Import LSST alerts

[nevencaplar]

Import part of the alerts database into LSDB. Capture difficulties and potential problems with the process.

[Better definition of the ticket needed.]

[nevencaplar]

As a first step, we should aim to import, hipscat and show crossmatching capability with the following dataset:

You will find the list of objects ids in the file oids.pickle and a series of lcs_%04i.pickle files with batches of 10,000 objects each. Note that this is only for objects with at least 20 detections! I also include the non detection upper limits from the difference images in the nondet_%04i.pickle files and information about the reference image used for every object in the ref_%04i.pickle files.
https://www.dropbox.com/scl/fo/pnb8kz4v9txlmc0nkcg4c/h?rlkey=jfpt2iq7q2110w7506lqwi19f&dl=0
You can see the description of the columns of the detection table in here (you should use magpsf_corr and sigmapsf_corr_ext for AGN)
https://alerce.readthedocs.io/en/latest/models.html
To understand how the corrected fluxes are obtained look at the preprocessing section here https://alerce.science/alerce-pipeline/ and for more details, the Appendix in Förster et al. 2021 (https://ui.adsabs.harvard.edu/abs/2021AJ....161..242F/abstract)