What are the key features of a voorwerpje?


I read somewhere that the WISE 12-micron dust map is helpful but I can’t see any helpfulness of it on HsV here. What are the telltale signs to look for?

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For starters the colours, these objects usually emit at a very particular wavelength so most of the time they are almost completely blue or green in the RGB images, meaning only in one band and hardly or not in the other two bands

Secondly they are usually associated with disturbed galaxies

At some point I made the serendipitous discovery that using both WISE layers in tandem (flipping with spacebar) is a very efficient / effective way of finding good Voorwerp candidates relatively quickly.

An initial check with the original 1+19 Voorwerpjes revealed that ~75% of them indeed contained one or both WISE signatures

Which in hindsight might be obvious since one denotes hot dust and the other can signify an AGN (pointing at a disturbed galaxy + an active nucleus)

But ofcourse that leaves out the other ~25% of Possible Voorwerpjes, which are unfortunately probably also the most interesting, given that there is no WISE AGN signal (and thus can give valuable information on the timescales AGN can go on/off, restraints on how long ago etc.)

Hope this helps,

  • Alexander
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Very much - thank you

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If you go on a Voorwerpje hunt I recommend you go check out the active Voorwerpje Hunt thread on Galaxy Zoo, there is also a seperate thread now where I,ve dumped all coordinates of candidates that have already been posted before; good to check before posting a candidate because that list now contains over 1500 candidates!

Also there is now a paper in prep by Professor Emeritus Bill Keel with 38 new confirmed Voorwerpjes, but obviously the correct number for the final paper should be 42…

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Sadly I couldn’t possibly cheat on the jellyfish team but I’m trying to learn a bunch of other unusual objects so that if I come across them in the jellyfish search I can flag them correctly to the relevant people. Thank you so much for the help in this!

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