2009 May 20
Over the course of this spring Geoff and I have converged toward a vision of what my next project will be. This is an interesting subject since (barring catastrophes) the next project will be the basis of my thesis. Or, perhaps a better way to phrase it is that the project that I start next will be the jumping-off point that leads to all of the pieces that make up my thesis.
This project is … drumroll … the ATA Galactic Center Transient Survey, or AGCTS for short. Over the course of the next six months, the ATA is going to observe the Galactic Center (GC) nearly every night. We’ll stack up all of those observations to get a really good map of the GC region. Then we’ll subtract off each night’s data individually from the stack and see what’s left over. Most of the time, it’ll just be noise, but if any sources appear, disappear, or fluctuate strongly, they’ll pop out in the subtracted image.
That’s the basic outline, at least. The actual procedures are a bit more complicated, and there are countless ways to bell-n-whistlify the way you search for transient events. I’m not going to go into any more detail at the moment, though. This is partially because the information would be overkill, and partially because we haven’t worked out all of the specifics just yet. The particulars of the project will undoubtedly evolve as it transitions from concept to reality.
The project is shaped by a few key constraints. People are pretty excited about detecting transient astronomical phenomena, since they haven’t been able to do so very effectively until recently. And the GC is a good place to look for them, since it’s extremely crowded (compared to the rest of the galaxy) and it’s got that big ol’ black hole sitting in the center. Both of those factors could quite plausibly lead to more things crashing into one another, exploding, or otherwise going bump in the night. Finally, the actual observing plan is dictated by the fact that the SETI Institute is going to be running a survey of the GC this summer. Due to the ATA’s fancy commensal-observing capabilities, we can take data while they’re doing their search. The SETI folks are interested in looking at the GC for precisely the same reasons we are, and the practicalities of their search mesh well with our needs. We could plan to survey some other part of the sky, but we might as well piggyback on the SETI Institute’s observing program.
Above is an image that I made tonight with some preliminary data. I think it looks pretty good, although there’s much improvement to be made — the ripple patterns are indicative of imperfections in the data analysis, and the magnitude of the background noise is much larger than it should be. But it’s a better-looking image than I expected to get from a night’s work. Hopefully this bodes well for the rest of the project.
I’ll be showing a poster announcing the AGCTS at the Summer AAS conference in Pasadena in a couple of weeks. There certainly won’t be any concrete science to talk about, but we can describe our plans to the community and see how much interest we can stimulate.