Disk Detective Talk

Percentages of true image of a body

  • onetimegolfer by onetimegolfer

    Any body have an idea as to the % of gravitational lensing vs true body observation would be. If the simbad says no Astronomical Object found; does that mean we are observing a gravitational image ? I do not want to put in comments #nosimbad if it is actually no AO found

    Posted

  • abans by abans scientist, moderator

    our PI, Marc said it best in his blog post about SIMBAD:

    "For example, as I’m writing this article, SIMBAD contains about 7.4 million objects. That’s a lot of sources. But for example, the WISE mission found about 747 million objects: 100 times as many as there are in SIMBAD. Looking at those numbers, you might get the impression that most of the time, when you click the “More Info on SIMBAD” button, you’d draw a blank. But it’s not that bad; we pre-selected objects for DiskDetective that are relatively bright, so the overlap with SIMBAD is pretty good. But it is pushing the limits."

    http://blog.diskdetective.org/2014/02/02/the-power-and-danger-of-simbad/

    So not every object we will see is included in the SIMBAD database.

    I don't know too much about lensing but I can tell you it's not too common. I know the most prominent searches for strong lensing in SDSS catalogue have found a few hundred cases of lensing around something like 50,000 sources... those searches were specifically targeting galaxy clusters where you easily see lensing. So I'm guessing that even if we could see lensed images (and they'd likely be dim so that itself is hard), the percentage estimate you are looking for is very small maybe less than1%.

    Hope that helps!

    Posted