RE: Queries to multiple databases

        Hi folks,

        I wasn't in Kyoto, so apologies if I'm repeating things said there.

        I agree with the statements that astronomers generally don't want to use data of unknown provenance, and that that's especially dangerous in automated workflows, where data of different qualities from different sources can get mixed in a way that's obscure to the astronomer, who could just end up with a result whose validity they cannot readily assess.

        However, I can think of a few examples, from the initial, more exploratory stage of analysis where a template query submitted to a number of databases could be very useful. Much of my own work involves catalogue matching exercises, to generate multi-wavelength datasets, and I could imagine wanting to have workflow steps that do things like the following:

1. "plot the spectral energy distributions of these matched sources, against models from X, using photometric redshifts from Y or, if possible, spectroscopic redshifts, from wherever you can find them."
2. "add onto these plots any other photometric datapoints you can find for these sources."
3. "produce for each source a plot marking the positions and error ellipses of all the catalogue entries merged by the cross-matching exercise, and any other sources found in 2, overlaid on any optical image you can find".

        In all of these cases, I could imagine being happy with having general queries sent out to multiple databases to find any data that might be useful. Of course, I'd have to perform lots of checks before I could use these data in producing final science results, but I do think that what Tony proposes would be very valuable at this exploratory stage - and, moreover, it's at that stage where I see the VO being most useful.

        cheers

        Bob Received on 2005-05-30Z12:47:13