I’m trying to understand why 2026 ED138 appears in Rubin’s single-visit source catalogs but not in the public alert stream. I checked its trajectory using JPL Horizons coordinates and performed cone searches in the Fink alert archive, but found nothing.
I recently applied for access to additional Rubin data products because I’m interested in moving objects and developing my own linking/orbit pipeline. My application was declined, and I was told that the public alert stream should be sufficient for this kind of work for an independent/amateur researcher.
But the case of 2026 ED138 seems to suggest that some scientifically interesting moving objects may be present in internal/single-visit data without appearing in the alert stream. Could someone please explain how this is expected to work, and what data source an independent researcher should use in such cases?
Since you don’t have an official answer, I’ll go ahead and say that I think that the problem is simply that templates do not yet exist for much of the sky. Alerts are only generated once there are templates. This is a problem that goes away over months (or at worst a year). You can see a lot of discussion on community about how hard they’re working to get templates, but it’s a problem for everyone in Year 1.
Thank you, that explains a lot! I was actually wondering how such a bright object could possibly fail to appear in the alert stream, but if that area of the sky doesn’t have templates yet, then the chances are simply zero.
In particular, you may be interested in section 9.2 on why 2026 ED138 was initially missed in Rubin visits, and as John says difference imaging could not be performed on many of these visits due to a lack of templates. The source catologues used in the orbit search were actually detections on the direct images (section 2.1), and ED138 has been at low galactic latitude in crowded stellar fields where it is tricky to deblend the moving object from the background stars.