David Thompson
(NASA Goddard Space Flight Center, on behalf of the Fermi LAT collaboration)
10/8/08, 3:50 PM
With AGILE and Fermi now in orbit and TeV telescopes continuing to improve their performance, a variety of multiwavelength opportunities is increasingly available. One goal of such programs is to take advantage of the complementary capabilities of the two types of telescopes: the wide field surveys of the satellite detectors and the high sensitivity and resolution of the ground-based...
Dr
Javier Rico
(ICREA/IFAE)
10/9/08, 10:00 AM
The Major Atmospheric Gamma Imaging Cherenkov (MAGIC) telescope is a last-generation instrument for very high energy gamma-ray observations. It is located at La Palma (Spain) hence with an optimal view on the Northern sky. Sensitive in the 30 GeV - 30 TeV band (thanks mainly to its large, 17 m diameter reflector), it is nowadays the only ground-based instrument being able to measure...
Dr
Matthias Beilicke
(Washington University)
10/9/08, 10:30 AM
The VERITAS collaboration operates an array of four imaging atmospheric Cherenkov telescopes in southern Arizona. The first season of observations (including all four telescopes) was performed in 2007/2008.
Two new gamma-ray sources were discovered and a variety of other TeV sources were observed and detected, in many cases within coordinated multi-wavelength campaigns. The status,...
Prof.
Ocker Cornelis de Jager
(North-West University, Potchefstroom, South Africa)
10/9/08, 11:30 AM
By solving the Euler equations with magnetization constraints, we can establish the time evolution of composite supernova remnants in the interstellar medium. For given pulsar/SNR parameters and ISM density, we obtain the radial profiles of the pulsar wind nebular field strength (for different sigma parameters) and adiabatic loss rates. Using these constraints we then solve for the time...
Dr
Anita Reimer
(Stanford University)
10/9/08, 11:50 AM
Colliding winds of massive stars in binary systems are candidate sites of non-thermal high-energy photon emission. Long since, coincidences between massive star systems/associations and unidentified gamma-ray sources have been proposed. Only now, with the sensitivity of the Fermi Gamma Ray Observatory and current very-high-energy (VHE) Cherenkov instruments, will it be possible to conclusively...
Fabrice Feinstein
(Université Montpellier 2)
10/9/08, 12:10 PM
Shell-type supernova remnants (SNR) are suspected to be hadronic cosmic-ray
(CR) accelerators within our Galaxy. Several shell-type SNR emit very high
energy gamma rays detected with H.E.S.S., including RX J1713.7-3946,
RX J0852.0-4622, RCW 86 and most recently SN 1006. These observations confirm
that these objects accelerate particles up to at least 100 TeV
Dense molecular clouds...
Dr
Ana Yaiza Rodriguez Marrero
(IEEC-CSIC)
10/9/08, 12:30 PM
We present a theoretical model that explains the high energy phenomenology of the neighborhood of SNR IC 443, as observed with the Major Atmospheric Gamma Imaging Cherenkov (MAGIC) telescope and the Energetic Gamma-Ray Experiment Telescope (EGRET). We interpret MAGIC J0616+225 as delayed TeV emission of cosmic-rays diffusing from IC 443, what naturally explains the displacement between EGRET...
Maxim Shayduk
(Max-Planck-Institut fuer Physik, D-80805 Muenchen),
Michael Rissi
(ETH Zuerich, CH-8093 Switzerland)
10/9/08, 2:45 PM
We present the detection of the Crab Pulsar above 25 GeV
by the 17m diameter MAGIC telescope. We observed the
Crab Pulsar between October 2007 and February 2008 using
a newly developed trigger system, which allowed us to lower
the energy threshold of the telescope from 55 GeV to 25 GeV.
From previous non-detections of the Crab pulsar above 55 GeV
and from the observations by the EGRET...
Dr
Pablo Saz Parkinson
(University of California, Santa Cruz)
10/9/08, 3:05 PM
The Large Area Telescope on the recently launched Fermi Gamma-ray Space Telescope (formerly GLAST), with its large field of view and effective area, combined with its excellent timing capabilities is poised to revolutionize the field of gamma-ray astrophysics. The significant improvement in sensitivity of Fermi over EGRET is expected to result in the discovery of a large number of new...
Dmitry Khangulyan
(MPI f. Kernphysik, Heidelberg)
10/9/08, 4:00 PM
The energy spectra of TeV gamma-rays from blazars,
after being corrected for intergalatic absorption in the Extragalactic
Background Light, appear unusually hard. We show that the
internal absorption of gamma-rays caused by interactions with dense
narrow-band radiation fields in the vicinity of compact gamma-ray production
regions should lead to the formation of very hard gamma-ray...
Dr
Fabrizio Tavecchio
(INAF)
10/9/08, 4:50 PM
I discuss the concept and the consequences of the so-called "blazar sequence", connecting the position of the peaks in the spectral energy distribution of blazars with the emitted luminosity. I also present a recent revision of the theoretical basis of the blazar sequence, which, contrary to the simplest interpretation, predicts a large population of low-power "red" blazars and possibly the...
Dr
Gianfranco Brunetti
(INAF-IRA, Bologna)
10/9/08, 5:20 PM
The presence of non-thermal components in galaxy clusters, like relativistic electrons and magnetic fields, is demonstrated by radio observations that detect large scale synchrotron emission from the inter-galactic-medium of a fraction of massive clusters. On the other hand present observations can provide only upper limits to the energy content of relativistic protons.
GLAST has the...
Daniel Mazin
(IFAE, Barcelona)
10/9/08, 6:10 PM
Very high energy (VHE, E > 30 GeV) gamma-rays are absorbed via interaction with low-energy photons from the
extragalactic background light (EBL) if the involved photon energies are above the threshold for electron-positron pair creation. The VHE gamma-ray absorption,
which is energy dependent and increases strongly with redshift, distorts the VHE energy spectra observed from distant...
Dr
Stefano Covino
(INAF / Brera)
10/10/08, 11:50 AM
The availability of a new generation of instruments with capabilities to observe at high or very-high energies open an exciting perspective for GRB studies. The very large accessible energy band, including lower energy observations (soft X-rays down to optical and radio), will allow a reliable modeling of the GRB spectra both during the prompt phase and the afterglows. These information can...
Dr
Robert Wagner
(Max-Planck-Institut für Physik, München)
10/10/08, 12:30 PM
Some models for quantum gravity (QG) violate Lorentz invariance (LIV) and predict an energy dependence of the speed of light, leading to a dispersion of high-energy gamma-ray signals that travel over cosmological distances. Limits on the dispersion from short-duration substructures observed in gamma-rays emitted by gamma-ray bursts (GRBs) at cosmological distances have provided interesting...
Dr
Kanbach Gottfried
(MPE, Garching)
10/10/08, 3:00 PM
We describe a new generation gamma-ray observatory capable of
unprecedented spectroscopy over a wide range of gamma-ray energies (200
keV–50 MeV) and polarimetry (100–1000 keV). This mission was proposed to
ESA in the Cosmic Vision programme in 2008 and was presented to, but not
selected by ESA's Astronomy working group.
The primary scientific goal of the GRIPS mission is to revolutionize...
Dr
Vincenzo Vitale
(Dip. Fisica Roma 2)
10/10/08, 3:50 PM
The FERMI gamma ray satellite, previously known as GLAST, is in orbit, since June 2008. After a commissioning period is now delivering data.
The Large Area Telescope (LAT), onboard of FERMI, is the most sensitive gamma-ray detector to date, in the 20 MeV - 300GeV energy band.
It provides large effective collection area(>8000cm^2@1GeV), wide field of view (>2sr) and good energy resolution...
Dr
Dario Grasso
(INFN, Pisa)
10/10/08, 4:10 PM
We model the transport of cosmic ray (CR) nuclei in the Galaxy by means of a new numerical code which allows to account for a generic spatial distribution of the diffusion coefficient. We found that in the case of uniform diffusion, the main secondary/primary nuclei ratios and the modulated antiproton spectrum match consistently the available observations. We include in our analysis the...
Giulia Vannoni
(Max-Planck-Institut für Kernphysik, Heidelberg)
10/10/08, 5:00 PM
Clusters of galaxies are believed to be able to accelerate Cosmic Rays to ultrahigh energies (~10^18 eV and beyond) at accretion shocks. At this energies, the energy losses induced by the interaction with the CMB
radiation become effective and determine the maximum energy of protons and the shape of the cutoff in the proton energy spectrum. In particular, the dominant energy loss channel...
Dr
Sabrina Casanova
(Max Planck fuer Kernphysik)
10/10/08, 5:20 PM
The bulk of cosmic rays (CRs) which we measure within the Solar System is believed to be representative of the sea CRs everywhere in the Galaxy . However, the local CR flux might be due to one or few local sources . Here we investigate the possibility of measuring the level of Galactic sea CRs by combining the high spatial resolution gamma ray maps, becoming available now from
state of...
