Are past small cutouts (visit, template, difference) accessible via PPDB, or must they be retrieved through butler/SIA or broker?

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#1

Similar questions have been discussed before, but I’m still unclear , so I am asking again (apologies for any repetition).

Context:
I am aiming to identify a transient class (e.g., lensed SNe) in the LSST alert stream using an image time series. Suppose I get an alert for a transient today. I want to retrieve small cutouts at that location for visits over the last two months. Some of those visits may have triggered alerts in the past; others would have had no alert (and thus no alert packet).

Currently, retrieving cutouts via Butler or SIA takes a few seconds per request, which limits how many transients I can process daily. So I am looking for a more efficient way.

Questions:

  1. Will the Prompt Products Database (PPDB) contain any images or small cutouts?
  2. If not, what about the small cutouts that would be sent in alert packets to brokers? Are these not stored in PPDB?
  3. If yes,
    (a) Will PPDB include cutouts for all visits, even when no alert was issued?
    (b) Will PPDB retain images/cutouts only for a limited period in the past?
    (c) Will the 80H embargo apply on the small cutouts (those were sent to the broker)?

Thank you in advance.

#2

Cutouts will be included in the alerts, but will not be included in the Prompt Products Database (PPDB). If the cutouts included with the alerts are too small or you need cutouts for diaObjects before their first detection you currently need to use the Butler. In the future there will be a cutout service that should make that retrieval easier and faster, though I don’t have an exact timeframe for when that will be ready.

1 Like
#3

Thanks a lot for clearing the doubts. I have two more follow-up questions.

  1. I wonder why the small cutouts (those included in the alert packages) won’t be included in PPDB. To control the data volume? Once passed to the brokers, these cutouts will not be retained anywhere ?
  2. I suppose the 80h embargo will apply while retrieving the small cutouts for the past visits butler. Please correct me if I am mistaken.
#4

  1. Yes, we are limited by data volume in the PPDB. The original alerts that are sent to the brokers will also be stored in the Alert Archive at the USDF, which should be available to data rights holders.

  2. Yes, the 80h embargo will apply to retrieving cutouts from the butler, as this will require the same permissions as accessing the full images.