[Heig] Comments on HE ObsCore note

[Mathieu Servillat]

Dear all,

There has been several additions to the HEIG ObsCore document (thnaks 
Ian for a lot of inputs), and there are still some parts missing that 
were proposed after the Paris workshop, though this was discuseed by 
email (datalink, vocabularies).

I think the document needs a refined structure (I'll post something 
similar as an issue on Github), e.g. :

--------
2 High Energy Astrophysics Data
     2.1 Observation techniques and data specificities --> as is now, 
defining events, event-list and IRFs in particular
     2.2 HE data access
         --> this could be a summary of use cases, the orientations of 
the extension would be shown, e.g. the complex time intervals, the 
energy dependant values, the event counting impact on data description, 
the complex instruments used (all those are answered in some way in 
sections 4, or 3)
         --> I would separate the direct search of event-lists+IRFs, and 
the search via a catalog of sources (more advanced and complex)

3 ObsCore Attribute Definitions for High Energy Astrophysics Data
   --> this should not be too developed, i.e. is the keyword ok ? should 
it be adapted ? is the current REC blocking ?
   --> for example, it would be said here that we need to define more 
dataproduct_types (particularly event-list), but those would be defined 
later in a Vocabulary section

4 Extensions to ObsCore Specific to High Energy Astrophysics Data
   --> the new attribute proposed

5 DataLink for HE data
   --> particularly suited to explore IRFs for an event-list (see 
Bruno's email and associated comments)
   --> requires a product vocabulary (developped below), maybe other 
attributes

6 Vocabularies
   6.1 HE product types
   6.2 instrument response functions (if not in product types)
   6.3 UCD terms (for o_ucd
--------

On the content of the note, I think we should distinguish ObsCore HE 
data products ant other HE data products. The first scenario that should 
show up is a better access to event-lists and their IRFs. However 
currently, there are definition for draws, pdf an regions, that 
correspond to analysed data, and so may not be best searched via ObsCore 
(but could be in additional tables via TAP in a similar way -- I just 
see Laurent comment that points in that direction).

The IRFs would thus come before in the document. I am not sure about the 
latest choice of "response-functions" for the name, which is quite 
general. I would say that "instrument-response" in a more appropriate 
category, then in a vocabulary there would be child terms for each parts 
or functions for this response.

The name of "advanced data products" is not so clear to me. Are they 
products after analysis of the observed data ? or are they more precise 
descriptions of the IRFs ?

I think it was proposed by François and other to develop our own 
vocabulary and hierarchy for HE product types, and we would then 
associate this vocabulary to product_type, or other TAP tables and 
attributes. In a way, this would be the follow up of the context data 
model propose in the HE Note, but with the simple approach of just 
defining a hierarchical vocabulary.

Best regards,

Mathieu


-- 
Dr. Mathieu Servillat
LUX - Laboratoire d'étude de l'Univers et des phénomènes eXtrêmes
Bât 18, Bur. 222
Observatoire de Paris, Site de Meudon
5 place Jules Janssen
92195 Meudon, France
Tél. +33 1 45 07 78 62
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