VODataService waveband: multi-messenger vocabulary?

[Markus Demleitner]

Dear Registry folks,

When I thought about what the Semantics chair might have to say to
the authors of the VODataService 1.2 PR, it occured to me that, as we
did with VOResource 1.1, we might want to take some word lists out of
the schema and into a vocabulary.

The prime candidate I'd see there is waveband.  This is currently an
exhaustive list of the electromagnetic spectrum:

  "Radio" | "Millimeter" | "Infrared" | "Optical" | "UV" | "EUV" |
  "X-ray" | "Gamma-ray"

-- the documentation gives more or less precise limits for where they
are.

As this is exhaustive, there'd be no real reason to put it into a
vocabulary, were it not for non-electromagnetic messengers; we
already have several neutrino services, gravitation and possibly
diverse charged particles (in particular in the solar system) can
reasonably expected to come.  And in the solar system, even dust
particles might count as messengers one day.

VODataService 1.2's coverage could cope with that on the spectral
axis, now that we're writing this in energy.  But there's no
information on the messenger particle(s) yet.  You can ask "give me
services with messengers between 1 GeV and 1 TeV" but not "give mie
services with neutrinos between 1 GeV and 1 TeV".

We *could* add a messenger attribute on spectral (defaulting to
photon), which probably would be the tidiest thing to do.  That would
be for VODataService 1.3, though, unless someone had a very urgent
use case.

A much lighter alternative would be to abuse waveband.  I give you
that <waveband>neutrino</waveband>, <waveband>gravitation</waveband>,
or even <waveband>He</waveband> would look somewhat odd, but other
than that I think the reasonable uses cases (see above) would be
covered with very little extra effort (like a new attribute).


Given that I have a bit of a conflict of interest here, I'd welcome
any kind of feedback.  If no one else comes forward, I guess the
editor of VODataService 1.2 will politely ask the Semantics chair to
forget this until VODataService 1.3.  On the other hand, both of them
would like to have something to say about non-EM spectral coverage
just about now, so they'd certainly be very open to community
comments of every kind.

        -- Markus