Workshop on Blazar Variability across the Electromagnetic Spectrum

Europe/Paris
Amphitheater Becquerel (Ecole Polytechnique)

Amphitheater Becquerel

Ecole Polytechnique

Palaiseau
Berrie GIEBELS (LLR)
Description
Les blazars sont connus comme étant variables sur différentes échelles de temps, allant des temps courts (entre la minute et le jour) aux longs (entre la semaine et l'année). Différents modèles existent pour expliquer les mécanismes à l'origine de la variabilité observée, et les identifier a été jusque là très difficile. Une grande gamme d'outils sont utlilsés pour définir et caractériser la variabilité, avec des limitations dépendant de la méthode d'analyse et l'uniformité de l'observation. Nous prévoyons plusieurs exposés de synthèse sur la variabilité des blazars, dépendant de la longueur d'onde des observations, allant des ondes radio aux Très Hautes Energies, avec une mention particulière pour les résultats issus des télescopes à effet Cherenkov atmosphériques qui mesurent les temps caractéristiques les plus courts. Les exposés donneront une meilleure compréhension de leurs fluctuations et leurs spectres de puissance, les asymétries dans les courbes de lumière, leur possible origine intrinsèque ou extrinsèque, mais aussi les limitations des méthodes d'analyse. L'objectif principal du colloque est d'avoir une vue globale de la variabilité dans le spectre électromagnétique des blazars, et de comprendre quelles sont les caractéristiques fondamentales (échelles de temps, distributions de puissance), les corrélations, et quelle physique sous-jacente peut être mise en évidence avec la gérération actuelle d'instruments.

En-dehors des exposés invités, beacoup de temps sera consacré aux posters pour lesquels nous attendons des contributions, et qui seront également publiés sous forme de compte-rendu de conférence dans PoS - Proceedings of Science

It has been known for a long time that blazars are variable, both on short (minutes to days) and long (weeks to years) timescales. Various models exist to explain the mechanisms causing variability, and disentangling them has also been particularly hard. A wide variety of tools are used to define and characterize variability, with varying limitations depending on the analysis method and observation uniformity. We plan to have several wavelength-dependent review talks about variability of blazars, ranging from radio to Very High Energy wavelengths, with a special emphasis on Atmospheric Cherenkov Telescope results - and possibly from GLAST - where the timescales have been the shortest. A better view of their fluctuations and power spectra, flare asymmetries in lightcurves, their possible intrinsic or extrinsic origin, as well as different talks on analysis methods strengths and limitations. The main objective of the meeting is to have a view across the spectrum of what the relevant characteristics are (timescales, power distributions), their correlations, the caveats of their assessment, and what underlying physics can realistically be probed with the current generation of instruments.

Besides the invited talks, plenty of time will be devoted to Poster sessions for which contributions are welcomed! All contributions will be published as proceedings (probably with PoS - Proceedings of Science)

In order to estimate the attendance, and hence define the workshop fee, we strongly encourage potential participants to pre-register now on the website. The pre-registration is also necessary to give your intended contribution (poster or not). Given the limited seating capacity we might stop registrations once the capacity limit is reached.

    • 14:00 14:45
      blazars: the broad-band observational point of view 45m Amphitheater Becquerel

      Amphitheater Becquerel

      Ecole Polytechnique

      Palaiseau
      Orateur: Prof. Annalisa Celotti
      Slides
    • 14:45 15:30
      Relativistic flows in active galaxies 45m Amphitheater Becquerel

      Amphitheater Becquerel

      Ecole Polytechnique

      Palaiseau
      Orateur: Prof. Amir Levinson
      Slides
    • 16:00 16:45
      Pair production and cascades in AGN 45m Amphitheater Becquerel

      Amphitheater Becquerel

      Ecole Polytechnique

      Palaiseau
      Orateur: Prof. Juri Poutanen
      Slides
    • 16:45 17:30
      Can short variability time scales be reconciled with hadronic emission? 45m Amphitheater Becquerel

      Amphitheater Becquerel

      Ecole Polytechnique

      Palaiseau
      Orateur: Prof. Karl Mannheim
      Slides
    • 09:00 09:45
      VLBI observations of blazars 45m Amphitheater Becquerel

      Amphitheater Becquerel

      Ecole Polytechnique

      Palaiseau
      Orateur: Prof. Svetlana Jorstadt
      Slides
    • 09:45 10:30
      VLBI polarisation variability and implications for jet models 45m Amphitheater Becquerel

      Amphitheater Becquerel

      Ecole Polytechnique

      Palaiseau
      Orateur: Prof. Denise Gabuzda
      Slides
    • 11:00 11:45
      Total intensity radio variability in blazars 45m Amphitheater Becquerel

      Amphitheater Becquerel

      Ecole Polytechnique

      Palaiseau
      Orateur: Prof. Esko Valtaoja
      Slides
    • 11:45 12:30
      IR/optical/UV variability (photometric, spectral,polarization) in blazars 45m Amphitheater Becquerel

      Amphitheater Becquerel

      Ecole Polytechnique

      Palaiseau
      Orateur: Prof. Gino Tosti
      Slides
    • 14:00 14:45
      thermal AGN signatures in Blazars 45m Amphitheater Becquerel

      Amphitheater Becquerel

      Ecole Polytechnique

      Palaiseau
      Orateur: Prof. Eric Perlman
      Slides
    • 14:45 15:30
      Long-term X-ray variability in blazars and its multiwaveband context 45m Amphitheater Becquerel

      Amphitheater Becquerel

      Ecole Polytechnique

      Palaiseau
      Orateur: Prof. Alan Marscher
      Slides
    • 16:00 16:45
      HE gamma-ray variability, what we know, where we will know more 45m Amphitheater Becquerel

      Amphitheater Becquerel

      Ecole Polytechnique

      Palaiseau
      Orateur: Dr Julie McEnery
      Slides
    • 16:45 17:30
      Variability of Very High Energy Gamma-ray Blazars 45m Amphitheater Becquerel

      Amphitheater Becquerel

      Ecole Polytechnique

      Palaiseau
      The third generation of Very High Energy (VHE; E>100 GeV) gamma-ray telescopes (e.g. HESS, VERITAS & MAGIC) are an order of magnitude more sensitive than their predecessors. Over the past four years observations with these instruments have increased the catalog of VHE emitters to more than 70 sources, of which 22 are extragalactic. While only limited variability is found from the 15 newly discovered VHE blazars, the more sensitive studies of the 7 previously known extragalactic VHE emitters (6 blazars & the radio-galaxy M 87) have yielded unprecedented results. Recent highlights include the discovery of minute-scale VHE flux variability, significant VHE spectral changes on sub-hour time-scales, and strong correlations of these rapid VHE variations (flux & spectrum) with those simultaneously observed at X-ray energies. A summary of the variability properties of VHE blazars will be presented.
      Orateur: Dr Wystan Benbow
      Slides
    • 19:00 21:00
      Workshop Cocktail!! 2h Amphitheater Becquerel (Salon de Marbre)

      Amphitheater Becquerel

      Salon de Marbre

      next to the Amphitheater
    • 09:00 09:45
      Correlations within/between the two radiative populations 45m Amphitheater Becquerel

      Amphitheater Becquerel

      Ecole Polytechnique

      Palaiseau
      Orateur: Dr Wagner Robert
      Slides
    • 09:45 10:30
      Characterising X-Ray Variability in Blazars 45m Amphitheater Becquerel

      Amphitheater Becquerel

      Ecole Polytechnique

      Palaiseau
      Orateur: Prof. Ian McHardy
      Slides
    • 11:00 11:45
      Characterizing X-ray Variability of TeV blazars 45m Amphitheater Becquerel

      Amphitheater Becquerel

      Ecole Polytechnique

      Palaiseau
      Orateur: Prof. Jun Kataoka
      Slides
    • 11:45 12:30
      The variability of blazars viewed as a random stationary process: the case of PKS2155-304 with Atmospheric Cherenkov Telescopes 45m Amphitheater Becquerel

      Amphitheater Becquerel

      Ecole Polytechnique

      Palaiseau
      Orateur: Prof. Bernard Degrange
      Slides
    • 14:00 14:45
      particle acceleration mechanisms and variability in relativistic flows (stochastic processes, shocks, magnetic reconnection, matter/radiation dominated scenarios) 45m Amphitheater Becquerel

      Amphitheater Becquerel

      Ecole Polytechnique

      Palaiseau
      Orateur: Prof. John Kirk
      Slides
    • 14:45 15:30
      A unified time-dependant view of relativistic jets 45m Amphitheater Becquerel

      Amphitheater Becquerel

      Ecole Polytechnique

      Palaiseau
      Orateur: Prof. Gilles Henri
      Slides
    • 16:00 16:45
      Multiwavelength Synchrotron/Compton Spectral Analysis of TeV Blazars and FSRQs: A New Approach 45m Amphitheater Becquerel

      Amphitheater Becquerel

      Ecole Polytechnique

      Palaiseau
      Orateur: Prof. Chuck Dermer
      Slides
    • 16:45 17:30
      Radiative outputs from blazars (radiative processes, escape, light crossing, KN effects, emphasis on what we learn from the synchrotron bump about the underlying particle distributions). 45m Amphitheater Becquerel

      Amphitheater Becquerel

      Ecole Polytechnique

      Palaiseau
      Orateur: Dr Rafal Moderski
      Slides
    • 17:30 18:15
      propagation effects in VHE gamma-rays: the physics, how to find them (e.g. Quantum gravity effects, Lorentz invariance violations..) 45m Amphitheater Becquerel

      Amphitheater Becquerel

      Ecole Polytechnique

      Palaiseau
      Orateur: Prof. Stefan Wagner
      Slides
    • 18:15 18:35
      Highlight: new results from AGILE on blazars 20m Amphitheater Becquerel

      Amphitheater Becquerel

      Ecole Polytechnique

      Palaiseau
      Orateur: Dr Marco Tavani
    • 09:00 09:45
      Unification scenarios: the case of M87 45m Amphitheater Becquerel

      Amphitheater Becquerel

      Ecole Polytechnique

      Palaiseau
      Orateur: Dr Hélène Sol
      Slides
    • 09:45 10:30
      The next generation of X-ray sensitive space-based observatories and their potential for blazar variability studies 45m Amphitheater Becquerel

      Amphitheater Becquerel

      Ecole Polytechnique

      Palaiseau
      Orateur: Dr Greg Madejski
      Slides
    • 11:00 11:45
      Strengths and limitations of ACTs (present and future) for transient VHE sources 45m Amphitheater Becquerel

      Amphitheater Becquerel

      Ecole Polytechnique

      Palaiseau
      Orateur: Dr Michael Punch
      Slides
    • 11:45 12:30
      Summary talk, what have we learned, outstanding questions 45m Amphitheater Becquerel

      Amphitheater Becquerel

      Ecole Polytechnique

      Palaiseau
      Orateur: Dr Philip Kaaret
      Slides