The One That Got Away

Home Forums Deep Sky A supernova impostor in NGC 3362 ? The One That Got Away

Ron Arbour

If you enter a suspect SN’s coordinates into the TNS report form and a supernova has already been found within ~3 arc seconds of that location, it will treat your data as a follow-up observation. You cannot enter it as a “new” discovery. As my object was located less than a couple of arc second from SN 2010ct, and almost 9 years had elapsed since the event it couldn’t possibly be a follow-up observation of the same object.

Additionally, the chances of a 2nd SN exploding at an almost identical position (~2 arc seconds) in this galaxy are virtually nil so it was quite logical to think it terms of a recurrent object i.e. an new LBV Luminous Blue Variable.

The discovery of a new LBV event usually creates a lot of professional interest but, because of SN 2010ct’s position in the *archives*, several thousand of objects below the latest, it would go completely unnoticed. This why I reported the problem of LBV’s to the TNS staff a couple of years ago and one of the reasons for the creation of the new AstroNotes scheme.

On many occasions, several in the last few months, I have entered a suspect SN’s coordinates in the report form only to be informed that a report claim has already been posted for an object at the same position which means that I could claim discovery for it. This is exactly what happened in this case.

Believing the object to be an LBV which I could not enter, I sent all the relevant data directly to the TNS team just as they were going to announce the launch of AstroNotes and they suggested I use that to convey the discovery information to the community. As it happens I was the first person to use the system.

I couldn’t believe it when I saw the ISSP (Italian Supernova Search Project’s) discovery announcement on the TNS. I have since learned from the TNS staff that a new object *can* be entered for the same position if the original report is over 5 years old, now they tell me!

So, 40,000 images have been taken since my last discovery in Nov. 2017 and to miss this one after sending all the relevant data to the powers to be, leaves me somewhat displeased.