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We report the discovery of a compact object (R_e = 32 pc, M_B = -12.34 mag) at a projected distance of 9 kpc from Messier 59, a giant elliptical in the Virgo cluster. Using HST imaging and SDSS spectroscopy, both available in the Virtual Observatory, we find that this object has a blue core containing one-quarter of the light, and a redder n=1 Sersic envelope, as well as luminosity-weighted age of 9.3 +/- 1.4 Gyr, a metallicity of -0.03 +/- 0.04 dex and a velocity dispersion of 48 +/- 5 km/s. While ultra-compact dwarfs (UCDs) in the face-on view of the Fundamental Plane are found to form a sequence connecting the highest-luminosity globular clusters with the lowest-luminosity dwarf ellipticals, the compact object near M59 lies in between this UCD sequence and the positions of compact ellipticals. Its stellar age, metallicity, and effective surface brightness are similar to low-luminosity ellipticals and lenticulars, suggesting that SDSSJ124155.33+114003.7 is a result of the tidal stripping of such an object., Comment: 5 pages, 4 figures, accepted to MNRAS Letters

We present spatially resolved kinematics and stellar population parameters for three low-luminosity galaxies in the NGC128 group obtained by means of 3D spectroscopy. We briefly discuss their evolutionary scenarii., Comment: 2 pages, 1 figure, submitted to the proceedings of ``Pathways through an eclectic Universe''. The original PDF-version of the poster is attached as well

We present a middleware for visualization and exploration of complex datasets in a VO framework, that performs interaction between data archives and existing VO client applications using PLASTIC. It comprises: (1) PLASTIC-enabled Java control applet, integrated into archive web-pages and interacting with VO applications; (2) cross-browser compatible JavaScript part managing PLASTIC-aware VO Clients (launch, data manipulation) by means of Java LiveConnect. This (or similar) solution is an essential for the new generation VO-enabled data archives providing access to complex observational and theoretical datasets (3D-spectroscopy, N-body simulations, etc.) through web-interface. Thanks to PLASTIC capabilities it is possible to start all necessary client software with a single-click in the archive query result page in a web-browser. This simplifies the scientific usage of the VO resources and makes it easy even for users with no experience in the VO technologies., Comment: 4 pages, 1 figure, to appear in the proceedings of ADASS-XVII (ASP Conf. Series)

Our presentation is aimed at data centers providing access to complex observational and theoretical data and to the users of these resources. We show how to visualize complex datasets stored in the VO enabled data archives using existing VO client software and PLASTIC, a prototype of an application messaging protocol, for interaction between archive query results and tools. We demonstrate how to display and explore observable IFU datasets, provided within the ASPID-SR archive, using CDS Aladin, ESA VOSpec, and VO-Paris Euro3D Client. In the second part of the paper we show how to use TOPCAT for displaying results of N-body simulations of galaxy mergers available in the HORIZON GalMer database., Comment: 4 pages, 2 figures, to appear in the proceedings of ADASS-XVII (ASP Conf. Series)

Three cornerstones for the 3D data support in the Virtual Observatory are: (1) data model to describe them, (2) data access services providing access to fully-reduced datasets, and (3) client applications which can deal with 3D data. Presently all these components became available in the VO. We demonstrate an application of the IVOA Characterisation data model to description of IFU and Fabry-Perot datasets. Two services providing SSA-like access to 3D-spectral data and Characterisation metadata have been implemented by us: ASPID-SR at SAO RAS for accessing IFU and Fabry-Perot data from the Russian 6-m telescope, and the Giraffe Archive at the VO Paris portal for the VLT FLAMES-Giraffe datasets. We have implemented VO Paris Euro3D Client, handling Euro3D FITS format, that interacts with CDS Aladin and ESA VOSpec using PLASTIC to display spatial and spectral cutouts of 3D datasets. Though the prototype we are presenting is yet rather simple, it demonstrates how 3D spectroscopic data can be fully integrated into the VO infrastructure., Comment: 4 pages, 1 figure. To appear in the proceedings of the ESA Workshop "Astronomical Spectroscopy and the Virtual Observatory" held in Villafranca del Castillo, Spain, in March 2007

We use PostgreSQL DBMS for storing XML metadata, described by the IVOA Characterisation Data Model. Initial XML type support in the PostgreSQL has recently been implemented. We make heavy use of this feature in order to provide comprehensive search over Characterisation metadata tree. We built a prototype of the Characterisation metadata query service, implementing two access methods: (1) HTTP-GET/POST based interface implements almost direct translation of the query parameter name into XPath of the data model element in the XML serialisation; (2) Web-Service based interface to receive XQuery which is also directly translated into XPath. This service will be used in the ASPID-SR archive, containing science-ready data obtained with the Russian 6-m telescope., Comment: 3 pages, 1 figure. Proceedings of ADASS-XVI held in Tucson, AZ, USA, Oct.2006. To appear in the ASP Conference Series

ASPID stands for the "Archive of Spectral, Photometric, and Interferometric Data". The world largest collection of raw 3D spectroscopic observations of galactic and extragalactic sources is provided. ASPID-SR is a prototype of an archive of heterogeneous science ready data, fed by ASPID, where we try to exploit all the power of the IVOA Characterisation Data Model. Multi-level Characterisation metadata is provided for every dataset. The archive provides powerful metadata query mechanism with access to every data model element, vital for the efficient scientific usage of a complex informational system. We provide a set of access interfaces: SIAP/SSAP, HTTP-based characterisation metadata query, Web-service accepting ADQL/x., Comment: 3 pages, no figures. Proceedings of ADASS-XVI held in Tucson, AZ, USA, Oct.2006. To appear in the ASP Conference Series. Formal presentation of the ASPID-SR archive (http://alcor.sao.ru/php/aspid-sr/)

The MAGIC Project: Contributions to ICRC 2007, Merida, Mexico. Contents pages for the Contribution on behalf of the MAGIC Collaboration to the 30th ICRC that took place in July 2007 in Merida, Mexico. The contents are in html form with clickable links to the papers that exist on the Astrophysics archive. We hope that this will make it easier to access the output of the conference in a systematic way. Comments on how useful this is/ how it could be improved should be sent to michela.demaria@iuav.it., Comment: HTML file with clickable links to papers

A great effort is being made by the international Virtual Observatory community to build tools ready to be used by scientists. Presently, providing access to theoretical spectra in general, and synthetic spectra of galaxies in particular, is a matter of current interest in the Virtual Observatory. Several ways of accessing such spectra are available. We present two of them for accessing PEGASE.HR evolutionary synthesis models: HTTP-access to a limited number of parameters using Simple Spectral Access Protocol (SSAP), and full-featured WEB-service based access using Common Execution Architecture (CEA)., Comment: 2 pages, 1 figure, to appear in the proceedings of IAU Symposium 241 (Stellar Populations as Building Blocks of Galaxies)

We present a novel approach for simultaneous extraction of stellar population parameters and internal kinematics from the spectra integrated along a line of sight. We fit a template spectrum into an observed one in a pixel space using a non-linear $\chi^2$ minimization in the multidimensional parameter space, including characteristics of the line-of-sight velocity distribution (LOSVD) and parametrized star formation history (SFH). Our technique has been applied to IFU and multi-object spectroscopy of low-luminosity early type galaxies., Comment: 2 pages, to appear in the proceedings of IAU Symposium 241 (Stellar Populations as Building Blocks of Galaxies)

We have undertaken a large set of simulations of galaxy interactions and mergers (GalMer Project) in order to study the physical processes related to galaxy encounters. All morphological types along the Hubble sequence are considered in the initial conditions of the two colliding galaxies, with varying bulge-to-disk ratios and gas mass fractions. Different types of orbits are simulated, direct and retrograde, according to the initial relative energy and impact parameter. The self gravity of stars, gas and dark matter is taken into account through a tree-code algorithm, the gas hydrodynamics through SPH. Star formation is included adopting a density-dependent Schmidt law. This wide library of galaxy interactions and mergers, containing, at present, about 900 simulations of major encounters, represents an unique tool to investigate statistically the chemodynamical evolution of interacting systems. In the following, we present and discuss some results obtained exploring the dataset, together with some future perspectives., Comment: 4 pages, 5 figures. To appear in the proceedings of "SF2A-2007: Semaine de l'Astrophysique Francaise", (J. Bouvier, A. Chalabaev, and C. Charbonnel eds)

Aims: ``Compact ellipticals'' are so rare that a search for M32 analogs is needed to ensure the very existence of this class. Methods: We report here the discovery of A496cE, a M32 twin in the cluster Abell 496, located in the halo of the central cD. Results: Based on CFHT and HST imaging we show that the light profile of A496cE requires a two component fit: a Sersic bulge and an exponential disc. The spectrum of A496cE obtained with the ESO-VLT FLAMES/Giraffe spectrograph can be fit by a stellar synthesis spectrum dominated by old stars, with high values of [Mg/Fe] and velocity dispersion. Conclusions: The capture of A496cE by the cD galaxy and tidal stripping of most of its disc are briefly discussed., Comment: 4 pages, 4 figures, accepted for publication in A&A Letters

We have compared simple stellar populations (SSPs) generated with different population synthesis tools: BC03, Vazdekis and Pegase.HR and different stellar libraries: ELODIE3.1, SteLib and MILES. We find that BC03/SteLib SSPs are biased toward solar metallicity, however Pegase.HR/ELODIE3.1 and Vazdekis/MILES are extremely consistent. The extensive coverage of the space of atmospheric parameters in the large stellar libraries allows precise synthesis for a large range of ages (0.1 .. 10 Gyr) and metallicities (-2 .. +0.4 dex) limited by the quality of the determination of stellar parameters (like temperature scale of the giants)., Comment: 2 pages; proceedings of IAU Symposium No. 241, "Stellar Populations as Building Blocks of Galaxies", editors A. Vazdekis and R. Peletier

We present the first 3D observations of a diffuse elliptical galaxy (dE). The good quality data (S/N up to 40) reveal the kinematical signature of an embedded stellar disc, reminiscent of what is commonly observed in elliptical galaxies, though similarity of their origins is questionable. Colour map built from HST ACS images confirms the presence of this disc. Its characteristic scale (about 3 arcsec = 250 pc) is about a half of galaxy's effective radius, and its metallicity is 0.1-0.2 dex larger than the underlying population. Fitting the spectra with synthetic single stellar populations (SSP) we found an SSP-equivalent age of 5 Gyr and nearly solar metallicity [Fe/H]=-0.06 dex. We checked that these determinations are consistent with those based on Lick indices, but have smaller error bars. The kinematical discovery of a stellar disc in dE gives additional support to an evolutionary link from dwarf irregular galaxies due to stripping of the gas against the intra-cluster medium., Comment: 15 pages, 10 figures, accepted to MNRAS

The fast repositioning system of the MAGIC Telescope has allowed during its first data cycle, between 2005 and the beginning of year 2006, observing nine different GRBs as possible sources of very high energy gammas. These observations were triggered by alerts from Swift, HETE-II, and Integral; they started as fast as possible after the alerts and lasted for several minutes, with an energy threshold varying between 80 and 200 GeV, depending upon the zenith angle of the burst. No evidence for gamma signals was found, and upper limits for the flux were derived for all events, using the standard analysis chain of MAGIC. For the bursts with measured redshift, the upper limits are compatible with a power law extrapolation, when the intrinsic fluxes are evaluated taking into account the attenuation due to the scattering in the Metagalactic Radiation Field (MRF)., Comment: 25 pages, 9 figures, final version accepted by ApJ. Changet title to "MAGIC upped limits on the VERY high energy emission from GRBs", re-organized chapter with description of observation, removed non necessaries figures, added plot of effective area depending on zenith angle, added an appendix explaining the upper limit calculation, added some references

This thesis presents observational studies of evolution of dwarf elliptical galaxies. dE's are numerically dominant population in clusters of galaxies, but their origin and evolution is a matter of debate. Several scenarios of gas removal from dE's exist: galactic winds, ram pressure stripping, gravitaional harassment. We present new method to estimate stellar population parameters and internal kinematics, based on fitting observed spectra in the pixel space by PEGASE.HR synthetic populations. We apply this technique to 3D-spectroscopic observations of dE galaxies in the Virgo cluster and nearby groups and multiobject spectroscopy of several dozens of dE's in the Abell 496 cluster. We present discovery of young nuclei in bright dE galaxies in the Virgo cluster. Based on the analysis of observational data we conclude that: (1) there is an evolutionary connection between dE's and dIrr's, (2) the most probable scenario of gas removal is ram pressure stripping by the intergalactic medium., Comment: Full manuscript of the PhD thesis (revised version). Includes a short abstract in French. 107 pages, 28 figures, 12 tables. Defended on the 23rd of November, 2006 as a bilateral PhD between Moscow State University (Russia) and Universite Claude Bernard Lyon-1 (France). This is an unofficial English version used by referees and French members of the jury. Official version (Russian + French summary) is available at http://www.sai.msu.su/~chil/manuscript_fr.pdf

During the last decade ground-based very high-energy gamma-ray astronomy achieved a remarkable advancement in the development of the observational technique for the registration and study of gamma-ray emission above 100 GeV. It is widely believed that the next step in its future development will be the construction of telescopes of substantially larger size than the currently used 10 m class telescopes. This can drastically improve the sensitivity of the ground-based detectors for gamma rays of energy from 10 to 100 GeV. Based on Monte Carlo simulations of the response of a single stand-alone 30 m imaging atmospheric Cherenkov telescope (IACT) the maximal rejection power against background cosmic ray showers for low energy gamma-rays was investigated in great detail. An advanced Bayesian multivariate analysis has been applied to the simulated Cherenkov light images of the gamma-ray- and proton-induced air showers. The results obtained here quantitatively testify that the separation between the signal and background images degrades substantially at low energies, and consequently the maximum overall quality factor can only be about 3.1 for gamma rays in the 10-30 GeV energy range. Various selection criteria as well as optimal combinations of the standard image parameters utilized for effective image separation have been also evaluated., Comment: Accepted for publication in the Journal of Physics G

We report discovery of young embedded structures in three diffuse elliptical galaxies (dE) in the Virgo cluster: IC 783, IC 3468, and IC 3509. We performed 3D spectroscopic observations of these galaxies using the MPFS spectrograph at the Russian 6-m telescope, and obtained spatially resolved distributions of kinematical and stellar population parameters by fitting high-resolution PEGASE.HR synthetic single stellar populations (SSP) in the pixel space. In all three galaxies, the luminosity weighted age of the nuclei, about 4 Gyr, is considerably younger than population in the outer regions of the galaxies. We discuss two possibilities to acquire the observed structures -- dissipative merger event and different ram pressure stripping efficiency during two consequent crossings of the Virgo cluster centre., Comment: accepted to "Astronomy Letters". Version for astro-ph with colour figures. 14 pages, 3 figures, 2 tables

The MAGIC collaboration has studied the high peaked BL-Lac object 1ES1218+30.4 at a redshift z = 0.182, using the MAGIC imaging air Cherenkov telescope located on the Canary island of La Palma. A gamma-ray signal was observed with 6.4sigma significance. The differential energy spectrum for an energy threshold of 120GeV can be fitted by a simple power law yielding F_E(E) = (8.1+-2.1)*10^-7 (E/250GeV)^(-3.0+-0.4) TeV^-1 m^-2 s^-1. During the six days of observation in January 2005 no time variability on time scales of days was found within the statistical errors. The observed integral flux above 350GeV is nearly a factor two below the the upper limit reported by the Whipple Collaboration in 2003., Comment: 5 pages, 4 figures, submitted to ApJ

3D spectroscopy produces hundreds of spectra from which maps of the characteristics of stellar populations (age-metallicity) and internal kinematics of galaxies can be derived. We carried on simulations to assess the reliability of inversion methods and to define the requirements for future observations. We quantify the biases and show that to minimize the errors on the kinematics, age and metallicity (in a given observing time) the size of the spatial elements and the spectral dispersion should be chosen to obtain an instrumental velocity dispersion comparable to the physical dispersion., Comment: 5 pages, 3 figures, extended version of a poster proceeding to appear in "Science Perspectives for 3D Spectroscopy", eds. M. Kissler-Patig, M. M. Roth and J. R. Walsh, ESO Astrophysics Symposia. (The two last pages with figures are not in the conference proceedings.)

The long-duration GRB050713a was observed by the MAGIC Telescope, 40 seconds after the burst onset, and followed up for 37 minutes, until twilight. The observation, triggered by a SWIFT alert, covered energies above ~175 GeV. Using standard MAGIC analysis, no evidence for a gamma signal was found. As the redshift of the GRB was not measured directly, the flux upper limit, estimated by MAGIC, is still compatible with the assumption of an unbroken power-law spectrum extending from a few hundred keV to our energy range., Comment: 14 pages, 4 figures, submitted to ApJ

What is the origin of the numerous population of diffuse elliptical galaxies (dE) in clusters? These galaxies formed their stars several billion years ago and lost their gas. Though the stellar winds resulting from star formation and the interactions with the environment undoubedtly play a role, their respective role and details of the mechanism of this evolution is still debated. In this presentation we will review the first 3D spectroscopic observations of a handful of dE galaxies. These data reveal complex kinematical structures, with embedded discs and counter rotating cores, and they open extremely promising perspectives for studying the history of the stellar population throughout these various features. The presence of disks, which was already known from detailed image analysis, and of complex kinematics and the new constraints on the stellar population enforce the hypothesis of the evolutionary connection between dEs and disk galaxies., Comment: To be published in the proceedings of IAU Colloquium 198 on a "near-field cosmology with dwarf elliptical galaxies"

We are investigated possible correlations between the calculated arrival times of the first relativistic ions at Earth and GLE start times registered by surface monitors. The analysis is based on the arrival times and energies of the first solar ions, registered by the Solar Isotope Spectrometer (SIS) on board of the ACE satellite, and protons, registered by GOES satellites. We consider both cases when the interplanetary propagation of the first high energy ions is essentially scatter-free and the diffusion of high energy ions during propagation in the interplanetary magnetic field. We extrapolate the time-velocity and time-rigidity relationships to calculate the expected arrival times of the relativistic ions that are energetic enough to enter the atmosphere at the Aragats geographical location and produce secondary fluxes that reach the monitors., Comment: 4 pages, 3 figures, 29th International Cosmic Ray Conference Pune (2005)

Diffuse elliptical galaxies (or dwarfs) are the numerically dominant population in clusters like Virgo and Fornax. They carry only a few percent of the baryonic mass but are very sensitive to the environment; so they keep a fossil record of the environmental conditions over the life of the cluster. Recent observations of their kinematics and stellar populations cast new insights to their evolutionary history. The most promising constraints come from integral field spectroscopy. We present for the first time 3D observations of a dwarf elliptical galaxy, IC 3653. These good signal to noise data (S/N=30) obtained with the Russian 6 meters telescope reveal a complex kinematics reminiscent of that commonly observed in elliptical galaxies. The disk-like feature has no morphological counterpart in ACS data. Kinematical evidences for thin stellar disks confirm and enforce the earlier imagery observations and strengthen the connection with disk galaxies. We suggest that dE galaxies formed from small units, developing a disk. This disk was heated or destroyed by the winds induced by the star formation, and the galaxy was later depleted from the remaining gas by ram-pressure stripping when crossing the cluster., Comment: Oral contribution at the JENAM 2004 conference, Granada (8 pages, 3 figures)

The MIGALE project (http://www.sai.msu.su/migale) provides databases and data analysis tools to study the evolution of galaxies from z=1 to z=0. It develops and maintain a general database, HyperLeda, to give a homogenized parameterization for 3 million objects, and several archives or specialized databases. It also develops tools to analyse on-the-fly data extracted from the database or obtained through the Virtual Observatory (Virtual Instruments). The package made for this project, Pleinpot, is distributed as open source., Comment: SF2A-2004 conference, 4 pages, 1 figure

Using the EAS size spectra measured with the MAKET ANI array on Mt. Aragats, Armenia (3200m a.s.l.) in the range of the shower size 10^5 - 10^7 for different angles-of-incidence, the EAS attenuation length has been determined applying different analysis methods. The analysis is based on a data sample of 2.5*10^6 events collected in the period of June, 97 - April, 99. The results are compared with results deduced from data of the EAS TOP and KASCADE experiments., Comment: 9 pages, to appear in the ANI99 workshop proceedings, FZKA report Forschungszentrum Karlsruhe, ed. by A.Chilingarian, A.Haungs, H.Rebel and Kh.N.Sanosyan

The quality of the MAKET-ANI detector installation in view of the uniformity of the registration efficiency is demonstrated. Based on a data sample collected by the MAKET-ANI array in the period of June 1997 - March 1999, the dependencies of the age parameter on the zenith angle and the EAS size (10^5-10^7) are studied. The variation of the age parameter with the shower size can be approximately related to the elongation rate., Comment: 6 pages, to appear in the ANI99 workshop proceedings, FZKA report Forschungszentrum Karlsruhe, ed. by A.Chilingarian, A.Haungs, H.Rebel and Kh.N.Sanosyan

We report a characterization of the multiband flux variability and correlations of the nearby (z=0.031) blazar Markarian 421(Mrk 421) using data from Mets ̈ahovi, Swift, Fermi-LAT, MAGIC, FACT, and other collaborations and instruments from 2014November till 2016 June. Mrk 421 did not show any prominent flaring activity, but exhibited periods of historically low activity above 1 TeV (F>1TeV<1.7×10−12ph cm−2s−1) and in the 2–10 keV (X-ray) band (F2−10 keV<3.6×10−11erg cm−2s−1),during which the Swift-BAT data suggest an additional spectral component beyond the regular synchrotron emission. The highest flux variability occurs in X-rays and very high-energy (E>0.1 TeV)γ-rays, which, despite the low activity, show a significant positive correlation with no time lag. The HRkeV and HRTeV show the harder-when-brighter trend observed in many blazars, but the trend flattens at the highest fluxes, which suggests a change in the processes dominating the blazar variability. Enlarging our dataset with data from years 2007 to 2014, we measured a positive correlation between the optical and the GeV emission over a range of about 60 d centred at time lag zero, and a positive correlation between the optical/GeV and the radio emission over a range of about 60 d centred at a time lag of 43+9−6d. This observation is consistent with the radio-bright zone being located about 0.2 parsec downstream from the optical/GeV emission regions of the jet. The flux distributions are better described with a lognormal function in most of the energy bands probed, indicating that the variability in Mrk 421 is likely produced by a multiplicative process.