EAS SYMPOSIUM 4: High-Energy Astrophysics: the keV-TeV connection

23-24 August 2007

Contact: Thierry Courvoisier (Switzerland)

In the frame of the European Astronomical Society (EAS) annual meeting in Yerevan August 20-25 2007 (JENAM 2007) we are organising a 2.5 days EAS symposium on high energy astrophysics.

The main goal of this meeting is to bring together the high energy astrophysics community working not only on the space based X-ray and gamma ray energy domains (keV-GeV), but also the ground based GeV-TeV community. We have indeed seen a number of breakthroughs in the Cerenkov detection technology that have brought many very new results. These results are important for the understanding of the physics of many high energy astrophysical sources. It is therefore particularly timely to bring closer the communities working on all aspects of observations and modeling of these sources to cross fertilise.

The meeting will also discuss a number of space borne and ground based projects that are being discussed now with a view to harmonise the developments. This latter element will be of particular importance in Europe in the next years with the implementation of ESA's Cosmic Vision programme and the progress of some European Union initiatives in ground based high energy astrophysics.

SOC

Felix Aharonian (Germany), Xavier Barcons (Spain), Thierry Courvoisier (Switzerland, Chair), Gunter Hasinger (Germany).

Topics:

- The high redshift high energy Universe
- High Energy Phenomena in Relativistic Jets
- Dark Matter, Neutrinos and Cosmic Rays
- Galactic sources
- The instrumental landscape now and in the future

Program

Thursday, August 23, 2007

Session 1. Extragalactic objects.

11:00-11:30       Alberto Castro-Tirado: Gamma-ray Bursts and their Afterglows in the Whole Electromagnetic Domain (invited)

11:30-12:00       Paulo Coppi: Diffuse Extragalactic Emission in keV-TeV (invited)

12:00-12:15       Roman A. Krivonos: Anisotropy of Hard X-ray Emitting Active Galactic Nuclei in the Local Universe 

12:15-12:30       Yana Tikhomirova: Search for Nearby Galaxies in BATSE/IPN Short Gamma-ray Bursts Locations

12:30-14:00       Lunch break

Session 2. High Energy Phenomena in Relativistic Jets.

14:00-14:30       Gennady Bisnovatyi-Kogan: Jet Collimation in Active Galactic Nuclei (invited)      

14:30-15:00       Rita Sambruna: Blazars at the Brink of the GLAST Era: What to Expect (invited)  

15:00-15:30       Josep Paredes: Observational Status of Microquasars in the Radio and Gamma-ray Domain (invited) 

15:30-16:00       Coffee break

16:00-16:30       Diana Hannikainen: X-ray Properties of Microquasars (invited)

16:30-16:45       Pol Bordas: High Energy Processes in the Interactions of Microquasar Jets with their Surroundings  

16:45-17:00       Valenti Bosch-Ramon: Processes behind the keV-TeV Connection in Galactic Jet Sources

Session 3. Dark Matter, Neutrinos and Cosmic Rays

17:00-17:30       John Carr: Exploring the Universe with Large Neutrino Telescopes (invited)

17:30-18:00       Pasquale Blasi: Auger invited talk (invited)

Friday, August 24, 2007

Session 4. Galactic sources

09:00-09:30       Andrei Bykov: Supernova Remnants (invited)

09:30-10:00       Sergei Bogovalov: Pulsar Driven Nebulae (invited)  

10:00-10:30       Yves Gallant: VHE Gamma-rays from Supernova Remnants and Pulsar Wind Nebulae (invited) 

10:30-11:00       Coffee break

11:00-11:15       Razmick Mirzoyan: Highlights of VHE Gamma Ray Observations With the 17m Diameter MAGIC Telescope 

11:15-11:30       Maria Chernyakova: Broad Band Emission of Gamma-ray Loud Binary Systems

11:30-11:45       Andrii Neronov: Gamma-ray Loud Binary Systems  

11:45-12:00       Sergey Tsygankov: Pulse Profile and Cyclotron Energy of X-ray Pulsars

12:00-12:15       Dmitry Khangulyan: On the Physics of the VHE Emission in LS 5039  

12:15-12:30       Anatoli Iyudin: 44Ti Content of Supernova Remnants     

12:30-14:00       Lunch break

Session 5. The instrumental landscape now and in the future

14:00-14:30       Arvind Parmar: X- and Gamma-ray Astronomy in Europe (invited)   

14:30-15:00       Thierry Courvoisier: Results from INTEGRAL and the European Perspective in Soft Gamma Rays (invited)  

15:00-15:30       Marco Tavani: The GeV Landscape (invited)

15:30-16:00       Coffee break

16:00-16:30       Maria Victoria Fonseca, for the MAGIC COLLABORATION: Observations of Extragalactic Sources with the MAGIC Telescope 

16:30-17:00       Xavier Barcons: Future Opportunities in Europe in High-Energy Astrophysics (invited)     

Felix Mirabel: Microquasars  

Vahé Petrosian: Nonthermal Activity in Clusters of Galaxies    

17:00- 18:00      General discussion on the future projects

POSTERS

S4-P01. Artur Amirkhanian, Ashot Chilingarian: Nor-Amberd Optical mini-observatory for detection of energetic Transient events (NOMOT)

S4-P02. Ara Avetissian: On Cosmological Variability of Fundamental Constants   

S4-P03. Ara Avetissian, Hovhannes Pikichyan: High Energy Radiative Transfer Processes in the Superdense Degenerate Plasma   

S4-P04. Ashot Chilingarian: Research of the Galactic Cosmic Rays from “knee” till “cutoff” (10¹⁶-10¹⁹) eV at Aragatz Cosmic Ray Observatory    

S4-P05. Ashot Chilingarian, Gagik Hovsyapayan: Studies of the Energy Spectra of Incident Cosmic Radiation by the Networks of Particle Detectors      

S4-P06. Lidia Erastova, Lusine Sargsyan, Areg Mickaelian, Enrico Massaro, et al.: Study of Long-Term Variability of ON 231    

S4-P07. Ekaterina Filippova, M. Revnivtsev, A. Lutovinov: Numerical Simulations of a Prompt Hard X-ray Emission during its Bright Outburst

S4-P08. Omar Kurtanidze, Maria Nikolashvili: Optical Photometry of X-ray Selected Blazars

S4-P09. Athina Meli: Diffusive Shock Acceleration in Astrophysics   

S4-P10. Filip Munz: Observations of VHE Blazars with INTEGRAL      

S4-P11. Alexander Stepanov, Yu.T. Tsap, Yu.G. Kopylova: X-ray Oscillations and Diagnostics of Stellar Flare Plasma     

S4-P12. Sergei Trushkin, N.A. Nizhelskij, N.N. Bursov: Jets Activity from RATAN and X-ray Monitong of Microquasars    

S4-P13. Victor Zabalza, A.J. Munoz-Arjonilla, Josep Paredes, J. Marti: The Chandra Field around LS I+61303: Source Identification and Analysis

 

Oral contributed presentations:

Krivonos Roman Aleksandrovich kris@hea.iki.rssi.ru 
Anisotropy of Hard X-ray emitting Active Galactic Nuclei in the local Universe 
R.Krivonos,M. Revnivtsev,A.Lutovinov,S.Sazonov,E.Churazov,R.Sunyaev / IKI,Moscow,Russia; MPA,Garching,Germany 
All-sky hard X-ray survey performed with INTEGRAL observatory in 17-60 keV energy band allows one to map the distribution of matter in the local Universe using the sample of Active Galactic Nuclei (AGN) emitting in this energy band. We present evidence of strong inhomogeneity in the spatial distribution of nearby (<70 Mpc) AGNs, which reflects the large-scale structure in the local Universe. 

Search for nearby galaxies in BATSE/IPN short Gamma-Ray Bursts locations
Tikhomirova Y. (Astro Space Centre of Lebedev Physical Institute, Moscow, Russia), Pozanenko A. (Space Research Institute, Moscow, Russia), Hurley K. (UC Berkeley, USA)
Recent observations have shown an apparent association of short duration GRB with a variety of host galaxies at moderate redshifts. However, statistical analysis with large sample of BATSE short GRB indicate that at least some portion of short GRBs originate in local Universe. We have considered pre-Swift well-localized short GRBs to examine possible association of the burst with galaxies at low redshift. We have used BATSE/IPN localizations of short bursts and SDSS DR5/PSCz catalogs as galaxies surveys. 

Bordas / Pol pbordas@am.ub.es 
High energy processes in the interactions of microquasar jets with their surroundings 
P. Bordas / Universitat de Barcelona, Spain V. Bosch-Ramon / Max planck institut fur kernphysik,Germany J.M Paredes / Universitat de Barcelona,Spain 
High energy processes involved in the interactions of microquasar jets with their environments are studied. We focus on the shock fronts developed outwards in the ISM and inwards in the jet. The shocked regions will contain both a thermal population of particles as well as a significant fraction of accelerated particles following a non-thermal power-law distribution. Self-similar structure growing, first order Fermi acceleration and strong shock jump conditions including magnetic field behaviour are considered in our model. Adopting different values for the width-to-length ratio, the spectral index of the non-thermal emitting populations, and the shock compression factor in both shocked regions, we present the radiative outcomes through thermal Bremsstrahlung processes for the thermal shock-heated population and synchrotron, Inverse Compton (IC) and relativistic Bremsstrahlung processes for the non-thermal distributions of particles. Broadband spectral energy distributions (SEDs) are presented and discussed. We emphasize on those spectral features capable of distinguishing between different parameter range values through observational comparisons, in particular from the microquasars Cygnus X-1 and Circinus X-1.

Bosch-Ramon/Valenti vbosch@mpi-hd.mpg.de 
Processes behind the keV-TeV connection in Galactic jet sources 
Max Planck Institut fuer Kernphysik 
X-ray binaries with relativistic jets can produce very energetic radiation. The likely occurrence of shocks, and the presence of dense matter, magnetic and photon fields, render these sources very good candidates to produce non-thermal radiation, as shown by observations. In the X-ray and TeV domains, it is common to look for correlations in the emission at both energy ranges due to a likely physically linked origin: synchrotron/IC emission in leptonic models, neutral pion gamma-rays/secondary radiation in hadronic ones. We review here different mechanisms that encompass these keV--TeV connection to explore the radiation processes in galactic jet sources.

Mirzoyan/Razmick razmik@mppmu.mpg.de 
Highlights of VHE Gamma Ray Observations With the 17m Diameter MAGIC Telescope Max-Planck-Institute for Physics, Munich, Germany Since almost three years the 17m diameter MAGIC atmospheric air Cherenkov imaging telescope for ground-based very high energy gamma ray asronomy is taking data on various celestial objects. Along with the main scientific program of the telescope that is focused on extragalactic objects also the galactic objects like supernova remnants, microquasars and pulsar wind nebulae are measured. In this talk I will concentrate on the main scientific highlights of the MAGIC telescope. 

Chernyakova Maria masha@cp.dias.ie 
Broad band emission of gamma-ray loud binary systems. 
M. Chernyakova (DIAS), A. Neronov (ISDC) 
Despite the variety of the X-ray binary systems, there are only three gamma-ray loud binary systems, namely PSR B1259-63, LSI +61 303 and LS 5039. In my talk I will show that the observed timing and spectral properties of the broad band emission (from radio to TeV) from these systems can be explained assuming that they are powered by the rotation energy of a young pulsar. 

Andrii Neronov andrii.neronov@obs.unige.ch 
Gamma-ray loud binary systems A.Neronov (ISDC), M.Chernyakova (DIAS) We discuss physical mechanisms of radio-to-TeV gamma-ray emission from gamma-ray loud binary systems. The emission spectrum of such systems can be formed in interaciton of a relativistic wind (produced either by a young pulsar or via pair production by gamma rays in the photon field of companion star ) with the wind from companion star. We discuss the possibility to constrain the physical characteristics of the pulsar winds from the multiwavelength observations of such systems. 

Tsygankov Sergey st@hea.iki.rssi.ru 
Pulse profile and cyclotron energy of X-ray pulsars 
S.Tsygankov, A.Lutovinov 
We present the results of broad band (3-100 keV) observations of X-ray pulsars with INTEGRAL and RXTE observatories. We concentrate on the luminosity and energy dependence of pulse profiles, pulsed fraction and variations of the cyclotron line energy. In particular, in the source V0332+53 the line energy changes nearly linearly with the luminosity, while in 4U0115+63 its behavior is more complicated. It is firstly shown that the pulsed fraction dependence on the energy has an obvious feature near the cyclotron energy. Moreover, changes of the cyclotron energy with the luminosity are accompanied by changes of this feature. Strong variations of the pulse profile with the energy and source intensity were found for several pulsars; in V0332+53 the
changes of the pulse profile near the cyclotron line are especially drastic. Results and possible emission mechanisms are briefly discussed in terms of theoretical models of accreting pulsars.

Khangulyan/Dmitry dmitry.khangulyan@mpi-hd.mpg.de 
On the physics of the VHE emission in LS 5039 
Max Planck Institut fuer Kernphysik 
The recent detection of VHE gamma-rays from LS 5039 with the HESS allows deep theoretical studies of radiation processes in there. Assuming an IC origin of this radiation, we performed detailed calculations of the electron evolution taking into account geometrical effects. These effects play crucial role in the formation of the gamma-radiation through the anisotropic IC and pair-production. We show that for a combination of model parameters we can approximately explain both the energy spectrum of gamma-rays extending to 20 TeV, and the observed modulation of the gamma-ray signal with the orbital period. 

Iyudin Anatoli F. aiyudin@srd.sinp.msu.ru 
EAS Symp.4:High-Energy Astrophysics. The keV-TeV Connection. invited 
44Ti content of supernova remnants 
A. Iyudin, Moscow State University, Skobeltsyn Institute of Nuclear Physics
It is known that radioactive 44Ti is mostly produced in supernovae explosions and is a primary isotope in the radioactive decay chain of 44Ti???44Sc???44Ca. Here we present a critical review of the amount of radioactive 44Ti produced by the core-collapse supernovae (SNe) that have given birth to the Cas A and RX J0852.0-4622/GRO J0852-4642 supernova remnants (SNRs) [1]. The 1.157 MeV line detections by COMPTEL [2,3,4] and the following from those detections the 44Ti mass estimates, derived with the use of the 1.157 MeV line flux, are compared to the mass estimates based on the measurements of Beppo-SAX PDS [5] and IBIS (ISGRI) [6] of the 44Sc line intensities at ~68 and ~78 keV, for Cas A. The non-detection of 44Sc lines from RX J0852.0-4622/GRO J0852-4642 by IBIS (ISGRI) and SPI instruments of INTEGRAL is confronted with the COMPTEL detection of the 44Ti (44Ca) line flux, as well as with the derived by COMPTEL shape of the 1.157 MeV line. Most recent results on the expansion velocity of the high-velocity debris of Cas A SNR [7], and XMM-Newton results on the expansion velocity of RX J0852.0-4622/GRO J0852-4642 [8] are compared to the COMPTEL derived expansion velocities of both SNRs, and are used to evaluate possible consequences of the heavy ions interaction with the ambient and/or SNR shell matter and the contribution of such interactions to the 44Ca line shape and intensity. The X-ray and optical observations that can be, and were used to derive an amount of 44Ti produced in SNRs are described and discussed. Undisputable advantages of using multiwavelength observations to derive 44Ti mass in SNR are confronted with the critical restrictions of the appropriate observations. Difficulties of such measurements for point-like and extended sources are evaluated for each of the potential wavelength range available at present or in future experiments. The derived quantities of 44Ti and of 44Sc are compared with the latest nucleosynthesis theory predictions. The new estimates of the 44Ti masses that were derived with the use of the above analysis for two SNRs, as well as the dynamical properties of remnants are used to constrain SN explosion models [9,10]. 
1. A. F. Iyudin, Nucl.Phys., A654 (1990) 900c.
2. A. F. Iyudin, R. Diehl, H. Bloemen, et al., A&A, 284 (1994) L1.
3. A. F. Iyudin, K. Bennett, H. Bloemen, et al., ESA, SP-382 (1997) 119.
4. A. F. Iyudin, V. Schoenfelder, K. Bennett, et al., Nature, 396 (1998) 142.
5. J. Vink, M. Laming, J.S. Kaastra, et al., ApJ, 560 (2001) L79.
6. M. Renaud, J. Vink, A. Decourchelle, et al., NewAR, 50 (2006) 540.
7. R.A. Fesen, M.C. Molly, J. Morse, et al., ApJ, 645 (2006) 283.
8. A. F. Iyudin, B. Aschenbach, V. Burwitz, et al., ESA, SP-622 (2006) submitted.
9. L.-S. The, D.D. Clayton, R. Diehl, et al., A&A, 450 (2006) 1037.
10. A. F. Iyudin, B. Aschenbach, K. Dennerl, et al., A&A, (2007) submitted.

Fonseca, Maria Victoria fonseca@gae.ucm.es
Observations of extragalactic sources with the MAGIC telescope 
M.V. Fonseca for the MAGIC COLLABORATION MAGIC currently is the largest world-wide, single dish, ground based imaging atmospheric Cherenkov telescope. Since 2004, gamma-ray emission from several active galactic nuclei (AGN) in the GeV/TeV energy range has been detected, some of which were newly discovered as very-high energy gamma-ray sources. The
gamma rays are assumed to originate from particle acceleration processes in the AGN jets. In the presentation, an overview of the AGN detected by MAGIC is given. We discuss spectral and temporal properties of these sources and its relation with the extragalactic background light. 

Poster presentations:

Chilingarian Ashot A., Hovsyapayan Gagik G. chili@aragats.am 
Studies of the Energy Spectra of incident cosmic radiation by the networks of particle detectors, Alikhanyan Physics Institute 
There are numerous indications that particle acceleration took place in supernovae remnants, by pulsars, super-massive black holes, in the galaxy clusters and by stars. As a universal mechanism operated on different scales the stochastic and shock acceleration is pointed. It is very important to use our nearest star ??? the sun, as laboratory in studying particle acceleration phenomena. The surface particle detectors, along with space-born spectrometers are capable of detecting solar particles in the energy range from KeVs till several Tens of GeV. The large surface arrays are detecting particle in energy range from ~100 TeV till EeV. This richness??? of information on particle fluxes on different scales can be used in studying physical processes responsible for particle acceleration in Universe. Surface detectors measuring Extensive Air Showers (EAS) initiated by Primary Cosmic Rays (PCR) incident on terrestrial atmosphere have been in operation since the last 50 years with main goal to explore the major enigma of Cosmic Ray (CR) origin and acceleration. Recent achievements of the Atmospheric Cherenkov Telescopes and X-ray space laboratories, establishing the supernova remnants (SNRs) as source of hadronic cosmic rays pose stringent conditions on the quality of the EAS evidence. After establishing the existence of the ???knee??? in all particle spectrum the most pronounced result from EAS studies is the rigidity dependent shift of the knee position to the highest energies. This feature first observed by the exploiting the separation of the primary beam in different groups of mass in MAKET-ANI, EAS-TOP and KASCADE experiments also pointed to the SNR blast shocks as CR source. The MAKET ANI detector is placed on mountain Aragats (Armenia) on 3200m at see level (40.50N, 44.20E ). More than 1.3???106 showers with size greater than 105 were registered in 1997-2004. The detector has effectively collected the cores of EAS, initiated by primaries with energies of 5???1014 - 1017eVResults from the MAKET-ANI experiment on the energy spectra of the ???light???(p+He) and ???heavy??? (O+Si+Fe) nuclear groups are compared with spectra obtained by balloon experiments, as well as with other available EAS spectra.

Avetissian Ara Karapet aavetis@ysu.am 
ON COSMOLOGICAL VARIABILITY OF FUNDAMENTAL CONSTANTS 
A.K.Avetissian The hypotheses that fundamental constants may vary depending on cosmological time have been discussed and further analyzed using additional arguments by many researchers connected with alternative theories and tests of General Relativity, as well as due to Cosmological implications of this issue in GUT and Superstrong Theory. This review aims to make a note of one alternative possibility of understanding the Astrophysical observation of Atomic Spectra at their formation epoch and bring together the data-analyse of observations and laboratory experiments. As the Quasars? spectra registered now were formed nearly 12,7x109 years ago, one can postulate that observed wavelength in spectra is increasing compared to laboratory values due to cosmological variability of Rydberg constant. If we assume that time-variation 

STUDY OF LONG-TERM VARIABILITY OF ON231 
L.K.Erastova, L.A.Sargsyan, A.M.Mickaelian, E.Massaro, et al. 
ON 231 (W Com, m=16.5, z=0.102) has been studied by a number of authors for its short and long term variability (e.g. Erastova 2004, AATr 23, 209). However, more observations are needed for understanding and explanation of its possible multiple variations, including the quasi-periodic and non-periodic ones reaching up to 0.3 magnitudes. During 1969-1976, one of the authors (LKE) had carried out observations in the Coma field with R.A.=12h26m, DEC=+25d55m for study of the variations of the flare stars. 187 plates with \"chain\" images (by a slight shifting of the plate for multiple images) were obtained using the Byurakan 0.5m and 1m Schmidt telescopes giving 5x5 deg and 4x4 deg fields, respectively. It appeared that ON 231 was present in 141 of these plates with some 1200 total exposures, and an idea was put forward to scan and measure these images for further variability studies. All available plates were scanned: out of 141 plates with ON 231, useful measurements were done in about 80 ones (in others, the object was too faint or the images were not good). A script was written under MIDAS for reduction of the plates and measurements. The study of the variability was done by a comparison with the neighbouring standard stars, and the equivalent widths (EW) of the measured images (each point in the chains) were the main criteria for the comparison. There are also two other AGN in the field: FBQS J122424.3+243623 (z=0.218, a 87GB and ROSAT source) and FBQS J123014.1+251804 (z=0.135, a ROSAT source). These objects will be studied later for a possible variability as well, as they are also blazar candidates.

Zabalza, Victor vzabalza@am.ub.es 
The Chandra field around LS I+61303: source identification and analysis
V. Zabalza, A.J. Munoz-Arjonilla, J.M. Paredes, J. Mart?? 
The high mass X-ray binary LS I+61303 was observed during 50 ks with the ACIS-I array aboard Chandra. The field of view spans 10 arcminutes around the target and includes many fainter X-ray sources. We have studied in detail some of these objects and here we present a thorough analysis for cases with enough statistics. We also report on their plausible identification with counterparts detected in surveys at other wavelengths (optical and infrared) as well as in archive pointed VLA observations.

Meli / Athina ameli@phys.uoa.gr 
DIffusive Shock Acceleration in Astrophysics Athina Meli The role of the diffusive particle acceleration in both non-relativistic and relativistic astrophysical shocks is reviewed and evaluated. We dicsuss the properties of these shocks and we further present Monte Carlo simulations especially studying the relativistic shocks efficiency in accelerating particles (i.e. protons or electrons) 
in astrophysical regions such as Super Novae, Active Galactic Nuclei hot spots and Gamma Ray Burts.