal outlining what you want to look at, why you want to look at it (how will it further our understanding?) and the specific set up you want to use (the technical justification). There are usually so many proposals that there is physically not enough time to do everything that astronomers around the world would like to do, so the job of the panel is to read all the proposals and decide which ones should actually be given time. This whole process, as you might imagine, is not a quick one. It can take months from the proposal deadline before you finally hear a result from the panel, also known as a time allocation committee (TAC). The last deadline for the Very Large Array (VLA) was in October 2005 and today the decisions of the TAC were sent back to the researchers who asked for time.

My group asked for two chunks of time for two different proposals. The first is to look at M82, a nearby galaxy which is undergoing a burst of star formation more intense than anything occuring within our own Galaxy. We want to look at a group of objects known as OH masers (kind of like lasers, but naturally occuring in space and in the radio part of the spectrum rather than the visible) in more detail than has been done before in order to look for structure. This will hopefully tell us something about the physics of these star forming regions. Absorption and emission by the OH molecule across this galaxy can be seen in this little movie.

The other proposal was a continuation of a program monitoring ten star-forming galaxies every few months for five years. What we are looking for are new supernovae, massive stars which have reached the ends of their lives in massive explosions. In active star-forming regions such as the cores of these galaxies there is often a lot of dust which can block out ordinary visible light. This can mean that searches for new supernovae using optical telescopes may miss some if they occur within or behind a dust cloud. Radio waves pass straight through this obscuring dust so we should be able to spot any supernovae occuring in these regions. This project has already been going for two years and we've observed several supernovae already.

Happily for us, although some of the panel weren't totally convinced by our justifications (you can rarely convince everyone), both of our proposals have been given time on this occasion. Now we have to write a couple of schedules telling the telescope where to point and what calibrators to look at so we can make sense of the data. It takes quite a long time from writing the proposal to getting the data, but if you discover something exciting then it is worth the wait...

Posted by Megan on Thursday 05th Jan 2006 (22:59 UTC) | Add a comment | Permalink


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