Search

The location of objects hidden in dense matter and the analysis of metallic surfaces using gamma backscattering are two possible applications strongly suggested here with experiments, highlevel Monte Carlo simulations, and some supporting basic theory.

Building materials cause direct radiation exposure because of their radium, thorium and potassium content. In this paper, samples of commonly used building materials in Tiruvannamalai, city, have been collected randomly over the city. The samples were tested for their radioactivity contents by using gamma spectroscopic measurements. All samples under investigation are within the recommended safety limit when used as building construction.

Lessons learned by basic scientists in the study of experimental nuclear physics can often go unnoticed by cyclotron operator’s intent on meeting a demanding schedule of tracer production. Prompt neutrons and gammas are the signature that the desired reaction is occurring, providing a robust measure of the expected yield.

On July 23, 2008 GRB 080723B, a bright GRB lasting about 105 s was detected by the INTEGRAL burst alert system. This burst was also detected by the Fermi Gamma‐ray burst monitor. At this time no Fermi/GBM GCN notices were distributed to the public because Fermi was still in commissioning phase. The simultaneous detection of a bright GRB by both satellites gives us the opportunity to cross‐calibrate the GBM with the already well‐calibrated instruments on‐board INTEGRAL, the Spectrometer SPI and the Imager IBIS. Time‐resolved spectroscopy of this long and structured GRB is of special importance because Fermi was slewing during the GRB was still ongoing. In this paper we present a first and still preliminary analysis of the GBM spectra and compare them to those obtained by SPI for the same selection of time intervals. A more accurate cross‐calibration will be forthcoming when the improved in‐flight calibration of GBM is available and the corresponding data and responses can be reprocessed.

The AGATA Demonstrator Array is presently under installation at Laboratori Nazionali di Legnaro, Italy, where it will replace the CLARA array at the target position of the PRISMA magnetic spectrometer. In the present contribution, the details of the installation will be reviewed. Preliminary results from the first in‐beam commissioning test will be given.

The Fermi Gamma‐ray Space Telescope launched on June 11, 2008 carries two experiments onboard—the Large Area Telescope (LAT) and the Gamma‐ray Burst Monitor (GBM). The primary mission of the GBM instrument is to support the LAT in observing γ‐ray bursts (GRBs) by providing low‐energy measurements with high temporal and spectral resolution as well as rapid burst locations over a large field‐of‐view (⩾8 sr). The GBM will complement the LAT measurements by observing GRBs in the energy range 8 keV to 40 MeV, the region of the spectral turnover in most GRBs. The GBM detector signals are processed by the onboard digital processing unit (DPU). We describe some of the hardware features of the DPU and its expected limitations during intense triggers.

Since the launch of the Fermi observatory on June 11 2008, the Gamma‐ray Burst Monitor (GBM) has seen approximately 250 triggers of which about 150 were cosmic gamma‐ray bursts (GRBs). GBM operates dozens of trigger algorithms covering various energy bands and timescales and is therefore sensitive to a wide variety of phenomena, both astrophysical and not.

The recent observations of Gamma‐ray bursts (GRBs) with Swift have provided unprecedented information about nature of GRBs. The launch of GLAST in late 2007 will unveil the final spectral regime of GRB prompt emission and afterglows. Here we briefly review various theoretical suggestions of producing high energy photons from GRB fireballs, and discuss what observatons are expected from the GLAST observatory.

Gamma‐ray pulsars are among the best targets for the Large Area Telescope (LAT) aboard the GLAST mission. The higher sensitivity, time and energy resolution of the LAT will provide data of fundamental importance to understand the physics of these fascinating objects. Powerful tools for studying the LAT capabilities for pulsar science are the simulation programs developed within the GLAST Collaboration. Thanks to these simulations it is possible to produce a detailed distribution of gamma‐ray photons in energy and phase that can be folded through the LAT Instrument Response Functions (IRFs). Here we present some of the main interesting results from the simulations developed to study the discovery potential of the LAT. In particular we will focus on the capability of the LAT to discover new radio‐loud gamma‐ray pulsars, on the discrimination between Polar Cap and Outer Gap models, and on the LAT pulsar sensitivity.

In 2006 the GLAST LAT collaboration organized a detailed simulation of 55 days of the gamma‐ray sky and particle background in orbit to test the simulation and analysis tools of the collaboration. For this simulation, designated Data Challenge 2 (DC2), empirical models for SNRs as gamma‐ray sources in the energy range of the LAT were developed, in most cases informed by X‐ray or gamma‐ray observations. The development of these models and an example of analysis of one of the simulated SNRs are described here.

The Gamma‐Ray Large Area Space Telescope (GLAST), scheduled to be launched in 2007, will provide the capability to observe Gamma‐Ray Bursts (GRB) from 10 keV to more than 300 GeV. The spectral and temporal properties of GRBs above a few GeV are still almost unknown, extending these detections to higher energies with GLAST will have a large impact on our knowledge of the particle acceleration and emission processes occuring within these sources. In this work we review the requirements and the opportunities for good coordination of GLAST with ground‐based telescopes operating above a few tens of GeV, and examine the potential of such simultaneous observations in terms of expected rates of alerts.

With more than 50 % of unidentified sources, the third EGRET catalogue reflects the complexity of source identification in the GeV domain. In that context, we developed a dedicated GLAST ScienceTool dubbed gtsrcid for the general purpose of source identification. gtsrcid has been designed in a very flexible way and allows cross correlation with any counterpart catalogue using user‐definable figures‐of‐merit. Our source identification strategy, the results for DC2 as well as possible improvements of our identification procedures are presented.

INTEGRAL detects a large number of gamma‐ray bursts outside of its field of view with the SPI ACS. Several of these bursts are also detected by IBIS. We present the results of the spectral analysis using the ISRGI, PICSIT and Compton mode data of several bursts. These bursts show very hard spectra with the high energy index reaching −2 above 1 MeV We show that there is a group of bursts with the peak energy Epeak in the MeV range. We discuss the implications of these findings for GLAST.

The giant radio galaxy M 87 was observed at GeV/TeV γ‐ray energies with the H.E.S.S. (High Energy Stereoscopic System) Cherenkov telescopes in the years 2003–2006. The observations confirm M 87 as the first extragalactic TeV γ‐ray source not of the blazar type (first indications of a signal were reported by the HEGRA collaboration earlier). The TeV γ‐ray flux as measured with H.E.S.S. is variable on time‐scales of days which strongly constrains the size of the emission region, excluding several models. The H.E.S.S. results and theoretical interpretations are presented in this paper.

The wide‐band all‐sky monitor (WAM) onboard Suzaku has the largest effective area in 300–5000 keV, and thus very powerful to constrain the E peak and high energy tail of gamma‐ray burst prompt emission. Collaboration with GLAST will give us high‐quality data of gamma‐ray prompt emissions to probe and resolve the emission mechanism and central engine of gamma‐ray bursts. Here we report initial results of the WAM and address on the collaboration with GLAST.

The Gamma‐ray Large Area Space Telescope (GLAST) Large Area Telescope (LAT) has the opportunity to contribute to the discovery of the nature of dark matter, mainly if dark matter is composed of new Weakly Interacting Massive Particles (WIMPs). We outline the basic signatures, strategies, and experimental challenges for dark matter detection. We describe the various search techniques being developed within GLAST and how they compare with one another. We discuss the future need for precision follow‐up observations of potential GLAST dark matter sources.

The GLAST LAT instrument will monitor the GeV gamma‐ray sky with uniform exposure and high sensitivity. It will obtain a snapshot of the entire sky in a few hours and thus will allow us to observe, simultaneously, the emission of many blazars, having different level of activity (flaring, intermediate and steady states), with good timing and spectral resolution. Because of the broad‐band emission of blazars (from radio to TeV), LAT data should be combined with those obtained at all other wavelengths in order to derive most of the parameters which characterize the physical conditions of a source. Here, we present the multiwavelength campaigns planned by the LAT Science Group on Blazars and Other AGNs for 2008.

The GLAST Burst Monitor (GBM) comprises 12 NaI and 2 BGO detectors dispersed about the GLAST spacecraft. The GBM instrument simulation software must generate an accurate response function database for all detectors in their flight configuration to optimize the mission science return. Before science analysis codes use the response database, we must confirm that our simulation codes and models can reproduce laboratory observations. To validate the simulation effort, Monte Carlo results are compared to calibrated laboratory measurements collected with a variety of radiation sources.

The Advanced Compton Telescope (ACT), NASA’s next major step in gamma‐ray astronomy, will probe the fires where chemical elements are formed by enabling high‐resolution spectroscopy of nuclear emission from supernova explosions. During the past several years, our collaboration has been undertaking a NASA mission concept study for ACT. This study was designed to (1) transform the key scientific objectives into specific instrument requirements, (2) to identify the most promising technologies to meet those requirements, and (3) to design a viable mission concept for this instrument. We will present the results of this study, including scientific goals, instrument design, and mission requirements.

GLAST LAT will detect several solar flares in gamma rays. Motivated by the CGRO results on neutrons emitted during a solar flare, we try to estimate the possibility of the LAT to detect solar neutrons. Besides gamma rays, neutrons could indeed interact in the LAT instrument and mimic a gamma‐ray signal. An estimate of the contamination of gamma‐ray detection in solar flares by the neutron component is given.

A golden age of GRB astronomy will be upon us when GLAST launches in late 2007 and Swift continues its mission. The Swift NASA MIDEX launched in November 2004 and is detecting ∼100 gamma‐ray bursts (GRBs) each year. For almost every burst there is a prompt (within ∼90 s) spacecraft repointing to give X‐ray and UV/optical observations of the afterglow. Swift has already collected an impressive database, including prompt emission to higher sensitivities than BATSE, uniform monitoring of afterglows, and rapid follow‐up by other observatories notified through the GCN. With the launch of GLAST, there will be the opportunity to combine the powers of Swift and GLAST to make tremendous progress in the study of GRBs. GRBs detected by either mission will trigger observation by the other to give multiwavelength data on prompt and afterglow emission from optical through GeV gamma rays. This paper summarizes scientific results from Swift and CGRO/EGRET and discusses the ways that Swift and GLAST can work together on GRB observations.

The Minimal Spanning Tree (MST) algorithm is a graph‐theoretical method of finding clusters in a given set of points. We apply MST to gamma‐ray bidimensional images and associate possible sources with the regions where photons’ arrival directions clusterize. Additional filters to select clusters are included to reduce spurious detections. We present some applications to simulated GLAST data.

The Gamma‐ray Large Area Space Telescope (GLAST) will observe the gamma‐ray sky in the MeV and GeV energy range. It will detect a number of gamma‐ray bursts (GRBs) every year, depending on their emission at high energies, which is still unknown. GLAST will be the first instrument observing GRBs at energies above 20 GeV. A systematic study prior to launch, which is foreseen for 15 November 2007, was the GLAST Data Challenge 2 (DC 2). For GLAST DC 2 two month of data taking were simulated. Based on these simulations the GRB Working Group performed systematic studies of the performance of GLAST in observing GRBs. These studies included the spectral analysis of the prompt emission, a position fit of the GRB, and the search for prompt and afterglow emissions in the LAT data.

We report on how the the GLAST Burst Monitor (GBM) Flight Software will detect gamma‐ray rate increases, a process known as “triggering”, and on how the Flight Software will locate and classify the causes of the triggers.

We provide an overview of the GLAST Guest Investigator (GI) program, which will support basic research relevant to the GLAST mission in yearly cycles beginning approximately two months after launch. Current details about the GLAST GI program will always be posted on the GLAST Science Support Center (GSSC) website: http://glast.gsfc.nasa.gov/ssc/.

At the end of the EGRET mission, only 6 Galactic sources in the 3rd EGRET catalog had firm identifications: 5 young pulsars and a solar flare. Another dozen or so had plausible counterparts. Now, at the dawn of the GLAST era, around 30 sources detected at other wavelengths have been identified as probable or plausible counterparts. These include nearly all of the sources with significant emission above 1 GeV, which will be the sources GLAST will best be able to study. I review the current status of our knowledge of these sources based on radio, infrared, and X‐ray data. These Galactic sources are destined to be the first sources firmly identified by GLAST.

The LAT Instrument Science Operations Center (ISOC) will perform various tasks to support coordination of multiwavelength observations for transient sources. In this paper, we describe the prototype implementation of the Automated Science Processing (ASP) for the detection and analysis of gamma‐ray bursts (GRBs) in LAT and GBM data. The GRB‐related tasks include: position refinement using LAT data given initial GBM or GCN locations, spectral analysis using LAT data alone, joint spectral fitting with GBM data, gamma‐ray afterglow detection and characterization, and blind searches for prompt burst emission in LAT data.

A virtual laboratory via internet to provide a highly iterative and powerful teaching tool for scientific and technical discipline is given. The experimenter takes advantage of a virtual laboratory and he can execute nuclear experiment at introductory level e.g. Gamma ray detection with Geiger‐Muller Counter at remote location using internet communication technology.

During its first cycle, the MAGIC (Major Atmospheric Gamma‐ray Imaging Cherenkov) telescope was performing an observational campaign covering a total of about 250 hours on galactic sources. Here we review the results for the very high energy (> 100 GeV) γ‐ray emission from some of those sources. We focus on LS I +61 303 and PSR 1951+32.

The Gamma‐ray Large Area Space Telescope, GLAST, is a mission to measure the cosmic gamma‐ray flux in the energy range 20 MeV to > 300 GeV, with supporting measurements for gamma‐ray bursts from 8 keV to 30 MeV. With its launch in late 2007, GLAST will open a new and important window on a wide variety of high‐energy phenomena, including black holes and active galactic nuclei, gamma‐ray bursts, the origin of cosmic rays and studies of supernova remnants, and searches for hypothetical new phenomena. Along with the major science questions for GLAST, this talk will include the mission status, operations plans, and the opportunities for Guest Investigators.

The results of alpha, beta, gamma global activity measurements and gamma spectrometric measurements are presented. For more detailed characterization of samples, gamma‐spectrometric measurement, implying identification of radionuclides and their activities are carried‐out on significant ambiental annual samples.

High-energy gamma-ray sources are inherently nonthermal, multiwavelength objects. With the launch of the Gamma-ray Large Area Space Telescope (GLAST) scheduled for later this year, the GLAST Large Area Telescope (LAT) Collaboration invites cooperative efforts from observers at all wavelengths. Among the many topics where multiwavelength studies will maximize the scientific understanding, two stand out for particular emphasis: (1) Active Galactic Nuclei. The study of AGN gamma-ray jets through time variability and spectral modeling can help link the accretion processes close to the black hole with the large-scale interaction of the AGN with its environment; (2) Unidentified Gamma-ray Sources. New gamma-ray sources need first to be identified with known objects seen at other wavelengths using position, spectrum, or time variability, and then multiwavelength studies can be used to explore the astrophysical implications of high-energy radiation from these sources. Observers interested in any type of coordinated observations should contact the LAT Multiwavelength Coordinating Group.

The poster presents a set of simple tools being developed to predict GLAST’s performance for specific cases, like the accumulation time needed to reach a given significance or statistical accuracy for a particular source. Different examples are given, like the generation of a full‐sky sensitivity map.

The Electron Multiplying CCD (EMCCD) astronomical camera, under development at the Institute of Astronomy UNAM, will be able to obtain images of faint optical objects with very low instrumental noise and short integration times. The EMCCD is a normal CCD with an additional multiplication register located before the input of the readout amplifier. This will be a very suitable instrument to search for optical pulsations of unidentified gamma‐ray sources, specially with GLAST entering the realm of radio quiet gamma‐ray loud pulsars.

The Suzaku Wide‐band All‐sky Monitor (WAM), realized by large thick anti‐coincidence shields of the Hard X‐ray Detector (HXD), can be powerful gamma‐ray burst (GRB) detector which is sensitive to 50–5000 keV gamma‐rays. The WAM is now in a full operational phase, and we have already detected some GRBs simultaneously with other satellites (Swift, Konus‐Wind, HETE2 and INTEGRAL SPI/ACS). The most impressive event among detected GRBs is GRB051008, which was detected up to 2 MeV with the WAM. In this paper, we report on the WAM in‐flight performance as a GRB monitor from initial three‐months operations, focusing on the GRB trigger status and spectral analysis of GRB051008 and GRB051111 combined with Swift.

The observational properties of the short‐duration gamma‐ray bursts are reviewed. The time histories and energy spectra of these bursts, whether they are observed by the interplanetary network, HETE, Swift, or BATSE, appear to be drawn from the same sample. However, the fluences of the bursts differ considerably; in order of decreasing fluence, they are the bursts observed by the IPN, HETE, Swift, and BATSE. This suggests that, just as for the long duration bursts, Swift may be observing a more distant population. The question of whether some events could be extragalactic giant magnetar flares is examined. One recent event, GRB051103, may be in this category.

It has been demonstrated that the colors of optical afterglows (OAs) of GRBs are unique and almost identical for most of these events detected and analyzed in detail so far. This enables conclusions toward physics of the source and physics of the source environment. In addition, OAs can be identified on CCD images taken at one time but in various filters. In this study, we compare the color behaviour of OAs of GRBs with those of other extragalactic objects. We will show that not only the physical processes involved as well as environment of the objects can be studied this way but also a classification of objects of various types is possible with color photometric data provided e.g. by deep CCD searches and experiments.

We refer on the recent developments of LOBSTER project suggesting novel wide‐field Lobster‐Eye type of X‐ray All Sky Monitor to detect and to analyze GRBs including XRF and X‐ray rich GRBs. The triggers can be detected and localized by their X‐ray emission in the 0.1 – 8 keV energy range. The system exhibits fine detecting sensitivities of order of 10–12 ergcm−2s−1 and the localization accuracy is of order of a few arcmin. The LOBSTER is expected to contribute significantly to analyses of GRBs and especially the XRFs.

The majority of practical radioactive materials decay by modes that include γ‐ray emission. For questions of “how much” or “how pure,” one must know the absolute intensities of the major radiations. We are using liquid scintillation counting (LSC) to measurements of disintegration rates, coupled with γ‐ray spectroscopy to measure absolute γ‐ray emission probabilities. Described is a study of the 227Th chain yielding absolute γ‐ray intensities with ∼0.5% accuracy and information on LSC efficiencies.

BART is a 25 cm aperture, intelligent robotic CCD telescope, devoted for observation of prompt gamma ray burst emission and early afterglow. It’s operating since early 2001. Till now, it responded to many GCN GRB alerts.

VERITAS (Very Energetic Radiation Imaging Telescope Array System), is one of a new generation of TeV gamma‐ray observatories. The current status of its construction is described here. The first two telescopes and cameras have been completed and meet the design specifications; the full array of four telescopes could be operational by the end of 2006.

GRB 031203 was discovered by the INTEGRAL burst analysis system in near real time. It was about 10° off axis, thus well within the partially coded IBIS FoV and within the SPI fully coded FoV. This led to prompt follow up observations, reported on elsewhere, which resulted in red shift and luminosity information and estimates of the prompt soft X‐ray intensity. Here we have revisited the INTEGRAL observations, notably including an analysis of the SPI germanium spectrograph data, which allows improved characterization of the spectral energy distribution to energies in excess of 200 keV. We explore the possibility of imposing new constraints on Epeak and on the hard‐soft temporal lag determination.

The GLAST Large Area Telescope (LAT) is the next generation satellite experiment for high‐energy gamma‐ray astronomy. It is a pair conversion telescope built with a plastic anticoincidence shield, a segmented CsI electromagnetic calorimeter, and the largest silicon strip tracker ever built. It will cover the energy range from 30 MeV to 300 GeV, shedding light on many issues left open by its predecessor EGRET. One of the most exciting science topics is the detection and observation of gamma‐ray bursts (GRBs). In this paper we present the work done so far by the GRB LAT science group in studying the performance of the LAT detector to observe GRBs. We report on the simulation framework developed by the group as well as on the science tools dedicated to GRBs data analysis. We present the LAT sensitivity to GRBs obtained with such simulations, and, finally, the general scheme of GRBs detection that will be adopted on orbit.

This paper focus on the necessary requirements for a modern astroparticle physics detector based either on stratospheric balloons, either on satellite. The main technical solutions used to build a reliable detector are described. Finally, the most relevant experiments that have been developed with the INFN contribution and that will be ready in the near future (both for γ and charged cosmic rays detection) are described.

Thanks to the IBIS Compton mode, the INTEGRAL satellite is able to detect and localize bright and hard (E > 200 keV) GRBs, which happen outside of the nominal INTEGRAL telescopes field of view. We have developed a method to analyze INTEGRAL data and to produce spectra. We present results for two bursts 030406A and 030722A of dozen detected by the IBIS Compton mode during the first year of the INTEGRAL mission.

Within the framework of our studies of proton rich nuclei around the N = 126 and N = 152 neutron shells we have performed a series of α‐γ‐coincidence studies. The nuclei of interest were separated in‐flight by the velocity filter SHIP and implanted into a position sensitive 16‐strip PIPS‐detector where their arrival and subsequent α‐decays were registered. Associated γ‐rays were detected by a Ge‐Clover‐detector. In the present work recent results concerning 216Th and α‐decay chains of 251No and 257Db are given together with brief discussion.

In the range E{gamma}=0.24-18.565 MeV investigations were carried out of the absolute efficiency of {gamma}-ray detection with the HPGe-detector GC 5019 (CANBERRA). The investigations were performed in connection with measurements of proton radiation capture reaction cross sections on the lightest nuclei.

X‐ray light curves for 4 gamma‐ray bursts detected with the All‐Sky Monitor on RXTE are presented. For two of the bursts, we also present simultaneous higher energy light curves obtained by BATSE and the BeppoSAX GRBM. We discuss the important features of the 4 sets of light curves and their shortcomings. We also briefly discuss future observations of X‐ray light curves and the problems they could address.

We have developed a simple scheme using a 1‐dimensional discrete wavelet transform, to search for bursts in the ground analysis of HETE data. The method, which complements the on‐board HETE triggering systems, has proven useful for verifying that these systems are functioning and for detecting untriggered bursts. We outline the method and discuss the results obtained.