[Radioig] Notes from last week's telecon

[Mark Lacy]

Hi All,

Notes from last week's radio interest group video/telecon are below. Let 
me know if I've missed anything or got something wrong. I hope to 
hear/see some of you at the interop session in a couple of weeks.

Cheers,

Mark

Radio interest group 3rd Zooms 6th May 2021

ObsCore extension:

Francois presented the proposal for the ObsCore extension that had been 
developed by him and the ESCAPE team. It allows for ranges in resolution 
and field-of-view for wide-band observations, includes the concept of 
largest angular scale, and also other uv-plane and instrumental 
characterizations (longest/shortest baselines, number of antennas, 
uv-plane filling factor). It also includes time resolution ranges, and 
spectral ranges expressed as frequencies instead of wavelengths. The 
proposal will be placed on GitHub for comments, and discussed in the DM 
session in the Interop.

In meeting 1, most of the discussion revolved around how a row in the 
ObsCore table should be defined, especially in terms of what common key 
could be used to link the ObsCore extension to the primary ObsCore Table 
(although the desirability of adding some of these new fields to ObsCore 
was also discussed), and how DataLink services could be implemented to 
fetch the relevant data.

For ALMA, Felix Stoehr broke out target+spw combinations into separate 
rows. Mark Kettenis said that JIVE takes the path of assigning a single 
obs_publisher_did to an observation (which can contain many sources and 
calibrators, and multiple bands). James Dempsey said that ASKAP is 
relatively straightforward (one band), but ATCA data has similar issues 
(multiple sources and bands in a single observation).

It may be that datalink services could be used to download what the user 
will need, e.g. a whole raw observation including calibrators in some 
cases, or a calibrated dataset or image of a single source in others.

Frequency for specifying spectral range was widely supported.

In meeting 2, the discussion was more focussed on what should be in the 
ObsCore extension - Severin Gaudet pointed out that obscore was designed 
to focus on the core properties of an observation for data discovery, 
and perhaps some of the uv-plane and instrumental characteristics might 
not be searched on much. Baptiste Cecconi wondered whether frequencies 
need be added as they are redundant given the wavelength ranges already 
in obscore, and a tool on the search front end could be used to do the 
conversion. He also suggested that we should work on mapping keywords 
from common data formats ((A)SDM/SDFITS/PSRFITS etc) to ObsCore and the 
proposed extension.

Implementation note:

Stories from CASDA (JD), ASTRON (Yan?), MERLIN (PH) missing, JIVE story 
needs an update (MK)
ML will try to tidy it up in time for the Interop.

Interop schedule:

A 1hr session is tentatively scheduled for May 25th 22:00-23:00 UT.

Speakers who’ve volunteered already:
Mark Kettenis (VO implementation at JIVE and uv-plane characterization)
Yan Grange (FRBs)
Hendrik Heinl (LoFAR DR1)
Peter Teuben (Single dish radio data in the VO and SDFITS)
Ricardo Rizzo

Other possible contributions:
Susana Sanchez - provenance for radio data (may be scheduled in the DM 
session, also dependent on approval from company working on the problem)
Arecibo/CI CoE (may be scheduled in CSP)