isdiffpos check to remove negative flux?

[sjoertvv]

Hi. I noticed a recent transient (ZTF19acssnul) is classified as a possible SN on TNS. But the difference flux of this source is negative (ie, the flux has gone down with respect to the reference image). These cases can be interesting, but are unlikely to be SNe. They can be removed by filtering on the isdiffpos parameters of the avro packets.

[fforster]

Dear Sjoert, thanks a lot for the information and sorry about this mistake. We were doing the final filtering by hand using isdiffpos as you suggest, but we made a mistake in this particular candidate. We have automated this for the problem not to repeat when submitting to TNS and we will exclude these candidates from the SN hunter tool as well.

[fforster]

Btw, you can see the notebook https://github.com/alercebroker/TNS_upload for more information on how we submit candidates to TNS if you are interested.