Dr
Gloria DUBNER
(Institute of Astronomy and Space Physics, IAFE)
27/06/2011 09:00
Supernova remnants (SNRs) are believed to be the main source of Galactic cosmic rays with energies up to 10^15 eV. Strong SNR shocks provide ideal acceleration sites for electrons and maybe ions.
In fact, among the identified Galactic gamma-ray sources the majority are associated with the violent, late phases of the stellar life.
Good radio continuum observations at different frequencies...
Dr
Yasuo Fukui
(Nagoya University)
27/06/2011 10:10
I present recent results on comparison between gamma ray SNRs and the interacting neutral clouds. I shall discuss on SNRs including RX J1713.7-3946, W28, W44 and RX J0852.0-4622 with an emphasis on the role of dense atomic and molecular gas in the interaction. In RX J1713.7-3946, I shall present highly clumped distribution of dense gas which exhibits good correlation with gamma rays and X...
Dr
Marco Miceli
27/06/2011 11:00
Dr
Yves Gallant
(LUPM Montpellier)
27/06/2011 11:35
Dr
Terri Brandt
(IRAP Toulouse)
27/06/2011 12:10
With the detection of more than 7 Supernova Remnants (SNRs) by the Fermi-LAT telescope, we now have access to an energy range opening a window onto emission mechanisms not previously available for these objects. In particular in combination with multiwavelength observations, we are now better able to determine the probable particle populations accelerated by the SNRs as well as the...
M.
Ignasi Reichardt
(IFAE Barcelona)
27/06/2011 14:35
Located in a dense complex environment, W51C provides an excellent scenario to probe accelerated protons in SNRs and their interaction with surrounding target material. Here we report the observation of extended Very High Energy (VHE) gamma-ray emission from the W51C supernova remnant (SNR) with MAGIC. Detections of extended gamma-ray emission in the same region have already been reported by...
Dr
Matthieu Renaud
(LUPM Montpellier)
27/06/2011 14:55
The Cherenkov Telescope Array (CTA) project, currently under its Preparatory Phase, is an initiative to build the next generation of ground-based very high energy gamma-ray instruments. It will serve as an open observatory to a wide astrophysics community and will provide a deep insight into the non-thermal high-energy universe. It foresees a factor of ~10 improvement in sensitivity above 100...
Dr
Francesco Giordano
(university & INFN Bari)
27/06/2011 15:15
Dr
Ryan Chaves
(MPIK Heidelberg)
27/06/2011 15:35
Dr
Fabio Acero
(LUPM Montpellier)
27/06/2011 16:25
PSR J0855–4644 is an energetic pulsar (Edot = 1.1 × 10^36 erg/s) with a period of 65 ms recently discovered near the South-East rim of the supernova remnant RX J0852.0-4622 (aka VelaJr) by the Parkes Multibeam Survey.The position of the pulsar is in spatial coincidence with an enhancement in X-rays and TeV gamma-rays, which could represent its pulsar wind nebula (PWN).
We have revealed with...
M.
Jérémie Méhault
(LUPM Monptellier)
27/06/2011 16:45
Supernova from massive stars are exploding in giant molecular cloud
(MC). Thus it is possible to see supernova remnants (SNR) expending in
dense material. The physical interaction between SNR and MC can
produce OH maser (1720 MHz) emission tracing the shocked surrounding
medium.
High and very-high energy (HE and VHE) gamma rays have been detected
in coincidence with OH maser,...
Dr
Stefano Gabici
(APC Paris)
27/06/2011 17:05
Dr
Marianne Lemoine-Goumard
(CENBG Bordeaux)
27/06/2011 17:40
Particle acceleration in massive star forming regions can proceed via a large variety of possible emission scenarios, including high-energy gamma-ray production in the colliding wind zone of the massive Wolf-Rayet binary (here WR 20a and WR121a), collective wind scenarios, diffusive shock acceleration at the boundaries of wind-blown bubbles in the stellar cluster, and outbreak phenomena from...
M.
Luigi Tibaldo
(university & INFN Parma)
27/06/2011 18:00
Supernova remnants are generally considered as the accelerators of the Galactic cosmic rays. The majority of supernovae have massive star progenitors and explode in a highly turbulent medium sustained by stellar winds and intense ionizing radiation in and around the parent stellar clusters. The early evolution of cosmic rays after their injection in the turbulent medium and the potential...
Dr
Vikram Dwarkadas
28/06/2011 09:35
I will review the evolution of SN shock waves in the surrounding medium, using analytic solutions and numerical simulations. I will discuss both white-dwarf and core-collapse SNe, the medium surrounding these SNe, and their evolution through various phases.
Dr
Nikos Prantzos
(IAP Paris)
28/06/2011 10:10
I explore the implications of a model in which cosmic rays
are accelerated by the forward shocks of supernovae exploding
within massive star winds, by using realistic stellar models
with mass loss and rotation. Using the same models, I
also show that the idea that the bulk of Galactic cosmic
rays are accelerated in superbubbles fails to reproduce
the key observable of GCR composition,...
Dr
Salavtore Orlando
(INAF osservatorio di Palermo)
28/06/2011 10:30
The thermal structure of the post-shock region of a young supernova remnant (SNR) is heavily affected by two main physical effects, namely the back-reaction of accelerated cosmic rays and the Rayleigh-Taylor instabilities developing at the contact discontinuity between the ejecta and the shocked interstellar medium (ISM). In this contribution, we investigate the role played by both physical...
Dr
Christian Farnier
(ISDC Geneva)
28/06/2011 11:20
One of the most outstanding stellar object in our Galaxy, eta Carinae, a colliding wind binary with the largest mass loss rate observed, presents a hard X-ray emission and is therefore a primary candidate to search for particle acceleration by probing its gamma-ray emission.
The detection of eta Carinae at high energy through analysis of Fermi/LAT data between 0.2 to 100 GeV was reported in...
Dr
Daria Kosenko
(Astronomical Institut Utrecht)
28/06/2011 11:40
We present numerical models for supernova remnant evolution, using a
new version of the hydrodynamical code SUPREMNA. We added cosmic ray
diffusion equation to the code scheme, employing two-fluid
approximation. We investigate the dynamics of the simulated supernova
remnants with different values of cosmic ray acceleration efficiency
and diffusion coefficient. We compare the...
Dr
Elena Amato
(Arcetri observatory)
28/06/2011 14:00
Streaming instabilities are thought to play a fundamental role in both
the processes of acceleration and propagation of Cosmic Rays in the
Galaxy.
Resonant scattering on self-generated magnetic turbulence has long
been recognized as the most plausible mechanism for the confinemet of
energetic particles. The streaming of these particles along magnetic
field lines at super-alfvenic...
Dr
Klara Schure
(Oxford University)
28/06/2011 14:35
Diffusive shock acceleration is the prime candidate for efficient acceleration of cosmic rays. Galactic cosmic rays are believed to originate predominantly from this process in supernova remnant shock waves. Confinement of the cosmic rays in the shock region is key in making the mechanism effective. It has been known that on small scales (smaller than the typical gyroradius) high-amplitude...
Dr
Giovanni Morlino
(Arcetri observatory)
28/06/2011 14:55
We calculate the flux of non-thermal radiation from the Tycho's supernova remnant in the context of the non-linear theory of particle acceleration at shocks, which allows us to take into account self-consistently the dynamical reaction of the accelerated particles, the generation of magnetic fields in the shock proximity and the dynamical reaction of the magnetic field on the plasma....
Dr
Igor Telezhinsky
(Deutsches Elektronen-Synchrotron Zeuthen)
28/06/2011 15:15
It is known that two shocks co-exist in young Supernova Remnants (SNRs) during their free expansion into the circumstellar/interstellar medium. It is widely accepted that the forward shock is responsible for the bulk of accelerated particles and the creation of a non-thermal power-law distribution of cosmic-rays. Under a test-particle approach the index of the power-law spectrum at high...
Dr
Sabrina Casanova
(Ruhr University)
28/06/2011 15:35
The advent of high sensitivity, high resolution gamma-ray detectors,
together with a knowledge of the distribution of the atomic hydrogen and
especially of the molecular hydrogen in the Galaxy on sub-degree scales
creates a unique opportunity to explore the flux of cosmic rays in the
Galaxy. We here present a methodology which aims to provide a test bed for
current and future gamma-ray...
Dr
Katia Ferrière
(IRAP Toulouse)
28/06/2011 16:25
I will review the observational properties of interstellar magnetic fields
in the disk and halo of our Galaxy. These properties are inferred from
a variety of observational methods, primarily based on polarization
of starlight, polarization of dust infrared emission, Zeeman splitting,
Faraday rotation, and synchrotron emission. I will discuss each of these
methods in some detail and...
Dr
Philipp Mertsch
(Rudolf Peierls Centre for Theoretical Physics Oxford)
28/06/2011 17:00
Gamma-ray data from Fermi-LAT reveal a bi-lobular structure extending up to 50 degrees above and below the galactic centre, which presumably originated in some form of energy release there less than a few million years ago. It has been argued that the gamma-rays arise from hadronic interactions of high energy cosmic rays which are advected out by a strong wind, or from inverse-Compton...
Dr
Jérome Péty
(IRAM & Observatoire de Paris)
28/06/2011 17:20
Summarizing 20 years of efforts, we will quantify the CO luminosity and CO-H2 conversion factor applicable to diffuse but partially molecular ISM when H2 and CO are present but C+ is the dominant form of gas-phase carbon. To do this, we will discuss galactic lines of sight observed in HI, HCO+ and CO where CO emission is present but the intervening clouds are diffuse (locally Av ~ 1 mag) with...
Dr
Patrick Hennebelle
(LERMA Paris)
28/06/2011 17:40
115.
Non-thermal emission from molecular clouds in the Galactic centre: Illumination vs cosmic rays.
Dr
Régis Terrier
(APC Paris)
28/06/2011 18:15
The molecular clouds at the Galactic centre (GC), Sgr B2 among others,
emit strong Fe Kalpha photons as well as hard X-rays up to 100 keV. The
origin of this emission has been the subject of a controversy.
Irradiation by subrelativistic cosmic rays, electrons or protons, might
account for the observed spectra, but it can also be the result of the
illumination of the clouds by a past high...
Prof.
Thomas Hartquist
(Leeds university)
29/06/2011 09:00
In the absence of magnetic fields and cosmic rays, radiative cooling laws with a range of dependences on
temperature affect the stability of interstellar gas. For about four and a half decades, astrophysicists have
recognised the importance of the thermal instability for the formation of clouds in the interstellar medium.
Even in the past several years, many papers have concerned the role...
Prof.
Yutaka Fujita
(Osaka University)
29/06/2011 09:35
We study the escape of cosmic-ray (CR) protons accelerated at a supernova remnant (SNR) by numerically solving a diffusion-convection equation from the vicinity of the shock front to the region far away from the front. We consider the amplifications of Alfven waves generated by the escaping CR particles and their effects on CR escape into interstellar medium (ISM). We find that the...
Prof.
Dejan Urosevic
(Department of mathematics Belgrade University)
29/06/2011 09:55
Equipartition or the minimum-energy calculation is a widespread method for
estimating magnetic field strength and energy in the magnetic field and cosmic rays particles
by using only the radio synchrotron emission. Despite of its approximate character,
it remains a useful tool in situations when no other data about the source are available. We give a modified calculation which we think is...
Dr
Beresnyak Andrey
(Ruhr University Bochum)
29/06/2011 11:20
We overview recent progress on small-scale dynamo and apply
the results to the the problem of nonlinear shock acceleration in which
particle mean free paths in front of the shock are greatly reduced
due to magnetic fields in the shock precursor which are generated
through small-scale dynamo in the density gradient's-induced
turbulence. Previous DSA models considered magnetic fields...
Dr
Laurent Derome
(LPSC Grenoble)
29/06/2011 11:55
M.
Roberto Iuppa
(University of Rome Tor Vergata - INFN sez.ne "Tor Vergata")
29/06/2011 12:30
The ARGO-YBJ experiment is a full coverage EAS array sensitive to cosmic rays with energy threshold few hundreds GeV.
Looking at all data collected since November 2007 several few-degree anisotropies in the arrival directions of cosmic rays have been found. The observation is highly significant (more than 17 s.d.) and the relative intensity with respect to the isotropic background flux...
Dr
Horst Fichtner
(Ruhr University Bochum)
30/06/2011 09:00
In recent years one could witness tremendous progress
regarding the physics of the transport of cosmic rays
in the heliosphere. This progress derives from both
theoretical advances and new measurements from the
outer boundary region of the heliosphere. At the same
time theory and observations give new constraints on
the local interstellar cosmic ray spectra. The talk
will address...
Dr
Yulia Kartavykh
(University of Würzburg / Ioffe Physical-Technical Institute)
30/06/2011 09:35
The missions STEREO A/B with large separation distances, together with ACE, SOHO, and WIND near Earth, provide a unique opportunity to observe solar energetic particles (SEP) over a large range of solar longitudes and latitudes in the inner heliosphere. It is evident from these observations that temporal and directional characteristics of solar energetic particles strongly depend on the...
Dr
Antje Putze
(Oskar Klein Laboratory Stockolm)
30/06/2011 11:00
We implemented a Markov Chain Monte Carlo (MCMC) technique within the USINE propagation package to estimate the probability-density functions for cosmic-ray transport and source parameters within an 1D diffusion model. From the measurement of the B/C ratio and radioactive cosmic-ray clocks, we calculate their probability density functions, with a special emphasis on the halo size L of the...
M.
Frederic Effenberg
(Ruhr University Bochum)
30/06/2011 11:20
In the description of Cosmic Ray transport following the well-known Parker Transport Equation, the spatial diffusion of energetic particles, in general, has to be treated by employing a tensorial quantity for the diffusion, i.e. using different diffusion strengths along and perpendicular to the magnetic field, respectively. This leads to results for the distribution function of these particles...
Dr
Julien Lavalle
(IFT-Madrid)
30/06/2011 11:40
Dr
Ilias Cholis
(SISSA Trieste)
30/06/2011 14:00
Recently published $\gamma$-ray spectral data from the Fermi Collaboration
have provided the possibility to study the diffuse $\gamma$-ray sky at medium and
high latitudes ($\mid b \mid > 10^{\circ}$) and energies of 1-100 GeV with unprecedented accuracy.
This provides us the chance of probing and constraining models of annihilating
and decaying Dark Matter, as well as studying and...
Dr
Pierrick Martin
(IPAG Grenoble)
30/06/2011 14:20
Cosmic-rays with energies up to the PeV are very likely related to stellar phenomena. As they propagate away from their sources, cosmic rays illuminate the various components of the interstellar medium and give rise to emissions in the radio and gamma-ray bands. The resulting galaxy‐wide radiation can provide insights into the physics of cosmic‐ray acceleration and transport. The recent...
Dr
Timur Delahaye
(IFT-Madrid)
30/06/2011 14:40
The Galactic gamma-ray diffuse emission is currently observed in the GeV-TeV energy range with unprecedented accuracy by the Fermi satellite. Understanding this component is crucial as it provides a background to many different signals such as extragalactic sources or annihilating dark matter. It is timely to reinvestigate how it is calculated and to assess the various uncertainties which are...
Dr
Vincent Tatischeff
30/06/2011 16:05
Dr
Jean-Christophe David
(CEA)
30/06/2011 16:40
Spallation reactions play a role in the production of stable and radioactive isotopes in meteorites by galactic cosmic ray (GCR) particles. For several decades cosmogenic nuclide production rates have been measured in different types of meteorites and calculation models have been improved. The main microscopic ingredients of these models are: i) the particle fluxes responsible of the nuclide...
Dr
Renzo Capelli
(MPE Garching)
30/06/2011 17:00
The X-ray reflection nebulae (XRN) in the Galactic Centre (GC) region have been proposed to be the smoking gun of a past low AGN activity of Sgr A*, which is suspected to have undergone a flare about 10^4 times brighter than the brightest flare ever measured, this high state happening some hundred years ago. This enhanced X-ray activity must have left a trace in the diffuse emission permeating...
Dr
Estelle Bayet
(Oxford University)
30/06/2011 17:20
The presence of cosmic rays in regions where stars are forming actually dramatically changes the gas and grain chemistry as compared to environments where photons less energetic such as FUV and UV photons usually dominate. In my talk, I will review first the main differences existing between these two illumination mechanisms of the interstellar matter. I will then present their respective...
Dr
Marco Padovani
(IEEC Barcelona)
30/06/2011 17:40
We explore the possibility that a low-energy component of cosmic rays, not directly measurable from the Earth, can account for the discrepancy between the ionisation rate measured in diffuse and dense interstellar clouds. Starting from different extrapolations at low energies of the demodulated cosmic-ray proton and electron spectra, we computed the propagated spectra in molecular clouds in...
Mme
Sladjana Nikolic
(MPIA Heidelberg)
30/06/2011 18:00
Supernova remnants are laboratories for studying optical shocks. Shocks with velocities of a few hundred km/s (or more) produce two-component Hα lines: a narrow spike atop a broad base. The widths of these lines serve as thermometers for the pre- and post-shock ambient interstellar medium, the ratio of the line strengths is a diagnostic for plasma conditions in the shock, and the offset...
M.
Christian Fernando MEJíA GUAMáN
(PUC Rio)
30/06/2011 18:05
Methane (CH$_{4}$) and methanol (CH$_{3}$OH) ices are present in various astrophysical environments, from dense molecular clouds to several small objects in the outer solar system, in particular on Saturn satellite Triton and to be a constituent of the icy mantle on interstellar grain [1]. There is a clear lack of information about the phenomena induced by the heavy-ion component of...
Dr
Cecilia Ceccarelli
01/07/2011 09:35
Dr
Paul Rimmer
(Ohio State university Colombus)
01/07/2011 10:10
MOTIVATION: Low energy ($< 1$ GeV) cosmic rays drive interstellar chemistry and may cause specific spectral features recently measured, such as the 6.7 keV emission line. Yet the origin and flux of low energy cosmic rays is currently unknown because the Sun's magnetic field deflects these particles, so that they cannot be directly observed. A robust model of cosmic ray transport in molecular...
Dr
Alexandre Faure
(IPAG Grenoble)
01/07/2011 10:30
In the most energetic regions of space (shocks, photodissociation regions, comets, etc.), the electron fraction, xe, can increase by several orders of magnitude. When xe exceeds about 10-5, free electrons can compete or even dominate over neutrals in the collisional excitation of molecules. Recent theoretical studies, based on the UK molecular R-matrix method, have revisited the...
Dr
Franck Lepetit
(LUTH Meudon)
01/07/2011 11:20
Cosmic rays have a strong impact on interstellar chemistry. By ionizing some species, they initiate fast ion-neutral reactions that lead to the formation of complex molecules. So, the measurement of the cosmic ionization rate in different media is crucial to understand the chemical mechanism leading to the composition of interstellar clouds.
In diffuse interstellar gas, the abundances of...
Dr
Edouard Bard
(CEREGE Aix-en-Provence)
01/07/2011 12:15
We analyzed phase lags between the 11-year cycles of solar activity (sunspot numbers, SSN), cosmic ray flux (CRF) and 0.5-year oscillations of the length of day (LOD). The analysis is performed for the solar cycles number 20-23 (1965-2010). Phase lags are calculated by using different methods: time lag between maxima of corresponding cycles, according to maximal coefficient of...
Prof.
Hartquist Tom
(School of Physics and Astronomy - Leeds University)
