Check list to confirm the discovery of a supernovae
Alain Klotz - 28 Aug 2012
Emmanuel Conseil - 08 Sep 2020 (update)

What to do if a new object is detected ? This page is dedicaded to people that are using the SN_TAROT  tool to discover supernovae. However, the main lines can be used by any discovery program.

Follow the steps of this check list :

At time T+0h, one must confirm that the candidate is not an artifact, not a known star neither an asteroid.

Step 1 : Searching for image artifacts
Step 2 : Comparison with an atlas image
Step 3 : Check known solar system objects
Step 4 : Check variable stellar objects
Step 5 : Verify if the candidate has been already recently found
Step 6 : First measurements of the candidate

Between T > +1h and T < +24h, the goal is to confirm the candidate is really a star.

Step 7 : Obtain additional images of the candidate, by the same telescope or any other telescope, at least separated by 1 hour or more from the first detection image.

At this step you must decide if the candidate is true or not.
Don't hesitate to ask the Tarot team for help, especially if it's your first detection.
Step 8 : Post a new candidate on the Transient Name Server (TNS)
Step 9 : Post an Astronomer TELegram (if possible)

To include additional observations

Step 10 : Follow-up of the discovery

Detailed check list procedures

Step 1 : Searching for image artifacts

Some rare cosmic traces appear to be star like. In this case, if the image is a stacked frame the only way to discriminated a cosmic from a real celestial object is to vizualize the individual frames. If you don't have access to the individual frames, feel free to ask to the team through the Tarot_sn mailing-list to check for yourself.

Step 2 : Comparison with an atlas image

You must compare your recent image with another one taken few years ago.  Sometimes your candidate is only an active region (HII) of the galaxy that seems apparently brighter and could be erronenously attributed to a candidate when the seeing is better.

The Digital Sky Survey allows to download an old image. The Sloan Digital Sky Survey provide more recent deeper images.

Don't hesitate to look at the images from all available wavelengths. And always compare your image with an archive of better quality, at least.

Step 3 : Check for known solar system objects

There is statistically about 90% of stellar candidates that are in fact close approaches of asteroids

Step 4 : Check variable stellar objects

Cataclysmic variable stars of our galaxy can lie foreground of the galaxy. In particullar dwarf novae (U Gem type). Crisis phase of such a star spend about 2 to 20 days and the brightness increases by 2 to 5 magnitudes. Long periods are observed during two crisis. A dwarf nova is red and its spectrum is completly different than a supernova (not easy to diagnotic with only images).

Strong erratic brightness rising of a background quasar can provide the apparence of a supernova. Check if your candidate coincide with a known quasar:
Classical variable stars must be check using the GCVS database or the International Variable Star Index (VSX) of the AAVSO :

Step 5 : Verify if the candidate has been already recently found

Concerning the most recent informations, the CBAT "Transient Objects Confirmation Page" provides non officialized recent discovered sources that have been declared to the IAU. The ATEL telegrams can also provide non official candidates: 

Step 6 : First measurements of the candidate

The declaration of a new supernova candidate needs to indicate :
You can use any astronomical tool to measure the brightness of the candidate. Don't forget the estimated error of your measure.

Step 7 : Obtain additional images of the candidate

Before its declaration, the supernova candidate needs to have been observed at least two nights or many times a night, and if possible by more than one telescope.

Step 8 : Post a new candidate on the Transient Name Server (TNS)

The TNS is the place where the IAU gathers all the supernovae candidates, and the confirmed ones.

You will need :
Don't forget to fill the "Reporting group" with the value "TAROT".

Step 9 : Post an Astronomer TELegram (if possible)

The ATELs are posted on various hot subjects. It is the same objective than TOCPs.

The ATEL text will be on-line instantaneously.

WARNING : You need to be a professional astronomer, or associated with a professional team of scientists to get an account on this website and post ATELs. Or you need to known someone who has got such credentials and ask him to post the telegram for you. Example :

Authors(Affiliation): A. Klotz (Institut de Recherche en Astrophysique et Planetologie, France)
E-Mail Address: alain.klotz@free.fr
Telegram Title: PSN J19065165-6142163 a supernova candidate by TAROT in IC 4815
Wavebands: Optical
Objects : Supernovae
Text:
From images taken on 2012 June 20.36
with the TAROT La Silla telescope
A. Klotz report the discovery of a
supernova candidate located at R.A. = 19h06m51.65s,
Decl. = -61o42'16.3" (equinox 2000.0),
which is offset of 6" E and 12" S from the
nucleus of IC 4815. The image was R filtered
and magnitude was R~19.
<P>
The presence of the candidate is confirmed
on two images taken on 2012 June 26.34 with the
same telescope. R=17.6.
<P>
The candidate is not detected in images
taken by TAROT on 2012 June 08.34 (limiting
magnitude R=20).

Step 10 : Follow-up of the discovery

To include additional observations you can post comments on the TNS page of your candidate : https://wis-tns.weizmann.ac.il/object/
You must be loggued in on the TNS server to post comments. Your comments can include text or images.