Shedding new light on Gamma-Ray Bursts with polarization data

26 Nov 2018, 09:00 → 30 Nov 2018, 11:30 Europe/Zurich

Other Institutes

During 2016 and 2017 the POLAR instrument detected a total 55 GRBs. It performed polarization measurements for a subset of these and the first results of this will soon be published to add to the first set of GRB polarization measurements performed by GAP earlier this decade. During this workshop the new POLAR results will be presented in detail while results of ongoing analysis projects will also be presented. This workshop serves to discus these new results, together with previous polarization measurements, in light of the different existing emission models.

The goal of the workshop is to produce a clear overview of the different existing theoretical predictions in the field and to discus these in light of these new results. The outcome of the discussions is foreseen to be part of an overview paper which will be organized during this workshop. A second goal is to define the most urgent open tasks within this upcoming field of astrophysics. Such tasks do not only concern theoretical work but also data analysis and hardware projects.

The workshop will take place in Geneva and will be attended by both experts in the field of GRB emission theory, general GRB experts and members of the POLAR collaboration.

A total of 15 participants from outside of Switzerland are invited and funding is available for both travel and accommodation for these participants. Additionally there is place for several other researchers from the field of GRB astrophysics who can contact the organizers in case they're interested in joining the meeting, the total number of participants is limited to 30.

 

The following topics will be covered:

- Recent GRB polarization measurements by GAP and POLAR

- Recent GRB afterglow polarization measurements

- Theoretical predictions of the polarization of GRB prompt and afterglow emission

- Implications of new measurement results on existing predictions

- Upcoming polarization results using existing data

- Focus of future theoretical work

- Focus of future analysis/measurements

 

Monday 26 November

11:00 → 12:00 Introduction: Introduction/Welcome

Introduction by local organizers, introduction to the goals of the meeting

talk.pdf

12:00 → 13:00 Lunch

Lunch at Campus Biotech

13:00 → 14:00 Measurements past and future: GAP results: overview

Introduction to theoretical emission models

13:00 GRB prompt emission polarization measurements by GAP

Speaker: Prof. Daisuke Yonetoku

14:00 → 15:00 Measurements past and future: POLAR: the first science results

Introduction to theoretical emission models

14:00 Detailed polarization measurements of 5 GRBs by POLAR

Speaker: Prof. Shuang-Nan Zhang (IHEP)

14:30 Details of the first POLAR analysis

Speaker: Mr Zhengheng Li (IHEP)

15:00 → 15:30 Coffee Break

15:30 → 16:15 Measurements past and future: Polarization measurements without a Compton Telescope and not for GRBs

Introduction to theoretical emission models

15:30 Polarization measurements without a Compton Telescope and not for GRBs

Speaker: Dr Thomas Siegert (MPE)

16:15 → 17:15 Measurements past and future: Polarization measurements of the afterglow

Introduction to theoretical emission models

16:15 Polarization measurements of the GRB afterglow

Speaker: Prof. Carole Mundell

Tuesday 27 November

10:00 → 11:45 CERN visit

Visit and tour of CERN

11:45 → 13:15 Lunch (back at biotech)

13:15 → 14:45 GRB: Prompt Emission Theories: Prompt emission Theory: Overview

GRB prompt emission and predictions on overall GRB polarization

13:15 GRB Prompt Emission: an overview

Speaker: Prof. Kenji Toma (Tohoku University)

14:00 Polarization of GRB Prompt Emission: An overview

Speaker: Ramandeep Gill (CITA)

Gill-2018.pdf

14:45 → 15:15 Coffee Break

15:15 → 18:00 GRB: Prompt Emission Theories: Polarization Predictions Details

GRB prompt emission and predictions on overall GRB polarization

15:15 Polarization Predictions of Photospheric Models

Speaker: Prof. Andrei Beloborodov

16:00 Synchrotron and Jitter Polarization Models towards POLAR Observations

Speaker: Prof. Jirong Mao (YNAO)

16:45 Discussion

How do the theories presented today compare to the measured data?

Are there clear problems with any of the existing models given recent results?

Are we able to exclude any models?

Speaker: Dr Damien Bégué (MPE)

19:00 → 21:00 Conference Dinner

Wednesday 28 November

09:30 → 12:30 Future prospects: Polarimetry with 170817A: afterglow models

eXTP - 20181128-Geneva.pdf

09:30 Polarization measurements of the afterglow

Speaker: Prof. Carole Mundell

10:30 Review of the GRB afterglow polarization and recent work on GRB 170817A

Speaker: Prof. Jonathan Granot

Granot_Geneva_28Nov2018(1).pdf

11:15 GRB 170817A afterglow measurements

Speaker: Prof. Carole Mundell

11:45 Theoretical interpretation of the detected circular polarization and the polarimetry of kilonova 170817

Speaker: Prof. Kenji Toma (Tohoku University)

12:30 → 13:15 Lunch

13:15 → 13:45 Discussions: What do we need from future instruments?

13:15 What do we need from future instruments?

In light of the discussions from yesterday, what type of measurements are most important for the future? Energy dependence, time dependence? Do we prefer many "ok" measurements or do we prefer a few very detailed ones (quantity vs quality)?

What are the lessons learned from previous missions which can benefit the future ones?

Speaker: Nicolas Produit (Universite de Geneve (CH))

next_instrument.pdf

13:45 → 14:10 Future prospects: GAP2

eXTP - 20181128-Geneva.pdf

13:45 Future prospects with GAP2

Speaker: Prof. Daisuke Yonetoku

14:10 → 14:35 Future prospects: POLAR-2

eXTP - 20181128-Geneva.pdf

14:10 POLAR-2

Speaker: Merlin Reynaard Kole (Universite de Geneve (CH))

14:35 → 15:00 Future prospects: SPHiNX

eXTP - 20181128-Geneva.pdf

14:35 SPHiNX

Speaker: Mark Pearce (KTH)

SPHiNX_Geneva_Pearce.pdf

15:00 → 15:30 Coffee Break

15:30 → 16:00 Future prospects: eXTP

eXTP - 20181128-Geneva.pdf

15:30 Polarization measurements with the eXTP mission

Speaker: Prof. Shuang-Nan Zhang (IHEP)

16:00 → 17:00 Discussions: What do we need from theory?

19:00 → 21:00 Dinner (@ Bain de Paquis)

Thursday 29 November

09:30 → 09:45 Data Analysis: GRB localization: importance for polarization

Ongoing data analysis projects

09:30 The importance of localization

Speaker: Merlin Reynaard Kole (Universite de Geneve (CH))

talk.pdf

09:45 → 10:15 Data Analysis: GRB localization with POLAR

Ongoing data analysis projects

09:45 GRB Localization with POLAR

Speaker: Mr Yuanhao Wang

10:15 → 11:10 Data Analysis: GRB localization with BALROG

Ongoing data analysis projects

10:15 POLARIZATION ANALYSIS FOR REAL INSTRUMENTS

The future of x-ray polarimetry looks bright. Unfortunately, the sources we look at are not. Low and high count measurements both require proper statistical treatment and the literature on polarization statistics is derived from regularity conditions designed for optical measurements. I will discuss these approaches and present a new approach appropriate for both idealized and real x-ray polarimeters. Additionally, I will show that concepts such as "bias" are purely the result of improper statistical treatment.

Speaker: Dr J. Michael Burgess (MPE)

10:35 The BALROG for GRB localization

Speaker: Mr Francesco Berlato (MPE)

11:10 → 11:30 Data Analysis: Future plans with POLAR data: Geneva

Ongoing data analysis projects

11:10 Plans for future analysis POLAR data in Geneva

Speaker: Merlin Reynaard Kole (Universite de Geneve (CH))

presentation_future_work.pdf

11:30 → 12:00 Data Analysis: Future plans with POLAR data: IHEP

Ongoing data analysis projects

11:30 Plans for GRB analysis with POLAR data at IHEP

Speaker: Jianchao Sun (Institute of High Energy Physics, Chinese Academy of Sciences)

12:00 → 13:00 Lunch

13:00 → 14:00 Novel Analysis methods: Forward folding polarization data

13:00 Synchrotron emission and polarization

We present the first joint fits of POLAR and GBM using proper likelihoods, a new forward-folding technique, and physical models. We will discuss the approach, the software (3ML) that enabled this analysis and the physical framework within which we interpret our results.

Speaker: Dr J. Michael Burgess (MPE)

14:00 → 15:00 Novel Analysis methods: CDCI: Plans for online analysis tools for polarization data

15:00 → 15:30 Coffee Break

15:30 → 16:15 Novel Analysis methods: CDCI: POLAR data demonstration

15:30 CDCI: POLAR data demonstration

Speaker: Dr Neal Gauvin (Universite de Geneve (CH))

cdci.pdf

reduced_data_format.pdf

16:15 → 17:15 Novel Analysis methods: Discussion: What do we need to make polarization analysis accessible?

16:15 How do we make polarization analysis open?

With the increase in available polarization data it becomes possible to make this data public and allow any interested party to perform analysis on it. This requires simple, transparent thoroughly tested public tools as well as data in easy to use formats.

We aim to discus here what people from the theory and analysis community would like to do with public polarization data and how we can best provide such tools.

Speaker: Merlin Reynaard Kole (Universite de Geneve (CH))

Friday 30 November

09:30 → 11:15 Final discussions: Planning future projects

11:15 → 11:30 Final discussions: Closing