Difference: TransientWGMinutes (34 vs. 35)

Minutes 28/11/2018

Attending

Steve Schulze (moderator) Rachel Bruch, Maayane Soumagnac, Yi Yang, Avishay Gal-Yam (WIS), Adam Miller (Northwestern), Cristina, Leonardo (OKC), Christoffer Fremling, Anna Ho (Caltech), Dan Perley (LJMU)

Items

Bright stars appearing as transient

Some bright stars are being reported to the TNS as transients. This phenomenon has been noticed also in the RCF program. AMPEL is also affected. Example: ZTF18acgxbkd passed the RDF filter. Some of these objects exist in GAIA but have no proper motion or parallax measurement.

Reviewing ongoing projects

Maayane has been working lately on the object ZTF18abokyfk (2018fif) , a Type II-P supernova with early and nice UV light curve. Several spectra were obtained for this object (including a GEMINI spectrum which might need a re-reduction.). There are lines in the early light curve which could suggest the existence of flash features, however it is not conclusive enough. The Rabinak & Waxman model is going to be used to fit the early light curve. From this modelling and the early UV-light curve data, some progenitors properties can be extracted (e.g.: energy, radius…). Indeed, early UV-data allows to generate contraints on the total energy. If we compare this candidate to 13dqy, a preliminary conclusion is that 18fif is not a slow cooler as expected. There is however not enough SN-Type II-P with such detailed data to have a meaningful insight on the matter. Hopefully we will have more of these in the coming years!

If you have a suggestion or help to bring to this paper, please, talk to Maayane.

Marshal

UV data disappearance from the Marshal: some data (especially data added manually from e.g. UVOT) is disappearing on the marshal. To be investigated…

_Interesting Transients: _

…The partnership is on vacation! However there are still some rapidly rising transients popping up.

ZTF18acrewey: rised by about 1mag in a day. Same night SEDm spectrum: unfortunately spectrum is noisy. Object was at 19.5 mag.There is some continuum and spikes. No redshift. Tried to match them galaxy emission lines, not conclusive. If redshift is at 0.02: some of these features could match some flash features.

ZTF18acrdlrp: Rising relatively fast. Ia. No non-detection

ZTF18acrdwag: Moderatly rapid rise. SEDm triggered, was not really observed yet.

ZTF18achaqmd: Object has been rising for 2 weeks. SNIa. Luminosity g-band is at -20.25. Too luminous for a Ia SN. Object should be monitored more closely. Uncertainty on the redshift. Should get another spectrum.

ZTF18acrcyqw: Fast rising transient. Don’t know redshift. Core Collapse SN, probably. Photometry: rose a mag in a day. No features from SEDm.

There is still a chance of detecting young or fast rising transient even though we are not in the high cadence extra galactic survey anymore.

Have a great week!

Minutes 06/12/2018

Attending

Ragnhild Lunnan (moderator, OKC), Anna Ho (Caltech), Arial Goobar (OKC), Avishay Gal-Yam, Steve Schulze, Yi Yang (Weizmann), Dan Perley (LJMU)

Items

Operations update

-From Matthew’s email

1) The window frame of the filter exchanger controls the position of the EPMs at the instrument docking position. There has been some slippage so that not all of the EPMs are correctly positioned which is causing a filter exchanger error. A fix has now been put in place to prevent additional motion of the window frame.

2) We are tracking an issue with the cryocooler again with varying cryostat temperatures - again we may be looking at some contamination. We will try a new ambient clean out procedure today on the mountain as the weather looks bad for the next couple of nights.

Lin forwarded an email from Roger Stone last night (UT convention). The problem with the cooler is much more complicated than expected.

-Avishay noticed problems with the Marshal alert processing. He discussed this with Jakob Nordin (DESY) who experienced the same issue. Furthermore, UVOT data are occasionally disappearing from the Marshal. We are in touch with Mansi to solve this issue.

New Marshal feature

The Marshal has a new feature to display recently obtained spectra (http://skipper.caltech.edu:8080/cgi-bin/growth/spec_summary.cgi)

Last SWG Co-Chairs telecon

Two hours before the WG telecon, Ragnhild and Steve attended the SWG co-Chairs telecon. We spoke about the reference images, Year 2 and the new call for proposal for SEDm.

There was a miscommunication about the new strategy for the reference images. The new strategy aims to generate two sets of references: 1) a set of reference images with relaxed constraints, to build up instantaneous coverage and 2) the original (tighter) set of reference images. The new strategy was implemented before discussing it; however, there was no complaint about this change.

We briefly discussed the strategy for the second year of the ZTF partnership programme. We were all content with the high-cadence programme. The Ia group is also happy with the i' band survey. Anna is worried that no orphan afterglow was detected with the high-cadence programme, yet. If you have worries, too, please let us know ASAP so that we can discuss this at the next SWG Co-Chairs telecon.

The new call for SEDm time is out. The deadline is 20 December. Like for the first call, it is likely that we will submit multiple proposals. Please, prepare for the next telecon a summary of your SEDm usage and whether you are planning to re-submit your proposal. Will the RCF project continue in Year 2?

AAS (6-10 January 2019, Seattle, Washington)

Several group members will attend the meeting (https://aas.org/meetings/aas233). Avishay will present results about infant SNe, Ragnhild about PTF16eh, and Dan and Anna about AT2018cow. ZTF will have a splinter session on 8 January between 11 and 12.30. The scope of this session is to introduce the community to the alert stream. If you want to help, please email Matthew.

EWASS (24-28 June 2019, Lyon, France)

The upcoming EWASS will have 14 symposia, 41 special sessions and 9 lunch sessions. You can find more information at https://eas.unige.ch/EWASS2019/index.jsp. Our transient symposium (S1) will take place from 26 to 27 June. The abstract submission deadline is 3 March 2019.

Interesting transients

ZTF18acapyww: SLSN-I. The spectrum is similar to PTF10nmn. If the first data point is real, it could be reminiscent of the SLSN-I SN2018bsz (https://arxiv.org/pdf/1806.10609.pdf).

ZTF18acrewey: Fast-rising but low-luminosity (~-16) transient. The existing spectra do not allow us to classify the object. The latest Keck spectrum might show undulations. However, one could interpret that as an emerging p-Cygni profile at the wavelength of H-a. A further spectrum is needed to classify the object.

ZTF18abwlupf: Rise time of >70 days!

ZTF18abxbmqh: SLSN-II