16-20 September 2019
Torino - Italy
Europe/Rome timezone

Special Session Outlines

Thursday, September 19, 11:00am - 12:30pm

SPECIAL SESSIONS:  A, B, C, in parallel




Special Session A:  Radio Galaxy Classification - Larry RUDNICK (convener)

After 5 decades, it’s time to revisit how we classify radio galaxies. The science demands a more sophisticated approach, and the massive new surveys provide the opportunity to do a more robust and useful  job.  The community needs to decide the proper balance between fixed naming, and what those classes would be, and more flexible systems where objective criteria are used by researchers to define samples as needed. The goals for the session are to:  A)  See where we have consensus on critical issues;  B) Identify issues needing further investigation; C) Provide guidance to the major new survey teams.

Session Outline:

Welcome and introduction to the classification challenge:  L. Rudnick  (10m+5m discussion)
The Fanaroff-Riley Classification - Past and Future:  B. Fanaroff (in absentia) (5m)
Perspectives on RG classification, I: J. Hlavacek-Larrondo (8m+2m) 
Perspectives on RG classification, II: B. McNamara (8m+2m)

Panel + Open Discussion, Critical Issues* (42m)
Moderator: R. Laing
Panelists: B. Mingo, W. Forman, D. Koziel-Wierzbowska, M. Hardcastle

Take-away messages from the session
L. Rudnick (4 min)

Thoughts on next steps
A. Kapinska (4 min)
Critical questions from surveys and on-line discussion (to be ordered, prioritized by panel):

What do we do with the large and increasing numbers of sources that don’t fit into our simple categories?
Are our simple labels meaningful? Do they isolate distinct physical phenomena?    
What roles should Machines play in RG classification?
What measurements can/should we include in catalogs, to allow future classification?
Which labels are most important, and how do we choose?



Special Session B. Multi-wavelength data - Barbara BALMAVERDE and Isabella Prandoni (co-conveners)

In the last two decades a suite of ground and space based observations has been built for the 3C at all accessible wavelengths with all major observing facilities from HST (with images from the UV to the IR and including also emission line imaging), to Chandra, Spitzer, Herschel, JVLA, as well as ground-based integral field optical spectra (e.g. with Muse). Each electromagnetic bands offer a different and complementary prospective of the radio galaxies phenomenon (not only from the 3C catalogue! ) and allow the investigation of different scientific questions.


The main driver for this session is that  it is usually very instructive to approach a problem from different perspectives. Therefore, we have checked out the expertise and interests of the audience with a questionnaire:  we scheduled two talks and we invited  four people, one for each broad research aerea (radio/sub-mmm, IR/oprtical-UV, X-ray/gamma, simulations), to pose their "key question” about radio galaxies during the session to theoreticians and observers working on different wavelength bands.

Lead-off talks - 10 minute slots (8 minute talk, 2 minute questions) each.

Dorota KOZIEL-WIERZBOWSKA  "How to distinguish radio AGN in a catalogue of radio sources"       
Fumiya IMAZATO             "Origin of optical to X-ray emission explored from variability analysis of radio galaxy NGC 1275"                                          

KEY QUESTIONS from Marie-Lou Gendron-Marsolais, Belinda Wilkes, Dipanjan Mukherjee and Ranieri Baldi.



Special Session C : Polarimetry - Eric PERLMAN (in absentia) and Margo ALLER (co-conveners)

Polarimetry is useful for AGN and radio galaxies in several ways. It allows one to probe the structure of the central engine from other angles, by looking for scattered light.  It also allows one to probe the ordering of the magnetic field in the emitting and scattering regions.  It therefore is a key to AGN physics in a number of regions, both within the central engine as well as within the extended jets.  It allows us to test particle acceleration models as well as geometrical and unification models.  A special session would allow us to focus on these ideas.

 Review talk (15 min +5 min for questions)
10 minute slots (8 min +2 min  for questions)
 5 minute slot (4 min  +1 min for questions)

TIME                     PRESENTER             TITLE
11:00-11:20              Alan Marscher         Polarimetry Review
11:20-11:30              Margo Aller           Recent Results from MOJAVE: VLBA 15 GHz Linear Polarization Imaging of AGN Jets 
11:30-11:40              Vincenzo Galluzzi     Multi-frequency Polarimetry of a complete sample of faint PACO sources
11:40:11:45              Vijay Mahatma         The Low-frequency Polarization Statistics of Bright Radio Galaxies from the LOFAR Two-Metre Sky Survey (LoTSS)
11:45-11:55              Evgenia Kravchenko    Polarimetric Structure in the M87 Jet within the Innermost 150 Rs
11:55-12:05              Rick Perley           High Resolution, High Sensitivity Polarimetry with Cygnus A and Hydra A
12:05-12:15              Herman Marshall       Observing Blazars with the Imaging X-Ray Polarimeter Explorer
12:15-12:30              Discussion