EBL/ALP/IGMF/LIV call

Monday 3 Oct 2016, 10:00 → 11:00 Europe/Berlin

Minutes Minutes_2016-10-03.pdf

more information eZuce information

10:00 → 10:05 Introduction of the task force

Speakers: Dr Jonathan Biteau (SCIPP), Mr Manuel Meyer (University of Stockholm)

Slides TaskForce_Intro.pdf

Participants

In random order: David Sanchez, Tomislav Terzi, Jonathan Biteau, Fabrizio Tavecchio, Tarek Hassan, Paolo Goldoni, Oscar Blanch Bigas, Abelardo Moralejo Olaizola, Miguel Sanchez-Conde, Jean-Philippe Lenain, Helene Sol, John E Ward, Vitor de Souza, Manuel Meyer, Leyre Nogues, Malcolm Fairbairn, Alberto Dominguez, Ievgen Vovk, Garret Cotter, Santiago Pita

Introduction

• Abelardo asks about level of detail we should get into.
• Jonathan: Goal today is to trigger discussions.  

10:05 → 10:13 EBL & Intrinsic spectra

Speaker: Dr Jonathan Biteau (SCIPP)

Slides EBL_IntSpec.pdf

EBL and intrinsic spectra

• Abelardo: how much does it matter how we treat the EBL fitting splines vs gaussian given the width of the gamma-gamma cross section?
• Jonathan answers: study is for a broad wavelength in EBL, so might be important. Could be studied with simulations.

10:13 → 10:23 ALPs and IGMF

Speaker: Mr Manuel Meyer (University of Stockholm)

Slides mmeyer_ALPs+IGMF_kickoff.pdf

ALPs & IGMF

• Jonathan asks about possible progress with CTA study
• Manuel: more sources will help, only handful of most promising sources was considered so far. Input from source number estimation will help. For ALPs he prefers search for irregularities since a) we might be able to probe ALP DM parameter space, b) space for reduced opacity becomes more and more constrained, but we should discuss this further. For IGMF: spatial information could improve constraints especially for larger field strenghts.
• Ievgen Vovk makes remark that B field filling factor should be taken into account and probed with CTA, something similar could be done for efficiency of plasma instabilities (Manuel). Also possible: look at AGN close to clusters and far away, with this one could probe filling factor if we actually saw the cascade contribution
• To our knowledge there is no publicly available code for plasma instabilities.
• Vitor is in favour of using (and waiting for) 3D monte carlo code.

10:23 → 10:31 LIV

Speaker: Dr Fabrizio Tavecchio (INAF-Oservatorio Astronomico di Brera)

Slides gpropaTavecchio.pdf

LIV

• Malcolm’s comment: Thanks for the nice talk Fabrizio, We were just TRYING to follow the philosophy set out in Protheroe and Meyer - http://inspirehep.net/record/527519?ln=en (different Meyer). If this different in the approach became an issue, we could think about it a bit more. To be honest we didn't think about this in great great depth.
• Question by Manuel: How can we improve current bounds (Fermi GRB) best with CTA.
• Fabrizio: best possibility is to search for effects kicking in at TeV energies, n = 2, n = 3 terms.
• Vitor: a student of mine is working on a modification of SimProp including LIV effects in the gamma/eletron/position cascade.

10:31 → 10:39 Simulations

Speaker: Dr Tarek Hassan (IFAE)

Simulations

• Tarek: IRFs for North and South ready, update on publicly available IRFs should come shortly / mid term. One should use those that are public. Threshold implementations are still being discussed, especially for South. Needs to be discussed on a political level.
• Tarek: IRFs for energy or angular resolution : could be produced in short / medium timescale. Changing IRFs does not change the analysis.
• Abelardo: threshold implementation have not changed so far, southern side has no LSTs at the moment, but partners could invest to change that. Threshold implementations should be available when made public
• Follow up by Jonathan: what is meant by short / mid term:
• Tarek & Abelardo: less than 6 months, performance curves will be shown in Bologna for prod3b, but formats need to be fixed. Internal:  should be there for Bologna meeting. Public curves: will take months
• One could start with internal root formats but Tarek recommends to start with ctools in the IRFs that are available now.
• Could be started right away especially for intrinsic spectrum task

10:39 → 10:47 Analysis tools

Speaker: Dr David Sanchez (LAPP)

Transparents David_tools.pdf

Analysis Tools

• Question by Jonathan: could we use code to simulate spectra with ctools? Or are developments needed? David: should be possible in short amount of time
• gammaPy and ctools should both be used
• Vitor: we should use two independent lines of analyses. Is this already clear? David: there will be science tools that will be uniquely used, so it will be hard to have a cross check.
• Jonathan: what’s the difference between gammaPy and ctools? Using both of them, would that be a cross check? David: philosophies are very different, ctools is stand alone, gammaPy is the opposite. Why both: not decided which one will go into the final science tools.

10:47 → 11:00 To-do list & Discussion

See to-do list table at https://portal.cta-observatory.org/WG/PHYS/SitePages/Consortium%20Publication%20EBL,%20ALP,%20LIV,%20IGMF.aspx

Speakers: Dr Jonathan Biteau (SCIPP), Mr Manuel Meyer (University of Stockholm)

• check out the list of tasks and sign up: https://portal.cta-observatory.org/WG/PHYS/SitePages/Consortium%20Publication%20EBL,%20ALP,%20LIV,%20IGMF.aspx
• Important to have progress until next meeting in terms of e.g. intrinsic spectra or source selections.