Example Notebook/script to access forced sources parameters from the database.

LSSTDESC / Monitor

Extract light curves for time-variable cosmological objects

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Example Notebook/script to access forced sources parameters from the database. #37

Open rbiswas4 opened 8 years ago

rbiswas4 commented 8 years ago

@jchiang87 I am looking for an example of how we can find parameters relating to all point like forced sources in the database. I would love to start with SN only, but would be OK if other classes of objects were there as well. I am trying to figure out how to generally associate objects quickly between the reference and outputs of DM.

jchiang87 commented 8 years ago

@rbiswas4 Which forced source parameters were you interested in searching on? For the comparisons I made in #29, I'm just doing a positional query on RA, Dec, e.g., here.

rbiswas4 commented 8 years ago

Yes, that is the kind of thing I would like, let me look more carefully after the meeting:

I wanted to get RA, Dec, sequence of MJD where they were measured to have 'significant' non zero fluxes, or SNR values.
I want to iterate over all such objects with various thresholds. So what I am really looking for is the sequence of ID for all forced sources.
How do you figure out if they are like SN and not AGN for example?

jchiang87 commented 8 years ago

How do you figure out if they are like SN and not AGN for example?

This might be a useful thing to discuss during the meeting. If you histogram the peak normalized light curves from the Level 2 data, the distributions clearly show three families: constant sources, AGNs and SNe. The AGNs tend to have a broad distribution of fluxes while the SNe have mostly quiescent values and a tail of higher fluxes. (There is actually a fourth class: bright constant sources near the edges of the sensors from some visits. These have a tail of lower flux values. I think this is an artifact of our single sensor runs and/or phosim.)

rbiswas4 commented 8 years ago

Ok. When you say broad distribution of fluxes do you really mean that AGN are long lived and SN are short lived so most of the SN fluxes are consistent with 0 ? That is true and an easy way to distinguish over long time periods.