• Mickael R, Mat S, Young-Lo K, Martin B (Lyon) Joel J, Ariel G, Suhail D, Mattia B, Ana S (Stockholm), Bastien C, Ben R, Fabrice F, Julian B (Marseille), Jakob N, Simeon R, Valery B (Berlin), Kate M, Maxime D, Jacco T, (Dublin), Melissa A (Cleremont), Nicolas R (Paris)

• ZTF21aaglamm (sibling with CC pair)
• ZTF21aagogqe and ZTF21aaihala
  • Should we try and get a second spectrum near max of objects confirmed early (for velocity measurements and a spec_z)?
  • SEDm is overloaded with targets; LT (with Simon P/Kate) or NOT?
• ZTF21aajtstm (Iax)

• Discovered very early by ZTF (~1 day after last non-discovery).
• Has lots of data, including swift, with spectra from Gemini, LT and NOT + polarimetry.
• No evidence of a bump => no signs of interation with companion, but this could be a viewing angle effect?
• Most likely a Ch mass deflaglaration explosion?
• Comparison with deflaglaration model from Magee. The models over-predict the amount of carbon. Could be tweaked in the models.
• Joel: is the swift photometry weird? Kate: we don't have a template for subtraction.
• The light-curve has a rise, with power law slope n=3.2; this matches the model well throughout.

• Want to get a ZTF-only distance ladder. There are 5 ZTF SNeIa within 30 Mpc, with plenty at 60Mpc.
  • The most distant ones are going to be JWST'able.
• AT2021J (10.6), AT2020nlb (15), SN2019np (20), SN2020hvf (26), SN2020ftl (32
  • Lets HST the first 4 of these.
  • One event might have archival data, but we still need data to TRGB it.
• Writing a proposal with the Chicago group. Deadline mid-April. 2 proposals: one ZTF only; one with all local SNe.
• Suhail to pull together an early draft. Meeting in 2 weeks. Circulatable draft in a week or so.

• Talked us through the cuts required to go from 800 SNe to the final sample of 204 objects.
• Of the initial sample, 4 objects are lost as duplicates; 1 is actually a QSO and one is actually a 2019 explosion.
• Host galaxy matching is finalised. That reduces the sample to ~300 objects.
• After this, all of the cuts are straight-forward. One is thrown away as being a massive HR outlier, but it doesn't affect anything.
• One big thing to note is that there are 23 reddened SN that are thrown away. This is a huge fraction.
  • We should write a paper on this.

• Approached the Munich group about shared follow-up of lensed SNe.
  • Going to collaborate on NOT.
  • Going to propose for OPTICON; shared program in ePESSTO+.
  • Everyone's happy
• The search is conducted mostly through comparing redshifts with magnitudes, so relies on spectra.
  • Could do better, but the heart of the problem is that lensed SNe look like normal SNe.
• Will update us next week on where people can help out.
  • There is a dedicated phone-con for those that are interested.

• Rahul has circulated a version of the 'sibling paper'. Comments before 26th Feb :).

ZTF Ia Phone-con: 2021-Feb-17

Meeting Agenda:

1. SNe of the week [Joel J]

2. The physics of SNe: "SN2020udy" [Kate M]

3. Finding H0: "HST'ing TRGB candidates in ZTF" [Suhail D] + Mat to remember to mention DEBASS

4. The Y1 dataset: "The composition of the Y1 sample" [Suhail D]

5. Real time updates: "The search for lensed SNe" [Ariel G]

6. AOB / Close

Participants (X):

Notes:

Transients of the Week:

Kate on: SN2020udy

Suhail on HST:

Suhail on Y1:

Ariel on Lensing:

Closing Remarks:

• Rahul has circulated a version of the 'sibling paper'. Comments by 26th Feb :).