This page is out of date. Please ignore, and contact Cameron instead.

POSSUM Value-Added Catalogue (PVACat)

Status page for the value added catalog for the ASKAP POSSUM Survey.
    Assumes already existing data in PPC.     Back to Pipeline
Powerpoint presentation on corresponding EMU effort: EVACat

      Team members, please edit as necessary.
Questions can be posted as comments or email to larry@umn.edu





Mission Critical Products

Multiple spatial components

Identification and characterization of multiple POSSUM components associated with a single EMU component



Complex Faraday spectra

Dominant and secondary RMs (if they exist) for each POSSUM component in PPC or added as above






Special Use Products

Faraday thick components

A further categorization of Faraday properties of existing PPC entries and/or multiple POSSUM components as above



RM statistics classes

Generate statistics of RM properties for well-defined classes of objects (e.g., by optical ID, redshift)



Diffuse RMs

Cubes of RM for whole sky [includes diffuse emission, not just around EMU sources, as in PPC], with and without single dish data. Does this belong in Mission Critical?



Lower resolution

Added by LR: do we create lower resolution products for better surface brightness sensitivity? where might we want to average P instead of Q,U?




Larry Rudnick

Re: the PVACat, there was general consensus on the existing Calgary definitions. The one exception was RM statistics on defined classes, which LR originally suggested, but now feels that it is more appropriate a derived individual research product, not something that belongs in a formal catalog.

There was a long discussion, based on questions raised prior by Lisa Harvey-Smith, about how the PVACat would be organized and managed. Some general understandings are summarized below, however, this all needs to be developed further, formalized, approved and clearly communicated as appropriate.

Structure: we can distinguish between two types of products in the PVACat. First are those that are basic, critical and of very broad general use. These need to be managed in a formal way, with people assigned, timelines, etc. One example in this category is the identification of multiple polarized components for a single EMU component. Another set of products may be more targeted scientifically, and emerge out of research projects by students or others. One example might be the identification of Faraday thick components. This second category needs to be managed, but differently, because it is largely voluntary/entrepreneurial.

A wide range of policy decisions remain, with respect to PVACat.
These include:

a) How/when will be management structure for PVACat be set up;
b) Process for vetting both basic (managed) and enhanced (voluntary) products prior to inclusion;
c) Temporary or permanents proprietary nature of enhanced data products and timing (probably staged) of public releases; (EMU's bias is to disseminate everything as quickly as possible.)
d) How to reserve projects for students;
e) Publication policies;
f) Coordination with EMU.