Data Source vocabulary

[Vandana Desai]

Hello!

During the recent IVOA meeting, Markus pointed me to this thread
started by Stéphane
Erard describing a suggestion for Data Source vocabulary.

http://mail.ivoa.net/pipermail/semantics/2026-June/003220.html

I wanted to share use cases that could benefit from the further development
of this proposal:

*OpenUniverse2024*

OpenUniverse2024 data includes mock galaxy catalogs and simulated images
that both "belong to the same universe", but resemble our universe only on
a statistical basis.

The proposed term "Modeled" says :"This includes the current case of no
attempt to simulated existing objects", and so seems to fit the
OpenUniverse2024 mock galaxy catalogs and simulated images.

However, the proposed term "Simulation" says "simulation of an instrument
output", which seems like it it also applies.

Aside from that, we'd like metadata that would make it easier for
visualization tools to understand that I can overlay the OU2024 catalogs on
the OU2024 images, but it would not make sense to overlay 2MASS on OU2024
images.

*Rubin *(summarized from Gregory Dubois-Felsmann, cc'd)

One could have a concept of a set of universes, one of which is the real
one, while the others are theoretical ones that are not expected to align
with the real one other than statistically.

For example, Rubin avoids combining DP0.2 data and DP1 data on the same
ObsTAP service, because the former is derived from a cosmological
simulation, not at all aligned in detail with the real one, while DP1 is
based on real on-sky data.


*SPHEREx (also from Gregory)*
In SPHEREx, we have real data but we also have an image simulation that is
driven off of real on-sky catalogs of objects -- and the two look
remarkably similar, to the point where it's meaningful to blink them.

It would be helpful if the standards could steer users away from comparing
data products that are incompatible.

I hope this input is helpful! Happy to discuss.

Thanks,
Vandana

*Dr**. **Vandana* *Desai* | Science Lead | NASA-IPAC Infrared Science
Archive | Caltech/IPAC
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