WorldWideScience

Sample records for extragalactic experiment ege

  1. EXTRAGALACTIC DARK MATTER AND DIRECT DETECTION EXPERIMENTS

    International Nuclear Information System (INIS)

    Baushev, A. N.

    2013-01-01

    Recent astronomical data strongly suggest that a significant part of the dark matter content of the Local Group and Virgo Supercluster is not incorporated into the galaxy halos and forms diffuse components of these galaxy clusters. A portion of the particles from these components may penetrate the Milky Way and make an extragalactic contribution to the total dark matter containment of our Galaxy. We find that the particles of the diffuse component of the Local Group are apt to contribute ∼12% to the total dark matter density near Earth. The particles of the extragalactic dark matter stand out because of their high speed (∼600 km s –1 ), i.e., they are much faster than the galactic dark matter. In addition, their speed distribution is very narrow (∼20 km s –1 ). The particles have an isotropic velocity distribution (perhaps, in contrast to the galactic dark matter). The extragalactic dark matter should provide a significant contribution to the direct detection signal. If the detector is sensitive only to the fast particles (v > 450 km s –1 ), then the signal may even dominate. The density of other possible types of the extragalactic dark matter (for instance, of the diffuse component of the Virgo Supercluster) should be relatively small and comparable with the average dark matter density of the universe. However, these particles can generate anomaly high-energy collisions in direct dark matter detectors.

  2. Experiences with the GLUE information schema in the LCG/EGEE production grid

    International Nuclear Information System (INIS)

    Burke, S; Andreozzi, S; Field, L

    2008-01-01

    A common information schema for the description of Grid resources and services is an essential requirement for interoperating Grid infrastructures, and its implementation interacts with every Grid component. In this context, the GLUE information schema was originally defined in 2002 as a joint project between the European DataGrid and DataTAG projects and the US iVDGL. The schema has major components to describe Computing and Storage Elements, and also generic Service and Site information. It has been used extensively in the LCG/EGEE Grid, for job submission, data management, service discovery and monitoring. In this paper we present the experience gained over the last five years, highlighting both successes and problems. In particular, we consider the importance of having a clear definition of schema attributes; the construction of standard information providers and difficulties encountered in mapping an abstract schema to diverse real systems; the configuration of publication in a way which suits system managers and the varying characteristics of Grid sites; the validation of published information; the ways in which information can be used (and misused) by Grid services and users; and issues related to managing schema upgrades in a large distributed system

  3. Blueprint and First Experiences Bridging Hardware Virtualization and Global Grids for Advanced Scientific Computing: Designing and Building a Global Edge Services Framework (ESF) for OSG, EGEE, and LCG

    CERN Document Server

    Rana, A S; Vaniachine, A; Wurthwein, F; Foster, I; Sotomayor, B; Freeman, T

    2006-01-01

    We report on first experiences with building and operating an edge services framework (ESF) based on Xen virtual machines instantiated via the workspace service in Globus toolkit, and developed as a joint project between EGEE, LCG, and OSG. Many computing facilities are architected with their compute and storage clusters behind firewalls. Edge services (ES) are instantiated on a small set of gateways to provide access to these clusters via standard grid interfaces. Experience on EGEE, LCG, and OSG has shown that at least two issues are of critical importance when designing an infrastructure in support of ES. The first concerns ES configuration. It is impractical to assume that each virtual organization (VO) using a facility will employ the same ES configuration, or that different configurations will coexist easily. Even within a VO, it should be possible to run different versions of the same ES simultaneously. The second issue concerns resource allocation: it is essential that an ESF be able to effectively gu...

  4. EGEE enters second phase

    CERN Multimedia

    2006-01-01

    This month has seen the launch of the second two-year phase of the Enabling Grids for E-sciencE project (EGEE-II), with a transition meeting for the partners held at CERN on 12-13 April. Co-funded by the European Commission and coordinated by CERN, the EGEE project is providing an international Grid computing infrastructure - now numbering some 200 sites and 20 000 CPUs in 39 countries - to support the scientific community worldwide. 'We are all very happy about the smooth start of the second phase of EGEE,' said Project Director Bob Jones. 'The project builds on the successes of its first two years and we are now focussing on the stability of the deployed infrastructure. Growing beyond our pilot application areas of HEP and biomedicine, we now see increasing use by researchers from other fields. Recently we've added finance and fusion to the list of disciplines we support, and we are always looking for new users.' More information on EGEE can be found at www.eu-egee.org.

  5. Data management in EGEE

    Energy Technology Data Exchange (ETDEWEB)

    Frohner, Akos; Baud, Jean-Philippe; Rioja, Rosa Maria Garcia; Mollon, Remi; Smith, David; Tedesco, Paolo [CERN (Switzerland); Grosdidier, Gilbert [LAL/IN2P3/CNRS (France)

    2010-04-01

    Data management is one of the cornerstones in the distributed production computing environment that the EGEE project aims to provide for a e-Science infrastructure. We have designed and implemented a set of services and client components, addressing the diverse requirements of all user communities. LHC experiments as main users will generate and distribute approximately 15 PB of data per year worldwide using this infrastructure. Another key user community, biomedical projects, have strict security requirements with less emphasis on the volume of data. We maintain three service groups for grid data management: The Disk Pool Manager (DPM) Storage Element (with more than 100 instances deployed world-wide), the LCG File Catalogue (LFC) and the File Transfer Service (FTS) which sustains an aggregated transfer rate of 1.5GB/sec. They are complemented by individual client components and also tools which help coordinating more complex uses cases with multiple services (GFAL-client, lcg util, eds-cli). In this paper we show how these services, keeping clean and standard interfaces among each other, can work together to cover the data flow and how they can be used as individual components to cover diverse requirements. We will also describe areas that we consider for further improvements, both for performance and functionality.

  6. EGEE helping bridge digital divide EGEE'06 Conference preview

    CERN Multimedia

    2006-01-01

    "In this GRIDtoday Q&A, EGEE project director Bob Jones discusses where EGEEE began and where it is now as the project enters the EGEE II era. In addition, Jones previews the EGEE'06 conference, which kicks off Sept. 25 in Geneva, Switzerland, and features for the first time a prominent businee track." (2 pages)

  7. Data management in WLCG and EGEE

    CERN Document Server

    Donno, Flavia; CERN. Geneva. IT Department

    2008-01-01

    This work is a contribution to a book on Scientific Data Management by CRC Press/Taylor and Francis Books. Data Management and Storage Access experience in WLCG is described together with the major use cases. Furthermore, some considerations about the EGEE requirements are also reported.

  8. The ATLAS software installation system for LCG/EGEE

    Energy Technology Data Exchange (ETDEWEB)

    Salvo, A D [Istituto Nazionale di Fisica Nucleare, sez. Roma 1 (Italy); Barchiesi, A [Universita di Roma I ' La Sapienza' (Italy); Gnanvo, K [Queen Mary and Westfield College (United Kingdom); Gwilliam, C [University of Liverpool (United Kingdom); Kennedy, J; Krobath, G [Ludwig-Maximilians-Universitaet Muenchen (Germany); Olszewski, A [Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences (Poland); Rybkine, G [Royal Holloway College (United Kingdom)

    2008-07-15

    The huge amount of resources available in the Grids, and the necessity to have the most up-to-date experimental software deployed in all the sites within a few hours, have driven the need for an automatic installation system for the LHC experiments. In this work we describe the ATLAS system for the experiment software installation in LCG/EGEE, based on the Light Job Submission Framework for Installation (LJSFi), an independent job submission framework for generic submission and job tracking in EGEE. LJSFi is able to automatically discover, check, install, test and tag the full set of resources made available in LCG/EGEE to the ATLAS Virtual Organization in a few hours, depending on the site availability.

  9. Atlas event production on the EGEE infrastructure

    CERN Document Server

    Espinal, X; Perini, L; Rod, W

    2007-01-01

    ATLAS is one of the four LHC (Large Hadron Collider) experiments at CERN, is devoted to study proton-proton and ion-ion collisions at 14TeV. ATLAS collaboration is composed of about 2000 scientists spread around the world. The activity of the experiment requirements for next year is of about 300TB of storage and a CPU power of about 13 Mski2sk, and is relying on GRID philosophy and EGEE infrastructure. Simulated events are distributed over EGEE by the Atlas production system. Data has to be processed and must be accessible by a huge number of scientists for analysis. The throughput of data for Atlas experiment is expected to be of 320 MB/s with an integrated amount of data per year of ~10Pb. The processing and storage need a distributed share of resources, spread worldwide and interconnected with GRID technologies as the requirements are so demanding for the LHC. In that sense event production is the way to produce, process and store data for analysis before the experiment startup, and is performed in a distr...

  10. Using EGEE against avian flu

    CERN Multimedia

    2006-01-01

    During April 2006 avian flu was spreading across the world with the potential of turning into a pandemic, a drug to treat the deadly H5N1 strain was needed. Such a task required the huge processing power provided by EGEE, which analysed 300 000 possible drug components for their suitability. This map shows the network of computer centres and their activity during this time.

  11. The EGEE user support infrastructure

    CERN Document Server

    Antoni, T; Mills, A

    2007-01-01

    User support in a grid environment is a challenging task due to the distributed nature of the grid. The variety of users and VOs adds further to the challenge. One can find support requests by grid beginners, users with specific applications, site administrators, or grid monitoring operators. With the GGUS infrastructure, EGEE provides a portal where users can find support in their daily use of the grid. The current use of the system has shown that the goal has been achieved with success. The grid user support model in EGEE can be captioned ‘regional support with central coordination’. Users can submit a support request to the central GGUS service, or to their Regional Operations' Centre (ROC) or to their Virtual Organisation helpdesks. Within GGUS there are appropriate support groups for all support requests. The ROCs and VOs and the other project wide groups such as middleware groups (JRA), network groups (NA), service groups (SA) and other grid infrastructures (OSG, NorduGrid, etc.) are connected via a...

  12. The EGEE user support infrastructure

    CERN Document Server

    Antoni, Torsten

    2008-01-01

    Grid user support is a challenging task due to the distributed nature of the Grid. The variety of users and Virtual Organisations adds further to the challenge. Support requests come from Grid beginners, from users with specific applications, from site administrators, or from Grid monitoring operators. With the GGUS infrastructure, EGEE provides a portal where users can find support in their daily use of the Grid. The current use of the system shows that the goal has been achieved with success. The Grid user support model in EGEE can be captioned "regional support with central coordination". This model is realised through a support process which is clearly defined and involves all the parties that are needed to run a project-wide support service. This process is sustained by a help desk system which consists of a central platform integrated with several satellite systems belonging to the Regional Operations Centres (ROCs) and the Virtual Organisations (VOs). The central system (Global Grid User Support, GGUS)...

  13. Encrypted Data Storage in EGEE

    CERN Document Server

    Frohner, Ákos

    2006-01-01

    The medical community is routinely using clinical images and associated medical data for diagnosis, intervention planning and therapy follow-up. Medical imaging is producing an increasing number of digital images for which computerized archiving, processing and analysis are needed. Grids are promising infrastructures for managing and analyzing the huge medical databases. Given the sensitive nature of medical images, practiotionners are often reluctant to use distributed systems though. Security if often implemented by isolating the imaging network from the outside world inside hospitals. Given the wide scale distribution of grid infrastructures and their multiple administrative entities, the level of security for manipulating medical data should be particularly high. In this presentation we describe the architecture of a solution, the gLite Encrypted Data Storage (EDS), which was developed in the framework of Enabling Grids for E-sciencE (EGEE), a project of the European Commission (contract number INFSO--508...

  14. World view of the EGEE infrastrucutre

    CERN Multimedia

    2007-01-01

    This view is of the Enabling Grids for E-sciencE (EGEE) project seen on the world scale. The EGEE allows the processing power of many computers to be shared so that the huge amount of data produced at CERN's new collider, the Large Hadron Collider (LHC) can be processed. The sites used in the Grid can be downloaded in a zipped .kmz format, which can be imported into Google Earth.

  15. European view of the EGEE infrastructure

    CERN Multimedia

    2007-01-01

    This view is of the Enabling Grids for E-sciencE (EGEE) infrastructure zoomed in on Europe. The EGEE allows the processing power of many computers to be shared so that the huge amount of data produced at CERN's new collider, the Large Hadron Collider (LHC) can be processed. The sites used in the Grid can be downloaded in a zipped .kmz format, which can be imported into Google Earth.

  16. Environmental consequences of the Chernobyl accident and their remediation: Twenty years of experience. Report of the UN Chernobyl Forum Expert Group 'Environment' (EGE). Working material

    International Nuclear Information System (INIS)

    2005-08-01

    remediation and special health-care programmes, and to suggest areas where further research is required; and to accept the following Terms of Reference (TOR) of the Forum. The objectives of the Chernobyl Forum were defined as follows: To explore and refine the current scientific assessments on the long-term health and environmental consequences of the Chernobyl accident, with a view to producing authoritative consensus statements focusing on: the health effects attributable to radiation exposure caused by the accident, the environmental consequences induced by the radioactive materials released due to the accident, e.g., contamination of foodstuffs, and additionally to address the consequences attributable to the accident although not directly related to the radiation exposure or radioactive contamination; To identify gaps in scientific research relevant to the radiation-induced or radioactive contamination-induced health and environmental impacts of the accident, and suggest areas where further work is required based on an assessment of the work done in the past, and bearing in mind ongoing work and projects; To provide advice on, and to facilitate implementation of scientifically sound programmes on mitigation of the accident consequences, including possible joint actions of the organizations participating in the Forum, such as: agricultural, economic and social life under safe conditions, special health care of the affected population, monitoring of the long-term human exposure to radiation, and addressing the environmental issues pertaining to the decommissioning of the Shelter and management of radioactive waste originating from the Chernobyl accident. The Chernobyl Forum itself continued as a high-level organisation of senior officials from UN agencies and the three more affected countries. The actual work has been accomplished by two expert groups: Expert Group -Environment - (EGE) and Expert Group 'Health' (EGH). Members of each of these two groups consisted of

  17. Environmental consequences of the Chernobyl accident and their remediation: Twenty years of experience. Report of the UN Chernobyl Forum Expert Group 'Environment' (EGE). Working material

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-08-01

    remediation and special health-care programmes, and to suggest areas where further research is required; and to accept the following Terms of Reference (TOR) of the Forum. The objectives of the Chernobyl Forum were defined as follows: To explore and refine the current scientific assessments on the long-term health and environmental consequences of the Chernobyl accident, with a view to producing authoritative consensus statements focusing on: the health effects attributable to radiation exposure caused by the accident, the environmental consequences induced by the radioactive materials released due to the accident, e.g., contamination of foodstuffs, and additionally to address the consequences attributable to the accident although not directly related to the radiation exposure or radioactive contamination; To identify gaps in scientific research relevant to the radiation-induced or radioactive contamination-induced health and environmental impacts of the accident, and suggest areas where further work is required based on an assessment of the work done in the past, and bearing in mind ongoing work and projects; To provide advice on, and to facilitate implementation of scientifically sound programmes on mitigation of the accident consequences, including possible joint actions of the organizations participating in the Forum, such as: agricultural, economic and social life under safe conditions, special health care of the affected population, monitoring of the long-term human exposure to radiation, and addressing the environmental issues pertaining to the decommissioning of the Shelter and management of radioactive waste originating from the Chernobyl accident. The Chernobyl Forum itself continued as a high-level organisation of senior officials from UN agencies and the three more affected countries. The actual work has been accomplished by two expert groups: Expert Group -Environment - (EGE) and Expert Group 'Health' (EGH). Members of each of these two groups consisted of

  18. Interpretation of astrophysical neutrinos observed by IceCube experiment by setting Galactic and extra-Galactic spectral components

    CERN Document Server

    Marinelli, Antonio; Grasso, Dario; Urbano, Alfredo; Valli, Mauro

    2016-01-01

    The last IceCube catalog of High Energy Starting Events (HESE) obtained with a livetime of 1347 days comprises 54 neutrino events equally-distributed between the three families with energies between 25 TeV and few PeVs. Considering the homogeneous flavors distribution (1:1:1) and the spectral features of these neutrinos the IceCube collaboration claims the astrophysical origin of these events with more than $5\\sigma$. The spatial distribution of cited events does not show a clear correlation with known astrophysical accelerators leaving opened both the Galactic and the extra-Galactic origin interpretations. Here, we compute the neutrino diffuse emission of our Galaxy on the basis of a recently proposed phenomenological model characterized by radially-dependent cosmic-ray (CR) transport properties. We show that the astrophysical spectrum measured by IceCube experiment can be well explained adding to the diffuse Galactic neutrino flux (obtained with this new model) a extra-Galactic component derived from the as...

  19. THE COSMIC INFRARED BACKGROUND EXPERIMENT (CIBER): A SOUNDING ROCKET PAYLOAD TO STUDY THE NEAR INFRARED EXTRAGALACTIC BACKGROUND LIGHT

    Energy Technology Data Exchange (ETDEWEB)

    Zemcov, M.; Bock, J.; Hristov, V.; Levenson, L. R.; Mason, P. [Department of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Arai, T.; Matsumoto, T.; Matsuura, S.; Tsumura, K.; Wada, T. [Department of Space Astronomy and Astrophysics, Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara, Kanagawa 252-5210 (Japan); Battle, J. [Jet Propulsion Laboratory (JPL), National Aeronautics and Space Administration (NASA), Pasadena, CA 91109 (United States); Cooray, A. [Center for Cosmology, University of California, Irvine, Irvine, CA 92697 (United States); Keating, B.; Renbarger, T. [Department of Physics, University of California, San Diego, San Diego, CA 92093 (United States); Kim, M. G. [Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); Lee, D. H.; Nam, U. W. [Korea Astronomy and Space Science Institute (KASI), Daejeon 305-348 (Korea, Republic of); Sullivan, I. [Department of Physics, The University of Washington, Seattle, WA 98195 (United States); Suzuki, K., E-mail: zemcov@caltech.edu [Instrument Development Group of Technical Center, Nagoya University, Nagoya, Aichi 464-8602 (Japan)

    2013-08-15

    The Cosmic Infrared Background Experiment (CIBER) is a suite of four instruments designed to study the near infrared (IR) background light from above the Earth's atmosphere. The instrument package comprises two imaging telescopes designed to characterize spatial anisotropy in the extragalactic IR background caused by cosmological structure during the epoch of reionization, a low resolution spectrometer to measure the absolute spectrum of the extragalactic IR background, and a narrow band spectrometer optimized to measure the absolute brightness of the zodiacal light foreground. In this paper we describe the design and characterization of the CIBER payload. The detailed mechanical, cryogenic, and electrical design of the system are presented, including all system components common to the four instruments. We present the methods and equipment used to characterize the instruments before and after flight, and give a detailed description of CIBER's flight profile and configurations. CIBER is designed to be recoverable and has flown four times, with modifications to the payload having been informed by analysis of the first flight data. All four instruments performed to specifications during the subsequent flights, and the scientific data from these flights are currently being analyzed.

  20. Tycoon market-based system: integration with EGEE

    CERN Document Server

    Dana Perez, J M

    2007-01-01

    Tycoon is a market-based system for trading resources. The idea is to integrate Tycoon with EGEE, obtaining a dynamic Grid ready to share resources with others (Universities, research centres, etc.). Tycoon will run as a new service, deploying and destroying virtual machines (Worker Nodes and Computing Elements) on demand. Tycoon will give to EGEE a dynamic, flexible, secure and transparent platform/service to trade resources more efficiently. It could attract small and medium VOs to the EGEE project, they could take advantage of the Grid resources and obtain extra computing power while EGEE could obtain credits/money for its service. Our goal is to integrate Tycoon as a new service of EGEE, we do not have special requirements, we do not need to modify the EGEE middleware, Grid special services, etc. Standard and ‘tycoonized’ nodes (Computing Elements and Worker Nodes) must coexist in the same Grid, working without problems. Our main issue would be to ensure the security of the whole system (EGEE platform...

  1. Extragalactic infrared astronomy

    International Nuclear Information System (INIS)

    Gondhalekar, P.M.

    1985-05-01

    The paper concerns the field of Extragalactic Infrared Astronomy, discussed at the Fourth RAL Workshop on Astronomy and Astrophysics. Fifteen papers were presented on infrared emission from extragalactic objects. Both ground-(and aircraft-) based and IRAS infrared data were reviewed. The topics covered star formation in galaxies, active galactic nuclei and cosmology. (U.K.)

  2. Structural Biology in the context of EGEE

    CERN Document Server

    García, D; Carazo, J M; Valverde, J R; Moscicki, J; Muraru, A

    2007-01-01

    Electron microscopy (EM) is a crucial technique, which allows Structural Biology researchers to characterize macromolecular assemblies in distinct functional states. Image processing in three dimensional EM (3D-EM) is used by a flourishing community (exemplarized by the EU funded 3D-EM NoE) and is characterized by voluminous data and large computing requirements, making this a problem well suited for Grid computing and the EGEE infrastructure. There are various steps in the 3D-EM refinement process that may benefit from Grid computing. To start with, large numbers of experimental images need to be averaged. Nowadays, typically tens of thousands of images are used, while future studies may routinely employ millions of images. Our group has been developing Xmipp, a package for single-particle 3D-EM image processing. Using Xmipp, the classification of 91,000 ribosome projections into 4 classes took more than 2500 CPU hours using the resources of the MareNostrum supercomputer at the Barcelona Supercomputing Centr...

  3. User and virtual organisation support in EGEE

    CERN Document Server

    Donno, Flavia

    2006-01-01

    User and virtual organisation support in EGEE Providing adequate user support in a grid environment is a very challenging task due to the distributed nature of the grid. The variety of users and the variety of Virtual Organizations (VO) with a wide range of applications in use add further to the challenge. The people asking for support are of various kinds. They can be generic grid beginners, users belonging to a given Virtual Organization and dealing with a specific set of applications, site administrators operating grid services and local computing infrastructures, grid monitoring operators who check the status of the grid and need to contact the specific site to report problems; to this list can be added network specialists and others. Wherever a user is located and whatever the problem experienced is, a user expects from a support infrastructure a given set of services. A non-exhaustive list is the following: a) a single access point for support; b) a portal with a well structured sources of information a...

  4. Monitoring the EGEE/WLCG grid services

    International Nuclear Information System (INIS)

    Duarte, A; Nyczyk, P; Retico, A; Vicinanza, D

    2008-01-01

    Grids have the potential to revolutionise computing by providing ubiquitous, on demand access to computational services and resources. They promise to allow for on demand access and composition of computational services provided by multiple independent sources. Grids can also provide unprecedented levels of parallelism for high-performance applications. On the other hand, grid characteristics, such as high heterogeneity, complexity and distribution create many new technical challenges. Among these technical challenges, failure management is a key area that demands much progress. A recent survey revealed that fault diagnosis is still a major problem for grid users. When a failure appears at the user screen, it becomes very difficult for the user to identify whether the problem is in the application, somewhere in the grid middleware, or even lower in the fabric that comprises the grid. In this paper we present a tool able to check if a given grid service works as expected for a given set of users (Virtual Organisation) on the different resources available on a grid. Our solution deals with grid services as single components that should produce an expected output to a pre-defined input, what is quite similar to unit testing. The tool, called Service Availability Monitoring or SAM, is being currently used by several different Virtual Organizations to monitor more than 300 grid sites belonging to the largest grids available today. We also discuss how this tool is being used by some of those VOs and how it is helping in the operation of the EGEE/WLCG grid

  5. The impact and adoption of GLUE 2.0 in the LCG/EGEE production Grid

    International Nuclear Information System (INIS)

    Burke, Stephen; Andreozzi, Sergio; Donno, Flavia; Ehm, Felix; Field, Laurence; Litmaath, Maarten; Millar, Paul

    2010-01-01

    The GLUE information schema has been in use in the LCG/EGEE production Grid since the first version was defined in 2002. In 2007 a major redesign of GLUE, version 2.0, was started in the context of the Open Grid Forum following the creation of the GLUE Working Group. This process has taken input from a number of Grid projects, but as a major user of the version 1 schema LCG/EGEE has had a strong interest that the new schema should support its needs. In this paper we discuss the structure of the new schema in the light of the LCG/EGEE requirements and explain how they are met, and where improvements have been achieved compared with the version 1 schema. In particular we consider some difficulties encountered in recent extensions of the use of the version 1 schema to aid resource accounting in LCG, to enable the use of the SRM version 2 storage protocol by the LHC experiments, and to publish information about a wider range of services to improve service discovery. We describe how these can be better met by the new schema, and we also discuss the way in which the transition to the new schema is being managed.

  6. EGEE leaves a lasting legacy for the future

    CERN Multimedia

    Catherine Gater and Bob Jones

    2010-01-01

    With the LHC running smoothly since March this year, the World LHC Computing Grid, WLCG, is proving itself well up to the task of serving the particle physics community. It has also played an increasingly important role in other areas of science through the Enabling Grids for E-sciencE project, EGEE-III.   The final EGEE user forum held in Uppsala, Sweden in April 2010. It marked the end of the EGEE series of projects and the beginning of EGI. EGEE has been the primary grid infrastructure supporting WLCG (along with OSG and Nordugrid) and has nurtured innovative, world-class research across Europe and around the globe. EGEE-III brought together a computing infrastructure, software tools and services to support more than 10,000 scientific researchers across more than 170 research communities. Grids bring together computing and storage resources located in, owned and operated by different organisations located around the world. Connecting securely through the GÉANT internet network, gri...

  7. Distributed analysis using GANGA on the EGEE/LCG infrastructure

    International Nuclear Information System (INIS)

    Elmsheuser, J; Brochu, F; Harrison, K; Egede, U; Gaidioz, B; Liko, D; Maier, A; Moscicki, J; Muraru, A; Lee, H-C; Romanovsky, V; Soroko, A; Tan, C L

    2008-01-01

    The distributed data analysis using Grid resources is one of the fundamental applications in high energy physics to be addressed and realized before the start of LHC data taking. The need to facilitate the access to the resources is very high. In every experiment up to a thousand physicist will be submitting analysis jobs into the Grid. Appropriate user interfaces and helper applications have to be made available to assure that all users can use the Grid without too much expertise in Grid technology. These tools enlarge the number of grid users from a few production administrators to potentially all participating physicists. The GANGA job management system (http://cern.ch/ganga), developed as a common project between the ATLAS and LHCb experiments provides and integrates these kind of tools. GANGA provides a simple and consistent way of preparing, organizing and executing analysis tasks within the experiment analysis framework, implemented through a plug-in system. It allows trivial switching between running test jobs on a local batch system and running large-scale analyzes on the Grid, hiding Grid technicalities. We will be reporting on the plug-ins and our experiences of distributed data analysis using GANGA within the ATLAS experiment and the EGEE/LCG infrastructure. The integration with the ATLAS data management system DQ2 into GANGA is a key functionality. In combination with the job splitting mechanism large amounts of jobs can be sent to the locations of data following the ATLAS computing model. GANGA supports tasks of user analysis with reconstructed data and small scale production of Monte Carlo data

  8. Geographical failover for the EGEE-WLCG grid collaboration tools

    International Nuclear Information System (INIS)

    Cavalli, A; Pagano, A; Aidel, O; L'Orphelin, C; Mathieu, G; Lichwala, R

    2008-01-01

    Worldwide grid projects such as EGEE and WLCG need services with high availability, not only for grid usage, but also for associated operations. In particular, tools used for daily activities or operational procedures are considered to be critical. The operations activity of EGEE relies on many tools developed by teams from different countries. For each tool, only one instance was originally deployed, thus representing single points of failure. In this context, the EGEE failover problem was solved by replicating tools at different sites, using specific DNS features to automatically failover to a given service. A new domain for grid operations (gridops.org) was registered and deployed following DNS testing in a virtual machine (vm) environment using nsupdate, NS/zone configuration and fast TTLs. In addition, replication of databases, web servers and web services have been tested and configured. In this paper, we describe the technical mechanism used in our approach to replication and failover. We also describe the procedure implemented for the EGEE/WLCG CIC Operations Portal use case. Furthermore, we present the interest in failover procedures in the context of other grid projects and grid services. Future plans for improvements of the procedures are also described

  9. Extragalactic Gravitational Collapse

    Science.gov (United States)

    Rees, Martin J.

    After some introductory "numerology", routes towards black hole formation are briefly reviewed; some properties of black holes relevant to theories for active galactic nuclei are then described. Applications are considered to specific models for energy generation and the production of relativistic beams. The paper concludes with a discussion of extragalactic sources of gravitational waves.

  10. From EGEE Operations Portal towards EGI Operations Portal

    Science.gov (United States)

    Cordier, Hélène; L'Orphelin, Cyril; Reynaud, Sylvain; Lequeux, Olivier; Loikkanen, Sinikka; Veyre, Pierre

    Grid operators in EGEE have been using a dedicated dashboard as their central operational tool, stable and scalable for the last 5 years despite continuous upgrade from specifications by users, monitoring tools or data providers. In EGEE-III, recent regionalisation of operations led the Operations Portal developers to conceive a standalone instance of this tool. We will see how the dashboard reorganization paved the way for the re-engineering of the portal itself. The outcome is an easily deployable package customized with relevant information sources and specific decentralized operational requirements. This package is composed of a generic and scalable data access mechanism, Lavoisier; a renowned php framework for configuration flexibility, Symfony and a MySQL database. VO life cycle and operational information, EGEE broadcast and Downtime notifications are next for the major reorganization until all other key features of the Operations Portal are migrated to the framework. Features specifications will be sketched at the same time to adapt to EGI requirements and to upgrade. Future work on feature regionalisation, on new advanced features or strategy planning will be tracked in EGI- Inspire through the Operations Tools Advisory Group, OTAG, where all users, customers and third parties of the Operations Portal are represented from January 2010.

  11. CORRELATIONS OF THE ARRIVAL DIRECTIONS OF ULTRA-HIGH ENERGY COSMIC RAYS WITH EXTRAGALACTIC OBJECTS AS OBSERVED BY THE TELESCOPE ARRAY EXPERIMENT

    Energy Technology Data Exchange (ETDEWEB)

    Abu-Zayyad, T.; Allen, M.; Anderson, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Hanlon, W. [High Energy Astrophysics Institute and Department of Physics and Astronomy, University of Utah, Salt Lake City, UT (United States); Aida, R. [Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Kofu, Yamanashi (Japan); Azuma, R.; Fukuda, T. [Graduate School of Science and Engineering, Tokyo Institute of Technology, Meguro, Tokyo (Japan); Cheon, B. G.; Cho, E. J. [Department of Physics and The Research Institute of Natural Science, Hanyang University, Seongdong-gu, Seoul (Korea, Republic of); Chiba, J. [Department of Physics, Tokyo University of Science, Noda, Chiba (Japan); Chikawa, M. [Department of Physics, Kinki University, Higashi Osaka, Osaka (Japan); Cho, W. R. [Department of Physics, Yonsei University, Seodaemun-gu, Seoul (Korea, Republic of); Fujii, H. [Institute of Particle and Nuclear Studies, KEK, Tsukuba, Ibaraki (Japan); Fujii, T. [Graduate School of Science, Osaka City University, Osaka (Japan); Fukushima, M. [Institute for Cosmic Ray Research, University of Tokyo, Kashiwa, Chiba (Japan); and others

    2013-11-10

    We search for correlations between the positions of extragalactic objects and the arrival directions of ultra-high energy cosmic rays (UHECRs) with primary energy E ≥ 40 EeV as observed by the surface detector array of the Telescope Array (TA) experiment during the first 40 months of operation. We examine several public astronomical object catalogs, including the Veron-Cetty and Veron catalog of active galactic nuclei. We count the number of TA events correlated with objects in each catalog as a function of three parameters: the maximum angular separation between a TA event and an object, the minimum energy of the events, and the maximum redshift of the objects. We determine the combination of these parameters that maximizes the correlations, and we calculate the probability of having the same levels of correlations from an isotropic distribution of UHECR arrival directions. No statistically significant correlations are found when penalties for scanning over the above parameters and for searching in several catalogs are taken into account.

  12. Parallel execution of chemical software on EGEE Grid

    CERN Document Server

    Sterzel, Mariusz

    2008-01-01

    Constant interest among chemical community to study larger and larger molecules forces the parallelization of existing computational methods in chemistry and development of new ones. These are main reasons of frequent port updates and requests from the community for the Grid ports of new packages to satisfy their computational demands. Unfortunately some parallelization schemes used by chemical packages cannot be directly used in Grid environment. Here we present a solution for Gaussian package. The current state of development of Grid middleware allows easy parallel execution in case of software using any of MPI flavour. Unfortunately many chemical packages do not use MPI for parallelization therefore special treatment is needed. Gaussian can be executed in parallel on SMP architecture or via Linda. These require reservation of certain number of processors/cores on a given WN and the equal number of processors/cores on each WN, respectively. The current implementation of EGEE middleware does not offer such f...

  13. Gridification: Porting New Communities onto the WLCG/EGEE Infrastructure

    CERN Document Server

    Méndez-Lorenzo, P; Lamanna, M; Muraru, A

    2007-01-01

    The computational and storage capability of the Grid are attracting several research communities and we will discuss the general patterns observed in supporting new applications, porting them on the EGEE environment. In this talk we present the general infrastructure we have developed inside the application and support team at CERN (PSS and GD groups) to merge in a fast and feasible way all these applications inside the Grid, as for example Geant4, HARP, Garfield, UNOSAT or ITU. All these communities have different goals and requirements and the main challenge is the creation of a standard and general software infrastructure for the immersion of these communities onto the Grid. This general infrastructure effectively ‘shields’ the applications from the details of the Grid (the emphasis here is to run applications developed independently from the Grid middleware).It is stable enough to require few controls and supports by the members of the Grid team and also of the members of the user communities. Finally...

  14. EoR Foregrounds: the Faint Extragalactic Radio Sky

    Science.gov (United States)

    Prandoni, Isabella

    2018-05-01

    A wealth of new data from upgraded and new radio interferometers are rapidly improving and transforming our understanding of the faint extra-galactic radio sky. Indeed the mounting statistics at sub-mJy and μJy flux levels is finally allowing us to get stringent observational constraints on the faint radio population and on the modeling of its various components. In this paper I will provide a brief overview of the latest results in areas that are potentially important for an accurate treatment of extra-galactic foregrounds in experiments designed to probe the Epoch of Reionization.

  15. Extragalactic sources in Cosmic Microwave Background maps

    Energy Technology Data Exchange (ETDEWEB)

    Zotti, G. De; Castex, G. [SISSA, via Bonomea 265, 34136 Trieste (Italy); González-Nuevo, J. [Departamento de Física, Universidad de Oviedo, C. Calvo Sotelo s/n, 33007 Oviedo (Spain); Lopez-Caniego, M. [European Space Agency, ESAC, Planck Science Office, Camino bajo del Castillo, s/n, Urbanización Villafranca del Castillo, Villanueva de la Cañada, Madrid (Spain); Negrello, M.; Clemens, M. [INAF-Osservatorio Astronomico di Padova, vicolo dell' Osservatorio 5, I-35122 Padova (Italy); Cai, Z.-Y. [CAS Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, University of Science and Technology of China, Hefei, Anhui 230026 (China); Delabrouille, J. [APC, 10, rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13 (France); Herranz, D.; Bonavera, L. [Instituto de Física de Cantabria (CSIC-UC), avda. los Castros s/n, 39005 Santander (Spain); Melin, J.-B. [DSM/Irfu/SPP, CEA-Saclay, F-91191 Gif-sur-Yvette Cedex (France); Tucci, M. [Département de Physique Théorique and Center for Astroparticle Physics, Université de Genève, 24 quai Ansermet, CH-1211 Genève 4 (Switzerland); Serjeant, S. [Department of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Bilicki, M. [Astrophysics, Cosmology and Gravity Centre, Department of Astronomy, University of Cape Town, Private Bag X3, Rondebosch (South Africa); Andreani, P., E-mail: gianfranco.dezotti@oapd.inaf.it, E-mail: gcastex@sissa.it, E-mail: gnuevo@uniovi.es, E-mail: marcos.lopez.caniego@sciops.esa.int [European Southern Observatory, Karl-Schwarzschild-Straße 2, D-85748, Garching (Germany); and others

    2015-06-01

    We discuss the potential of a next generation space-borne CMB experiment for studies of extragalactic sources with reference to COrE+, a project submitted to ESA in response to the call for a Medium-size mission (M4). We consider three possible options for the telescope size: 1 m, 1.5 m and 2 m (although the last option is probably impractical, given the M4 boundary conditions). The proposed instrument will be far more sensitive than Planck and will have a diffraction-limited angular resolution. These properties imply that even the 1 m telescope option will perform substantially better than Planck for studies of extragalactic sources. The source detection limits as a function of frequency have been estimated by means of realistic simulations taking into account all the relevant foregrounds. Predictions for the various classes of extragalactic sources are based on up-to-date models. The most significant improvements over Planck results are presented for each option. COrE+ will provide much larger samples of truly local star-forming galaxies (by about a factor of 8 for the 1 m telescope, of 17 for 1.5 m, of 30 for 2 m), making possible analyses of the properties of galaxies (luminosity functions, dust mass functions, star formation rate functions, dust temperature distributions, etc.) across the Hubble sequence. Even more interestingly, COrE+ will detect, at |b| > 30°, thousands of strongly gravitationally lensed galaxies (about 2,000, 6,000 and 13,000 for the 1 m, 1.5 m and 2 m options, respectively). Such large samples are of extraordinary astrophysical and cosmological value in many fields. Moreover, COrE+ high frequency maps will be optimally suited to pick up proto-clusters of dusty galaxies, i.e. to investigate the evolution of large scale structure at larger redshifts than can be reached by other means. Thanks to its high sensitivity COrE+ will also yield a spectacular advance in the blind detection of extragalactic sources in polarization: we expect that

  16. Extragalactic sources in Cosmic Microwave Background maps

    Science.gov (United States)

    De Zotti, G.; Castex, G.; González-Nuevo, J.; Lopez-Caniego, M.; Negrello, M.; Cai, Z.-Y.; Clemens, M.; Delabrouille, J.; Herranz, D.; Bonavera, L.; Melin, J.-B.; Tucci, M.; Serjeant, S.; Bilicki, M.; Andreani, P.; Clements, D. L.; Toffolatti, L.; Roukema, B. F.

    2015-06-01

    We discuss the potential of a next generation space-borne CMB experiment for studies of extragalactic sources with reference to COrE+, a project submitted to ESA in response to the call for a Medium-size mission (M4). We consider three possible options for the telescope size: 1 m, 1.5 m and 2 m (although the last option is probably impractical, given the M4 boundary conditions). The proposed instrument will be far more sensitive than Planck and will have a diffraction-limited angular resolution. These properties imply that even the 1 m telescope option will perform substantially better than Planck for studies of extragalactic sources. The source detection limits as a function of frequency have been estimated by means of realistic simulations taking into account all the relevant foregrounds. Predictions for the various classes of extragalactic sources are based on up-to-date models. The most significant improvements over Planck results are presented for each option. COrE+ will provide much larger samples of truly local star-forming galaxies (by about a factor of 8 for the 1 m telescope, of 17 for 1.5 m, of 30 for 2 m), making possible analyses of the properties of galaxies (luminosity functions, dust mass functions, star formation rate functions, dust temperature distributions, etc.) across the Hubble sequence. Even more interestingly, COrE+ will detect, at |b| > 30°, thousands of strongly gravitationally lensed galaxies (about 2,000, 6,000 and 13,000 for the 1 m, 1.5 m and 2 m options, respectively). Such large samples are of extraordinary astrophysical and cosmological value in many fields. Moreover, COrE+ high frequency maps will be optimally suited to pick up proto-clusters of dusty galaxies, i.e. to investigate the evolution of large scale structure at larger redshifts than can be reached by other means. Thanks to its high sensitivity COrE+ will also yield a spectacular advance in the blind detection of extragalactic sources in polarization: we expect that it

  17. Infrared observations of extragalactic sources

    International Nuclear Information System (INIS)

    Kleinmann, D.E.

    1977-01-01

    The available balloon-borne and airborne infrared data on extragalactic sources, in particular M 82, NGC 1068 and NGC 253, is reviewed and discussed in the context of the extensive groundbased work. The data is examined for the clues they provide on the nature of the ultimate source of the energy radiated and on the mechanism(s) by which it is radiated. Since the discovery of unexpectedly powerful infrared radiation from extragalactic objects - a discovery now about 10 years old - the outstanding problems in this field have been to determine (1) the mechanism by which prodigious amounts of energy are released in the infrared, and (2) the nature of the underlying energy source. (Auth.)

  18. Stellar candles for the extragalactic distance scale

    CERN Document Server

    Gieren, Wolfgang

    2003-01-01

    This volume reviews the current status with respect to both theory and observation of the extragalactic distance scale. A sufficient accuracy is required both for a precise determination of the cosmological parameters and also in order to achieve a better understanding of physical processes in extragalactic systems. The "standard candles", used to set up the extragalactic distance scale, reviewed in this book include cepheid variables, RR Lyrae variables, novae, Type Ia and Type II supernovae as well as globular clusters and planetary nebulae.

  19. Radio outbursts in extragalactic sources

    International Nuclear Information System (INIS)

    Kinzel, W.M.

    1989-01-01

    Three aspects of the flux density variability of extragalactic radio sources were examined: millimeter wavelength short timescale variability, the spectral evolution of outbursts, and whether the outbursts are periodically spaced. Observations of extragalactic radio sources were conducted using the Five College Radio Astronomy Observatory between January and June 1985 at 88.2 GHz and during June and July 1985 at 40.0 GHz. Many of the sources exhibited significant flux density variations during the observing span. In addition, the most rapid variations observed were comparable with those reported in previous works. Two sources, 0355+50 and OJ287, both exhibited outbursts whose rise and fall timescales were less than a month. An anomalous flux density dropout was observed in 3C446 and was interpreted as an occultation event. Data at five frequencies between 2.7 and 89.6 GHz from the Dent-Balonek monitoring program were used to investigate the spectral evolution of eight outbursts. Outburst profile fitting was used to deconvolve the individual outbursts from one another at each frequency. The fit profiles were used to generate multiple epoch spectra to investigate the evolution of the outbursts. A phase residual minimization method was used to examine four sources for periodic behavior

  20. HEAO A-2 extragalactic results

    Science.gov (United States)

    Boldt, E. A.

    1979-01-01

    The all-sky surveys made with the A-2 instrument aboard HEAO-1 involved spectroscopy over a broad enough band width, with sufficient resolution, to obtain the basic spectral characteristics for two extreme aspects of the extragalactic X-ray sky. The overall spectrum (above 3 KeV) is remarkably well decribed by a thermal model. At the other extreme, the detailed broad-band observations of individual sources are restricted to objects within the present epoch. The objects include several individual active galaxies studied in detail for the first time as well as clusters of galaxies. Relating these results to the vast spatially unresolved hard X-ray flux measured with this instruments as well as the softer X-rays (at less than 3 keV) spatially resolved to high redshifts with the Einstein Observatory remains a challenge.

  1. Superluminal motion of extragalactic objects

    Energy Technology Data Exchange (ETDEWEB)

    Matveenko, L.I. (AN SSSR, Moscow. Inst. Kosmicheskikh Issledovanij)

    1983-07-01

    Extragalactic objects with active nuclei are reviewed. Experimental data are obtained with the method of superfar radiointerferometry. The main peculiarities of the complex structure of Seyfert galaxies, quasars and lacertae objects are considered: the distribution of radiobrightness, spectra, alteration of the density of radiation flux and the distance between the components of sources. The superluminal velocities of component divergence observed are explained by different reasons: fast motion of components considerable difference of the Hubble component or non-cosmologic nature of the red shift of objects, effect of echoreflection of radiation, gravitation lens, systematic alteration of the optical thickness of the object, synchronouys radiation of electrons in the dipole magnetic field, as well as different kinematic illusions connected with the final time of signal propagation.

  2. Superluminal motion of extragalactic objects

    International Nuclear Information System (INIS)

    Matveenko, L.I.

    1983-01-01

    Extragalactic objects with active nuclei are reviewed. Experimental data are obtained with the method of superfar radiointerferometry. The main peculiarities of the complex strUcture of Seyfert galaxies quasars and lacertae ob ects are considered: the distribution of radiobrightness, spectra, alteration of the density of radiation flux and the distance between the components of sources. The superluminal velocities of component divergence observed are explained by different reasons: fast motion of components considerable difference of the Hubble component or non-cosmologic nature of the red shift of objects, effect of echoreflection of radiation, gravitation lens, systematic alteration of the optical thickness of the object, synchronoUs radiation of electrons in the dipole magnetic field, as well as different kinematic illusions connected with the final time of signal propagation

  3. "EGEE'06 - Capitalising on e-infrastructure" 25-29 September 2006, International Conference Centre (CICG) Geneva Switzerland

    CERN Multimedia

    2006-01-01

    EGEE'06 is the key Grid event of 2006, bringing together researchers, politicians, members of industry and the international community to discuss how to capitalise on past investments and plan for a sustainable future for Grid technology.

  4. XACML profile and implementation for authorization interoperability between OSG and EGEE

    International Nuclear Information System (INIS)

    Garzoglio, G; Altunay, M; Chadwick, K; Hesselroth, T D; Levshina, T; Sfiligoi, I; Alderman, I; Miller, Z; Ananthakrishnan, R; Bester, J; Ciaschini, V; Ferraro, A; Forti, A; Demchenko, Y; Groep, D; Koeroo, O; Hover, J; Packard, J; Joie, C La; Sagehaug, H

    2010-01-01

    The Open Science Grid (OSG) and the Enabling Grids for E-sciencE (EGEE) have a common security model, based on Public Key Infrastructure. Grid resources grant access to users because of their membership in a Virtual Organization (VO), rather than on personal identity. Users push VO membership information to resources in the form of identity attributes, thus declaring that resources will be consumed on behalf of a specific group inside the organizational structure of the VO. Resources contact an access policies repository, centralized at each site, to grant the appropriate privileges for that VO group. Before the work in this paper, despite the commonality of the model, OSG and EGEE used different protocols for the communication between resources and the policy repositories. Hence, middleware developed for one Grid could not naturally be deployed on the other Grid, since the authorization module of the middleware would have to be enhanced to support the other Grid's communication protocol. In addition, maintenance and support for different authorization call-out protocols represents a duplication of effort for our relatively small community. To address these issues, OSG and EGEE initiated a joint project on authorization interoperability. The project defined a common communication protocol and attribute identity profile for authorization call-out and provided implementation and integration with major Grid middleware. The activity had resonance with middleware development communities, such as the Globus Toolkit and Condor, who decided to join the collaboration and contribute requirements and software. In this paper, we discuss the main elements of the profile, its implementation, and deployment in EGEE and OSG. We focus in particular on the operations of the authorization infrastructures of both Grids.

  5. XACML profile and implementation for authorization interoperability between OSG and EGEE

    Energy Technology Data Exchange (ETDEWEB)

    Garzoglio, G.; Alderman, I.; Altunay, M.; Ananthakrishnan, R.; Bester, J.; Chadwick, K.; Ciaschini, V.; Demchenko, Y.; Ferraro, A.; Forti, A.; Groep, D.; /Fermilab /Wisconsin U., Madison /Argonne /INFN, CNAF /Amsterdam U. /NIKHEF, Amsterdam /Brookhaven /SWITCH, Zurich /Bergen Coll. Higher Educ.

    2009-05-01

    The Open Science Grid (OSG) and the Enabling Grids for E-sciencE (EGEE) have a common security model, based on Public Key Infrastructure. Grid resources grant access to users because of their membership in a Virtual Organization (VO), rather than on personal identity. Users push VO membership information to resources in the form of identity attributes, thus declaring that resources will be consumed on behalf of a specific group inside the organizational structure of the VO. Resources contact an access policies repository, centralized at each site, to grant the appropriate privileges for that VO group. Before the work in this paper, despite the commonality of the model, OSG and EGEE used different protocols for the communication between resources and the policy repositories. Hence, middleware developed for one Grid could not naturally be deployed on the other Grid, since the authorization module of the middleware would have to be enhanced to support the other Grid's communication protocol. In addition, maintenance and support for different authorization call-out protocols represents a duplication of effort for our relatively small community. To address these issues, OSG and EGEE initiated a joint project on authorization interoperability. The project defined a common communication protocol and attribute identity profile for authorization call-out and provided implementation and integration with major Grid middleware. The activity had resonance with middleware development communities, such as the Globus Toolkit and Condor, who decided to join the collaboration and contribute requirements and software. In this paper, we discuss the main elements of the profile, its implementation, and deployment in EGEE and OSG. We focus in particular on the operations of the authorization infrastructures of both Grids.

  6. Is PKS 2155 an extragalactic source

    International Nuclear Information System (INIS)

    Maraschi, L.; Treves, A.

    1981-01-01

    We present here observations in the far ultraviolet (1200-3000 Angstroem) obtained with I.U.E. The presence of weak variable emission features is discussed and the extragalactic nature of the object is questioned. (orig./WL)

  7. Is PKS 2155 an extragalactic source

    Energy Technology Data Exchange (ETDEWEB)

    Maraschi, L.; Treves, A. (Consiglio Nazionale delle Ricerche, Milan (Italy). Lab. di Fisica Cosmica e Tecnologie Relative; Milan Univ. (Italy). Ist. di Fisica); Tanzi, E.G. (Consiglio Nazionale delle Ricerche, Milan (Italy). Lab. di Fisica Cosmica e Tecnologie Relative); Tarenghi, M. (European Southern Observatory, Garching (Germany, F.R.))

    1981-01-01

    We present here observations in the far ultraviolet (1200-3000 Angstroem) obtained with I.U.E. The presence of weak variable emission features is discussed and the extragalactic nature of the object is questioned.

  8. Operating the LCG and EGEE Production Grids for HEP

    CERN Multimedia

    CERN. Geneva

    2004-01-01

    In September 2003 the first LCG-1 service was put into production at most of the large Tier 1 sites and was quickly expanded up to 30 Tier 1 and Tier 2 sites by the end of the year. Several software upgrades were made and the LCG-2 service was put into production in time for the experiment data challenges that began in February 2004 and continued for several months. In particular LCG-2 introduced transparent access to mass storage and managed disk-only storage elements, and a first release of the Grid File Access library. Much valuable experience was gained during the data challenges in all aspects from the functionality and use of the middleware, to the deployment, maintenance, and operation of the services at many sites. Based on this experience a program of work to address the functional and operational issues is being implemented. The goal is to focus on essential areas such as data management and to build by the end of 2004 a basic grid system capable of handling the basic needs of LHC c...

  9. A Worldwide Production Grid Service Built on EGEE and OSG Infrastructures Lessons Learnt and Long-term Requirements

    International Nuclear Information System (INIS)

    Shiers, J.; Dimou, M.; Mendez Lorenzo, P.

    2007-01-01

    Using the Grid Infrastructures provided by EGEE, OSG and others, a worldwide production service has been built that provides the computing and storage needs for the 4 main physics collaborations at CERN's Large Hadron Collider (LHC). The large number of users, their geographical distribution and the very high service availability requirements make this experience of Grid usage worth studying for the sake of a solid and scalable future operation. This service must cater for the needs of thousands of physicists in hundreds of institutes in tens of countries. A 24x7 service with availability of up to 99% is required with major service responsibilities at each of some ten T ier1 a nd of the order of one hundred T ier2 s ites. Such a service - which has been operating for some 2 years and will be required for at least an additional decade - has required significant manpower and resource investments from all concerned and is considered a major achievement in the field of Grid computing. We describe the main lessons learned in offering a production service across heterogeneous Grids as well as the requirements for long-term operation and sustainability. (Author)

  10. Definition and implementation of a SAML-XACML profile for authorization interoperability across grid middleware in OSG and EGEE

    Energy Technology Data Exchange (ETDEWEB)

    Garzoglio, Gabriele; Alderman, Ian; Altunay, Mine; Anathakrishnan, Rachana; Bester, Joe; Chadwick, Keith; Ciaschini, Vincenzo; Demchenko, Yuri; Ferraro, Andrea; Forti, Alberto; Groep, David; /Fermilab /NIKHEF, Amsterdam /Brookhaven /Amsterdam U. /SWITCH, Zurich /Bergen U. /INFN, CNAF /Argonne /Wisconsin U., Madison

    2009-04-01

    In order to ensure interoperability between middleware and authorization infrastructures used in the Open Science Grid (OSG) and the Enabling Grids for E-sciencE (EGEE) projects, an Authorization Interoperability activity was initiated in 2006. The interoperability goal was met in two phases: first, agreeing on a common authorization query interface and protocol with an associated profile that ensures standardized use of attributes and obligations; and second, implementing, testing, and deploying, on OSG and EGEE, middleware that supports the interoperability protocol and profile. The activity has involved people from OSG, EGEE, the Globus Toolkit project, and the Condor project. This paper presents a summary of the agreed-upon protocol, profile and the software components involved.

  11. Extragalactic Astronomy: The Universe Beyond Our Galaxy.

    Science.gov (United States)

    Jacobs, Kenneth Charles

    This booklet is part of an American Astronomical Society curriculum project designed to provide teaching materials to teachers of secondary school chemistry, physics, and earth science. The material is presented in three parts: one section provides the fundamental content of extragalactic astronomy, another section discusses modern discoveries in…

  12. Spectrum of the extragalactic background light

    Energy Technology Data Exchange (ETDEWEB)

    Bruzual A, G [Centro de Investigacion de Astronomia, Merida (Venezuela)

    1981-01-01

    The observed spectrum of the extragalactic background light in the range from ultraviolet to optical wavelengths is compared with a model prediction. The model uses the locally observed luminosity function of galaxies as well as evolutionary models for galaxy spectral energy distributions. The predicition is too faint by a factor of about 10.

  13. Extragalactic astronomy and cosmology an introduction

    CERN Document Server

    Schneider, Peter

    2015-01-01

    Accounting for the astonishing developments in the field of Extragalactic Astronomy and Cosmology, this second edition has been updated and substantially expanded. Starting with the description of our home galaxy, the Milky Way, this cogently written textbook introduces the reader to the astronomy of galaxies, their structure, active galactic nuclei, evolution and large scale distribution in the Universe. After an extensive and thorough introduction to modern observational and theoretical cosmology, the focus turns to the formation of structures and astronomical objects in the early Universe. The basics of classical astronomy and stellar astrophysics needed for extragalactic astronomy are provided in the appendix. The new edition incorporates some of the most spectacular results from new observatories like the Galaxy Evolution Explorer, Herschel, ALMA, WMAP and Planck, as well as new instruments and multi-wavelength campaigns which have expanded our understanding of the Universe and the objects populating it....

  14. Grid: From EGEE to EGI and from INFN-Grid to IGI

    International Nuclear Information System (INIS)

    Giselli, A.; Mazzuccato, M.

    2009-01-01

    In the last fifteen years the approach of the computational Grid has changed the way to use computing resources. Grid computing has raised interest worldwide in academia, industry, and government with fast development cycles. Great efforts, huge funding and resources have been made available through national, regional and international initiatives aiming at providing Grid infrastructures, Grid core technologies, Grid middle ware and Grid applications. The Grid software layers reflect the architecture of the services developed so far by the most important European and international projects. In this paper Grid e-Infrastructure story is given, detailing European, Italian and international projects such as EGEE, INFN-Grid and NAREGI. In addition the sustainability issue in the long-term perspective is described providing plans by European and Italian communities with EGI and IGI.

  15. Stellar and Extragalactic Radiation at the Earth's Surface Jean ...

    Indian Academy of Sciences (India)

    to propose an interpretation of the fluctuations now attributed to fluctuations of ... Finally, one of us (JVN) thanks Coll`ege de France for hospitality that made this ... Landolt, Börnstein 1965, Numerical Data, New Series, VI, 1, Section 5.2.6, (ed.) ...

  16. Optical spectroscopy of ten extragalactic radiosources

    International Nuclear Information System (INIS)

    Rawlings, S.; Riley, J.M.; Saunders, R.

    1989-01-01

    We present optical spectroscopy of ten objects associated with extra-galactic radiosources, using the University of Hawaii 2.2-m telescope. Redshifts are measured for four radiogalaxies (B20217 + 36A + B, 3C73, 0648 + 19A, 0648 + 19B) and for a galaxy which is probably associated with a double radio-source with highly unusual properties (0951 + 37); existing redshifts are confirmed for two radiogalaxies (4C39.04, 4C40.08); and a tentative redshift of z=2.87 measured for the quasar 3C82. (author)

  17. Fine structure of 25 extragalactic radio sources

    International Nuclear Information System (INIS)

    Wittels, J.J.; Knight, C.A.; Shapiro, I.I.; Hinteregger, H.F.; Rogers, A.E.E.; Whitney, A.R.; Clark, T.A.; Hutton, L.K.; Marandino, G.E.; Neill, A.E.; Ronnang, B.G.; Rydbeck, O.E.H.; Klemperer, W.K.; Warnock, W.W.

    1975-01-01

    Between 1972 April and 1973 May, 25 extragalactic radio sources were observed interferometrically at 7.8 GHz(lambdaapprox. =3.8 cm) with five pairings of antennas. These sources exhibit a broad variety of fine structures from very simple to complex. Although the structure and the total power of some of these sources have remained unchanged within the sensitivity of our measurements during the year of observations, both the total flux and the correlated flux of others have undergone large changes in a few weeks

  18. Migration to the GLUE 2.0 information schema in the LCG/EGEE/EGI production Grid

    International Nuclear Information System (INIS)

    Burke, Stephen; Field, Laurence; Horat, David

    2011-01-01

    The GLUE information schema has been in use in the LCG/EGEE production Grid since the first version was released in 2002. In 2008 a major redesign of GLUE, version 2.0, was defined in the context of the Open Grid Forum. The implementation of the publication and use of the new schema is a complex process which needs to be carefully managed to avoid any disruption to the production service, especially in the light of the end of the EGEE project and the transition to the new middleware and operational structures in EGI. In this paper we discuss the LDAP rendering of the schema, the upgrading of the Grid information system to allow both schemas to be used in parallel, the design and rollout of information providers, and the plans for migrating client software which uses the schema information. In particular we consider the implications for the specific requirements of the LCG project, especially regarding storage systems, accounting and monitoring.

  19. Analýza výrobního sortimentu firmy KEB-EGE spol.s r. o.

    OpenAIRE

    Chuová, Trang

    2011-01-01

    My diploma thesis is dedicated to the analysis of the product assortment of the KEB-EGE ltd. company that concentrates on producing autodiagnostics and steel constructions. The theoretical part involves basic marketing terms and the practical part introduces the company itself, its customers, competition and suppliers, the analysis of the company macro environment and the analysis of the marketing mix as for its four tools, which is product, price, distribution and marketing communication.

  20. Fast Radio Bursts from Extragalactic Light Sails

    Energy Technology Data Exchange (ETDEWEB)

    Lingam, Manasvi [John A. Paulson School of Engineering and Applied Sciences, Harvard University, 29 Oxford Street, Cambridge, MA 02138 (United States); Loeb, Abraham, E-mail: manasvi@seas.harvard.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2017-03-10

    We examine the possibility that fast radio bursts (FRBs) originate from the activity of extragalactic civilizations. Our analysis shows that beams used for powering large light sails could yield parameters that are consistent with FRBs. The characteristic diameter of the beam emitter is estimated through a combination of energetic and engineering constraints, and both approaches intriguingly yield a similar result that is on the scale of a large rocky planet. Moreover, the optimal frequency for powering the light sail is shown to be similar to the detected FRB frequencies. These “coincidences” lend some credence to the possibility that FRBs might be artificial in origin. Other relevant quantities, such as the characteristic mass of the light sail, and the angular velocity of the beam, are also derived. By using the FRB occurrence rate, we infer upper bounds on the rate of FRBs from extragalactic civilizations in a typical galaxy. The possibility of detecting fainter signals is briefly discussed, and the wait time for an exceptionally bright FRB event in the Milky Way is estimated.

  1. Statistical studies of powerful extragalactic radio sources

    Energy Technology Data Exchange (ETDEWEB)

    Macklin, J T

    1981-01-01

    This dissertation is mainly about the use of efficient statistical tests to study the properties of powerful extragalactic radio sources. Most of the analysis is based on subsets of a sample of 166 bright (3CR) sources selected at 178 MHz. The first chapter is introductory and it is followed by three on the misalignment and symmetry of double radio sources. The properties of nuclear components in extragalactic sources are discussed in the next chapter, using statistical tests which make efficient use of upper limits, often the only available information on the flux density from the nuclear component. Multifrequency observations of four 3CR sources are presented in the next chapter. The penultimate chapter is about the analysis of correlations involving more than two variables. The Spearman partial rank correlation coefficient is shown to be the most powerful test available which is based on non-parametric statistics. It is therefore used to study the dependences of the properties of sources on their size at constant redshift, and the results are interpreted in terms of source evolution. Correlations of source properties with luminosity and redshift are then examined.

  2. Probing the properties of extragalactic SNRs

    Science.gov (United States)

    Leonidaki, Ioanna

    2016-06-01

    The investigation of extragalactic SNRs gives us the advantage of surmounting the challenges we are usually confronted with when observing Galactic SNRs, most notably Galactic extinction and distance uncertainties. At the same time, by obtaining larger samples of SNRs, we are allowed to cover a wider range of environments and ISM parameters than our Galaxy, providing us a more complete and representative picture of SNR populations. I will outline the recent progress on extragalactic surveys of SNR populations focusing on the optical, radio, and X-ray bands. Multi-wavelength surveys can provide several key aspects of the physical processes taking place during the evolution of SNRs while at the same time can overcome possible selection effects that are inherent from monochromatic surveys. I will discuss the properties derived in each band (e.g. line ratios, luminosities, densities, temperatures) and their connection in order to yield information on various aspects of their behaviour and evolution. For example their interplay with the surrounding medium, their correlation with star formation activity, their luminosity distributions and their dependence on galaxy types.

  3. Fast Radio Bursts from Extragalactic Light Sails

    International Nuclear Information System (INIS)

    Lingam, Manasvi; Loeb, Abraham

    2017-01-01

    We examine the possibility that fast radio bursts (FRBs) originate from the activity of extragalactic civilizations. Our analysis shows that beams used for powering large light sails could yield parameters that are consistent with FRBs. The characteristic diameter of the beam emitter is estimated through a combination of energetic and engineering constraints, and both approaches intriguingly yield a similar result that is on the scale of a large rocky planet. Moreover, the optimal frequency for powering the light sail is shown to be similar to the detected FRB frequencies. These “coincidences” lend some credence to the possibility that FRBs might be artificial in origin. Other relevant quantities, such as the characteristic mass of the light sail, and the angular velocity of the beam, are also derived. By using the FRB occurrence rate, we infer upper bounds on the rate of FRBs from extragalactic civilizations in a typical galaxy. The possibility of detecting fainter signals is briefly discussed, and the wait time for an exceptionally bright FRB event in the Milky Way is estimated.

  4. Screening of some biological activities of Alyssum fulvescens var. fulvescens known as ege madwort.

    Science.gov (United States)

    Ozay, Cennet; Mammadov, Ramazan

    2017-09-01

    In this research, the phenolic composition, antioxidant, antibacterial and cytotoxic activities of the methanolic extracts obtained from Alyssum fulvescens var. fulvescens aerial parts known as Ege kuduzotu in western Turkey, were firstly investigated. The antioxidant activity of the extract was determined by DPPH, metal chelating, phosphomolybdenum, β-carotene/linoleic acid and ferric reducing power assays. Moreover, total phenolic and flavonoid contents in the extract were investigated. The brine shrimp (Artemia salina L.) lethality test was used to investigate for the possible cytotoxic activity of the extract. Microdilution broth method was used to study antibacterial potency of extract against Gram-positive and Gram-negative bacteria. The extract exhibited good biological activities. Total phenolic and flavonoid contents in the extract were significantly correlated with antioxidant potentials. HPLC analysis showed that chlorogenic acid was the major phenolic in extract tested. The results indicated that the extract of A. fulvescens var. fulvescens may be considered as a potential source of biological agents and in vivo investigations are needed to test the biological effects of A. fulvescens var. fulvescens.

  5. SURFACE DISTRIBUTION MODELLING FOR PRECIPITATION IN THE EGE REGION EGE BÖLGESİ’NDE YAĞIŞIN YÜZEYSEL DAĞILIM MODELLEMESİ

    Directory of Open Access Journals (Sweden)

    Muhammet BAHADIR

    2011-06-01

    Full Text Available The scope of this study was the surface distribution modeling of precipitation in Anatolia and the Aegean Region which covers the western part of our country. The precipitation was handled in terms of 10 year segments and applied with Interactive 3D Analysis, Geographically Intensive Regression, Radial Basis Function and Quadratic Trend Analysis after which a precipitation dispersion map was established. It was concluded that planetary factors had a primary impact on the dispersion and change of precipitation in the region. On the other hand, topographical characteristics were determining for local precipitation changes, it was particularly evident that the northern parts of the mountains subject to exposure received more precipitation. The temporal changes in the precipitation of the region has shown a general declining trend from 1975 up to 2010. Although the declined amount is more pronounced on the coastal parts, the situation is more critical in the inland parts with less precipitation. According to trend analysis results targeting the future, indications pertaining to the continuation of the declining precipitatıon trend have been observed Bu çalışmada Anadolu’nun ve ülkemizin batı kesimini kapsayan Ege Bölgesi’nde yağışın yüzeysel dağılım modellemesi gerçekleştirilmiştir. Yağışa 10’ar yıllık dönemler halinde Etkileşimli 3D Analizi, Coğrafi Ağırlıklı Regresyon, Radial Basis Function ve Quadratic Trend Analizleri uygulanmış ve yağış dağılış haritaları oluşturulmuştur. Bölgede yağışın dağılışı ve değişimi üzerinde plenater faktörlerin birinci derecede etkili olduğu sonucuna ulaşılmıştır. Yağışın lokal değişimleri üzerinde ise topoğrafik özellikler belirleyici olmuş, özellikle dağların kuzey kesimleri bakıya bağlı olarak daha fazla yağış aldığı tespit edilmiştir. Bölgede yağışın zamansal değişiminde, 1975’den 2010 yılına kadar genel anlamda

  6. Rapid variability of extragalactic radio sources

    Energy Technology Data Exchange (ETDEWEB)

    Quirrenbach, A.; Witzel, A.; Krichbaum, T.; Hummel, C.A.; Alberdi, A.; Schalinski, C.

    1989-02-02

    Since its discovery more than 20 years ago, variability of extragalactic radio sources on timescales of weeks to years has been the subject of many investigations. We have examined the variability of these sources on timescales of hours at wavelengths of 6 and 11 cm using the 100-m telescope of the Max-Planck-Institut fuer Radioastronomie and report the results for two sources. The quasar QSO0917 + 62 showed variations with amplitudes of up to 23% in /similar to/ 24 hours, which were correlated at the two wavelengths; in the BL Lac object 0716 + 71 we found variations with amplitudes of 7-11%. We discuss intrinsic effects, gravitational lensing and scattering in the interstellar medium as possible explanations for rapid radio variability.

  7. Probing Extragalactic Planets Using Quasar Microlensing

    Science.gov (United States)

    Dai, Xinyu; Guerras, Eduardo

    2018-02-01

    Previously, planets have been detected only in the Milky Way galaxy. Here, we show that quasar microlensing provides a means to probe extragalactic planets in the lens galaxy, by studying the microlensing properties of emission close to the event horizon of the supermassive black hole of the background quasar, using the current generation telescopes. We show that a population of unbound planets between stars with masses ranging from Moon to Jupiter masses is needed to explain the frequent Fe Kα line energy shifts observed in the gravitationally lensed quasar RXJ 1131–1231 at a lens redshift of z = 0.295 or 3.8 billion lt-yr away. We constrain the planet mass-fraction to be larger than 0.0001 of the halo mass, which is equivalent to 2000 objects ranging from Moon to Jupiter mass per main-sequence star.

  8. Rapid variability of extragalactic radio sources

    International Nuclear Information System (INIS)

    Quirrenbach, A.; Witzel, A.; Krichbaum, T.; Hummel, C.A.; Alberdi, A.; Schalinski, C.

    1989-01-01

    Since its discovery more than 20 years ago, variability of extragalactic radio sources on timescales of weeks to years has been the subject of many investigations. We have examined the variability of these sources on timescales of hours at wavelengths of 6 and 11 cm using the 100-m telescope of the Max-Planck-Institut fuer Radioastronomie and report the results for two sources. The quasar QSO0917 + 62 showed variations with amplitudes of up to 23% in ∼ 24 hours, which were correlated at the two wavelengths; in the BL Lac object 0716 + 71 we found variations with amplitudes of 7-11%. We discuss intrinsic effects, gravitational lensing and scattering in the interstellar medium as possible explanations for rapid radio variability. (author)

  9. A precise extragalactic test of General Relativity.

    Science.gov (United States)

    Collett, Thomas E; Oldham, Lindsay J; Smith, Russell J; Auger, Matthew W; Westfall, Kyle B; Bacon, David; Nichol, Robert C; Masters, Karen L; Koyama, Kazuya; van den Bosch, Remco

    2018-06-22

    Einstein's theory of gravity, General Relativity, has been precisely tested on Solar System scales, but the long-range nature of gravity is still poorly constrained. The nearby strong gravitational lens ESO 325-G004 provides a laboratory to probe the weak-field regime of gravity and measure the spatial curvature generated per unit mass, γ. By reconstructing the observed light profile of the lensed arcs and the observed spatially resolved stellar kinematics with a single self-consistent model, we conclude that γ = 0.97 ± 0.09 at 68% confidence. Our result is consistent with the prediction of 1 from General Relativity and provides a strong extragalactic constraint on the weak-field metric of gravity. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  10. Extragalactic background light measurements and applications.

    Science.gov (United States)

    Cooray, Asantha

    2016-03-01

    This review covers the measurements related to the extragalactic background light intensity from γ-rays to radio in the electromagnetic spectrum over 20 decades in wavelength. The cosmic microwave background (CMB) remains the best measured spectrum with an accuracy better than 1%. The measurements related to the cosmic optical background (COB), centred at 1 μm, are impacted by the large zodiacal light associated with interplanetary dust in the inner Solar System. The best measurements of COB come from an indirect technique involving γ-ray spectra of bright blazars with an absorption feature resulting from pair-production off of COB photons. The cosmic infrared background (CIB) peaking at around 100 μm established an energetically important background with an intensity comparable to the optical background. This discovery paved the way for large aperture far-infrared and sub-millimetre observations resulting in the discovery of dusty, starbursting galaxies. Their role in galaxy formation and evolution remains an active area of research in modern-day astrophysics. The extreme UV (EUV) background remains mostly unexplored and will be a challenge to measure due to the high Galactic background and absorption of extragalactic photons by the intergalactic medium at these EUV/soft X-ray energies. We also summarize our understanding of the spatial anisotropies and angular power spectra of intensity fluctuations. We motivate a precise direct measurement of the COB between 0.1 and 5 μm using a small aperture telescope observing either from the outer Solar System, at distances of 5 AU or more, or out of the ecliptic plane. Other future applications include improving our understanding of the background at TeV energies and spectral distortions of CMB and CIB.

  11. Extragalactic active objects in the radio and infrared bands

    Energy Technology Data Exchange (ETDEWEB)

    Sikora, M [Polska Akademia Nauk, Warsaw. Centrum Astronomiczne

    1981-01-01

    This paper is the second in a series of papers concerning extragalactic active objects. We discuss the properties of Seyfert's galaxies, radiogalaxies, quasars and BL Lacertae objects in the radio and infrared bands.

  12. A Worldwide Production Grid Service Built on EGEE and OSG Infrastructures – Lessons Learnt and Long-term Requirements

    CERN Document Server

    Shiers, J; Dimou, M; CERN. Geneva. IT Department

    2007-01-01

    Using the Grid Infrastructures provided by EGEE, OSG and others, a worldwide production service has been built that provides the computing and storage needs for the 4 main physics collaborations at CERN's Large Hadron Collider (LHC). The large number of users, their geographical distribution and the very high service availability requirements make this experience of Grid usage worth studying for the sake of a solid and scalable future operation. This service must cater for the needs of thousands of physicists in hundreds of institutes in tens of countries. A 24x7 service with availability of up to 99% is required with major service responsibilities at each of some ten "Tier1" and of the order of one hundred "Tier2" sites. Such a service - which has been operating for some 2 years and will be required for at least an additional decade - has required significant manpower and resource investments from all concerned and is considered a major achievement in the field of Grid computing. We describe the main lessons...

  13. Transition from galactic to extra-galactic cosmic rays

    International Nuclear Information System (INIS)

    Aloisio, Roberto

    2006-01-01

    In this paper we review the main features of the observed Cosmic Rays spectrum in the energy range 10 17 eV to 10 20 eV. We present a theoretical model that explains the main observed features of the spectrum, namely the second Knee and Dip, and implies a transition from Galactic to Extra-Galactic cosmic rays at energy E ≅ 10 18 eV, with a proton dominated Extra-Galactic spectrum

  14. The transition from galactic to extragalactic cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Stanev, Todor [Bartol Research Institute, Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States)

    2007-06-15

    We discuss the region of transition between galactic and extragalactic cosmic rays. The exact shapes and compositions of these two components contain information about important parameters of powerful astrophysical sources and the conditions in extragalactic space. Several types of experimental data, including the exact shape of the ultrahigh energy cosmic rays, their chemical composition and their anisotropy, and the fluxes of cosmogenic neutrinos have to be included in the solution of this problem.

  15. Extragalactic dispersion measures of fast radio bursts

    International Nuclear Information System (INIS)

    Xu, Jun; Han, J. L.

    2015-01-01

    Fast radio bursts show large dispersion measures, much larger than the Galactic dispersion measure foreground. Therefore, they evidently have an extragalactic origin. We investigate possible contributions to the dispersion measure from host galaxies. We simulate the spatial distribution of fast radio bursts and calculate the dispersion measures along the sightlines from fast radio bursts to the edge of host galaxies by using the scaled NE2001 model for thermal electron density distributions. We find that contributions to the dispersion measure of fast radio bursts from the host galaxy follow a skew Gaussian distribution. The peak and the width at half maximum of the dispersion measure distribution increase with the inclination angle of a spiral galaxy, to large values when the inclination angle is over 70°. The largest dispersion measure produced by an edge-on spiral galaxy can reach a few thousand pc cm −3 , while the dispersion measures from dwarf galaxies and elliptical galaxies have a maximum of only a few tens of pc cm −3 . Notice, however, that additional dispersion measures of tens to hundreds of pc cm −3 can be produced by high density clumps in host galaxies. Simulations that include dispersion measure contributions from the Large Magellanic Cloud and the Andromeda Galaxy are shown as examples to demonstrate how to extract the dispersion measure from the intergalactic medium. (paper)

  16. In situ acceleration in extragalactic radio jets

    International Nuclear Information System (INIS)

    Bicknell, G.V.; Melrose, D.B.

    1982-01-01

    We have examined the energy dissipated by large-scale turbulence in an extragalactic jet. The turbulence is driven by a shear instability which does not disrupt the jet. Fluid theory should be used to treat the evolution of the turbulence, and this allows us to estimate the rate of dissipation without detailed knowledge of the dissipation process. Dissipation occurs due to Fermi acceleration at a scale length approx.10 -3 R and that resonant acceleration plays no role. The Alfvenic component in the turbulent spectrum is dissipated by first being converted into magneto-acoustic waves. An alternative dissipation process due to formation of weak shocks is shown to be equivalent in some respects to Fermi acceleration. Dissipation in the thermal gas should not exceed that due to Fermi acceleration. The effect of Fermi acceleration, adiabatic losses, and radiative losses on an initial power-law distribution with an upper cutoff is studied. Radio emission extending to at least 100 GHz is shown to be possible, and no spectral index gradients are introduced by the acceleration. The upper cutoff can increase due to the acceleration alone or when the acceleration is balanced by radiative losses. The northern jet in NGC 315 is studied in detail. Using our model for the acceleration, we estimate a jet velocity > or approx. =5000 km s -1 with Mach number not much greater than 1, and a density -4 f -1 cm -3 at the turn-on of the jet at 6 cm, where 0.05 5 yr, and it is predicted that the radius of the jet at the turn-on point should vary with frequency either as ν/sup 2/3/ or as ν/sup 3/2/, or there may be no frequency dependence, contingent upon the details of the acceleration

  17. White Paper on the Status and Future of Ground-based Gamma-Ray Astronomy - Extragalactic Science Working Group

    Science.gov (United States)

    Krawczynski, H.; Coppi, P.; Dermer, C.; Dwek, E.; Georganopoulos, M.; Horan, D.; Jones, T.; Krennrich, F.; Mukherjee, R.; Perlman, E.; Vassiliev, V.

    2007-04-01

    In fall 2006, the Division of Astrophysics of the American Physical Society requested a white paper about the status and future of ground based gamma-ray astronomy. The white paper will largely be written in the year 2007. Interested scientists are invited to join the science working groups. In this contribution, we will report on some preliminary results of the extragalactic science working group. We will discuss the potential of future ground based gamma-ray experiments to elucidate how supermassive black holes accrete matter, form jets, and accelerate particles, and to study in detail the acceleration and propagation of cosmic rays in extragalactic systems like infrared galaxies and galaxy clusters. Furthermore, we discuss avenues to constrain the spectrum of the extragalactic infrared to optical background radiation, and to measure the extragalactic magnetic fields based on gamma-ray observations. Eventually, we discuss the potential of ground based experiments for conducting gamma-ray source surveys. More information about the white paper can be found at: http://cherenkov.physics.iastate.edu/wp/

  18. Inverse problem for extragalactic transport of ultra-high energy cosmic rays

    International Nuclear Information System (INIS)

    Ptuskin, V.S.; Rogovaya, S.I.; Zirakashvili, V.N.

    2015-01-01

    The energy spectra and composition of ultra-high energy cosmic rays are changing in a course of propagation in the expanding Universe filled with background radiation. We developed a numerical code for solution of inverse problem for cosmic-ray transport equations that allows the determination of average source spectra of different nuclei from the cosmic ray spectra observed at the Earth. Employing this approach, the injection spectra of protons and Iron nuclei in extragalactic sources are found assuming that only these species are accelerated at the source. The data from the Auger experiment and the combined data from the Telescope Array + HiRes experiments are used to illustrate the method

  19. Inverse problem for extragalactic transport of ultra-high energy cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Ptuskin, V.S.; Rogovaya, S.I.; Zirakashvili, V.N., E-mail: vptuskin@izmiran.ru, E-mail: rogovaya@izmiran.ru, E-mail: zirak@izmiran.ru [Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation of the Russian Academy of Sciences (IZMIRAN), Troitsk, Moscow, 142190 (Russian Federation)

    2015-03-01

    The energy spectra and composition of ultra-high energy cosmic rays are changing in a course of propagation in the expanding Universe filled with background radiation. We developed a numerical code for solution of inverse problem for cosmic-ray transport equations that allows the determination of average source spectra of different nuclei from the cosmic ray spectra observed at the Earth. Employing this approach, the injection spectra of protons and Iron nuclei in extragalactic sources are found assuming that only these species are accelerated at the source. The data from the Auger experiment and the combined data from the Telescope Array + HiRes experiments are used to illustrate the method.

  20. New Limits on Extragalactic Magnetic Fields from Rotation Measures

    Science.gov (United States)

    Pshirkov, M. S.; Tinyakov, P. G.; Urban, F. R.

    2016-05-01

    We take advantage of the wealth of rotation measures data contained in the NRAO VLA Sky Survey catalog to derive new, statistically robust, upper limits on the strength of extragalactic magnetic fields. We simulate the extragalactic magnetic field contribution to the rotation measures for a given field strength and correlation length, by assuming that the electron density follows the distribution of Lyman-α clouds. Based on the observation that rotation measures from distant radio sources do not exhibit any trend with redshift, while the extragalactic contribution instead grows with distance, we constrain fields with Jeans' length coherence length to be below 1.7 nG at the 2 σ level, and fields coherent across the entire observable Universe below 0.65 nG. These limits do not depend on the particular origin of these cosmological fields.

  1. Towards sustainability: An interoperability outline for a Regional ARC based infrastructure in the WLCG and EGEE infrastructures

    International Nuclear Information System (INIS)

    Field, L; Gronager, M; Johansson, D; Kleist, J

    2010-01-01

    Interoperability of grid infrastructures is becoming increasingly important in the emergence of large scale grid infrastructures based on national and regional initiatives. To achieve interoperability of grid infrastructures adaptions and bridging of many different systems and services needs to be tackled. A grid infrastructure offers services for authentication, authorization, accounting, monitoring, operation besides from the services for handling and data and computations. This paper presents an outline of the work done to integrate the Nordic Tier-1 and 2s, which for the compute part is based on the ARC middleware, into the WLCG grid infrastructure co-operated by the EGEE project. Especially, a throughout description of integration of the compute services is presented.

  2. The Elon Gap Experience: A Transformative First-Year Experience

    Science.gov (United States)

    Morrison, Stephen T.; Burr, Katherine H.; Waters, Rexford A.; Hall, Eric E.

    2016-01-01

    The Elon Gap Experience (EGE) was conceived out of Elon University's most recent strategic plan, the Elon Commitment (Elon University, 2009). One theme calls for "strategic and innovative pathways in undergraduate and graduate education," specifically "to launch a service program as part of a gap-year program" (Elon University,…

  3. Where does particle acceleration occur in extended extragalactic radio sources

    International Nuclear Information System (INIS)

    Hughes, P.A.

    1980-01-01

    It is suggested that particle acceleration does not occur in the extended lobes of extragalactic radio sources, but only in the compact heads. Away from these, waves capable of accelerating particles may not propagate. Although wave generation within the lobes would allow acceleration there, it is not obvious that the plasma is sufficiently disturbed for this to occur. (author)

  4. On the extragalactic origin of gamma-ray bursts

    International Nuclear Information System (INIS)

    Johnson, M.; Teller, E.

    1984-01-01

    A theory to explain the origin of extragalactic gamma ray bursts is presented. Collisions of black dwarf and neutron stars with a subsequent fragmentation of the dwarf producing relativistic particle accelerations toward the neutron star and a resulting turbulent flow of material at the neutron star surface is postulated

  5. Extragalactic Gamma Ray Excess from Coma Supercluster Direction ...

    Indian Academy of Sciences (India)

    a power-law spectrum for γ rays from extragalactic sources and concluded a power- law index between 1.4 and 3 with values between 1.8 and 2 being the most common. Scharf & Mukherjee (2002) used data obtained by the Compton γ ray observatory spacecraft. They found a “fog” of γ rays associated to the galaxy clusters ...

  6. Study of extragalactic sources with H.E.S.S

    International Nuclear Information System (INIS)

    Giebels, Berrie

    2007-01-01

    The field of Very High Energy (VHE) γ-ray emitting extragalactic sources has considerably evolved since the new generation of atmospheric Cerenkov telescopes (ACT) of improved sensitivity, such as H.E.S.S. array and the MAGIC ACT, have started operating. This has led to a wealth of new clues about emission mechanisms at high energy through the discovery of new sources, more accurate spectra and temporal studies of sources known previously, and simultaneous multi-wavelength (MWL) campaigns since broad band variability is a key phenomenon to the underlying physical mechanisms at play. The fact that some of these new sources are located at redshifts close to z ∼ 0.2 makes them powerful probes of the Extragalactic Background Light (EBL) through the attenuation of γ-rays above 100 GeV

  7. Adoption of a SAML-XACML Profile for Authorization Interoperability across Grid Middleware in OSG and EGEE

    International Nuclear Information System (INIS)

    Garzoglio, G; Chadwick, K; Dykstra, D; Hesselroth, T; Levshina, T; Sharma, N; Timm, S; Bester, J; Martin, S; Groep, D; Koeroo, O; Salle, M; Verstegen, A; Gu, J; Sim, A

    2011-01-01

    The Authorization Interoperability activity was initiated in 2006 to foster interoperability between middleware and authorization infrastructures deployed in the Open Science Grid (OSG) and the Enabling Grids for E-sciencE (EGEE) projects. This activity delivered a common authorization protocol and a set of libraries that implement that protocol. In addition, a set of the most common Grid gateways, or Policy Enforcement Points (Globus Toolkit v4 Gatekeeper, GridFTP, dCache, etc.) and site authorization services, or Policy Decision Points (LCAS/LCMAPS, SCAS, GUMS, etc.) have been integrated with these libraries. At this time, various software providers, including the Globus Toolkit v5, BeStMan, and the Site AuthoriZation service (SAZ), are integrating the authorization interoperability protocol with their products. In addition, as more and more software supports the same protocol, the community is converging on LCMAPS as a common module for identity attribute parsing and authorization call-out. This paper presents this effort, discusses the status of adoption of the common protocol and projects the community work on authorization in the near future.

  8. Adoption of a SAML-XACML profile for authorization interoperability across grid middleware in OSG and EGEE

    Energy Technology Data Exchange (ETDEWEB)

    Garzoglio, G. [Fermilab; Bester, J. [Argonne; Chadwick, K. [Fermilab; Dykstra, D. [Fermilab; Groep, D. [NIKHEF, Amsterdam; Gu, J. [LBL, Berkeley; Hesselroth, T. [Fermilab; Koeroo, O. [NIKHEF, Amsterdam; Levshina, T. [Fermilab; Martin, S. [Argonne; Salle, M. [NIKHEF, Amsterdam; Sharma, N. [Fermilab; Sim, A. [LBL, Berkeley; Timm, S. [Fermilab; Verstegen, A. [NIKHEF, Amsterdam

    2011-01-01

    The Authorization Interoperability activity was initiated in 2006 to foster interoperability between middleware and authorization infrastructures deployed in the Open Science Grid (OSG) and the Enabling Grids for E-sciencE (EGEE) projects. This activity delivered a common authorization protocol and a set of libraries that implement that protocol. In addition, a set of the most common Grid gateways, or Policy Enforcement Points (Globus Toolkit v4 Gatekeeper, GridFTP, dCache, etc.) and site authorization services, or Policy Decision Points (LCAS/LCMAPS, SCAS, GUMS, etc.) have been integrated with these libraries. At this time, various software providers, including the Globus Toolkit v5, BeStMan, and the Site AuthoriZation service (SAZ), are integrating the authorization interoperability protocol with their products. In addition, as more and more software supports the same protocol, the community is converging on LCMAPS as a common module for identity attribute parsing and authorization call-out. This paper presents this effort, discusses the status of adoption of the common protocol and projects the community work on authorization in the near future.

  9. High-energy X-ray observations of extragalactic objects

    International Nuclear Information System (INIS)

    Pietsch, W.; Reppin, C.; Truemper, J.; Voges, W.; Lewin, W.; Kendziorra, E.; Staubert, R.

    1981-01-01

    During a balloon flight from Alice Springs, Australia, six extragalactic sources which are known as potential X-ray sources have been observed in hard X-rays (E > 20 keV). We present X-ray spectra of 3C 273 and Cen-A as well as upper limits on 3C 120, MKN 509, NGC 5506, and MR 2251-178. (orig.)

  10. Ege Bölgesi Zeytinyağlarının Fenolik Bileşenleri

    Directory of Open Access Journals (Sweden)

    Hasan Hüseyin Kara

    2018-02-01

    Full Text Available Bu çalışmada, Türkiye’de başlıca zeytin yetiştiriciliği yapan Ege bölgesinin bazı illerinden (Muğla, Aydın, İzmir ve Manisa 2 hasat dönemi (2007-2008 ve 2008-2009 süresince yerli zeytin çeşitlerinin (Gemlik, Memecik, Ayvalık, Uslu ve Domat yağı incelenmiştir. Bu yağların toplam fenolik madde ve fenolik bileşimi belirlenmiştir. Yağların toplam fenolik madde içeriği, 2007-2008 hasat dönemi örneklerinde 23,69-153,64 mg kafeik asit/kg, 2008-2009 hasat dönemi örneklerinde 16,18-136,22 mg kafeik asit/kg aralığında belirlenmiştir. Tüm zeytinyağı örneklerinde tespit edilen fenolik maddeler; tirozol, oleuropein, 4-hidroksifenil asetik asit, luteolin, vanilik asit, hidroksitirozol, rutin, sinnamik asit, verbaskozit, hidroksi fenilkarboksilik asit, sirinjik asit, 3,4-dihidroksibenzoik asit, kafeik asit, ferulik asit, p-kumarik asit, taksifolin ve apigenindir. Tirozol ve oleuropeinin, 2007-2008 hasat döneminde 1,80-13,39 mg/kg, 1,26-19,50 mg/kg ve 2008-2009 hasat döneminde ise 1,76-11,66 mg/kg, 0,20-13,12 mg/kg aralığında en fazla miktarda değişen bileşenler olduğu saptanmıştır.

  11. Extragalactic origin of gamma-ray bursts. Revision 1

    International Nuclear Information System (INIS)

    Johnson, M.; Teller, E.

    1984-01-01

    Detectors of gamma-rays carried by satellites and later by high-flying balloons showed the existence of events lasting from fifteen milliseconds to about a hundred seconds, arriving from all directions in space. A few hundred events have been observed in a little more than a decade. The energy of gamma-rays range from a few kilovolts to millions of volts. Recent evidence indicates that considerable energy may be carried at least in some cases even above 10 MeV. But the bulk of the energy appeared to be emitted between 100 and 200 keV. The observed intensities range between 10 -3 and 10 -7 ergs/cm 2 . The simple facts about intensity distribution are compatible with two extreme assumptions but exclude intermediate hypotheses. Either the events occur in our own galaxy in a region smaller than the thickness of the galaxy or they are of extragalactic origin and come from distant galaxies. Practically all attempted explanations have made the former explanation which requires that a mass of approximately 10 20 grams impinges on a neutron star (assuming a near to 100% conversion of gravitational energy available on the surface of the neutron star or 10 20 ergs/gram into gamma-rays which, of course, is unrealistic). In case of an extragalactic origin, the neutron star must attract and convert, as we shall see, about 2 x 10 30 grams or 10 -3 of the solar mass. It is perhaps the size of such events which deterred a detailed discussion of this alternative. Montgomery Johnson and I have tried to assume these big collisions, explore the consequences, and I shall talk about this extragalactic hypothesis

  12. Space distribution of extragalactic sources - Cosmology versus evolution

    International Nuclear Information System (INIS)

    Cavaliere, A.; Maccacaro, T.

    1990-01-01

    Alternative cosmologies have been recurrently invoked to explain in terms of global spacetime structure the apparent large increase, with increasing redshift, in the average luminosity of active galactic nuclei. These models interestingly seek to avoid the complexities of the canonical interpretation in terms of intrinsic population evolutions in a Friedmann universe. However, a problem of consistency for these cosmologies is pointed out, since they have to include also other classes of extragalactic sources, such as clusters of galaxies and BL Lac objects, for which there is preliminary evidence of a different behavior. 40 refs

  13. Rotationally symmetric structure in two extragalactic radio sources

    International Nuclear Information System (INIS)

    Lonsdale, C.J.; Morison, I.

    1980-01-01

    The new multi-telescope radio-linked interferometer (MTRLI) at Jodrell Bank was used during January and February 1980 at a frequency of 408 MHz to map the extragalactic radio sources 3C196 and 3C305 with a resolution of approximately 1 arc s. It is shown here that both the markedly symmetric structures observed and the spectral index distributions inferred from comparisons with previously published 5 GHz maps provide evidence for the source axes having rotated during the lifetime of the emitting regions. (U.K.)

  14. EGE BÖLGESİNDEKİ İLLERDE PENCERELER İÇİN OPTİMUM HAVA TABAKASI KALINLIĞININ ARAŞTIRILMASI

    Directory of Open Access Journals (Sweden)

    Ali Keçebaş

    2016-06-01

    Full Text Available Bu çalışmada Ege Bölgesi’ndeki sekiz (Manisa, İzmir, Kütahya, Uşak, Afyon, Aydın, Denizli, Muğla il için düşey konumda iki cam plaka arasındaki hava tabakası 1 mm’den başlayıp 280 mm’ye kadar hava boşluğunun penceredeki yalıtıma etkileri araştırılmıştır. Araştırma sonuçlarına göre; Ege Bölgesi’ndeki iller için pencerelerde optimum hava boşluğu yaklaşımı getirilmiştir. Bu yaklaşımla İzmir’de 14 mm, Denizli’de 13 mm, Uşak’ta 12,5 mm ve dış hava sıcaklığı aynı olan üç ilde (Aydın, Manisa, Muğla 13,4 mm ve iki ilde (Afyon, Kütahya 12,2 mm olarak optimum hava tabakası kalınlığı hesaplanmıştır. Bu çalışma ile literatüre Ege Bölgesi’ndeki her il için optimum hava tabakası kalınlığı yaklaşımı getirilmiştir.

  15. An Optical View of Extragalactic γ-Ray Emitters

    Energy Technology Data Exchange (ETDEWEB)

    Paiano, Simona [Osservatorio Astronomico di Padova (INAF), Padua (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Padova, Padua (Italy); Falomo, Renato [Osservatorio Astronomico di Padova (INAF), Padua (Italy); Landoni, Marco [Osservatorio Astronomico di Brera (INAF), Merate (Italy); Treves, Aldo [Università degli Studi dell' Insubria, Varese (Italy); Scarpa, Riccardo, E-mail: simona.paiano@oapd.inaf.it [Instituto de Astrofísica de Canarias, Santa Cruz de Tenerife (Spain); Departamento de Astrofsica, Universidad de La Laguna, San Cristóbal de La Laguna (Spain)

    2017-11-23

    The Fermi Gamma-ray Observatory discovered about a thousand extragalactic sources emitting energy from 100 MeV to 100 GeV. The majority of these sources belong to the class of blazars characterized by a quasi-featureless optical spectrum (BL Lac Objects). This hampers the determination of their redshift and therefore hinders the characterization of this class of objects. To investigate the nature of these sources and to determine their redshift, we are carrying out an extensive campaign using the 10 m Gran Telescopio Canarias to obtain high S/N ratio optical spectra. These observations allow us to confirm the blazar nature of the targets, to find new redshifts or to set stringent limits on the redshift based on the minimum equivalent width of specific absorption features that can be measured in the spectrum and are expected from their host galaxy, assuming it is a massive elliptical galaxy. These results are of importance for the multi-frequencies emission models of the blazars, to test their extreme physics, to shed light on their cosmic evolution and abundance in the far Universe. These gamma emitters are also of great importance for the characterization of the extragalactic background light through the absorption by the IR-optical background photons.

  16. Dust and molecules in extra-galactic planetary nebulae

    Science.gov (United States)

    Garcia-Hernandez, Domingo Aníbal

    2015-08-01

    Extra-galactic planetary nebulae (PNe) permit the study of dust and molecules in metallicity environments other than the Galaxy. Their known distances lower the number of free parameters in the observations vs. models comparison, providing strong constraints on the gas-phase and solid-state astrochemistry models. Observations of PNe in the Galaxy and other Local Group galaxies such as the Magellanic Clouds (MC) provide evidence that metallicity affects the production of dust as well as the formation of complex organic molecules and inorganic solid-state compounds in their circumstellar envelopes. In particular, the lower metallicity MC environments seem to be less favorable to dust production and the frequency of carbonaceous dust features and complex fullerene molecules is generally higher with decreasing metallicity. Here, I present an observational review of the dust and molecular content in extra-galactic PNe as compared to their higher metallicity Galactic counterparts. A special attention is given to the level of dust processing and the formation of complex organic molecules (e.g., polycyclic aromatic hydrocarbons, fullerenes, and graphene precursors) depending on metallicity.

  17. THE EXTRAGALACTIC DISTANCE DATABASE: ALL DIGITAL H I PROFILE CATALOG

    International Nuclear Information System (INIS)

    Courtois, Helene M.; Bonhomme, Nicolas; Tully, R. Brent; Zavodny, Maximilian; Barnes, Austin; Fisher, J. Richard

    2009-01-01

    An important component of the Extragalactic Distance Database is a group of catalogs related to the measurement of H I line profile parameters. One of these is the All Digital H I catalog which contains an amalgam of information from new data and old. The new data result from observations with Arecibo and Parkes Telescopes and with the Green Bank Telescope, including continuing input since the award of the NRAO Cosmic Flows Large Program. The old data have been collected from archives, wherever available, particularly the Cornell University Digital H I Archive, the Nancay Telescope extragalactic H I archive, and the Australia Telescope H I archive. The catalog currently contains information on ∼15, 000 profiles relating to ∼13, 000 galaxies. The channel-flux per channel files, from whatever source, is carried through a common pipeline. The derived parameter of greatest interest is W m50 , the profile width at 50% of the mean flux. After appropriate adjustment, the parameter W mx is derived, the line width that statistically approximates the peak-to-peak maximum rotation velocity before correction for inclination, 2V max sini.

  18. Energy spectrum of extragalactic gamma-ray sources

    Science.gov (United States)

    Protheroe, R. J.

    1985-01-01

    The result of Monte Carlo electron photon cascade calculations for propagation of gamma rays through regions of extragalactic space containing no magnetic field are given. These calculations then provide upper limits to the expected flux from extragalactic sources. Since gamma rays in the 10 to the 14th power eV to 10 to the 17th power eV energy range are of interest, interactions of electrons and photons with the 3 K microwave background radiation are considered. To obtain an upper limit to the expected gamma ray flux from sources, the intergalactic field is assumed to be so low that it can be ignored. Interactions with photons of the near-infrared background radiation are not considered here although these will have important implications for gamma rays below 10 to the 14th power eV if the near infrared background radiation is universal. Interaction lengths of electrons and photons in the microwave background radiation at a temperature of 2.96 K were calculated and are given.

  19. Simulations of extragalactic magnetic fields and of their observables

    Science.gov (United States)

    Vazza, F.; Brüggen, M.; Gheller, C.; Hackstein, S.; Wittor, D.; Hinz, P. M.

    2017-12-01

    The origin of extragalactic magnetic fields is still poorly understood. Based on a dedicated suite of cosmological magneto-hydrodynamical simulations with the ENZO code we have performed a survey of different models that may have caused present-day magnetic fields in galaxies and galaxy clusters. The outcomes of these models differ in cluster outskirts, filaments, sheets and voids and we use these simulations to find observational signatures of magnetogenesis. With these simulations, we predict the signal of extragalactic magnetic fields in radio observations of synchrotron emission from the cosmic web, in Faraday rotation, in the propagation of ultra high energy cosmic rays, in the polarized signal from fast radio bursts at cosmological distance and in spectra of distant blazars. In general, primordial scenarios in which present-day magnetic fields originate from the amplification of weak (⩽nG ) uniform seed fields result in more homogeneous and relatively easier to observe magnetic fields than astrophysical scenarios, in which present-day fields are the product of feedback processes triggered by stars and active galaxies. In the near future the best evidence for the origin of cosmic magnetic fields will most likely come from a combination of synchrotron emission and Faraday rotation observed at the periphery of large-scale structures.

  20. The Advanced Gamma-ray Imaging System (AGIS): Extragalactic Science

    Science.gov (United States)

    Coppi, Paolo S.; Extragalactic Science Working Group; AGIS Collaboration

    2010-03-01

    The Advanced Gamma-ray Imaging System (AGIS), a proposed next-generation array of Cherenkov telescopes, will provide an unprecedented view of the high energy universe. We discuss how AGIS, with its larger effective area, improved angular resolution, lower threshold, and an order of magnitude increase in sensitivity, impacts the extragalactic science possible in the very high energy domain. Likely source classes detectable by AGIS include AGN, GRBs, clusters, star-forming galaxies, and possibly the cascade radiation surrounding powerful cosmic accelerators. AGIS should see many of the sources discovered by Fermi. With its better sensitivity and angular resolution, AGIS then becomes a key instrument for identifying and characterizing Fermi survey sources, the majority of which will have limited Fermi photon statistics and localizations.

  1. A Clustered Extragalactic Foreground Model for the EoR

    Science.gov (United States)

    Murray, S. G.; Trott, C. M.; Jordan, C. H.

    2018-05-01

    We review an improved statistical model of extra-galactic point-source foregrounds first introduced in Murray et al. (2017), in the context of the Epoch of Reionization. This model extends the instrumentally-convolved foreground covariance used in inverse-covariance foreground mitigation schemes, by considering the cosmological clustering of the sources. In this short work, we show that over scales of k ~ (0.6, 40.)hMpc-1, ignoring source clustering is a valid approximation. This is in contrast to Murray et al. (2017), who found a possibility of false detection if the clustering was ignored. The dominant cause for this change is the introduction of a Galactic synchrotron component which shadows the clustering of sources.

  2. IS THERE AN UNACCOUNTED FOR EXCESS IN THE EXTRAGALACTIC COSMIC RADIO BACKGROUND?

    Energy Technology Data Exchange (ETDEWEB)

    Subrahmanyan, Ravi [Raman Research Institute, CV Raman Avenue, Sadashivanagar, Bangalore 560080 (India); Cowsik, Ramanath, E-mail: rsubrahm@rri.res.in, E-mail: cowsik@physics.wustl.edu [Physics Department and McDonnell Center for the Space Sciences, Washington University, Campus Box 1105, St. Louis, MO 63130 (United States)

    2013-10-10

    Analyses of the distribution of absolute brightness temperature over the radio sky have recently led to suggestions that there exists a substantial unexplained extragalactic radio background. Consequently, there have been numerous attempts to place constraints on plausible origins of this 'excess'. We suggest here that this expectation of a large extragalactic background, over and above that contributed by the sources observed in the surveys, is based on an extremely simple geometry adopted to model the Galactic emission and the procedure adopted in the estimation of the extragalactic contribution. In this paper, we derive the extragalactic radio background from wide-field radio images using a more realistic modeling of the Galactic emission and decompose the sky maps at 150, 408, and 1420 MHz into anisotropic Galactic and isotropic extragalactic components. The anisotropic Galactic component is assumed to arise from a highly flattened spheroid representing the thick disk, embedded in a spherical halo, both centered at the Galactic center, along with Galactic sources, filamentary structures, and Galactic loops and spurs. All components are constrained to be positive and the optimization scheme minimizes the sky area occupied by the complex filaments. We show that in contrast with simple modeling of Galactic emission as a plane parallel slab, the more realistic modeling yields estimates for the uniform extragalactic brightness that are consistent with expectations from known extragalactic radio source populations.

  3. Differences in the size-internal velocity relation of galactic and extragalactic HII regions

    International Nuclear Information System (INIS)

    Odell, C.R.

    1990-01-01

    The nature of the size-internal velocity relation in extragalactic HII regions is examined in order to improve their use as distance determinants. The relation between the linear size and the internal velocity was compared for HII regions in the Galaxy and in external galaxies. Data for the former are from the researcher's own studies at high spatial resolution, while the latter have been the subject of spectroscopy that includes almost the entire objects. The Galactic HII regions are corrected to values of the internal velocity that would be observed if they were at extragalactic distances. A very different size-internal velocity relation was found for the two types of objects in the sense that the extragalactic objects are some ten times larger at the same internal velocity. This is interpreted to mean that the extragalactic HII regions are actually complexes of small HII regions comparable in size to their Galactic counterparts

  4. Forecasting the Contribution of Polarized Extragalactic Radio Sources in CMB Observations

    Science.gov (United States)

    Puglisi, G.; Galluzzi, V.; Bonavera, L.; Gonzalez-Nuevo, J.; Lapi, A.; Massardi, M.; Perrotta, F.; Baccigalupi, C.; Celotti, A.; Danese, L.

    2018-05-01

    We combine the latest data sets obtained with different surveys to study the frequency dependence of polarized emission coming from extragalactic radio sources (ERS). We consider data over a very wide frequency range starting from 1.4 GHz up to 217 GHz. This range is particularly interesting since it overlaps the frequencies of the current and forthcoming cosmic microwave background (CMB) experiments. Current data suggest that at high radio frequencies (ν ≥ 20 GHz) the fractional polarization of ERS does not depend on the total flux density. Conversely, recent data sets indicate a moderate increase of polarization fraction as a function of frequency, physically motivated by the fact that Faraday depolarization is expected to be less relevant at high radio frequencies. We compute ERS number counts using updated models based on recent data, and we forecast the contribution of unresolved ERS in CMB polarization spectra. Given the expected sensitivities and the observational patch sizes of forthcoming CMB experiments, about ∼200 (up to ∼2000) polarized ERS are expected to be detected. Finally, we assess that polarized ERS can contaminate the cosmological B-mode polarization if the tensor-to-scalar ratio is <0.05 and they have to be robustly controlled to de-lens CMB B-modes at the arcminute angular scales.

  5. MODELING EXTRAGALACTIC EXTINCTION THROUGH GAMMA-RAY BURST AFTERGLOWS

    Energy Technology Data Exchange (ETDEWEB)

    Zonca, Alberto; Mulas, Giacomo; Casu, Silvia; Aresu, Giambattista [INAF—Osservatorio Astronomico di Cagliari, Via della Scienza 5, I-09047 Selargius (Italy); Cecchi-Pestellini, Cesare, E-mail: azonca@oa-cagliari.inaf.it, E-mail: gmulas@oa-cagliari.inaf.it, E-mail: silvia@oa-cagliari.inaf.it, E-mail: garesu@oa-cagliari.inaf.it, E-mail: cecchi-pestellini@astropa.inaf.it [INAF—Osservatorio Astronomico di Palermo, P.za Parlamento 1, I-90134 Palermo (Italy)

    2016-09-20

    We analyze extragalactic extinction profiles derived through gamma-ray burst afterglows, using a dust model specifically constructed on the assumption that dust grains are not immutable but respond, time-dependently, to the local physics. Such a model includes core-mantle spherical particles of mixed chemical composition (silicate core, sp{sup 2}, and sp{sup 3} carbonaceous layers), and an additional molecular component in the form of free-flying polycyclic aromatic hydrocarbons. We fit most of the observed extinction profiles. Failures occur for lines of sight, presenting remarkable rises blueward of the bump. We find a tendency for the carbon chemical structure to become more aliphatic with the galactic activity, and to some extent with increasing redshifts. Moreover, the contribution of the molecular component to the total extinction is more important in younger objects. The results of the fitting procedure (either successes and failures) may be naturally interpreted through an evolutionary prescription based on the carbon cycle in the interstellar medium of galaxies.

  6. Extragalactic stellar astronomy with the brightest stars in the universe

    Energy Technology Data Exchange (ETDEWEB)

    Kudritzki, R P; Urbaneja, M A; Bresolin, F [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Przybilla, N [Dr Remeis-Sternwarte Bamberg, Erlangen University, Sternwartstr. 7, D-96049 Bamberg (Germany)], E-mail: kud@ifa.hawaii.edu

    2008-12-15

    Supergiants are objects in transition from the blue to the red (and vice versa) in the uppermost HRD. They are the intrinsically brightest 'normal' stars at visual light with absolute visual magnitudes up to -9. They are ideal to study young stellar populations in galaxies beyond the Local Group to determine chemical composition and evolution, interstellar extinction, reddening laws and distances. We discuss the most recent results on the quantitative spectral analysis of such objects in galaxies beyond the Local Group based on medium and low-resolution spectra obtained with the ESO VLT and Keck. We describe the analysis method including the determination of metallicity and metallicity gradients. A new method to measure extragalactic distances accurately based on stellar gravities and effective temperatures is presented, the flux-weighted gravity-luminosity relationship (FGLR). The FGLR is a purely spectroscopic method that overcomes the uncertainties, introduced by interstellar extinction and variations of metallicity, which plague all methods of photometric stellar distance determination. We discuss the perspectives of future work using the giant ground-based telescopes of the next generation such as the TMT, the GMT and the E-ELT.

  7. Extragalactic circuits, transmission lines, and CR particle acceleration

    CERN Document Server

    Kronberg, Philipp P

    2014-01-01

    A non-negligible fraction of a Supermassive Black Hole's (SMBH) rest mass energy gets transported into extragalactic space by a remarkable process in jets which are incompletely understood. What are the physical processes which transport this energy? It is likely that the energy flows electromagnetically, rather than via a particle beam flux. The deduced electromagnetic fields may produce particles of energy as high as $\\sim 10^{20}$ eV. The energetics of SMBH accretion disk models and the electromagnetic energy transfer imply that a SMBH should generate a $10^{18} - 10^{19}$ Amp\\`eres current close to the black hole and its accretion disk. We describe the so far best observation-based estimate of the magnitude of the current flow along the axis of the jet extending from the nucleus of the active galaxy in 3C303. The current is measured to be $I \\sim 10^{18}$ Amp\\`eres at $\\sim 40$ kpc away from the AGN. This indicates that organized current flow remains intact over multi-kpc distances. The electric current $...

  8. THE DYNAMIC EVOLUTION OF YOUNG EXTRAGALACTIC RADIO SOURCES

    International Nuclear Information System (INIS)

    An Tao; Baan, Willem A.

    2012-01-01

    The evolution of symmetric extragalactic radio sources can be characterized by four distinct growth stages of the radio luminosity versus size of the source. The interaction of the jet with the ambient medium results in the formation and evolution of sources with non-standard (flaring) morphology. In addition, cessation or restarting of the jet power and obstruction of the jet will also result in distinct morphological structures. The radio source population may thus be classified in morphological types that indicate the prevailing physical processes. Compact symmetric objects (CSOs) occupy the earliest evolutionary phase of symmetric radio sources and their dynamical behavior is fundamental for any further evolution. Analysis of CSO dynamics is presented for a sample of 24 CSOs with known redshift and hotspot separation velocity and with a large range of radio power. Observables such as radio power, separation between two hotspots, hotspot separation velocity, and kinematic age of the source are found to be generally consistent with the self-similar predictions for individual sources that reflect the varying density structure of the ambient interstellar medium. Individual sources behave different from the group as a whole. The age and size statistics confirm that a large fraction of CSOs does not evolve into extended doubles.

  9. A model for extremely powerful extragalactic water masers

    International Nuclear Information System (INIS)

    Wu, Ying-Cheng; Alcock, C.

    1988-08-01

    The reasons for the differences between extremely powerful extragalatic water masers (EPEWMs) and strong Galactic H 2 O masers are discussed. This model quite successfully explains many important characteristics of EPEWMs; the rapid time variations, the broad range and random velocity distribution, the extremely high luminosities, the various heights or widths of features in spectra, the strong infrared radiation from the galaxies, how an active nucleus contributes to an EPEWM, how some parts of EPEWMs producing strong features are pumped, why this pump mechanism can work, and why EPEWMs are different from strong Galactic H 2 O masers. Recent observations of extragalactic water masers which have extremely high luminosities raise the possibility that the stimulated emission rate in the maser emission line in these regions is much higher than in Galactic masers. It is possible that the local stimulated emission rate exceeds the local bandwidth for the radiation. In this case the standard expression relating the photon emission rate to the profile averaged mean intensity does not apply. A new expression for the photon emission rate is derived

  10. A model for extremely powerful extragalactic water masers

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Ying-Cheng; Alcock, C.

    1988-08-01

    The reasons for the differences between extremely powerful extragalatic water masers (EPEWMs) and strong Galactic H/sub 2/O masers are discussed. This model quite successfully explains many important characteristics of EPEWMs; the rapid time variations, the broad range and random velocity distribution, the extremely high luminosities, the various heights or widths of features in spectra, the strong infrared radiation from the galaxies, how an active nucleus contributes to an EPEWM, how some parts of EPEWMs producing strong features are pumped, why this pump mechanism can work, and why EPEWMs are different from strong Galactic H/sub 2/O masers. Recent observations of extragalactic water masers which have extremely high luminosities raise the possibility that the stimulated emission rate in the maser emission line in these regions is much higher than in Galactic masers. It is possible that the local stimulated emission rate exceeds the local bandwidth for the radiation. In this case the standard expression relating the photon emission rate to the profile averaged mean intensity does not apply. A new expression for the photon emission rate is derived.

  11. Secular Extragalactic Parallax and Geometric Distances with Gaia Proper Motions

    Science.gov (United States)

    Paine, Jennie; Darling, Jeremiah K.

    2018-06-01

    The motion of the Solar System with respect to the cosmic microwave background (CMB) rest frame creates a well measured dipole in the CMB, which corresponds to a linear solar velocity of about 78 AU/yr. This motion causes relatively nearby extragalactic objects to appear to move compared to more distant objects, an effect that can be measured in the proper motions of nearby galaxies. An object at 1 Mpc and perpendicular to the CMB apex will exhibit a secular parallax, observed as a proper motion, of 78 µas/yr. The relatively large peculiar motions of galaxies make the detection of secular parallax challenging for individual objects. Instead, a statistical parallax measurement can be made for a sample of objects with proper motions, where the global parallax signal is modeled as an E-mode dipole that diminishes linearly with distance. We present preliminary results of applying this model to a sample of nearby galaxies with Gaia proper motions to detect the statistical secular parallax signal. The statistical measurement can be used to calibrate the canonical cosmological “distance ladder.”

  12. The ALFALFA Extragalactic Catalog and Data Processing Pipeline

    Science.gov (United States)

    Kent, Brian R.; Haynes, Martha P.; Giovanelli, Riccardo; ALFALFA Team

    2018-06-01

    The Arecibo Legacy Fast ALFA 21cm HI Survey has reached completion. The observations and data are used by team members and the astronomical community in a variety of scientific initiatives with gas-rich galaxies, cluster environments, and studies of low redshift cosmology. The survey covers nearly 7000 square degrees of high galactic latitude sky visible from Arecibo, Puerto Rico and ~4400 hours of observations from 2005 to 2011. We present the extragalactic HI source catalog of over ~31,000 detections, their measured properties, and associated derived parameters. The observations were carefully reduced using a custom made data reduction pipeline and interface. Team members interacted with this pipeline through observation planning, calibration, imaging, source extraction, and cataloging. We describe this processing workflow as it pertains to the complexities of the single-dish multi-feed data reduction as well as known caveats of the source catalog and spectra for use in future astronomical studies and analysis. The ALFALFA team at Cornell has been supported by NSF grants AST-0607007, AST-1107390 and AST-1714828 and by grants from the Brinson Foundation.

  13. THE DYNAMIC EVOLUTION OF YOUNG EXTRAGALACTIC RADIO SOURCES

    Energy Technology Data Exchange (ETDEWEB)

    An Tao [Shanghai Astronomical Observatory, Chinese Academy of Sciences, 200030 Shanghai (China); Baan, Willem A., E-mail: antao@shao.ac.cn, E-mail: baan@astron.nl [ASTRON, P.O. Box 2, 7990-AA Dwingeloo (Netherlands)

    2012-11-20

    The evolution of symmetric extragalactic radio sources can be characterized by four distinct growth stages of the radio luminosity versus size of the source. The interaction of the jet with the ambient medium results in the formation and evolution of sources with non-standard (flaring) morphology. In addition, cessation or restarting of the jet power and obstruction of the jet will also result in distinct morphological structures. The radio source population may thus be classified in morphological types that indicate the prevailing physical processes. Compact symmetric objects (CSOs) occupy the earliest evolutionary phase of symmetric radio sources and their dynamical behavior is fundamental for any further evolution. Analysis of CSO dynamics is presented for a sample of 24 CSOs with known redshift and hotspot separation velocity and with a large range of radio power. Observables such as radio power, separation between two hotspots, hotspot separation velocity, and kinematic age of the source are found to be generally consistent with the self-similar predictions for individual sources that reflect the varying density structure of the ambient interstellar medium. Individual sources behave different from the group as a whole. The age and size statistics confirm that a large fraction of CSOs does not evolve into extended doubles.

  14. Evolution of Extragalactic Radio Sources and Quasar/Galaxy Unification

    Science.gov (United States)

    Onah, C. I.; Ubachukwu, A. A.; Odo, F. C.; Onuchukwu, C. C.

    2018-04-01

    We use a large sample of radio sources to investigate the effects of evolution, luminosity selection and radio source orientation in explaining the apparent deviation of observed angular size - redshift (θ - z) relation of extragalactic radio sources (EGRSs) from the standard model. We have fitted the observed θ - z data with standard cosmological models based on a flat universe (Ω0 = 1). The size evolution of EGRSs has been described as luminosity, temporal and orientation-dependent in the form DP,z,Φ ≍ P±q(1 + z)-m sinΦ, with q=0.3, Φ=59°, m=-0.26 for radio galaxies and q=-0.5, Φ=33°, m=3.1 for radio quasars respectively. Critical points of luminosity, logPcrit=26.33 WHz-1 and logDc=2.51 kpc (316.23 kpc) of the present sample of radio sources were also observed. All the results were found to be consistent with the popular quasar/galaxy unification scheme.

  15. Investigation of some galactic and extragalactic gravitational phenomena

    Directory of Open Access Journals (Sweden)

    Jovanović P.

    2012-01-01

    Full Text Available Here we present a short overview of the most important results of our investigations of the following galactic and extragalactic gravitational phenomena: supermassive black holes in centers of galaxies and quasars, supermassive black hole binaries, gravitational lenses and dark matter. For the purpose of these investigations, we developed a model of a relativistic accretion disk around a supermassive black hole, based on the ray-tracing method in the Kerr metric, a model of a bright spot in an accretion disk and three different models of gravitational microlenses. All these models enabled us to study physics, spacetime geometry and effects of strong gravity in the vicinity of supermassive black holes, variability of some active galaxies and quasars, different effects in the lensed quasars with multiple images, as well as the dark matter fraction in the Universe. We also found an observational evidence for the first spectroscopically resolved sub-parsec orbit of a supermassive black hole binary system in the core of active galaxy NGC 4151. Besides, we studied applications of one potential alternative to dark matter in the form of a modified theory of gravity on Galactic scales, to explain the recently observed orbital precession of some S-stars, which are orbiting around a massive black hole at the Galactic center. [Projekat Ministarstva nauke Republike Srbije, br. 176003: Gravitation and the Large Scale Structure of the Universe

  16. Magnetic field, reconnection, and particle acceleration in extragalactic jets

    Science.gov (United States)

    Romanova, M. M.; Lovelace, R. V. E.

    1992-01-01

    Extra-galactic radio jets are investigated theoretically taking into account that the jet magnetic field is dragged out from the central rotating source by the jet flow. Thus, magnetohydrodynamic models of jets are considered with zero net poloidal current and flux, and consequently a predominantly toroidal magnetic field. The magnetic field naturally has a cylindrical neutral layer. Collisionless reconnection of the magnetic field in the vicinity of the neutral layer acts to generate a non-axisymmetric radial magnetic field. In turn, axial shear-stretching of reconnected toroidal field gives rise to a significant axial magnetic field if the flow energy-density is larger than the energy-density of the magnetic field. This can lead to jets with an apparent longitudinal magnetic field as observed in the Fanaroff-Riley class II jets. In the opposite limit, where the field energy-density is large, the field remains mainly toroidal as observed in Fanaroff-Riley class I jets. Driven collisionless reconnection at neutral layers may lead to acceleration of electrons to relativistic energies in the weak electrostatic field of the neutral layer. A simple model is discussed for particle acceleration at neutral layers in electron/positron and electron/proton plasmas.

  17. AXION DECAY AND ANISOTROPY OF NEAR-IR EXTRAGALACTIC BACKGROUND LIGHT

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Yan; Chen, Xuelei [National Astronomical Observatories, Chinese Academy of Sciences, Beijing, 100012 (China); Cooray, Asantha; Mitchell-Wynne, Ketron [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Zemcov, Michael [Center for Detectors, School of Physics and Astronomy, Rochester Institute of Technology, Rochester, NY 14623 (United States); Smidt, Joseph [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2016-07-10

    The extragalactic background light (EBL) is composed of the cumulative radiation from all galaxies and active galactic nuclei over cosmic history. In addition to point sources, the EBL also contains information from diffuse sources of radiation. The angular power spectra of the near-infrared intensities could contain additional signals, and a complete understanding of the nature of the infrared (IR) background is still lacking in the literature. Here we explore the constraints that can be placed on particle decays, especially candidate dark matter (DM) models involving axions that trace DM halos of galaxies. Axions with a mass around a few electronvolts will decay via two photons with wavelengths in the near-IR band and will leave a signature in the IR background intensity power spectrum. Using recent power spectra measurements from the Hubble Space Telescope and the Cosmic Infrared Background Experiment, we find that the 0.6–1.6 μ m power spectra can be explained by axions with masses around 4 eV. The total axion abundance Ω{sub a} ≃ 0.05, and it is comparable to the baryon density of the universe. The suggested mean axion mass and abundance are not ruled out by existing cosmological observations. Interestingly, the axion model with a mass distribution is preferred by the data, which cannot be explained by the standard quantum chromodynamics theory and needs further discussion.

  18. Probing the Extragalactic Cosmic-Ray Origin with Gamma-Ray and Neutrino Backgrounds

    Energy Technology Data Exchange (ETDEWEB)

    Globus, Noemie; Piran, Tsvi [Racah Institute of Physics, The Hebrew University, 91904 Jerusalem (Israel); Allard, Denis; Parizot, Etienne [Laboratoire Astroparticule et Cosmologie, Université Paris Diderot/CNRS, 10 rue A. Domon et L. Duquet, F-75205 Paris Cedex 13 (France)

    2017-04-20

    GeV–TeV gamma-rays and PeV–EeV neutrino backgrounds provide a unique window on the nature of the ultra-high-energy cosmic rays (UHECRs). We discuss the implications of the recent Fermi -LAT data regarding the extragalactic gamma-ray background and related estimates of the contribution of point sources as well as IceCube neutrino data on the origin of the UHECRs. We calculate the diffuse flux of cosmogenic γ -rays and neutrinos produced by the UHECRs and derive constraints on the possible cosmological evolution of UHECR sources. In particular, we show that the mixed-composition scenario considered in Globus et al., which is in agreement with both (i) Auger measurements of the energy spectrum and composition up to the highest energies and (ii) the ankle-like feature in the light component detected by KASCADE-Grande, is compatible with both the Fermi -LAT measurements and with current IceCube limits. We also discuss the possibility for future experiments to detect associated cosmogenic neutrinos and further constrain the UHECR models, including possible subdominant UHECR proton sources.

  19. Extragalactic Peaked-spectrum Radio Sources at Low Frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Callingham, J. R.; Gaensler, B. M.; Sadler, E. M.; Lenc, E. [Sydney Institute for Astronomy (SIfA), School of Physics, The University of Sydney, NSW 2006 (Australia); Ekers, R. D.; Bell, M. E. [CSIRO Astronomy and Space Science (CASS), Marsfield, NSW 2122 (Australia); Line, J. L. B.; Hancock, P. J.; Kapińska, A. D.; McKinley, B.; Procopio, P. [ARC Centre of Excellence for All-Sky Astrophysics (CAASTRO) (Australia); Hurley-Walker, N.; Tingay, S. J.; Franzen, T. M. O.; Morgan, J. [International Centre for Radio Astronomy Research (ICRAR), Curtin University, Bentley, WA 6102 (Australia); Dwarakanath, K. S. [Raman Research Institute (RRI), Bangalore 560080 (India); For, B.-Q. [International Centre for Radio Astronomy Research (ICRAR), The University of Western Australia, Crawley, WA 6009 (Australia); Hindson, L.; Johnston-Hollitt, M. [School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington 6140 (New Zealand); Offringa, A. R., E-mail: joseph.callingham@sydney.edu.au [Netherlands Institute for Radio Astronomy (ASTRON), Dwingeloo (Netherlands); and others

    2017-02-20

    We present a sample of 1483 sources that display spectral peaks between 72 MHz and 1.4 GHz, selected from the GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey. The GLEAM survey is the widest fractional bandwidth all-sky survey to date, ideal for identifying peaked-spectrum sources at low radio frequencies. Our peaked-spectrum sources are the low-frequency analogs of gigahertz-peaked spectrum (GPS) and compact-steep spectrum (CSS) sources, which have been hypothesized to be the precursors to massive radio galaxies. Our sample more than doubles the number of known peaked-spectrum candidates, and 95% of our sample have a newly characterized spectral peak. We highlight that some GPS sources peaking above 5 GHz have had multiple epochs of nuclear activity, and we demonstrate the possibility of identifying high-redshift ( z > 2) galaxies via steep optically thin spectral indices and low observed peak frequencies. The distribution of the optically thick spectral indices of our sample is consistent with past GPS/CSS samples but with a large dispersion, suggesting that the spectral peak is a product of an inhomogeneous environment that is individualistic. We find no dependence of observed peak frequency with redshift, consistent with the peaked-spectrum sample comprising both local CSS sources and high-redshift GPS sources. The 5 GHz luminosity distribution lacks the brightest GPS and CSS sources of previous samples, implying that a convolution of source evolution and redshift influences the type of peaked-spectrum sources identified below 1 GHz. Finally, we discuss sources with optically thick spectral indices that exceed the synchrotron self-absorption limit.

  20. The HST Key Project on the Extragalactic Distance Scale

    Science.gov (United States)

    Freedman, W. L.

    1994-12-01

    One of the major unresolved problems in observational cosmology is the determination of the Hubble Constant, (H_0). The Hubble Space Telescope (HST) Key Project on the Extragalactic Distance Scale aims to provide a measure of H_0 to an accuracy of 10%. Historically the route to H_0 has been plagued by systematic errors; hence there is no quick and easy route to a believeable value of H_0. Achieving plausible error limits of 10% requires careful attention to eliminating potential sources of systematic error. The strategy adopted by the Key Project team is threefold: First, to discover Cepheids in spiral galaxies located in the field and in small groups that are suitable for the calibration of several independent secondary methods. Second, to make direct Cepheid measurements of 3 spiral galaxies in the Virgo cluster and 2 members of the Fornax cluster. Third, to provide a check on the the Cepheid distance scale via independent distance estimates to nearby galaxies, and in addition, to undertake an empirical test of the sensitivity of the zero point of the Cepheid PL relation to heavy-element abundances. First results from the HST Key Project will be presented. We have now determined Cepheid distances to 4 galaxies using the HST: these are the nearby galaxies M81 and M101, the edge-on galaxy NGC 925, and the face-on spiral galaxy M100 in the Virgo cluster. Recently we have measured a Cepheid distance for M100 of 17 +/- 2 Mpc, which yields a value of H_0 = 80 +/- 17 km/sec/Mpc. This work was carried out in collaboration with the other members of the HST Key Project team, R. Kennicutt, J. Mould, F. Bresolin, S. Faber, L. Ferrarese, H. Ford, J. Graham, J. Gunn, M. Han, P. Harding, J. Hoessel, R. Hill, J. Huchra, S. Hughes, G. Illingworth, D. Kelson, B. Madore, R. Phelps, A. Saha, N. Silbermann, P. Stetson, and A. Turner.

  1. Cosmology from angular size counts of extragalactic radio sources

    International Nuclear Information System (INIS)

    Kapahi, V.K.

    1975-01-01

    The cosmological implications of the observed angular sizes of extragalactic radio sources are investigated using (i) the log N-log theta relation, where N is the number of sources with an angular size greater than a value theta, for the complete sample of 3CR sources, and (ii) the thetasub(median) vs flux density (S) relation derived from the 3CR, the All-sky, and the Ooty occulation surveys, spanning a flux density range of about 300:1. The method of estimating the expected N(theta) and thetasub(m)(S) relations for a uniform distribution of sources in space is outlined. Since values of theta>approximately 100second arc in the 3C sample arise from sources of small z, the slope of the N(theta) relation in this range is practically independent of the world model and the distribution of source sizes, but depends strongly on the radio luminosity function (RLF). From the observed slope the RLF is derived in the luminosity range of about 10 23 178 26 W Hz -1 sr -1 to be of the form rho(P)dP proportional to Psup(-2.1)dP. It is shown that the angular size data provide independent evidence of evolution in source properties with epoch. It is difficult to explain the data with the simple steady-state theory even if identified QSOs are excluded from ths source samples and a local deficiency of strong source is postulated. The simplest evolutionary scheme that fits the data in the Einstein-de Sitter cosmology indicates that (a) the local RLF steepens considerably at high luminosities, (b) the comoving density of high luminosity sources increases with z in a manner similar to that implied by the log N-log S data and by the V/Vsub(m) test for QSOs, and (c) the mean physical sizes of radio sources evolve with z approximately as (1+z) -1 . Similar evolutionary effects appear to be present for QSOs as well as radio galaxies. (author)

  2. Assembling the Infrared Extragalactic Background Light with CIBER-2: Probing Inter-Halo Light and the Epoch of Reionization.

    Science.gov (United States)

    Bock, James

    We propose to carry out a program of observations with the Cosmic Infrared Background Experiment (CIBER-2). CIBER-2 is a near-infrared sounding rocket experiment designed to measure spatial fluctuations in the extragalactic background light. CIBER-2 scientifically follows on the detection of fluctuations with the CIBER-1 imaging instrument, and will use measurement techniques developed and successfully demonstrated by CIBER-1. With high-sensitivity, multi-band imaging measurements, CIBER-2 will elucidate the history of interhalo light (IHL) production and carry out a deep search for extragalactic background fluctuations associated with the epoch of reionization (EOR). CIBER-1 has made high-quality detections of large-scale fluctuations over 4 sounding rocket flights. CIBER-1 measured the amplitude and spatial power spectrum of fluctuations, and observed an electromagnetic spectrum that is close to Rayleigh-Jeans, but with a statistically significant turnover at 1.1 um. The fluctuations cross-correlate with Spitzer images and are significantly bluer than the spectrum of the integrated background derived from galaxy counts. We interpret the CIBER-1 fluctuations as arising from IHL, low-mass stars tidally stripped from their parent galaxies during galaxy mergers. The first generation of stars and their remnants are likely responsible for the for the reionization of the intergalactic medium, observed to be ionized out to the most distant quasars at a redshift of 6. The total luminosity produced by first stars is uncertain, but a lower limit can be placed assuming a minimal number of photons to produce and sustain reionization. This 'minimal' extragalactic background component associated with reionization is detectable in fluctuations at the design sensitivity of CIBER-2. The CIBER-2 instrument is optimized for sensitivity to surface brightness in a short sounding rocket flight. The instrument consists of a 28 cm wide-field telescope operating in 6 spectral bands

  3. Exploring cosmic origins with CORE: Extragalactic sources in cosmic microwave background maps

    Science.gov (United States)

    De Zotti, G.; González-Nuevo, J.; Lopez-Caniego, M.; Negrello, M.; Greenslade, J.; Hernández-Monteagudo, C.; Delabrouille, J.; Cai, Z.-Y.; Bonato, M.; Achúcarro, A.; Ade, P.; Allison, R.; Ashdown, M.; Ballardini, M.; Banday, A. J.; Banerji, R.; Bartlett, J. G.; Bartolo, N.; Basak, S.; Bersanelli, M.; Biesiada, M.; Bilicki, M.; Bonaldi, A.; Bonavera, L.; Borrill, J.; Bouchet, F.; Boulanger, F.; Brinckmann, T.; Bucher, M.; Burigana, C.; Buzzelli, A.; Calvo, M.; Carvalho, C. S.; Castellano, M. G.; Challinor, A.; Chluba, J.; Clements, D. L.; Clesse, S.; Colafrancesco, S.; Colantoni, I.; Coppolecchia, A.; Crook, M.; D'Alessandro, G.; de Bernardis, P.; de Gasperis, G.; Diego, J. M.; Di Valentino, E.; Errard, J.; Feeney, S. M.; Fernández-Cobos, R.; Ferraro, S.; Finelli, F.; Forastieri, F.; Galli, S.; Génova-Santos, R. T.; Gerbino, M.; Grandis, S.; Hagstotz, S.; Hanany, S.; Handley, W.; Hervias-Caimapo, C.; Hills, M.; Hivon, E.; Kiiveri, K.; Kisner, T.; Kitching, T.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lamagna, L.; Lasenby, A.; Lattanzi, M.; Le Brun, A.; Lesgourgues, J.; Lewis, A.; Liguori, M.; Lindholm, V.; Luzzi, G.; Maffei, B.; Mandolesi, N.; Martinez-Gonzalez, E.; Martins, C. J. A. P.; Masi, S.; Massardi, M.; Matarrese, S.; McCarthy, D.; Melchiorri, A.; Melin, J.-B.; Molinari, D.; Monfardini, A.; Natoli, P.; Notari, A.; Paiella, A.; Paoletti, D.; Partridge, R. B.; Patanchon, G.; Piat, M.; Pisano, G.; Polastri, L.; Polenta, G.; Pollo, A.; Poulin, V.; Quartin, M.; Remazeilles, M.; Roman, M.; Rossi, G.; Roukema, B. F.; Rubiño-Martín, J.-A.; Salvati, L.; Scott, D.; Serjeant, S.; Tartari, A.; Toffolatti, L.; Tomasi, M.; Trappe, N.; Triqueneaux, S.; Trombetti, T.; Tucci, M.; Tucker, C.; Väliviita, J.; van de Weygaert, R.; Van Tent, B.; Vennin, V.; Vielva, P.; Vittorio, N.; Young, K.; Zannoni, M.

    2018-04-01

    We discuss the potential of a next generation space-borne Cosmic Microwave Background (CMB) experiment for studies of extragalactic sources. Our analysis has particular bearing on the definition of the future space project, CORE, that has been submitted in response to ESA's call for a Medium-size mission opportunity as the successor of the Planck satellite. Even though the effective telescope size will be somewhat smaller than that of Planck, CORE will have a considerably better angular resolution at its highest frequencies, since, in contrast with Planck, it will be diffraction limited at all frequencies. The improved resolution implies a considerable decrease of the source confusion, i.e. substantially fainter detection limits. In particular, CORE will detect thousands of strongly lensed high-z galaxies distributed over the full sky. The extreme brightness of these galaxies will make it possible to study them, via follow-up observations, in extraordinary detail. Also, the CORE resolution matches the typical sizes of high-z galaxy proto-clusters much better than the Planck resolution, resulting in a much higher detection efficiency; these objects will be caught in an evolutionary phase beyond the reach of surveys in other wavebands. Furthermore, CORE will provide unique information on the evolution of the star formation in virialized groups and clusters of galaxies up to the highest possible redshifts. Finally, thanks to its very high sensitivity, CORE will detect the polarized emission of thousands of radio sources and, for the first time, of dusty galaxies, at mm and sub-mm wavelengths, respectively.

  4. Searching for νμ→ντ oscillations with extragalactic neutrinos

    International Nuclear Information System (INIS)

    Iyer, Sharada; Reno, Mary Hall; Sarcevic, Ina

    2000-01-01

    We propose a novel approach for studying ν μ →ν τ oscillations with extragalactic neutrinos. Active galactic nuclei and gamma ray bursts are believed to be sources of ultrahigh energy muon neutrinos. With distances of 100 Mpc or more, they provide an unusually long baseline for possible detection of ν μ →ν τ with mixing parameters Δm 2 down to 10 -17 eV 2 , many orders of magnitude below the current accelerator experiments. By solving the coupled transport equations, we show that high-energy ν τ 's, as they propagate through the Earth, cascade down in energy, producing the enhancement of the incoming ν τ flux in the low energy region, in contrast with the high-energy ν μ 's, which get absorbed. For an AGN quasar model we find the ν τ flux to be a factor of 2 to 2.5 larger than the incoming flux in the energy range between 10 2 GeV and 10 4 GeV, while for a GRB fireball model, the enhancement is 10-27 % in the same energy range and for zero nadir angle. This enhancement decreases with larger nadir angle, thus providing a novel way to search for ν τ appearance by measuring the angular dependence of the muons. To illustrate how the cascade effect and the ν τ final flux depend on the steepness of the incoming ν τ , we show the energy and angular distributions for several generic cases of the incoming tau neutrino flux, F ν 0 ∼E -n for n=1, 2 and 3.6. We show that for the incoming flux that is not too steep, the signal for the appearance of high-energy ν τ is the enhanced production of lower energy μ and their distinctive angular dependence, due to the contribution from the τ decay into μ just below the detector. (c) 2000 The American Physical Society

  5. Dark Matter and Extragalactic Gas Clouds in the NGC 4532/DDO 137 System

    Science.gov (United States)

    Hoffman, G. L.; Lu, N. Y.; Salpeter, E. E.; Connell, B. M.

    1998-01-01

    H I synthesis mapping of NGC 4532 and DDO 137, a pair of Sm galaxies on the edge of the Virgo cluster, is used to determine rotation curves for each of the galaxies and to resolve the structure and kinematics of three extragalactic H I clouds embedded in an extended envelope of diffuse HI discovered in earlier Arecibo studies of the system.

  6. The NuSTAR Extragalactic Surveys: Overview And Catalog From The Cosmos Field

    DEFF Research Database (Denmark)

    Civano, F.; Hickox, R. C.; Puccetti, S.

    2015-01-01

    To provide the census of the sources contributing to the X-ray background peak above 10 keV, Nuclear Spectroscopic Telescope Array (NuSTAR) is performing extragalactic surveys using a three-tier "wedding cake" approach. We present the NuSTAR survey of the COSMOS field, the medium sensitivity...

  7. CANDELS : THE COSMIC ASSEMBLY NEAR-INFRARED DEEP EXTRAGALACTIC LEGACY SURVEY

    NARCIS (Netherlands)

    Grogin, Norman A.; Kocevski, Dale D.; Faber, S. M.; Ferguson, Henry C.; Koekemoer, Anton M.; Riess, Adam G.; Acquaviva, Viviana; Alexander, David M.; Almaini, Omar; Ashby, Matthew L. N.; Barden, Marco; Bell, Eric F.; Bournaud, Frederic; Brown, Thomas M.; Caputi, Karina I.; Casertano, Stefano; Cassata, Paolo; Castellano, Marco; Challis, Peter; Chary, Ranga-Ram; Cheung, Edmond; Cirasuolo, Michele; Conselice, Christopher J.; Cooray, Asantha Roshan; Croton, Darren J.; Daddi, Emanuele; Dahlen, Tomas; Dave, Romeel; de Mello, Duilia F.; Dekel, Avishai; Dickinson, Mark; Dolch, Timothy; Donley, Jennifer L.; Dunlop, James S.; Dutton, Aaron A.; Elbaz, David; Fazio, Giovanni G.; Filippenko, Alexei V.; Finkelstein, Steven L.; Fontana, Adriano; Gardner, Jonathan P.; Garnavich, Peter M.; Gawiser, Eric; Giavalisco, Mauro; Grazian, Andrea; Guo, Yicheng; Hathi, Nimish P.; Haeussler, Boris; Hopkins, Philip F.; Huang, Jia-Sheng; Huang, Kuang-Han; Jha, Saurabh W.; Kartaltepe, Jeyhan S.; Kirshner, Robert P.; Koo, David C.; Lai, Kamson; Lee, Kyoung-Soo; Li, Weidong; Lotz, Jennifer M.; Lucas, Ray A.; Madau, Piero; McCarthy, Patrick J.; McGrath, Elizabeth J.; McIntosh, Daniel H.; McLure, Ross J.; Mobasher, Bahram; Moustakas, Leonidas A.; Mozena, Mark; Nandra, Kirpal; Newman, Jeffrey A.; Niemi, Sami-Matias; Noeske, Kai G.; Papovich, Casey J.; Pentericci, Laura; Pope, Alexandra; Primack, Joel R.; Rajan, Abhijith; Ravindranath, Swara; Reddy, Naveen A.; Renzini, Alvio; Rix, Hans-Walter; Robaina, Aday R.; Rodney, Steven A.; Rosario, David J.; Rosati, Piero; Salimbeni, Sara; Scarlata, Claudia; Siana, Brian; Simard, Luc; Smidt, Joseph; Somerville, Rachel S.; Spinrad, Hyron; Straughn, Amber N.; Strolger, Louis-Gregory; Telford, Olivia; Teplitz, Harry I.; Trump, Jonathan R.; van der Wel, Arjen; Villforth, Carolin; Wechsler, Risa H.; Weiner, Benjamin J.; Wiklind, Tommy; Wild, Vivienne; Wilson, Grant; Wuyts, Stijn; Yan, Hao-Jing; Yun, Min S.

    2011-01-01

    The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) is designed to document the first third of galactic evolution, over the approximate redshift (z) range 8-1.5. It will image >250,000 distant galaxies using three separate cameras on the Hubble Space Telescope, from the

  8. Planck intermediate results: XLV. Radio spectra of northern extragalactic radio sources

    DEFF Research Database (Denmark)

    Ade, P. A R; Aghanim, N.; Aller, H. D.

    2016-01-01

    Continuum spectra covering centimetre to submillimetre wavelengths are presented for a northern sample of 104 extragalactic radio sources, mainly active galactic nuclei, based on four-epoch Planck data. The nine Planck frequencies, from 30 to 857 GHz, are complemented by a set of simultaneous gro...

  9. Search for a diffuse flux of extragalactic neutrinos with the IceCube neutrino observatory

    Energy Technology Data Exchange (ETDEWEB)

    Schukraft, Anne

    2013-06-07

    Since the discovery of cosmic rays it has been one of the major research goals to identify the sources and acceleration mechanisms behind these high-energy particles observed from space, with energies up to several EeV. The study of high-energy charged particles and photons has advantages and disadvantages: the detection techniques for charged cosmic rays are very advanced though high-energy charged nuclei are not able to reveal their sources due to magnetic deflection. In the last years, there have been discoveries of many gamma-ray sources, where photon fluxes up to energies of 100 TeV have been observed. However, the universe is opaque to photons with energies larger than 100 TeV since gamma rays interact with the cosmic microwave background. Neutrinos suffer from neither of these limitations. They are ideal messenger particles in order to investigate the sources of cosmic rays since they propagate unaffected, but their detection is difficult and no extraterrestrial neutrino sources at high energies have yet been found. The IceCube experiment, located at the geographic South Pole, was built in order to detect high-energy neutrinos from the universe. It was completed in December 2010 and is the largest neutrino observatory on Earth. It detects neutrinos via their interaction with the Antarctic ice inside and around the detection volume. In these interactions, high-energy leptons are produced, which follow the direction of the initial neutrino and produce a cone of Cherenkov light along their path. This light is detected by optical sensors deployed in the instrumented volume. The search for a diffuse neutrino flux is a very promising approach to look for an extragalactic flux of astrophysical neutrinos. Its sensitivity is mainly based on neutrino energies since astrophysical neutrinos are expected to be more energetic than atmospheric neutrinos. It searches for an astrophysical flux from the sum of all sources in the universe. These sources can be individually

  10. Search for a diffuse flux of extragalactic neutrinos with the IceCube neutrino observatory

    International Nuclear Information System (INIS)

    Schukraft, Anne

    2013-01-01

    Since the discovery of cosmic rays it has been one of the major research goals to identify the sources and acceleration mechanisms behind these high-energy particles observed from space, with energies up to several EeV. The study of high-energy charged particles and photons has advantages and disadvantages: the detection techniques for charged cosmic rays are very advanced though high-energy charged nuclei are not able to reveal their sources due to magnetic deflection. In the last years, there have been discoveries of many gamma-ray sources, where photon fluxes up to energies of 100 TeV have been observed. However, the universe is opaque to photons with energies larger than 100 TeV since gamma rays interact with the cosmic microwave background. Neutrinos suffer from neither of these limitations. They are ideal messenger particles in order to investigate the sources of cosmic rays since they propagate unaffected, but their detection is difficult and no extraterrestrial neutrino sources at high energies have yet been found. The IceCube experiment, located at the geographic South Pole, was built in order to detect high-energy neutrinos from the universe. It was completed in December 2010 and is the largest neutrino observatory on Earth. It detects neutrinos via their interaction with the Antarctic ice inside and around the detection volume. In these interactions, high-energy leptons are produced, which follow the direction of the initial neutrino and produce a cone of Cherenkov light along their path. This light is detected by optical sensors deployed in the instrumented volume. The search for a diffuse neutrino flux is a very promising approach to look for an extragalactic flux of astrophysical neutrinos. Its sensitivity is mainly based on neutrino energies since astrophysical neutrinos are expected to be more energetic than atmospheric neutrinos. It searches for an astrophysical flux from the sum of all sources in the universe. These sources can be individually

  11. Planck early results. XV. Spectral energy distributions and radio continuum spectra of northern extragalactic radio sources

    DEFF Research Database (Denmark)

    Aatrokoski, J.; Lähteenmäki, A.; Lavonen, N.

    2011-01-01

    Spectral energy distributions (SEDs) and radio continuum spectra are presented for a northern sample of 104 extragalactic radio sources, based on the Planck Early Release Compact Source Catalogue (ERCSC) and simultaneous multifrequency data. The nine Planck frequencies, from 30 to 857 GHz......, are complemented by a set of simultaneous observations ranging from radio to gamma-rays. This is the first extensive frequency coverage in the radio and millimetre domains for an essentially complete sample of extragalactic radio sources, and it shows how the individual shocks, each in their own phase...... of development, shape the radio spectra as they move in the relativistic jet. The SEDs presented in this paper were fitted with second and third degree polynomials to estimate the frequencies of the synchrotron and inverse Compton (IC) peaks, and the spectral indices of low and high frequency radio data...

  12. Topics in extragalactic astronomy with special reference to the southern hemisphere

    International Nuclear Information System (INIS)

    Vaucouleurs, G. De

    1977-01-01

    The following topics are covered: classification of galaxies; photometry, colorimetry, spectrophotometry of galaxies; type I supernovae as checks of cosmological models; diameters of galaxies; extragalactic distance indicators; Local Group and nearby group of galaxies; structure of the Local Supercluster of galaxies; anisotropy of the redshifts and kinematics of the Local Supercluster; large scale distribution of galaxies and clusters of galaxies; galaxy counts and probes in depth; problems in the southern hemisphere. (U.K.)

  13. Book review: “Extragalactic astronomy and cosmology—an introduction”

    International Nuclear Information System (INIS)

    Cappi, Alberto

    2015-01-01

    This is the second edition of a textbook conceived to be used in an introductory course on extragalactic astronomy and cosmology (the author is professor at Bonn University and a well-known specialist in gravitational lensing). A new edition is fully justified because, as Schneider () explains in the preface, the field has been evolving rapidly during the years which have passed since the first edition (published in 2006), with the advent of new observational facilities and new surveys.

  14. At what particle energy do extragalactic cosmic rays start to predominate?

    International Nuclear Information System (INIS)

    Wibig, Tadeusz; Wolfendale, Arnold W

    2005-01-01

    We have previously argued (e.g. Szabelski et al 2002 Astropart. Phys. 17 125) that the well-known 'ankle' in the cosmic ray energy spectrum, at log E (eV) ∼ 18.7-19.0, marks the transition from mainly galactic sources at lower energies to mainly extragalactic above. Recently, however, there have been claims for lower transitional energies, specifically from log E (eV) ∼ 17.0 (Thompson et al 2004 Proc. Catania Cosmic Ray Conf.) via 17.2-17.8 (Berezinsky et al 2004 Astropart. Phys. 21 617) to 18.0 (Hillas 2004 Proc. Leeds Cosmic Ray Conf.). In our model the ankle arises naturally from the sum of simple power law-spectra with slopes differing by Δγ ∼ 1.8; from differential slope γ = -3.8 for galactic particles (near log E = 19) to γ ∼ -2.0 for extragalactic sources. In the other models, on the other hand, the ankle is intrinsic to the extragalactic component alone, and arises from the shape of the rate of energy loss versus energy for the (assumed) protons interacting with the cosmic microwave background (CMB). Our detailed analysis of the world's data on the ultra-high energy spectrum shows that taken together, or separately, the resulting mean sharpness of the ankle (second derivative of the log(intensity x E 3 ) with respect to log E) is consistent with our 'mixed' model. For explanation in terms of extragalactic particles alone, however, the ankle will be at the wrong energy-for reasonable production models and of insufficient magnitude if, as seems likely, there is still a significant fraction of heavy nuclei at the ankle energy

  15. Book review: “Extragalactic astronomy and cosmology—an introduction”

    Energy Technology Data Exchange (ETDEWEB)

    Cappi, Alberto, E-mail: alberto.cappi@oabo.inaf.it [INAF - Osservatorio Astronomico di Bologna, Bologna (Italy)

    2015-09-16

    This is the second edition of a textbook conceived to be used in an introductory course on extragalactic astronomy and cosmology (the author is professor at Bonn University and a well-known specialist in gravitational lensing). A new edition is fully justified because, as Schneider () explains in the preface, the field has been evolving rapidly during the years which have passed since the first edition (published in 2006), with the advent of new observational facilities and new surveys.

  16. Searching for Extragalactic Sources in the VISTA Variables in the Vía Láctea Survey

    Science.gov (United States)

    Baravalle, Laura D.; Alonso, M. Victoria; Nilo Castellón, José Luis; Beamín, Juan Carlos; Minniti, Dante

    2018-01-01

    We search for extragalactic sources in the VISTA Variables in the Vía Láctea survey that are hidden by the Galaxy. Herein, we describe our photometric procedure to find and characterize extragalactic objects using a combination of SExtractor and PSFEx. It was applied in two tiles of the survey: d010 and d115, without previous extragalactic IR detections, in order to obtain photometric parameters of the detected sources. The adopted criteria to define extragalactic candidates include CLASSSTAR 0.002 and the colors: 0.5 0.44 mag. We detected 345 and 185 extragalactic candidates in the d010 and d115 tiles, respectively. All of them were visually inspected and confirmed to be galaxies. In general, they are small and more circular objects, due to the near-IR sensitivity to select more compact objects with higher surface brightness. The procedure will be used to identify extragalactic objects in other tiles of the VVV disk, which will allow us to study the distribution of galaxies and filaments hidden by the Milky Way.

  17. Isotropic extragalactic flux from dark matter annihilations: lessons from interacting dark matter scenarios

    International Nuclear Information System (INIS)

    Moliné, Ángeles; Schewtschenko, Jascha A.; Boehm, Céline; Palomares-Ruiz, Sergio; Baugh, Carlton M.

    2016-01-01

    The extragalactic γ-ray and neutrino emission may have a contribution from dark matter (DM) annihilations. In the case of discrepancies between observations and standard predictions, one could infer the DM pair annihilation cross section into cosmic rays by studying the shape of the energy spectrum. So far all analyses of the extragalactic DM signal have assumed the standard cosmological model (ΛCDM) as the underlying theory. However, there are alternative DM scenarios where the number of low-mass objects is significantly suppressed. Therefore the characteristics of the γ-ray and neutrino emission in these models may differ from ΛCDM as a result. Here we show that the extragalactic isotropic signal in these alternative models has a similar energy dependence to that in ΛCDM, but the overall normalisation is reduced. The similarities between the energy spectra combined with the flux suppression could lead one to misinterpret possible evidence for models beyond ΛCDM as being due to CDM particles annihilating with a much weaker cross section than expected.

  18. Isotropic extragalactic flux from dark matter annihilations: lessons from interacting dark matter scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Moliné, Ángeles [CFTP, Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); Schewtschenko, Jascha A.; Boehm, Céline [Institute for Particle Physics Phenomenology (IPPP), Durham University, Durham DH1 3LE (United Kingdom); Palomares-Ruiz, Sergio [Instituto de Física Corpuscular (IFIC), CSIC-Universitat de València, Apartado de Correos 22085, E-46071 Valencia (Spain); Baugh, Carlton M., E-mail: maria.moline@ist.utl.pt, E-mail: jascha@schewtschenko.net, E-mail: Sergio.Palomares.Ruiz@ific.uv.es, E-mail: c.m.boehm@durham.ac.uk, E-mail: c.m.baugh@durham.ac.uk [Institute for Computational Cosmology (ICC), Durham University, Durham DH1 3LE (United Kingdom)

    2016-08-01

    The extragalactic γ-ray and neutrino emission may have a contribution from dark matter (DM) annihilations. In the case of discrepancies between observations and standard predictions, one could infer the DM pair annihilation cross section into cosmic rays by studying the shape of the energy spectrum. So far all analyses of the extragalactic DM signal have assumed the standard cosmological model (ΛCDM) as the underlying theory. However, there are alternative DM scenarios where the number of low-mass objects is significantly suppressed. Therefore the characteristics of the γ-ray and neutrino emission in these models may differ from ΛCDM as a result. Here we show that the extragalactic isotropic signal in these alternative models has a similar energy dependence to that in ΛCDM, but the overall normalisation is reduced. The similarities between the energy spectra combined with the flux suppression could lead one to misinterpret possible evidence for models beyond ΛCDM as being due to CDM particles annihilating with a much weaker cross section than expected.

  19. Deep Extragalactic VIsible Legacy Survey (DEVILS): Motivation, Design and Target Catalogue

    Science.gov (United States)

    Davies, L. J. M.; Robotham, A. S. G.; Driver, S. P.; Lagos, C. P.; Cortese, L.; Mannering, E.; Foster, C.; Lidman, C.; Hashemizadeh, A.; Koushan, S.; O'Toole, S.; Baldry, I. K.; Bilicki, M.; Bland-Hawthorn, J.; Bremer, M. N.; Brown, M. J. I.; Bryant, J. J.; Catinella, B.; Croom, S. M.; Grootes, M. W.; Holwerda, B. W.; Jarvis, M. J.; Maddox, N.; Meyer, M.; Moffett, A. J.; Phillipps, S.; Taylor, E. N.; Windhorst, R. A.; Wolf, C.

    2018-06-01

    The Deep Extragalactic VIsible Legacy Survey (DEVILS) is a large spectroscopic campaign at the Anglo-Australian Telescope (AAT) aimed at bridging the near and distant Universe by producing the highest completeness survey of galaxies and groups at intermediate redshifts (0.3 < z < 1.0). Our sample consists of ˜60,000 galaxies to Y<21.2 mag, over ˜6 deg2 in three well-studied deep extragalactic fields (Cosmic Origins Survey field, COSMOS, Extended Chandra Deep Field South, ECDFS and the X-ray Multi-Mirror Mission Large-Scale Structure region, XMM-LSS - all Large Synoptic Survey Telescope deep-drill fields). This paper presents the broad experimental design of DEVILS. Our target sample has been selected from deep Visible and Infrared Survey Telescope for Astronomy (VISTA) Y-band imaging (VISTA Deep Extragalactic Observations, VIDEO and UltraVISTA), with photometry measured by PROFOUND. Photometric star/galaxy separation is done on the basis of NIR colours, and has been validated by visual inspection. To maximise our observing efficiency for faint targets we employ a redshift feedback strategy, which continually updates our target lists, feeding back the results from the previous night's observations. We also present an overview of the initial spectroscopic observations undertaken in late 2017 and early 2018.

  20. Cosmic Ray Origin: Lessons from Ultra-High-Energy Cosmic Rays and the Galactic/Extragalactic Transition

    Energy Technology Data Exchange (ETDEWEB)

    Parizot, Etienne

    2014-11-15

    We examine the question of the origin of the Galactic cosmic-rays (GCRs) in the light of the data available at the highest energy end of the spectrum. We argue that the data of the Pierre Auger Observatory and of the KASCADE-Grande experiment suggest that the transition between the Galactic and the extragalactic components takes place at the energy of the ankle in the all-particle cosmic-ray spectrum, and at an energy of the order of 10{sup 17} eV for protons. Such a high energy for Galactic protons appears difficult to reconcile with the general view that GCRs are accelerated by the standard diffusive shock acceleration process at the forward shock of individual supernova remnants (SNRs). We also review various difficulties of the standard SNR-GCR connection, related to the evolution of the light element abundances and to significant isotopic anomalies. We point out that most of the power injected by the supernovæ in the Galaxy is actually released inside superbubbles, which may thus play an important role in the origin of cosmic-rays, and could solve some persistent problems of the standard SNR-GCR scenario in a rather natural way.

  1. Capabilities of the NASA/IPAC extragalactic database in the era of a global virtual observatory

    Science.gov (United States)

    Mazzarella, Joseph M.; Madore, Barry F.; Helou, George

    2001-11-01

    We review the capabilities of the NASA/IPAC Extragalactic Database (NED, http://ned.ipac.caltech.edu) for information retrieval and knowledge discovery in the context of a globally distributed virtual observatory. Since it's inception in 1990, NED has provided astronomers world-wide with the results of a systematic cross-correlation of catalogs covering all wavelengths, along with thousands of extragalactic observations culled from published journal articles. NED is continuously being expanded and revised to include new catalogs and published observations, each undergoing a process of cross-identification to capture the current state of knowledge about extragalactic sources in a panchromatic fashion. In addition to assimilating data from the literature, the team in incrementally folding in millions of observations from new large-scale sky surveys such as 2MASS, NVSS, APM, and SDSS. At the time of writing the system contains over 3.3 million unique objects with 4.2 million cross-identifications. We summarize the recent evolution of NED from its initial emphasis on object name-, position-, and literature-based queries into a research environment that also assists statistical data exploration and discovery using large samples of objects. Newer capabilities enable intelligent Web mining of entries in geographically distributed astronomical archives that are indexed by object names and positions in NED, sample building using constraints on redshifts, object types and other parameters, as well as image and spectral archives for targeted or serendipitous discoveries. A pilot study demonstrates how NED is being used in conjunction with linked survey archives to characterize the properties of galaxy classes to form a training set for machine learning algorithms; an initial goal is production of statistical likelihoods that newly discovered sources belong to known classes, represent statistical outliers, or candidates for fundamentally new types of objects. Challenges and

  2. The width of jets in powerful edge-brightened extragalactic double radio sources

    International Nuclear Information System (INIS)

    Banhatti, D.G.

    1987-01-01

    The widths of primary and secondary jets are derived from a sample of 14 double hotspots in powerful extended extragalactic double radio sources. In the model employed, the primary jet extends from the core to the more compact primary hotspot and the secondary jet emerges from the primary hotspot and dissipates to form the diffuse secondary hotspot. Mean values of hotspot size/jet extent imply that the primary and secondary jets, if free, must be 2 0 and > 27 0 wide, respectively. (author)

  3. The nature of extragalactic radio-jets from high-resolution radio-interferometric observations

    OpenAIRE

    Perucho, Manel

    2014-01-01

    Extragalactic jets are a common feature of radio-loud active galaxies. The nature of the observed jets in relation to the bulk flow is still unclear. In particular it is not clear whether the observations of parsec-scale jets using the very long baseline interferometric technique (VLBI) reveal wave-like structures that develop and propagate along the jet, or trace the jet flow itself. In this contribution I review the evidence collected during the last years showing that the ridge-lines of he...

  4. VizieR Online Data Catalog: VIMOS Public Extragalactic Survey (VIPERS) DR1 (Garilli+, 2014)

    Science.gov (United States)

    Garilli, B.; Guzzo, L.; Scodeggio, M.; Bolzonella, M.; Abbas, U.; Adami, C.; Arnouts, S.; Bel, J.; Bottini, D.; Branchini, E.; Cappi, A.; Coupon, J.; Cucciati, O.; Davidzon, I.; de Lucia, G.; de la Torre, S.; Franzetti, P.; Fritz, A.; Fumana, M.; Granett, B. R.; Ilbert, O.; Iovino, A.; Krywult, J.; Le Brun, V.; Le Fevre, O.; Maccagni, D.; Malek, K.; Marulli, F.; McCracken, H. J.; Paioro, L.; Polletta, M.; Pollo, A.; Schlagenhaufer, H.; Tasca, L. A. M.; Tojeiro, R.; Vergani, D.; Zamorani, G.; Zanichelli, A.; Burden, A.; di Porto, C.; Marchetti, A.; Marinoni, C.; Mellier, Y.; Moscardini, L.; Nichol, R. C.; Peacock, J. A.; Percival, W. J.; Phleps, S.; Wolk, M.

    2014-09-01

    We present the first Public Data Release (PDR-1) of the VIMOS Public Extragalactic Survey (VIPERS). It comprises 57204 spectroscopic measurements together with all additional information necessary for optimal scientific exploitation of the data, in particular the associated photometric measurements and quantification of the photometric and survey completeness. VIPERS is an ESO Large Programme designed to build a spectroscopic sample of =~100000 galaxies with iABaccessing the data through the survey database (http://vipers.inaf.it) where all information can be queried interactively. (4 data files).

  5. High-Energy Cosmic Ray Self-Confinement Close to Extra-Galactic Sources.

    Science.gov (United States)

    Blasi, Pasquale; Amato, Elena; D'Angelo, Marta

    2015-09-18

    The ultrahigh-energy cosmic rays observed on the Earth are most likely accelerated in extra-Galactic sources. For the typical luminosities invoked for such sources, the electric current associated to the flux of cosmic rays that leave them is large. The associated plasma instabilities create magnetic fluctuations that can efficiently scatter particles. We argue that this phenomenon forces cosmic rays to be self-confined in the source proximity for energies Esources for energies Esource luminosity in units of 10^{44} erg/s.

  6. Dashboard for the LHC experiments

    International Nuclear Information System (INIS)

    Andreeva, J; Cirstoiu, C; Miguel, M D F D; Ivanchenko, A; Gaidioz, B; Herrala, J; Janulis, M; Maier, G; Maguire, E J; Rivera, R P; Rocha, R; Saiz, P; Sidorova, I; Belov, S; Berejnoj, A; Kodolova, O; Chen, Y; Chen, T; Chiu, S; Munro, C

    2008-01-01

    In this paper we present the Experiment Dashboard monitoring system, which is currently in use by four Large Hadron Collider (LHC) experiments. The goal of the Experiment Dashboard is to monitor the activities of the LHC experiments on the distributed infrastructure, providing monitoring data from the virtual organization (VO) and user perspectives. The LHC experiments are using various Grid infrastructures (LCG/EGEE, OSG, NDGF) with correspondingly various middleware flavors and job submission methods. Providing a uniform and complete view of various activities like job processing, data movement and publishing, access to distributed databases regardless of the underlying Grid flavor is the challenging task. In this paper we will describe the Experiment Dashboard concept, its framework and main monitoring applications

  7. Extragalactic adventure

    International Nuclear Information System (INIS)

    Heidmann, J.

    1982-01-01

    The subject is covered in chapters, entitled: our galaxy and its hundred billion stars; galaxies, population of the Universe; radioastronomy, a deeper foray in space; spectra, valuable messengers; the expansion of the Universe and the Big Bang; Einstein's General Relativity Theory or gravitation by the curvature of space; curved spaces, surprising worlds; models of the Universe; space-time; cosmological horizons, limits of the Universe; the past of the Universe, from the primeval soup to us; the future of the Universe; anomalous spectral redshifts; quasars, at the boundaries of space; the Space Telescope, a new leap in knowledge; black holes and their fantastic properties; extraterrestrials. (U.K.)

  8. Extragalactic radioastronomy

    International Nuclear Information System (INIS)

    Tovmasyan, G.M.

    1977-01-01

    The results of observations of radiogalaxies and quasars are presented in a popular form. Comparative data on the radioemission power, the distribution of radio-brightness of various galaxies and quasars, and statistical data confirming the similarity of their radiostructures are given. Comparative data on quasars and radiogalaxies with double radiostructures are presented. The data indicate that transition from galaxies to quasars goes on continuously. The results of observations of weak radioemissions of normal galaxies with optical sings of nuclear activity and of radiosources with an anomalous spectrun and spent radiation power are given. The results of investigations of galaxy clusters containing supergiant stars responsible for the observed radiation are considered. The concept of the existence of huge stores of hypothetic superdense protostellar matter, whose explosions must lead to the phenomena observed, is described. This concept is not well-grounded theoretically

  9. Extragalactic astronomy

    International Nuclear Information System (INIS)

    Sersic, J.L.

    1982-01-01

    This book condenses the author's yearly semester lectures on 'Extra galactic Astronomy' held almost without interruption over two decades at Cordoba University for students of Astronomy. After a first chapter on Morphology and Classification of galaxies, the second gives most of the basic information about normal galaxies as individuals. Active galaxies are described in chapter III whilst chapter IV deals with the mutual relationship between galaxies and their environment. The Scale of distance is considered in chapter V. Distance indicators are introduced and several conflicting viewpoints of different schools are presented. Chapter VI deals with Cosmology, just to give the necessary elements for chapter VII where the relation between gravitational instability and galaxy formation is discussed. Chapter VIII is an appendix containing additional notes. (Auth.)

  10. THE FIRST FLUORINE ABUNDANCE DETERMINATIONS IN EXTRAGALACTIC ASYMPTOTIC GIANT BRANCH CARBON STARS

    International Nuclear Information System (INIS)

    Abia, C.; Cristallo, S.; Dominguez, I.; Cunha, K.; Smith, V. V.; De Laverny, P.; Recio-Blanco, A.; Straniero, O.

    2011-01-01

    Fluorine ( 19 F) abundances (or upper limits) are derived in six extragalactic asymptotic giant branch (AGB) carbon stars from the HF(1-0) R9 line at 2.3358 μm in high-resolution spectra. The stars belong to the Local Group galaxies, Large Magellanic Cloud, Small Magellanic Cloud, and Carina dwarf spheroidal, spanning more than a factor of 50 in metallicity. This is the first study to probe the behavior of F with metallicity in intrinsic extragalactic C-rich AGB stars. Fluorine could be measured only in four of the target stars, showing a wide range in F enhancements. Our F abundance measurements together with those recently derived in Galactic AGB carbon stars show a correlation with the observed carbon and s-element enhancements. The observed correlations, however, display a different dependence on the stellar metallicity with respect to theoretical predictions in low-mass, low-metallicity AGB models. We briefly discuss the possible reasons for this discrepancy. If our findings are confirmed in a larger number of metal-poor AGBs, the issue of F production in AGB stars will need to be revisited.

  11. Archival Investigation of Outburst Sites and Progenitors of Extragalactic Intermediate-Luminosity Mid-IR Transients

    Science.gov (United States)

    Bond, Howard

    2017-08-01

    Our team is using Spitzer in a long-term search for extragalactic mid-infrared (MIR) variable stars and transients-the SPIRITS project (SPitzer InfraRed Intensive Transients Survey). In this first exploration of luminous astrophysical transients in the infrared, we have discovered a puzzling new class. We call them SPRITEs: eSPecially Red Intermediate-luminosity Transient Events. They have maximum MIR luminosities between supernovae and classical novae, but are not detected in the optical to deep limits. To date, we have discovered more than 50 SPRITEs in galaxies out to 17 Mpc. In this Archival Research proposal, we request support in order to investigate the pre-eruption sites in HST images of some 3 dozen SPRITEs discovered to date, and an additional 2 dozen that we are likely to find until the end of Spitzer observing in late 2018. Our aims are (1) characterize the pre-outburst environments at HST resolution in the visible and near-IR, to understand the stellar populations, stellar ages and masses, and interstellar medium at the outburst sites; (2) search for progenitors; (3) help prepare the way for a better understanding of the nature of extragalactic IR transients that will be investigated by JWST.

  12. VizieR Online Data Catalog: The VLBA Extragalactic Proper Motion Catalog (Truebenbach+, 2017)

    Science.gov (United States)

    Truebenbach, A. E.; Darling, J.

    2017-11-01

    We created our catalog of extragalactic radio proper motions using the 2017a Goddard VLBI global solution. The 2017a solution is computed from more than 30 years of dual-band VLBI observations --1979 August 3 to 2017 March 27. We also observed 28 objects with either no redshift or a "questionable" Optical Characteristic of Astrometric Radio Sources (OCARS; Malkin 2016ARep...60..996M) redshift at the Apache Point Observatory (APO) 3.5m telescope and/or at Gemini North. We conducted observations on the 3.5m telescope at Apache Point Observatory with the Dual Imaging Spectrograph (DIS) from 2015 April 18 to 2016 June 30. We chose two objects for additional observations with the Gemini Multi-Object Spectrograph-North (GMOS-N) at Gemini North Observatory. 2021+317 was observed on 2016 June 26 and 28, while 0420+417 was observed on 2016 November 8 and 26. We also observed 42 radio sources with the Very Long Baseline Array (VLBA) in the X-band (3.6cm/8.3GHz). Our targets had all been previously observed by VLBI. Our VLBA observations were conducted in two campaigns from 2015 September to 2016 January and 2016 October to November. The final extragalactic proper motion catalog (created primarily from archival Goddard VLBI data, with redshifts obtained from OCARS) contains 713 proper motions with average uncertainties of 24μas/yr. (5 data files).

  13. Planck Early Results. XV. Spectral Energy Distributions and Radio Continuum Spectra of Northern Extragalactic Radio Sources

    Science.gov (United States)

    Aatrokoski, J.; Ade, P. A. R.; Aghanim, N.; Aller, H. D.; Aller, M. F.; Angelakis, E.; Amaud, M.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; hide

    2011-01-01

    Spectral energy distributions (SEDs) and radio continuum spectra are presented for a northern sample of 104 extragalactic radio sources. based on the Planck Early Release Compact Source Catalogue (ERCSC) and simultaneous multi frequency data. The nine Planck frequencies, from 30 to 857 GHz, are complemented by a set of simultaneous observations ranging from radio to gamma-rays. This is the first extensive frequency coverage in the radio and millimetre domains for an essentially complete sample of extragalactic radio sources, and it shows how the individual shocks, each in their own phase of development, shape the radio spectra as they move in the relativistic jet. The SEDs presented in this paper were fitted with second and third degree polynomials to estimate the frequencies of the synchrotron and inverse Compton (IC) peaks, and the spectral indices of low and high frequency radio data, including the Planck ERCSC data, were calculated. SED modelling methods are discussed, with an emphasis on proper. physical modelling of the synchrotron bump using multiple components. Planck ERCSC data also suggest that the original accelerated electron energy spectrum could be much harder than commonly thought, with power-law index around 1.5 instead of the canonical 2.5. The implications of this are discussed for the acceleration mechanisms effective in blazar shock. Furthermore in many cases the Planck data indicate that gamma-ray emission must originate in the same shocks that produce the radio emission.

  14. The SUrvey for Pulsars and Extragalactic Radio Bursts III: Polarization properties of FRBs 160102 & 151230

    Science.gov (United States)

    Caleb, M.; Keane, E. F.; van Straten, W.; Kramer, M.; Macquart, J. P.; Bailes, M.; Barr, E. D.; Bhat, N. D. R.; Bhandari, S.; Burgay, M.; Farah, W.; Jameson, A.; Jankowski, F.; Johnston, S.; Petroff, E.; Possenti, A.; Stappers, B.; Tiburzi, C.; Krishnan, V. Venkatraman

    2018-05-01

    We report on the polarization properties of two fast radio bursts (FRBs): 151230 and 160102 discovered in the SUrvey for Pulsars and Extragalactic Radio Bursts (SUPERB) at the Parkes radio telescope. FRB 151230 is observed to be 6 ± 11% circularly polarized and 35 ± 13 % linearly polarized with a rotation measure (RM) consistent with zero. Conversely, FRB 160102 is observed to have a circular polarization fraction of 30 ± 11 %, linear polarization fraction of 84 ± 15 % for RM =-221(6) rad m-2 and the highest measured DM (2596.1 ± 0.3 pc cm-3) for an FRB to date. We examine possible progenitor models for FRB 160102 in extragalactic, non-cosmological and cosmological scenarios. After accounting for the Galactic foreground contribution, we estimate the intrinsic RM to be -256(9) rad m-2 in the low-redshift case and ˜-2.4 × 102 rad m-2 in the high-redshift case. We assess the relative likeliness of these scenarios and how each can be tested. We also place constraints on the scattering measure and study the impact of scattering on the signal's polarization position angle.

  15. A semianalytical method for calculating the parameters of the electromagnetic halos around extragalactic gamma-ray sources

    NARCIS (Netherlands)

    Kel'ner, [No Value; Khangulyan, DV; Aharonian, FA

    2004-01-01

    The ultrahigh-energy (>20 TeV) gamma rays emitted by active galactic nuclei can be absorbed in intergalactic space through the production of electron-positron pairs during their interaction with extragalactic background photon fields. The electrons and positrons produced by this interaction form an

  16. Planck early results. XIII. Statistical properties of extragalactic radio sources in the Planck Early Release Compact Source Catalogue

    DEFF Research Database (Denmark)

    Lähteenmäki, A.; Poutanen, T.; Natoli, P.

    2011-01-01

    The data reported in Planck's Early Release Compact Source Catalogue (ERCSC) are exploited to measure the number counts (dN/dS) of extragalactic radio sources at 30, 44, 70, 100, 143 and 217 GHz. Due to the full-sky nature of the catalogue, this measurement extends to the rarest and brightest sou...

  17. The SUrvey for Pulsars and Extragalactic Radio Bursts – II. New FRB discoveries and their follow-up

    NARCIS (Netherlands)

    Bhandari, S.; Keane, E.F.; Barr, E.D.; Jameson, A.; Petroff, E.; Johnston, S.; Bailes, M.; Bhat, N.D.R.; Burgay, M.; Burke-Spolaor, S.; Caleb, M.; Eatough, R.P.; Flynn, C.; Green, J.A.; Jankowski, F.; Kramer, M.; Krishnan, V Venkatraman; Morello, V.; Possenti, A.; Stappers, B.; Tiburzi, C.; van Straten, W.; Andreoni, I.; Butterley, T.; Chandra, P.; Cooke, J.; Corongiu, A.; Coward, D.M.; Dhillon, V.S.; Dodson, R.; Hardy, L.K.; Howell, E.J.; Jaroenjittichai, P.; Klotz, A.; Littlefair, S.P.; Marsh, T.R.; Mickaliger, M.; Muxlow, T.; Perrodin, D.; Pritchard, D.; Sawangwit, U.; Terai, T.; Tominaga, N.; Torne, P.; Totani, T.; Trois, A.; Turpin, D.; Niino, Y.; Wilson, R.W.; Albert, A.; André, M.; Anghinolfi, M.; Anton, G.; Ardid, M.; Aubert, J.J.; Avgitas, T.; Baret, B.; Barrios-Marti, J.; Basa, S.; Belhorma, B.; Bertin, V.; Biagi, S.; Bormuth, R.; Bourret, S.; Bouwhuis, M.C.; Brânzas, H.; Bruijn, R.; Brunner, J.; Busto, J.; Capone, A.; Caramete, L.; Carr, J.; Celli, S.; Cherkaoui El Moursli, R.; Chiarusi, T.; Circella, M.; Coelho, J.A.B.; Coleiro, A.; Coniglione, R.; Costantini, H.; Coyle, P.; Creusot, A.; Díaz, A.F.; Deschamps, A.; De Bonis, G.; Distefano, C.; Di Palma, I.; Domi, A.; Donzaud, C.; Dornic, D.; Drouhin, D.; Eberl, T.; El Bojaddaini, I.; El Khayati, N.; Elsässer, D.; Enzenhöfer, A.; Ettahiri, A.; Fassi, F.; Felis, I.; Fusco, L.A.; Gay, P.; Giordano, V.; Glotin, H.; Grégoire, T.; Gracia-Ruiz, R.; Graf, K.; Hallmann, S.; van Haren, H.; Heijboer, A.J.; Hello, Y.; Hernandez-Rey, J.J.; Hößl, J.; Hofestädt, J.; Hugon, C.; Illuminati, G.; James, C.W.; de Jong, M.; Jongen, M.; Kadler, M.; Kalekin, O.; Katz, U.; Kießling, D.; Kouchner, A.; Kreter, M.; Kreykenbohm, I.; Kulikovskiy, V.; Lachaud, C.; Lahmann, R.; Lefevre, D.; Leonora, E.; Loucatos, S.; Marcelin, M.; Margiotta, A.; Marinelli, A.; Martinez-Mora, J.A.; Mele, R.; Melis, K.; Michael, T.; Migliozzi, P.; Moussa, A.; Navas, S.; Nezri, E.; Organokov, M.; Pavalas, G.E.; Pellegrino, C.; Perrina, C.; Piattelli, P.; Popa, V.; Pradier, T.; Quinn, L.; Racca, C.; Riccobene, G.; Sanchez-Losa, A.; Saldaña, M.; Salvadori, I.; Samtleben, D.F.E.; Sanguineti, M.; Sapienza, P.; Schussler, F.; Sieger, C.; Spurio, M.; Stolarczyk, Th.; Taiuti, M.; Tayalati, Y.; Trovato, A.; Turpin, D.; Tönnis, C.; Vallage, B.; Van Elewyck, V.; Versari, F.; Vivolo, D.; Vizzocca, A.; Wilms, J.; Zornoza, J.D.; Zúñiga, J.

    2017-01-01

    We report the discovery of four Fast Radio Bursts (FRBs) in the ongoing SUrvey for Pulsars and Extragalactic Radio Bursts at the Parkes Radio Telescope: FRBs 150610, 151206, 151230 and 160102. Our real-time discoveries have enabled us to conduct extensive, rapid multimessenger follow-up at 12 major

  18. The Imprint of the Extragalactic Background Light in the Gamma-Ray Spectra of Blazars

    Science.gov (United States)

    Ackermann, M.; Ajello, M.; Allafort, A.; Schady, P.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bellazzini, R; Blandford, R. D.; hide

    2012-01-01

    The light emitted by stars and accreting compact objects through the history of the universe is encoded in the intensity of the extragalactic background light (EBL). Knowledge of the EBL isimportant to understand the nature of star formation and galaxy evolution, but direct measurements of the EBL are limited by galactic and other foreground emissions. Here, we report an absorption feature seen in the combined spectra of a sample of gamma-ray blazars out to a redshift of z approx. 1.6. This feature is caused by attenuation of gamma rays by the EBL at optical to ultraviolet frequencies and allowed us to measure the EBL flux density in this frequency band.

  19. Flavor ratios of extragalactic neutrinos and neutrino shortcuts in extra dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Aeikens, Elke; Päs, Heinrich [Fakultät für Physik, Technische Universität Dortmund,44221 Dortmund (Germany); Pakvasa, Sandip [Department of Physics & Astronomy, University of Hawaii,Honolulu, HI 96822 (United States); Sicking, Philipp [Fakultät für Physik, Technische Universität Dortmund,44221 Dortmund (Germany)

    2015-10-02

    The recent measurement of high energy extragalactic neutrinos by the IceCube Collaboration has opened a new window to probe non-standard neutrino properties. Among other effects, sterile neutrino altered dispersion relations (ADRs) due to shortcuts in an extra dimension can significantly affect astrophysical flavor ratios. We discuss two limiting cases of this effect, first active-sterile neutrino oscillations with a constant ADR potential and second an MSW-like resonant conversion arising from geodesics oscillating around the brane in an asymmetrically warped extra dimension. We demonstrate that the second case has the potential to suppress significantly the flux of specific flavors such as ν{sub μ} or ν{sub τ} at high energies.

  20. Flavor ratios of extragalactic neutrinos and neutrino shortcuts in extra dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Aeikens, Elke; Päs, Heinrich; Sicking, Philipp [Fakultät für Physik, Technische Universität Dortmund, 44221 Dortmund (Germany); Pakvasa, Sandip, E-mail: elke.aeikens@tu-dortmund.de, E-mail: heinrich.paes@tu-dortmund.de, E-mail: pakvasa@phys.hawaii.edu, E-mail: philipp.sicking@tu-dortmund.de [Department of Physics and Astronomy, University of Hawaii, Honolulu, HI 96822 (United States)

    2015-10-01

    The recent measurement of high energy extragalactic neutrinos by the IceCube Collaboration has opened a new window to probe non-standard neutrino properties. Among other effects, sterile neutrino altered dispersion relations (ADRs) due to shortcuts in an extra dimension can significantly affect astrophysical flavor ratios. We discuss two limiting cases of this effect, first active-sterile neutrino oscillations with a constant ADR potential and second an MSW-like resonant conversion arising from geodesics oscillating around the brane in an asymmetrically warped extra dimension. We demonstrate that the second case has the potential to suppress significantly the flux of specific flavors such as ν{sub μ} or ν{sub τ} at high energies.

  1. THE CENTAURUS A ULTRAHIGH-ENERGY COSMIC-RAY EXCESS AND THE LOCAL EXTRAGALACTIC MAGNETIC FIELD

    International Nuclear Information System (INIS)

    Yüksel, Hasan; Kronberg, Philipp P.; Stanev, Todor; Kistler, Matthew D.

    2012-01-01

    The ultrahigh-energy cosmic-ray (UHECR) anisotropies discovered by the Pierre Auger Observatory provide the potential to finally address both the particle origins and properties of the nearby extragalactic magnetic field (EGMF). We examine the implications of the excess of ∼10 20 eV events around the nearby radio galaxy Centaurus A. We find that, if Cen A is the source of these cosmic rays, the angular distribution of events constrains the EGMF strength within several Mpc of the Milky Way to ∼> 20 nG for an assumed primary proton composition. Our conclusions suggest that either the observed excess is a statistical anomaly or the local EGMF is stronger than conventionally thought. We discuss several implications, including UHECR scattering from more distant sources, time delays from transient sources, and the possibility of using magnetic lensing signatures to attain tighter constraints.

  2. 318-MHz variability of complete samples of extragalactic radio sources. II

    International Nuclear Information System (INIS)

    Dennison, B.; Broderick, J.J.; Ledden, J.E.; O'Dell, S.L.; Condon, J.J.

    1981-01-01

    We report the remainder of two- and three-epoch 318-MHz observations of extragalactic sources in samples complete to 3 Jy at 1400 MHz and 1 Jy at 5000 MHz. From analysis of this low-frequency variability survey, we find that steep-spectrum (α> or =0.5) sources do not appear to vary, but about 40% of all flat-spectrum (α<0.5) sources exhibit low-frequency variability exceeding 8% over approx.5 yr. Among the flat-spectrum sources, those with inverted spectra show the largest fractional variations. We also find that the incidence of low-frequency variability is strongly correlated with the determination that a source is an optically violent variable. These statistical properties are consistent with models invoking relativistic beaming of radio and optical emission

  3. The Green Bank Third (GB3) survey of extragalactic radio sources at 1400 MHz

    International Nuclear Information System (INIS)

    Rys, S.; Machalski, J.

    1987-01-01

    The NRAO 91-m radio telescope in Green Bank, West Virginia was used to make a 1400-MHz sky survey covering an area of 0.0988 sr at declinations 70 deg ≤ δ 1950 < 76.8 deg with 10.1 x 10.5 arcmin resolution. This survey ends the series of smaller than 1-sr surveys made at 1400 MHz with that telescope and four-feed radiometer. A catalogue of 502 radiosources is presented, statistically complete to 112 mJy, which is about five times the rms noise and extragalactic confusion. The observations and data reduction are briefly summarized; the position and flux density errors are discussed. 13 refs., 2 tabs. (author)

  4. Extragalactic Background Light expected from photon-photon absorption on spectra of distant Active Galactic Nuclei

    International Nuclear Information System (INIS)

    Sinitsyna, V. G.; Sinitsyna, V. Y.

    2013-01-01

    Extragalactic background radiation blocks the propagation of TeV gamma-ray over large distances by producing e + e - pairs. As a result, primary spectrum of gamma-source is changed, depending on spectrum of background light. So, hard spectra of Active Galactic Nuclei with high red shifts allow the determination of a EBL spectrum. The redshifts of SHALON TeV gamma-ray sources range from 0.018 to 1.375 those spectra are resolved at the energies from 800 GeV to 30 TeV. Spectral energy distribution of EBL constrained from observations of Mkn421 (z=0.031), Mkn501 (z=0.034), Mkn180 (z=0.046), OJ287 (z=0.306), 3c454.3 (z=0.859) and 1739+5220(z=1.375) together with models and measurements are presented. (authors)

  5. Methods for the determination of lunisolar precession from observations of extragalactic radio sources

    International Nuclear Information System (INIS)

    Elsmore, B.

    1976-01-01

    Although it is not practicable at present to determine the position or motion of the equinox using radio techniques, lunisolar precession may be determined from measurements at two epochs of differences of (i) Right Ascension -RA, and (ii) Declinations - Dec., of extragalactic radio sources. The determinations are largely free from systematic errors, and the magnitudes of random errors, arising principally from tropospheric irregularities, are given for observations with the Cambridge 5-km telescope. Some first epoch measure-ments have been made with this instrument and it is estimated that by carrying out second epoch measurements after an interval of 5 yr, the centennial value of lunisolar precession will be determined with a standard error of +- 0''.25. (author)

  6. Extragalactic Hard X-ray Surveys: From INTEGRAL to Simbol-X

    Science.gov (United States)

    Paltani, S.; Dwelly, T.; Walter, R.; McHardy, I. M.; Courvoisier, T. J.-L.

    2009-05-01

    We present some results of the deepest extragalactic survey performed by the INTEGRAL satellite. The fraction of very absorbed AGN is quite large. The sharp decrease in the absorption fraction with X-ray luminosity observed at lower-energy X-rays is not observed. The current lack of truly Compton-thick objects, with an upper limit of 14% to the size of this population, is just compatible with recent modeling of the cosmic X-ray background. We also study the prospects for a future hard X-ray serendipitous survey with Simbol-X. We show that Simbol-X will easily detect a large number of serendipitous AGN, allowing us to study the evolution of AGN up to redshifts about 2, opening the door to the cosmological study of hard X-ray selected AGN, which is barely possible with existing satellites like Swift and INTEGRAL.

  7. THE CENTAURUS A ULTRAHIGH-ENERGY COSMIC-RAY EXCESS AND THE LOCAL EXTRAGALACTIC MAGNETIC FIELD

    Energy Technology Data Exchange (ETDEWEB)

    Yueksel, Hasan; Kronberg, Philipp P. [Theoretical Division, MS B285, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Stanev, Todor [Bartol Research Institute, Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Kistler, Matthew D. [Lawrence Berkeley National Laboratory and Department of Physics, University of California, Berkeley, CA 94720 (United States)

    2012-10-10

    The ultrahigh-energy cosmic-ray (UHECR) anisotropies discovered by the Pierre Auger Observatory provide the potential to finally address both the particle origins and properties of the nearby extragalactic magnetic field (EGMF). We examine the implications of the excess of {approx}10{sup 20} eV events around the nearby radio galaxy Centaurus A. We find that, if Cen A is the source of these cosmic rays, the angular distribution of events constrains the EGMF strength within several Mpc of the Milky Way to {approx}> 20 nG for an assumed primary proton composition. Our conclusions suggest that either the observed excess is a statistical anomaly or the local EGMF is stronger than conventionally thought. We discuss several implications, including UHECR scattering from more distant sources, time delays from transient sources, and the possibility of using magnetic lensing signatures to attain tighter constraints.

  8. The SUrvey for Pulsars and Extragalactic Radio Bursts - I. Survey description and overview

    Science.gov (United States)

    Keane, E. F.; Barr, E. D.; Jameson, A.; Morello, V.; Caleb, M.; Bhandari, S.; Petroff, E.; Possenti, A.; Burgay, M.; Tiburzi, C.; Bailes, M.; Bhat, N. D. R.; Burke-Spolaor, S.; Eatough, R. P.; Flynn, C.; Jankowski, F.; Johnston, S.; Kramer, M.; Levin, L.; Ng, C.; van Straten, W.; Krishnan, V. Venkatraman

    2018-01-01

    We describe the Survey for Pulsars and Extragalactic Radio Bursts (SUPERB), an ongoing pulsar and fast transient survey using the Parkes radio telescope. SUPERB involves real-time acceleration searches for pulsars and single-pulse searches for pulsars and fast radio bursts. We report on the observational set-up, data analysis, multiwavelength/messenger connections, survey sensitivities to pulsars and fast radio bursts and the impact of radio frequency interference. We further report on the first 10 pulsars discovered in the project. Among these is PSR J1306-40, a millisecond pulsar in a binary system where it appears to be eclipsed for a large fraction of the orbit. PSR J1421-4407 is another binary millisecond pulsar; its orbital period is 30.7 d. This orbital period is in a range where only highly eccentric binaries are known, and expected by theory; despite this its orbit has an eccentricity of 10-5.

  9. Metre-wavelength fine structure in 30 extragalactic radio sources with sizes of a few arcsec

    International Nuclear Information System (INIS)

    Banhatti, D.G.; Ananthakrishnan, S.; Pramesh Rao, A.

    1983-01-01

    Interplanetary scintillation (IPS) observations at 327 MHz of an unbiased sample of 30 extragalactic radio sources having overall sizes between 1 and 4 arcsec, and flux densities greater than 1 Jy at 327 MHz are reported. From VLBI observations, these sources have been reported to contain compact components of sizes < approx.= to 0.02 arcsec contributing on an average about 25 per cent of the total emission at 5 HGz. The IPS observations show that about 45 per cent of the total emission at 327 MHz arises from structures of sizes between 0.05 and 0.5 arcsec (corresponding typically to 0.5 to 5 kpc). A comparison of the VLBI and IPS results indicates that the VLBI and IPS components probably refer to the same physical features in these sources. (author)

  10. Role of cosmic ray protons in two types of extragalactic objects

    International Nuclear Information System (INIS)

    Vestrand, W.T.

    1980-01-01

    For many years the physics of galactic cosmic rays has been studied in detail. Very little work, however, has been done concerning cosmic ray protons in extragalactic objects. Here the role cosmic ray protons can play in two types of extragalactic sites are examined: (1) clusters of galaxies, and (2) the active nuclei of Quasars that produce superluminal radio components. Models of Coma-type radio halos must explain both their large extent and their rarity. A model is presented wherein secondary electrons produced by the interaction of cosmic ray protons with the observed intracluster gas are responsible for the diffuse radio emission. This model predicts a correlation between a cluster's evolutionary state and the presence of Coma-type halos. If a cluster's x-ray morphology is an indication of the cluster's evolutionary state, this prediction is supported by observations. This model also predicts that clusters with Coma-type halos will emit π 0 γ-rays. If the intracluster magnetic field in Coma has the strength favored by many authors, B/sub c/ = 0.2 microgauss, these γ-rays should be detectable with the proposed GRO satellite. Superluminal radio sources may originate in highly compact and relativistically hot plasmas. The production of mesons and their secondaries in an ultrarelativistic plasma is examined. Source functions from a relativistic Maxwellian distribution of protons are numerically calculated for conditions likely during the formation of superluminal radio components. Analytic expressions for the source functions from a power law distribution of relativistic protons are also presented

  11. CANDELS: The Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey

    Science.gov (United States)

    Grogin, Norman A.; Koekemoer, anton M.; Faber, S. M.; Ferguson, Henry C.; Kocevski, Dale D.; Riess, Adam G.; Acquaviva, Viviana; Alexander, David M.; Almaini, Omar; Ashby, Matthew L. N.; hide

    2011-01-01

    The Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS) is designed to document the first third of galactic evolution, from z approx. 8 - 1.5. It will image > 250,000 distant galaxies using three separate cameras on the Hubble Space Tele8cope, from the mid-UV to near-IR, and will find and measure Type Ia supernovae beyond z > 1.5 to test their accuracy as standard candles for cosmology. Five premier multi-wavelength sky regions are selected, each with extensive ancillary data. The use of five widely separated fields mitigates cosmic variance and yields statistically robust and complete samples of galaxies down to a stellar mass of 10(exp 9) solar mass to z approx. 2, reaching the knee of the UV luminosity function of galaxies to z approx. 8. The survey covers approximately 800 square arc minutes and is divided into two parts. The CANDELS/Deep survey (5(sigma) point-source limit H =27.7mag) covers approx. 125 square arcminutes within GOODS-N and GOODS-S. The CANDELS/Wide survey includes GOODS and three additional fields (EGS, COSMOS, and UDS) and covers the full area to a 50(sigma) point-source limit of H ? or approx. = 27.0 mag. Together with the Hubble Ultradeep Fields, the strategy creates a three-tiered "wedding cake" approach that has proven efficient for extragalactic surveys. Data from the survey are non-proprietary and are useful for a wide variety of science investigations. In this paper, we describe the basic motivations for the survey, the CANDELS team science goals and the resulting observational requirements, the field selection and geometry, and the observing design.

  12. The Extragalactic Background Light and the Gamma-ray Opacity of the Universe

    Science.gov (United States)

    Dwek, Eli; Krennrich, Frank

    2012-01-01

    The extragalactic background light (EBL) is one of the fundamental observational quantities in cosmology. All energy releases from resolved and unresolved extragalactic sources, and the light from any truly diffuse background, excluding the cosmic microwave background (CMB), contribute to its intensity and spectral energy distribution. It therefore plays a crucial role in cosmological tests for the formation and evolution of stellar objects and galaxies, and for setting limits on exotic energy releases in the universe. The EBL also plays an important role in the propagation of very high energy gamma-rays which are attenuated en route to Earth by pair producing gamma-gamma interactions with the EBL and CMB. The EBL affects the spectrum of the sources, predominantly blazars, in the approx 10 GeV to 10 TeV energy regime. Knowledge of the EBL intensity and spectrum will allow the determination of the intrinsic blazar spectrum in a crucial energy regime that can be used to test particle acceleration mechanisms and VHE gamma-ray production models. Conversely, knowledge of the intrinsic gamma-ray spectrum and the detection of blazars at increasingly higher redshifts will set strong limits on the EBL and its evolution. This paper reviews the latest developments in the determination of the EBL and its impact on the current understanding of the origin and production mechanisms of gamma-rays in blazars, and on energy releases in the universe. The review concludes with a summary and future directions in Cherenkov Telescope Array techniques and in infrared ground-based and space observatories that will greatly improve our knowledge of the EBL and the origin and production of very high energy gamma-rays.

  13. The development and performance of the EXAM detector to search for extragalactic antimatter

    International Nuclear Information System (INIS)

    Coan, T.E.

    1989-01-01

    The design and development of a practical balloon borne instrument capable of detecting heavy (Z approximately equal to -26) antimatter in the cosmic rays are described. Emphasis is placed on describing the essential physics of the EXAM (extragalactic antimatter) instrument's individual detectors that make such a detection possible. In particular, it is shown that the responses from a plastic scintillator, a Cerenkov radiation detector, dielectric track detectors, and proportional drift tube arrays can be used to uniquely determine the speed, charge magnitude, and charge sign of a cosmic ray nucleus. This novel nonmagnetic detection scheme permits the construction of a relatively light weight (approximately 2,000 kg) detector with a large collecting power (approximately 10 sq m sr). The profound cosmological and elementary particle physics implications of the detection of just a single heavy antimatter nucleus are discussed in chapter one, along with arguments that imply that such a detected antinucleus must necessarily be extragalactic in origin. Chapters two through six describe the response of EXAM's individual detectors to the passage of heavily ionizing charged particles. Chapter seven is an overview of the mechanical construction of the entire instrument. Details of the measurement of the light collection efficiency of EXAM's Cerenkov detector and primary scintillator using sea-level muons and how this will be used to assist in the flight data analysis are contained in chapter eight. This chapter also includes a description of the instrument's electronic configuration and its data acquisition system. Finally, there are two appendices summarizing some important mechanical stress calculations that were required to actually build the instrument

  14. the present situation of smoking among col ege students and its inlfuencing factors%某高校大学生吸烟状况及影响因素分析

    Institute of Scientific and Technical Information of China (English)

    严锐

    2014-01-01

    目的:了解大学生吸烟现状及其影响因素,为大学生控烟提供科学依据。方法:自行设计问卷,采用分层整群抽样的方法,选择贵州某高校600例大学生为调查对象,描述大学生吸烟现状,采用logistic回归分析发现影响大学生吸烟行为的因素。结果:大学生尝试吸烟率为45.70%,吸烟率为17.53%。经logistic多因素回归分析发现吸烟行为受好友劝烟(OR=5.251,95%CI:2.943-9.369,P<0.05)、饮酒(OR=2.137,95%CI:1.162-3.929,P=0.0146)、对烟草危害认识度(OR=1.367,95%CI:1.0808-1.730,P=0.0092)、对烟草有害成分认知(OR=6.125,95%CI:2.314-16.216,P<0.05)、是否认为不接受别人递烟不礼貌(OR=3.147,95%CI:1.635-6.056,P<0.05)五个因素的影响。结论:应该改变大学生关于交际的认识,创造良好的氛围,同时对大学生饮酒进行控制,以引导大学生戒烟,促进大学生身心健康。%Objective:to investigation the present situation of smoking among col ege students and its inlfuencing factors, and to provide the scientiifc basis for col ege students’ smoking control. Methods:We adopt stratiifed cluster sampling method, choosing the hubei university of science and technology for 600 cases of college students as investigate object, describes the present situation of smoking col ege students, Finding the inlfuencing factors by logistic regression. Results:college students try-smoking was 45.70%, smoking was 17.53%. The logistic regression analysis found that smoking behavior inlfuenced by best friends advised smoke(OR=5.251, 95%CI:2.943-9.369,P<0.05), drinking alcohol (OR=2.137, 95%CI:1.162-3.929,P=0.0146), tobacco hazard to know whether degree(OR=1.367,95%CI:1.0808-1.730,P=0.0092), thinking that not accept others cigaret e is not polite factors (OR=3.147, 95%CI=1.635-6.056, P<0.05) Conclusion:We should change the understanding of college students’ communication, to create

  15. SPHEREx: Understanding the Origin and Evolution of Galaxies Through the Extragalactic Background Light

    Science.gov (United States)

    Zemcov, Michael; SPHEREx Science Team

    2018-01-01

    The near IR extragalactic background light (EBL) encodes the integrated light production over cosmic history, so traces the total emission from all galaxies along the line of sight up to the ancient first-light objects responsible for the epoch of reionization (EOR). The EBL can be constrained through measurements of anisotropies, taking advantage of the fact that extragalactic populations produce fluctuations with distinct spatial and spectral characteristics from local foregrounds. In particular, EBL anisotropies trace the underlying clustering of faint emission sources, such as stars, galaxies and accreting black holes present during the EOR, dwarf galaxies, and intra-halo light (IHL), all of which are components not readily detected in point source surveys. The fluctuation amplitude observed independently by a number of recent measurements exceeds that expected from the large-scale clustering of known galaxy populations, indicating the presence of a large integrated brightness from these faint and diffuse components. Improved large-area measurements covering the entire near-IR are required to constrain the possible models for the history of emission from stars back to the EOR.SPHEREx brings new capabilities to EBL fluctuation measurements, employing 96 spectral channels covering 0.75 to 5 microns with spectral resolving power R = 41 to 135 that enable SPHEREx to carry out a multi-frequency separation of the integrated light from galaxies, IHL, and EOR components using the rich auto- and cross-correlation information available from two 45 square degree surveys of the ecliptic poles. SPHEREx is an ideal intensity mapping machine, and has the sensitivity to disentangle the history of light production associated with EBL fluctuations. SPHEREx will search for an EOR component its to minimum required level through component separation and spectral fitting techniques optimized for the near-IR. In addition to broad-band intensity mapping that enhances and extends the

  16. Molecular transitions as probes of the physical conditions of extragalactic environments

    Science.gov (United States)

    Viti, Serena

    2017-11-01

    Aims: We present a method to interpret molecular observations and molecular line ratios in nearby extragalactic regions. Methods: Ab initio grids of time dependent chemical models, varying in gas density, temperature, cosmic ray ionization rate, and radiation field, are used as inputs into RADEX calculations. Tables of abundances, column densities, theoretical line intensities, and line ratios for some of the most used dense gas tracers are provided. The degree of correlation as well as degeneracy inherent in molecular ratios is discussed. Comparisons of the theoretical intensities with example observations are also provided. Results: We find that, within the parameters space explored, chemical abundances can be constrained by a well-defined set of gas density, gas temperature, and cosmic ray ionization rates for the species we investigate here. However, line intensities, and more importantly line ratios, from different chemical models can be very similar, thereby leading to a clear degeneracy. We also find that the gas subjected to a galactic cosmic ray ionization rate will not necessarily have reached steady state in 1 million years. The species most affected by time dependency effects are HCN and CS, which are both high density tracers. We use our ab initio method to fit an example set of data from two galaxies, I.e. M 82 and NGC 253. We find that (I) molecular line ratios can be easily matched even with erroneous individual line intensities; (II) no set of species can be matched by a one-component interstellar medium (ISM); and (III) a species may be a good tracer of an energetic process but only under specific density and temperature conditions. Conclusions: We provide tables of chemical abundances and line intensities ratios for some of the most commonly observed extragalactic tracers of dense gas for a grid of models. We show that by taking the chemistry behind each species and the individual line intensities into consideration, many degeneracies that arise

  17. Origin of the ankle in the ultrahigh energy cosmic ray spectrum, and of the extragalactic protons below it

    Science.gov (United States)

    Unger, Michael; Farrar, Glennys R.; Anchordoqui, Luis A.

    2015-12-01

    The sharp change in slope of the ultrahigh energy cosmic ray (UHECR) spectrum around 1 018.6 eV (the ankle), combined with evidence of a light but extragalactic component near and below the ankle and intermediate composition above, has proved exceedingly challenging to understand theoretically, without fine-tuning. We propose a mechanism whereby photo-disintegration of ultrahigh energy nuclei in the region surrounding a UHECR accelerator accounts for the observed spectrum and inferred composition at Earth. For suitable source conditions, the model reproduces the spectrum and the composition over the entire extragalactic cosmic ray energy range, i.e. above 1 017.5 eV . Predictions for the spectrum and flavors of neutrinos resulting from this process are also presented.

  18. Large-scale anisotropy in the extragalactic gamma-ray background as a probe for cosmological antimatter

    Science.gov (United States)

    Gao, Yi-Tian; Stecker, Floyd W.; Gleiser, Marcelo; Cline, David B.

    1990-01-01

    Intrinsic anisotropies in the extragalactic gamma-ray background (EGB), which should be detectable with the forthcoming Gamma Ray Observatory, can be used to examine some of the mechanisms proposed to explain its origin, one of which, the baryon-symmetric big bang (BSBB) model, is investigated here. In this simulation, large domains containing matter and antimatter galaxies produce gamma rays by annihilation at the domain boundaries. This mechanism can produce mountain-chain-shaped angular fluctuations in the EGB flux.

  19. First Results from the Dense Extragalactic GBT+ARGUS Survey (DEGAS): A Direct, Quantitative Test of the Role of Gas Density in Star Formation

    Science.gov (United States)

    Kepley, Amanda; Bigiel, Frank; Bolatto, Alberto; Church, Sarah; Cleary, Kieran; Frayer, David; Gallagher, Molly; Gundersen, Joshua; Harris, Andrew; Hughes, Annie; Jimenez-Donaire, Maria Jesus; Kessler, Sarah; Lee, Cheoljong; Leroy, Adam; Li, Jialu; Donovan Meyer, Jennifer; Rosolowsky, Erik; Sandstrom, Karin; Schinnener, Eva; Schruba, Andreas; Sieth, Matt; Usero, Antonio

    2018-01-01

    Gas density plays a central role in all modern theories of star formation. A key test of these theories involves quantifying the resolved gas density distribution and its relationship to star formation within a wide range of galactic environments. Until recently, this experiment has been difficult to perform owing to the faint nature of key molecular gas tracers like HCN and HCO+, but the superior sensitivity of modern millimeter instruments like ALMA and the IRAM 30m make these types of experiments feasible. In particular, the sensitivity and resolution provided by large aperture of the GBT combined with fast mapping speeds made possible by its new 16-pixel, 3mm focal plane array (Argus) make the GBT an almost-ideal instrument for this type of study. The Dense Extragalactic GBT+Argus Survey (DEGAS) will leverage these capabilities to perform the largest, resolved survey of molecular gas tracers in nearby galaxies, ultimately mapping a suite of four molecular gas tracers in the inner 2’ by 2’ of 36 nearby galaxies. When complete in 2020, DEGAS will be the largest resolved survey of dense molecular gas tracers in nearby galaxies. This talk will present early results from the first observations for this Green Bank Telescope large survey and highlight some exciting future possibilities for this survey.

  20. eXtragalactic astronomy: the X-games of adaptive optics

    Science.gov (United States)

    Lai, Olivier

    2000-07-01

    Observing active nuclei, Ultra-Luminous Infrared Galaxies, starburst and merging galaxies, is both a challenge and a requirement for adaptive optics. It is a requirement, because models needed to explain the high infrared flux and the physics of these monsters need constraints that come, in part, from the fine details gleaned on high angular resolution images, and it is a challenge because, being distant, these objects are usually faint in apparent visual magnitude, meaning that the wavefront sensors have to operate in a photon starved regime. Many observations have been controversial in the past, and it is always difficult to tell an artifact such as astigmatism from an inner bar. The importance of observing the point spread function is therefore even more crucial than on bright objects, as PSF reconstruction methods 'a la Veran' break down when the photon noise dominates the statistics of the wave front, or when locking the loop on extended objects. Yet, while some cases have been controversial, some very clear and profound results have been obtained in the extragalactic domain, such as the detection of host galaxy to quasars and star formation studies. It turns out that the fundamental prerequisite to such success stories is a stable, well understood and well calibrated PSF.

  1. Diffusion of cosmic rays at EeV energies in inhomogeneous extragalactic magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Batista, Rafael Alves; Sigl, Günter, E-mail: rafael.alves.batista@desy.de, E-mail: guenter.sigl@desy.de [II. Institut für Theoretische Physik, Universität Hamburg Luruper Chaussee 149, 22761, Hamburg (Germany)

    2014-11-01

    Ultra-high energy cosmic rays can propagate diffusively in cosmic magnetic fields. When their propagation time is comparable to the age of the universe, a suppression in the flux relative to the case in the absence of magnetic fields will occur. In this work we find an approximate parametrization for this suppression for energies below ∼ Z EeV using several magnetic field distributions obtained from cosmological simulations of the magnetized cosmic web. We assume that the magnetic fields have a Kolmogorov power spectrum with the field strengths distributed according to these simulations. We show that, if magnetic fields are coupled to the matter distribution, low field strengths will fill most of the volume, making the suppression milder compared to the case of a constant magnetic field with strength equal to the mean value of this distribution. We also derive upper limits for this suppression to occur for some models of extragalactic magnetic fields, as a function of the coherence length of these fields.

  2. CO Spectral Line Energy Distributions in Galactic Sources: Empirical Interpretation of Extragalactic Observations

    Energy Technology Data Exchange (ETDEWEB)

    Indriolo, Nick; Bergin, E. A. [Department of Astronomy, University of Michigan, 1085 S. University Avenue, Ann Arbor, MI 48109 (United States); Goicoechea, J. R.; Cernicharo, J. [Grupo de Astrofísica Molecular, Instituto de Ciencia de Materiales de Madrid (CSIC) E-28049 Madrid (Spain); Gerin, M.; Gusdorf, A. [LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, École normale supérieure, F-75005, Paris (France); Lis, D. C. [LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, F-75014, Paris (France); Schilke, P., E-mail: nindriolo@stsci.edu [I. Physikalisches Institut der Universität zu Köln, Zülpicher Str. 77, D-50937 Köln (Germany)

    2017-02-10

    The relative populations in rotational transitions of CO can be useful for inferring gas conditions and excitation mechanisms at work in the interstellar medium. We present CO emission lines from rotational transitions observed with Herschel /HIFI in the star-forming cores Orion S, Orion KL, Sgr B2(M), and W49N. Integrated line fluxes from these observations are combined with those from Herschel /PACS observations of the same sources to construct CO spectral line energy distributions (SLEDs) from 5≤ J{sub u} ≤ 48. These CO SLEDs are compared to those reported in other galaxies, with the intention of empirically determining which mechanisms dominate excitation in such systems. We find that CO SLEDs in Galactic star-forming cores cannot be used to reproduce those observed in other galaxies, although the discrepancies arise primarily as a result of beam filling factors. The much larger regions sampled by the Herschel beams at distances of several megaparsecs contain significant amounts of cooler gas, which dominate the extragalactic CO SLEDs, in contrast to observations of Galactic star-forming regions, which are focused specifically on cores containing primarily hot molecular gas.

  3. Double hotspots and flow redirection in the lobes of powerful extragalactic radio sources

    International Nuclear Information System (INIS)

    Lonsdale, C.J.; Barthel, P.D.; Owens Valley Radio Observatory, Pasadena, CA)

    1986-01-01

    Detailed observations of two powerful extragalactic radio sources that contain a prominent double hotspot in one of their two outer lobes are presented. These double hotspots display similar characteristics in both sources, suggesting a common mechanism for their formation. Several other examples of double hotspots are found in the literature that also display many of the characteristics of those in the present sources. These characteristics cannot easily be explained by beam-jitter models, in which secondary hotspots are interpreted as previous impact sites of a beam, which has moved on to form the primary in a new location. Instead, it is proposed that these double hotspots are caused by a flow of material from the more compact to the less compact of the two. It is found that the most probable cause of the outflow is a collision of a beam from the nucleus with a massive (100-million solar mass), dense (greater than 0.1/cm) cloud in intergalactic space. The details of the deflection process itself are unclear, but a possibility is that the beam inflates a bubble of very hot plasma inside the cloud, which then escapes through a weak point in the wall of the cloud. The existence of such intergalactic clouds is considered to be a strong possibility, based on the recent literature, as well as the present hotspot outflow arguments, despite the apparently extreme values postulated for their mass and density. 45 references

  4. The VIMOS Public Extragalactic Redshift Survey (VIPERS). Star formation history of passive red galaxies

    Science.gov (United States)

    Siudek, M.; Małek, K.; Scodeggio, M.; Garilli, B.; Pollo, A.; Haines, C. P.; Fritz, A.; Bolzonella, M.; de la Torre, S.; Granett, B. R.; Guzzo, L.; Abbas, U.; Adami, C.; Bottini, D.; Cappi, A.; Cucciati, O.; De Lucia, G.; Davidzon, I.; Franzetti, P.; Iovino, A.; Krywult, J.; Le Brun, V.; Le Fèvre, O.; Maccagni, D.; Marchetti, A.; Marulli, F.; Polletta, M.; Tasca, L. A. M.; Tojeiro, R.; Vergani, D.; Zanichelli, A.; Arnouts, S.; Bel, J.; Branchini, E.; Ilbert, O.; Gargiulo, A.; Moscardini, L.; Takeuchi, T. T.; Zamorani, G.

    2017-01-01

    Aims: We trace the evolution and the star formation history of passive red galaxies, using a subset of the VIMOS Public Extragalactic Redshift Survey (VIPERS). The detailed spectral analysis of stellar populations of intermediate-redshift passive red galaxies allows the build up of their stellar content to be followed over the last 8 billion years. Methods: We extracted a sample of passive red galaxies in the redshift range 0.4 quality. The spectra of passive red galaxies were stacked in narrow bins of stellar mass and redshift. We use the stacked spectra to measure the 4000 Å break (D4000) and the Hδ Lick index (HδA) with high precision. These spectral features are used as indicators of the star formation history of passive red galaxies. We compare the results with a grid of synthetic spectra to constrain the star formation epochs of these galaxies. We characterize the formation redshift-stellar mass relation for intermediate-redshift passive red galaxies. Results: We find that at z 1 stellar populations in low-mass passive red galaxies are younger than in high-mass passive red galaxies, similar to what is observed at the present epoch. Over the full analyzed redshift range 0.4 web site is http://www.vipers.inaf.it/

  5. Eight new quasars discovered by the Guoshoujing Telescope (LAMOST) in one extragalactic field

    International Nuclear Information System (INIS)

    Wu Xuebing; Jia Zhendong; Chen Zhaoyu; Zuo Wenwen; Zhao Yongheng; Luo Ali; Bai Zhongrui; Chen Jianjun; Zhang Haotong; Yan Hongliang; Ren Juanjuan; Sun Shiwei; Wu Hong; Zhang Yong; Li Yeping; Lu Qishuai; Wang You; Ni Jijun; Wang Hai; Kong Xu

    2010-01-01

    We report the discovery of eight new quasars in one extragalactic field (a five-degree field centered at RA = 08 h 58 m 08.2 s , Dec = 01 o 32'29.7') with the Guoshoujing Telescope (LAMOST) commissioning observations made on 2009 December 18. These quasars, with i magnitudes from 16.44 to 19.34 and redshifts from 0.898 to 2.773, were not identified in the SDSS spectroscopic survey, though six of them with redshifts less than 2.5 were selected as quasar targets in SDSS. Except for one source without near-IR Y-band data, seven of these eight new quasars satisfy a newly proposed quasar selection criterion involving both near-IR and optical colors. Two of them were found in the 'redshift desert' for quasars (z from 2.2 to 3), indicating that the new criterion is efficient for uncovering missing quasars with similar optical colors to stars. Although LAMOST encountered some problems during the commissioning observations, we were still able to identify 38 other known SDSS quasars in this field, with i magnitudes from 16.24 to 19.10 and redshifts from 0.297 to 4.512. Our identifications imply that a substantial fraction of quasars may be missing in previous quasar surveys. The implication of our results to the future LAMOST quasar survey is discussed. (research papers)

  6. Safeguarding Old and New Journal Tables for the VO: Status for Extragalactic and Radio Data

    Directory of Open Access Journals (Sweden)

    Heinz Andernach

    2009-03-01

    Full Text Available Independent of established data centers, and partly for my own research, since 1989 I have been collecting the tabular data from over 2600 articles concerned with radio sources and extragalactic objects in general. Optical character recognition (OCR was used to recover tables from 740 papers. Tables from only 41 percent of the 2600 articles are available in the CDS or CATS catalog collections, and only slightly better coverage is estimated for the NED database. This fraction is not better for articles published electronically since 2001. Both object databases (NED, SIMBAD, LEDA as well as catalog browsers (VizieR, CATS need to be consulted to obtain the most complete information on astronomical objects. More human resources at the data centers and better collaboration between authors, referees, editors, publishers, and data centers are required to improve data coverage and accessibility. The current efforts within the Virtual Observatory (VO project, to provide retrieval and analysis tools for different types of published and archival data stored at various sites, should be balanced by an equal effort to recover and include large amounts of published data not currently available in this way.

  7. The Nature of the Unresolved Extragalactic Cosmic Soft X-Ray Background

    Science.gov (United States)

    Cappelluti, N.; Ranalli, P.; Roncarelli, M.; Arevalo, P.; Zamorani, G.; Comastri, A.; Gilli, R.; Rovilos, E.; Vignali, C.; Allevato, V.; hide

    2013-01-01

    In this paper we investigate the power spectrum of the unresolved 0.5-2 keV cosmic X-ray background (CXB) with deep Chandra 4-Msec (Ms) observations in the Chandra Deep Field South (CDFS). We measured a signal that, on scales >30 arcsec, is significantly higher than the shot noise and is increasing with angular scale. We interpreted this signal as the joint contribution of clustered undetected sources like active galactic nuclei (AGN), galaxies and the intergalactic medium (IGM). The power of unresolved cosmic source fluctuations accounts for approximately 12 per cent of the 0.5-2 keV extragalactic CXB. Overall, our modelling predicts that approximately 20 per cent of the unresolved CXB flux is produced by low-luminosity AGN, approximately 25 per cent by galaxies and approximately 55 per cent by the IGM. We do not find any direct evidence of the so-called 'warm hot intergalactic medium' (i.e. matter with 10(exp 5) less than T less than 10(exp 7) K and density contrast delta less than 1000), but we estimated that it could produce about 1/7 of the unresolved CXB. We placed an upper limit on the space density of postulated X-ray-emitting early black holes at z greater than 7.5 and compared it with supermassive black hole evolution models.

  8. Constraints on decaying dark matter from the extragalactic gamma-ray background

    International Nuclear Information System (INIS)

    Ando, Shin'ichiro

    2015-02-01

    If dark matter is unstable and the mass is within GeV-TeV regime, its decays produce high-energy photons that give contribution to the extragalactic gamma-ray background (EGRB). We constrain dark matter decay by analyzing the 50-month EGRB data measured with Fermi satellite, for different decay channels motivated with several supersymmetric scenarios featuring R-parity violation. We adopt the latest astrophysical models for various source classes such as active galactic nuclei and star-forming galaxies, and take associated uncertainties properly into account. The lower limits for the lifetime are very stringent for a wide range of dark matter mass, excluding the lifetime shorter than 10 28 s for mass between a few hundred GeV and ∝1TeV, e.g., for b anti b decay channel. Furthermore, most dark matter models that explain the anomalous positron excess are also excluded. These constraints are robust, being little dependent on astrophysical uncertainties, unlike other probes such as Galactic positrons or anti-protons.

  9. First extragalactic detection of submillimeter CH rotational lines from the Herschel space observatory

    Energy Technology Data Exchange (ETDEWEB)

    Rangwala, Naseem; Maloney, Philip R.; Glenn, Jason; Kamenetzky, Julia [Center for Astrophysics and Space Astronomy, University of Colorado, 1255 38th street, Boulder, CO 80303 (United States); Wilson, Christine D.; Schirm, Maximilien R. P. [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1 (Canada); Spinoglio, Luigi; Pereira Santaella, Miguel [Istituto di Fisica dello Spazio Interplanetario, INAF, Via del Fosso del Cavaliere 100, I-00133 Roma (Italy)

    2014-06-20

    We present the first extragalactic detections of several CH rotational transitions in the far-infrared in four nearby galaxies, NGC 1068, Arp 220, M82, and NGC 253, using the Herschel Space Observatory. The CH lines in all four galaxies are a factor of 2-4 brighter than the adjacent HCN and HCO{sup +} J = 6-5 lines (also detected in the same spectra). In the star-formation-dominated galaxies, M82, NGC 253, and Arp 220, the CH/CO abundance ratio is low (∼10{sup –5}), implying that the CH is primarily arising in diffuse and translucent gas where the chemistry is driven by UV radiation as found in the Milky Way interstellar matter. In NGC 1068, which has a luminous active galactic nucleus (AGN), the CH/CO ratio is an order of magnitude higher, suggesting that CH formation is driven by an X-ray-dominated region (XDR). Our XDR models show that both the CH and CO abundances in NGC 1068 can be explained by an XDR-driven chemistry for gas densities and molecular hydrogen column densities that are well constrained by the CO observations. We conclude that the CH/CO ratio may a good indicator of the presence of AGN in galaxies. We also discuss the feasibility of detecting CH in intermediate- to high-z galaxies with ALMA.

  10. The Atacama Cosmology Telescope: Extragalactic Sources at 148 GHz in the 2008 Survey

    Science.gov (United States)

    Marriage, T. A.; Juin, J. B.; Lin, Y. T.; Marsden, D.; Nolta, M. R.; Partridge, B.; Ade, P. A. R.; Aguirre, P.; Amiri, M.; Appel, J. W.; hide

    2011-01-01

    We report on extragalactic sources detected in a 455 square-degree map of the southern sky made with data at a frequency of 148 GHz from the Atacama Cosmology Telescope 2008 observing season. We provide a catalog of 157 sources with flux densities spanning two orders of magnitude: from 15 mJy to 1500 mJy. Comparison to other catalogs shows that 98% of the ACT detections correspond to sources detected at lower radio frequencies. Three of the sources appear to be associated with the brightest cluster galaxies of low redshift X-ray selected galaxy clusters. Estimates of the radio to mm-wave spectral indices and differential counts of the sources further bolster the hypothesis that they are nearly all radio sources, and that their emission is not dominated by re-emission from warm dust. In a bright (> 50 mJy) 148 GHz-selected sample with complete cross-identifications from the Australia Telescope 20 GHz survey, we observe an average steepening of the spectra between .5, 20, and 148 GHz with median spectral indices of alp[ha (sub 5-20) = -0.07 +/- 0.06, alpha (sub 20-148) -0.39 +/- 0.04, and alpha (sub 5-148) = -0.20 +/- 0.03. When the measured spectral indices are taken into account, the 148 GHz differential source counts are consistent with previous measurements at 30 GHz in the context of a source count model dominated by radio sources. Extrapolating with an appropriately rescaled model for the radio source counts, the Poisson contribution to the spatial power spectrum from synchrotron-dominated sources with flux density less than 20 mJy is C(sup Sync) = (2.8 +/- 0.3) x 1O (exp-6) micro K(exp 2).

  11. INFLUENCE OF THE GALACTIC GRAVITATIONAL FIELD ON THE POSITIONAL ACCURACY OF EXTRAGALACTIC SOURCES

    International Nuclear Information System (INIS)

    Larchenkova, Tatiana I.; Lutovinov, Alexander A.; Lyskova, Natalya S.

    2017-01-01

    We investigate the influence of random variations of the Galactic gravitational field on the apparent celestial positions of extragalactic sources. The basic statistical characteristics of a stochastic process (first-order moments, an autocorrelation function and a power spectral density) are used to describe a light ray deflection in a gravitational field of randomly moving point masses as a function of the source coordinates. We map a 2D distribution of the standard deviation of the angular shifts in positions of distant sources (including reference sources of the International Celestial Reference Frame) with respect to their true positions. For different Galactic matter distributions the standard deviation of the offset angle can reach several tens of μ as (microarcsecond) toward the Galactic center, decreasing down to 4–6 μ as at high galactic latitudes. The conditional standard deviation (“jitter”) of 2.5 μ as is reached within 10 years at high galactic latitudes and within a few months toward the inner part of the Galaxy. The photometric microlensing events are not expected to be disturbed by astrometric random variations anywhere except the inner part of the Galaxy as the Einstein–Chvolson times are typically much shorter than the jittering timescale. While a jitter of a single reference source can be up to dozens of μ as over some reasonable observational time, using a sample of reference sources would reduce the error in relative astrometry. The obtained results can be used for estimating the physical upper limits on the time-dependent accuracy of astrometric measurements.

  12. INFLUENCE OF THE GALACTIC GRAVITATIONAL FIELD ON THE POSITIONAL ACCURACY OF EXTRAGALACTIC SOURCES

    Energy Technology Data Exchange (ETDEWEB)

    Larchenkova, Tatiana I. [ASC of P.N.Lebedev Physical Institute, Leninskiy prospect 53, Moscow 119991 (Russian Federation); Lutovinov, Alexander A.; Lyskova, Natalya S. [Space Research Institute, Russian Academy of Sciences, Profsoyuznaya 84/32, 117997 Moscow (Russian Federation)

    2017-01-20

    We investigate the influence of random variations of the Galactic gravitational field on the apparent celestial positions of extragalactic sources. The basic statistical characteristics of a stochastic process (first-order moments, an autocorrelation function and a power spectral density) are used to describe a light ray deflection in a gravitational field of randomly moving point masses as a function of the source coordinates. We map a 2D distribution of the standard deviation of the angular shifts in positions of distant sources (including reference sources of the International Celestial Reference Frame) with respect to their true positions. For different Galactic matter distributions the standard deviation of the offset angle can reach several tens of μ as (microarcsecond) toward the Galactic center, decreasing down to 4–6 μ as at high galactic latitudes. The conditional standard deviation (“jitter”) of 2.5 μ as is reached within 10 years at high galactic latitudes and within a few months toward the inner part of the Galaxy. The photometric microlensing events are not expected to be disturbed by astrometric random variations anywhere except the inner part of the Galaxy as the Einstein–Chvolson times are typically much shorter than the jittering timescale. While a jitter of a single reference source can be up to dozens of μ as over some reasonable observational time, using a sample of reference sources would reduce the error in relative astrometry. The obtained results can be used for estimating the physical upper limits on the time-dependent accuracy of astrometric measurements.

  13. Galactic vs. extragalactic origin of the peculiar transient SCP 06F6

    Science.gov (United States)

    Soker, Noam; Frankowski, Adam; Kashi, Amit

    2010-02-01

    We study four scenarios for the SCP 06F6 transient event that was announced recently. Some of these were previously briefly discussed as plausible models for SCP 06F6, in particular with the claimed detection of a z = 0.143 cosmological redshift of a Swan spectrum of a carbon rich envelope. We adopt this value of z for extragalactic scenarios. We cannot rule out any of these models, but can rank them from most to least preferred. Our favorite model is a tidal disruption of a CO white dwarf (WD) by an intermediate-mass black hole (IMBH). To account for the properties of the SCP 06F6 event, we have to assume the presence of a strong disk wind that was not included in previous numerical simulations. If the IMBH is the central BH of a galaxy, this explains the non-detection of a bright galaxy in the direction of SCP 06F6. Our second favorite scenario is a type Ia-like SN that exploded inside the dense wind of a carbon star. The carbon star is the donor star of the exploded WD. Our third favorite model is a Galactic source of an asteroid that collided with a WD. Such a scenario was discussed in the past as the source of dusty disks around WDs, but no predictions exist regarding the appearance of such an event. Our least favorite model is of a core collapse SN. The only way we can account for the properties of SCP 06F6 with a core collapse SN is if we assume the occurrence of a rare type of binary interaction.

  14. Ultrahigh energy cosmic ray nuclei from extragalactic pulsars and the effect of their Galactic counterparts

    International Nuclear Information System (INIS)

    Fang, Ke; Olinto, Angela V.; Kotera, Kumiko

    2013-01-01

    The acceleration of ultrahigh energy nuclei in fast spinning newborn pulsars can explain the observed spectrum of ultrahigh energy cosmic rays and the trend towards heavier nuclei for energies above 10 19 eV as reported by the Auger Observatory. Pulsar acceleration implies a hard injection spectrum ( ∼ E −1 ) due to pulsar spin down and a maximum energy E max ∼ Z 10 19 eV due to the limit on the spin rate of neutron stars. We have previously shown that the escape through the young supernova remnant softens the spectrum, decreases slightly the maximum energy, and generates secondary nuclei. Here we show that the distribution of pulsar birth periods and the effect of propagation in the interstellar and intergalactic media modifies the combined spectrum of all pulsars. By assuming a normal distribution of pulsar birth periods centered at 300 ms, we show that the contribution of extragalactic pulsar births to the ultrahigh energy cosmic ray spectrum naturally gives rise to a contribution to very high energy cosmic rays (VHECRs, between 10 16 and 10 18 eV) by Galactic pulsar births. The required injected composition to fit the observed spectrum depends on the absolute energy scale, which is uncertain, differing between Auger Observatory and Telescope Array. The contribution of Galactic pulsar births can also bridge the gap between predictions for cosmic ray acceleration in supernova remnants and the observed spectrum just below the ankle, depending on the composition of the cosmic rays that escape the supernova remnant and the diffusion behavior of VHECRs in the Galaxy

  15. The VIMOS Public Extragalactic Redshift Survey (VIPERS). Full spectroscopic data and auxiliary information release (PDR-2)

    Science.gov (United States)

    Scodeggio, M.; Guzzo, L.; Garilli, B.; Granett, B. R.; Bolzonella, M.; de la Torre, S.; Abbas, U.; Adami, C.; Arnouts, S.; Bottini, D.; Cappi, A.; Coupon, J.; Cucciati, O.; Davidzon, I.; Franzetti, P.; Fritz, A.; Iovino, A.; Krywult, J.; Le Brun, V.; Le Fèvre, O.; Maccagni, D.; Małek, K.; Marchetti, A.; Marulli, F.; Polletta, M.; Pollo, A.; Tasca, L. A. M.; Tojeiro, R.; Vergani, D.; Zanichelli, A.; Bel, J.; Branchini, E.; De Lucia, G.; Ilbert, O.; McCracken, H. J.; Moutard, T.; Peacock, J. A.; Zamorani, G.; Burden, A.; Fumana, M.; Jullo, E.; Marinoni, C.; Mellier, Y.; Moscardini, L.; Percival, W. J.

    2018-01-01

    We present the full public data release (PDR-2) of the VIMOS Public Extragalactic Redshift Survey (VIPERS), performed at the ESO VLT. We release redshifts, spectra, CFHTLS magnitudes and ancillary information (as masks and weights) for a complete sample of 86 775 galaxies (plus 4732 other objects, including stars and serendipitous galaxies); we also include their full photometrically-selected parent catalogue. The sample is magnitude limited to iAB ≤ 22.5, with an additional colour-colour pre-selection devised as to exclude galaxies at z automated pipeline; all redshift determinations were then visually validated and assigned a quality flag. Measurements with a quality flag ≥ 2 are shown to have a confidence level of 96% or larger and make up 88% of all measured galaxy redshifts (76 552 out of 86 775), constituting the VIPERS prime catalogue for statistical investigations. For this sample the rms redshift error, estimated using repeated measurements of about 3000 galaxies, is found to be σz = 0.00054(1 + z). All data are available at http://vipers.inaf.it and on the ESO Archive. Based on observations collected at the European Southern Observatory, Cerro Paranal, Chile, using the Very Large Telescope under programmes 182.A-0886 and partly 070.A-9007. Also based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. This work is based in part on data products produced at TERAPIX and the Canadian Astronomy Data Centre as part of the Canada-France-Hawaii Telescope Legacy Survey, a collaborative project of NRC and CNRS. The VIPERS web site is http://www.vipers.inaf.it/

  16. Time evolution of primordial magnetic fields and present day extragalactic magnetism

    International Nuclear Information System (INIS)

    Saveliev, Andrey

    2014-05-01

    The topic of the present thesis is the time evolution of Primordial Magnetic Fields which have been generated in the Early Universe. Assuming this so-called Cosmological Scenario of magnetogenesis to be true, it is shown in the following that this would account for the present day Extragalactic Magnetic Fields. This is particularly important in light of recent gamma ray observations which are used to derive a lower limit for the corresponding magnetic field strength, even though also an alternative approach, claiming instead that these observations are due to interactions with the Intergalactic Medium, is possible and will be tested here with Monte Carlo simulations. In order to describe the aforementioned evolution of Primordial Magnetic Fields, a set of general Master Equations for the spectral magnetic, kinetic and helical components of the system are derived and then solved numerically for the Early Universe. This semianalytical method allows it to perform a full quantitative study for the time development of the power spectra, in particular by fully taking into account the backreaction of the turbulent medium onto the magnetic fields. Applying the formalism to non-helical Primordial Magnetic Fields created on some characteristic length measure, it is shown that on large scales L their spectrum 5 builds up a slope which behaves as B∝L -(5)/(2) and governs the evolution of the coherence (or integral) scale. In addition, the claim of equipartition between the magnetic and the kinetic energy is found to be true. Extending the analysis to helical magnetic fields, it is observed that the time evolution changes dramatically, hence confirming quantitatively that an Inverse Cascade, i.e. an efficient transport of energy from small to large scales, as predicted in previous works, indeed does take place.

  17. Extragalactic Ultra-High Energy Cosmic-Rays - Part One - Contribution from Hot Spots in Fr-II Radio Galaxies

    Science.gov (United States)

    Rachen, J. P.; Biermann, P. L.

    1993-05-01

    The hot spots of Fanaroff-Riley class II radio galaxies, considered as working surfaces of highly collimated plasma jets, are proposed to be the dominant sources of the cosmic rays at energies above 1 EeV^a^. We apply the model of first order Fermi acceleration at strong, nonrelativistic shock waves to the hot spot region. The strength of the model has been demonstrated by Biermann & Strittmatter (1987) and by Meisenheimer et al. (1989), who explain their radio-to optical spectra and infer the physical conditions of the radiating plasma. Using synchrotron radiating electrons as a trace, we can calculate the spectrum and the maximum energy of protons accelerated under the same conditions. For simplicity, we disregard heavy nuclei, but their probable role is discussed. The normalization of proton flux injected in extragalactic space is performed by using estimates from Rawlings & Saunders (1991) for the total energy stored in relativistic particles inside the jets and radio galaxy evolution models given by Peacock (1985). We calculate the spectral modifications due to interactions of the protons with the microwave background photons in an evolving universe, following Berezinsky & Grigor'eva (1988). Constraints on the extragalactic magnetic field can be imposed, since it must permit an almost homogeneous filling of the universe with energetic protons. The observed ultra-high energy cosmic ray spectrum is reproduced in slope and flux, limited at high energies by the Greisen-cutoff at about 80 EeV. The requirements on the content of relativistic protons in jets and the constraints to the extragalactic magnetic field are consistent with common estimates. The data beyond the Greisen cutoff for protons may be explained by including heavy nuclei in our model, since they can propagate over cosmological distances up to more than 100 EeV.

  18. Recent Advances and Coming Attractions in the NASA/IPAC Extragalactic Database

    Science.gov (United States)

    Mazzarella, Joseph M.; Baker, Kay; Pan Chan, Hiu; Chen, Xi; Ebert, Rick; Frayer, Cren; Helou, George; Jacobson, Jeffery D.; Lo, Tak M.; Madore, Barry; Ogle, Patrick M.; Pevunova, Olga; Steer, Ian; Schmitz, Marion; Terek, Scott

    2017-01-01

    We review highlights of recent advances and developments underway at the NASA/IPAC Extragalactic Database (NED). Extensive updates have been made to the infrastructure and processes essential for scaling NED for the next steps in its evolution. A major overhaul of the data integration pipeline provides greater modularity and parallelization to increase the rate of source cross-matching and data integration. The new pipeline was used recently to fold in data for nearly 300,000 sources published in over 900 recent journal articles, as well as fundamental parameters for 42 million sources in the Spitzer Enhanced Imaging Products Source List. The latter has added over 360 million photometric measurements at 3.6, 4.5, 5.8. 8.0 (IRAC) and 24 microns (MIPS) to the spectral energy distributions of affected objects in NED. The recent discovery of super-luminous spiral galaxies (Ogle et al. 2016) exemplifies the opportunities for science discovery and data mining available directly from NED’s unique data synthesis, spanning the spectrum from gamma ray through radio frequencies. The number of references in NED has surpassed 103,000. In the coming year, cross-identifications of sources in the 2MASS Point Source Catalog and in the AllWISE Source Catalog with prior objects in the database (including GALEX) will increase the holdings to over a billion distinct objects, providing a rich resource for multi-wavelength analysis. Information about a recent surge in growth of redshift-independent distances in NED is presented at this meeting by Steer et al. (2017). Website updates include a ’simple search’ to perform common queries in a single entry field, an interface to query the image repository with options to sort and filter the initial results, connectivity to the IRSA Finder Chart service, as well as a program interface to query images using the international virtual observatory Simple Image Access protocol. Graphical characterizations of NED content and completeness are

  19. CHARACTERIZING THE MID-INFRARED EXTRAGALACTIC SKY WITH WISE AND SDSS

    International Nuclear Information System (INIS)

    Yan Lin; Donoso, E.; Tsai, Chao-Wei; Cutri, R.; Jarrett, T.; Stern, D.; Assef, R. J.; Eisenhardt, P.; Blain, A. W.; Stanford, S. A.; Wright, E.; Bridge, C.; Riechers, D. A.

    2013-01-01

    The Wide-field Infrared Survey Explorer (WISE) has completed its all-sky survey in four channels at 3.4-22 μm, detecting hundreds of millions of objects. We merge the WISE mid-infrared data with optical data from the Sloan Digital Sky Survey (SDSS) and provide a phenomenological characterization of WISE extragalactic sources. WISE is most sensitive at 3.4 μm (W1) and least sensitive at 22 μm (W4). The W1 band probes massive early-type galaxies out to z ∼> 1. This is more distant than SDSS identified early-type galaxies, consistent with the fact that 28% of 3.4 μm sources have faint or no r-band counterparts (r > 22.2). In contrast, 92%-95% of 12 μm and 22 μm sources have SDSS optical counterparts with r ≤ 22.2. WISE 3.4 μm detects 89.8% of the entire SDSS QSO catalog at S/N W1 >7σ, but only 18.9% at 22 μm with S/N W4 > 5σ. We show that WISE colors alone are effective in isolating stars (or local early-type galaxies), star-forming galaxies, and strong active galactic nuclei (AGNs)/QSOs at z ∼ 0.8 and W2 –2 . (2) Selection of dust-obscured, type-2 AGN/QSO candidates. We show that WISE W1 – W2 > 0.8, W2 6 (Vega) colors can be used to identify type-2 AGN candidates. The fraction of these type-2 AGN candidates is one-third of all WISE color-selected AGNs. (3) Selection of ultraluminous infrared galaxies (ULIRGs) at z ∼ 2 with extremely red colors, r – W4 > 14 or well-detected 22 μm sources lacking detections in the 3.4 and 4.6 μm bands. The surface density of z ∼ 2 ULIRG candidates selected with r – W4 > 14 is 0.9 ± 0.07 deg –2 at S/N W4 ≥ 5 (the corresponding, lowest flux density of 2.5 mJy), which is consistent with that inferred from smaller area Spitzer surveys. Optical spectroscopy of a small number of these high-redshift ULIRG candidates confirms our selection, and reveals a possible trend that optically fainter or r – W4 redder candidates are at higher redshifts.

  20. The VIMOS Public Extragalactic Redshift Survey. Measuring the growth rate of structure around cosmic voids

    Science.gov (United States)

    Hawken, A. J.; Granett, B. R.; Iovino, A.; Guzzo, L.; Peacock, J. A.; de la Torre, S.; Garilli, B.; Bolzonella, M.; Scodeggio, M.; Abbas, U.; Adami, C.; Bottini, D.; Cappi, A.; Cucciati, O.; Davidzon, I.; Fritz, A.; Franzetti, P.; Krywult, J.; Le Brun, V.; Le Fèvre, O.; Maccagni, D.; Małek, K.; Marulli, F.; Polletta, M.; Pollo, A.; Tasca, L. A. M.; Tojeiro, R.; Vergani, D.; Zanichelli, A.; Arnouts, S.; Bel, J.; Branchini, E.; De Lucia, G.; Ilbert, O.; Moscardini, L.; Percival, W. J.

    2017-11-01

    We aim to develop a novel methodology for measuring thegrowth rate of structure around cosmic voids. We identified voids in the completed VIMOS Public Extragalactic Redshift Survey (VIPERS), using an algorithm based on searching for empty spheres. We measured the cross-correlation between the centres of voids and the complete galaxy catalogue. The cross-correlation function exhibits a clear anisotropy in both VIPERS fields (W1 and W4), which is characteristic of linear redshift space distortions. By measuring the projected cross-correlation and then de-projecting it we are able to estimate the un-distorted cross-correlation function. We propose that given a sufficiently well-measured cross-correlation function one should be able to measure the linear growth rate of structure by applying a simple linear Gaussian streaming model for the redshift space distortions (RSD). Our study of voids in 306 mock galaxy catalogues mimicking the VIPERS fields suggests that VIPERS is capable of measuring β, the ratio of the linear growth rate to the bias, with an error of around 25%. Applying our method to the VIPERS data, we find a value for the redshift space distortion parameter, β = 0.423-0.108+0.104 which, given the bias of the galaxy population we use, gives a linear growth rate of f σ8 = 0.296-0.078+0.075 at z = 0.727. These results are consistent with values observed in parallel VIPERS analyses that use standard techniques. Based on observations collected at the European Southern Observatory, Cerro Paranal, Chile, using the Very Large Telescope under programs 182.A-0886 and partly 070.A-9007. Also based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. This work is based in

  1. A Science Portal and Archive for Extragalactic Globular Cluster Systems Data

    Science.gov (United States)

    Young, Michael; Rhode, Katherine L.; Gopu, Arvind

    2015-01-01

    For several years we have been carrying out a wide-field imaging survey of the globular cluster populations of a sample of giant spiral, S0, and elliptical galaxies with distances of ~10-30 Mpc. We use mosaic CCD cameras on the WIYN 3.5-m and Kitt Peak 4-m telescopes to acquire deep BVR imaging of each galaxy and then analyze the data to derive global properties of the globular cluster system. In addition to measuring the total numbers, specific frequencies, spatial distributions, and color distributions for the globular cluster populations, we have produced deep, high-quality images and lists of tens to thousands of globular cluster candidates for the ~40 galaxies included in the survey.With the survey nearing completion, we have been exploring how to efficiently disseminate not only the overall results, but also all of the relevant data products, to the astronomical community. Here we present our solution: a scientific portal and archive for extragalactic globular cluster systems data. With a modern and intuitive web interface built on the same framework as the WIYN One Degree Imager Portal, Pipeline, and Archive (ODI-PPA), our system will provide public access to the survey results and the final stacked mosaic images of the target galaxies. In addition, the astrometric and photometric data for thousands of identified globular cluster candidates, as well as for all point sources detected in each field, will be indexed and searchable. Where available, spectroscopic follow-up data will be paired with the candidates. Advanced imaging tools will enable users to overlay the cluster candidates and other sources on the mosaic images within the web interface, while metadata charting tools will allow users to rapidly and seamlessly plot the survey results for each galaxy and the data for hundreds of thousands of individual sources. Finally, we will appeal to other researchers with similar data products and work toward making our portal a central repository for data

  2. TRACING MOLECULAR GAS MASS IN EXTREME EXTRAGALACTIC ENVIRONMENTS: AN OBSERVATIONAL STUDY

    International Nuclear Information System (INIS)

    Zhu Ming; Papadopoulos, Padeli P.; Xilouris, Emmanuel M.; Kuno, Nario; Lisenfeld, Ute

    2009-01-01

    We present a new observational study of the 12 CO(1-0) line emission as an H 2 gas mass tracer under extreme conditions in extragalactic environments. Our approach is to study the full neutral interstellar medium (H 2 , H I, and dust) of two galaxies whose bulk interstellar medium (ISM) resides in environments that mark (and bracket) the excitation extremes of the ISM conditions found in infrared luminous galaxies, the starburst NGC 3310, and the quiescent spiral NGC 157. Our study maintains a robust statistical notion of the so-called X = N(H 2 )/I CO factor (i.e., a large ensemble of clouds is involved) while exploring its dependence on the very different average ISM conditions prevailing within these two systems. These are constrained by fully sampled 12 CO(3-2) and 12 CO(1-0) observations, at a matched beam resolution of half-power beam width ∼15'', obtained with the James Clerk Maxwell Telescope (JCMT) on Mauna Kea (Hawaii) and the 45 m telescope of the Nobeyama Radio Observatory in Japan, combined with sensitive 850 μm and 450 μm dust emission and H I interferometric images which allow a complete view of all the neutral ISM components. Complementary 12 CO(2-1) observations were obtained with the JCMT toward the center of the two galaxies. We found an X factor varying by a factor of 5 within the spiral galaxy NGC 157 and about two times lower than the Galactic value in NGC 3310. In addition, the dust emission spectrum in NGC 3310 shows a pronounced submillimeter 'excess'. We tried to fit this excess by a cold dust component but very low temperatures were required (T C ∼ 5-11 K) with a correspondingly low gas-to-dust mass ratio of ∼5-43. We furthermore show that it is not possible to maintain the large quantities of dust required at these low temperatures in this starburst galaxy. Instead, we conclude that the dust properties need to be different from Galactic dust in order to fit the submillimeter 'excess'. We show that the dust spectral energy

  3. Kinetic Alfven Waves and the Depletion of the Thermal Population in Extragalactic Jets

    Science.gov (United States)

    Jafelice, L. C.; Opher, R.

    1990-11-01

    RESUMEN. Chorros Extragalacticos (CE) y Fuentes Radio Extendidas (FRE) son locales de ricos y complejos procesos de plasma magnetizado. Recien tes observaciones indican que esas fuentes son estructuradas en filamen tos. Nos concentramos aqui en el analisis de dos problemas: 1) el prob[e ma de injecci6n,queespropuesto porlas teorias de aceleraci6n de p ? las en plasmas de CE e FRE, que necesitan partfculas que ya tengan ener gfas moderadamente relativisticas para que los procesos de Fermi sean efectivos; y 2) la reciente evidencia observacional de la ausencia de partfculas termicas en CE. El presente modelo pone en evidencia que ambos problemas estan 1ntimamente relacionados uno con el otro. Jafelice y Opher (1987a) (Astrophys. Space Sci. 137, 303) muestram que es espera da una abundante generaci6n de olas Alf cineticas (OAC) en CE y FRE. En el presente trabajo estudiamos Ia cadena de procesos: a) OAC aceleran electrons termicos al largo del campo magnetico de fondo producien- do electrones supratermicos fugitivos; b) que generan olas Langmuir; y c) las cuales por su vez aceleran una fraccion de los electrones fugi- tivos hasta energias moderadamente relativfsticas. Mostramos que supo - niendo que no haya otra fuente de poblaci6n termica a no ser la , la secuencia de procesos arriba puede encargarse delconsumo de los elec- trones termicos en una escala de tiempo %< que el tiempo de vida de la fuente. ABSTRACT: Extragalactic Jets (EJ) and Extended Radio Sources (ERS) are sites of rich and complex magnetized plasma processes.Recent observa - tions indicate that these sources are filamentary structured. We concentrate here on the analysis of two problems:i) the injection problem, faced by theories of particle acceleration in EJ and ERS plasmas, which need particles with already moderately relativistic energies for the Fer mi processes `to be effective; and 2) the recent observational evidence of the abscence of thermal particles within EJ. The present model makes

  4. Experience with the gLite workload management system in ATLAS Monte Carlo production on LCG

    International Nuclear Information System (INIS)

    Campana, S; Sciaba, A; Rebatto, D

    2008-01-01

    The ATLAS experiment has been running continuous simulated events production since more than two years. A considerable fraction of the jobs is daily submitted and handled via the gLite Workload Management System, which overcomes several limitations of the previous LCG Resource Broker. The gLite WMS has been tested very intensively for the LHC experiments use cases for more than six months, both in terms of performance and reliability. The tests were carried out by the LCG Experiment Integration Support team (in close contact with the experiments) together with the EGEE integration and certification team and the gLite middleware developers. A pragmatic iterative and interactive approach allowed a very quick rollout of fixes and their rapid deployment, together with new functionalities, for the ATLAS production activities. The same approach is being adopted for other middleware components like the gLite and CREAM Computing Elements. In this contribution we will summarize the learning from the gLite WMS testing activity, pointing out the most important achievements and the open issues. In addition, we will present the current situation of the ATLAS simulated event production activity on the EGEE infrastructure based on the gLite WMS, showing the main improvements and benefits from the new middleware. Finally, the gLite WMS is being used by many other VOs, including the LHC experiments. In particular, some statistics will be shown on the CMS experience running WMS user analysis via the WMS

  5. The Tarantula Nebula as a template for extragalactic star forming regions from VLT/MUSE and HST/STIS

    Science.gov (United States)

    Crowther, Paul A.; Caballero-Nieves, Saida M.; Castro, Norberto; Evans, Christopher J.

    2017-11-01

    We present VLT/MUSE observations of NGC 2070, the dominant ionizing nebula of 30 Doradus in the LMC, plus HST/STIS spectroscopy of its central star cluster R136. Integral Field Spectroscopy (MUSE) and pseudo IFS (STIS) together provides a complete census of all massive stars within the central 30×30 parsec2 of the Tarantula. We discuss the integrated far-UV spectrum of R136, of particular interest for UV studies of young extragalactic star clusters. Strong He iiλ1640 emission at very early ages (1-2 Myr) from very massive stars cannot be reproduced by current population synthesis models, even those incorporating binary evolution and very massive stars. A nebular analysis of the integrated MUSE dataset implies an age of ~4.5 Myr for NGC 2070. Wolf-Rayet features provide alternative age diagnostics, with the primary contribution to the integrated Wolf-Rayet bumps arising from R140 rather than the more numerous H-rich WN stars in R136. Caution should be used when interpreting spatially extended observations of extragalactic star-forming regions.

  6. Peering Through the Muck: Notes on the the Influence of the Galactic Interstellar Medium on Extragalactic Observations

    Science.gov (United States)

    Lockman, Felix J.

    This paper considers some effects of foreground Galactic gas on radiation received from extragalactic objects, with an emphasis on the use of the 21cm line to determine the total N(HI). In general, the opacity of the 21cm line makes it impossible to derive an accurate value of N(HI) by simply applying a formula to the observed emission, except in directions where there is very little interstellar matter. The 21cm line can be used to estimate the likelihood that there is significant molecular hydrogen in a particular direction, but carries little or no information on the amount of ionized gas, which can be a major source of foreground effects. Considerable discussion is devoted to the importance of small-scale angular structure in HI, with the conclusion that it will rarely contribute significantly to the total error compared to other factors (such as the effects of ionized gas) for extragalactic sight lines at high Galactic latitude. The direction of the Hubble/Chandra Deep Field North is used as an example of the complexities that might occur even in the absence of opacity or molecular gas.

  7. Variations in the small-scale galactic magnetic field and short time-scale intensity variations of extragalactic radio sources

    International Nuclear Information System (INIS)

    Simonetti, J.H.

    1985-01-01

    Structure functions of the Faraday rotation measures (RMs) of extragalactic radio sources are used to investigate variations in the interstellar magnetic field on length scales of approx.0.01 to 100 pc. Model structure functions derived assuming a power-law power spectrum of irregularities in n/sub e/B, are compared with those observed. The results indicate an outer angular scale for RM variations of approximately less than or equal to 5 0 and evidence for RM variations on scales as small as 1'. Differences in the variance of n/sub e/B fluctuations for various lines of sight through the Galaxy are found. Comparison of pulsar scintillations in right- and left-circular polarizations yield an upper limit to the variations in n/sub e/ on a length scale of approx.10 11 cm. RMs were determined through high-velocity molecular flows in galactic star-formation regions, with the goal of constraining magnetic fields in and near the flows. RMs of 7 extragalactic sources with a approx.20 arcmin wide area seen through Cep A, fall in two groups separated by approx.150 rad m -2 - large given our knowledge of RM variations on small angular scales and possibly a result of the anisotropy of the high-velocity material

  8. DERIVING METALLICITIES FROM THE INTEGRATED SPECTRA OF EXTRAGALACTIC GLOBULAR CLUSTERS USING THE NEAR-INFRARED CALCIUM TRIPLET

    International Nuclear Information System (INIS)

    Foster, Caroline; Forbes, Duncan A.; Proctor, Robert N.; Spitler, Lee R.; Strader, Jay; Brodie, Jean P.

    2010-01-01

    The Ca II triplet (CaT) feature in the near-infrared has been employed as a metallicity indicator for individual stars as well as integrated light of Galactic globular clusters (GCs) and galaxies with varying degrees of success, and sometimes puzzling results. Using the DEIMOS multi-object spectrograph on Keck we obtain a sample of 144 integrated light spectra of GCs around the brightest group galaxy NGC 1407 to test whether the CaT index can be used as a metallicity indicator for extragalactic GCs. Different sets of single stellar population models make different predictions for the behavior of the CaT as a function of metallicity. In this work, the metallicities of the GCs around NGC 1407 are obtained from CaT index values using an empirical conversion. The measured CaT/metallicity distributions show unexpected features, the most remarkable being that the brightest red and blue GCs have similar CaT values despite their large difference in mean color. Suggested explanations for this behavior in the NGC 1407 GC system are (1) the CaT may be affected by a population of hot blue stars, (2) the CaT may saturate earlier than predicted by the models, and/or (3) color may not trace metallicity linearly. Until these possibilities are understood, the use of the CaT as a metallicity indicator for the integrated spectra of extragalactic GCs will remain problematic.

  9. Constraint on dark matter annihilation with dark star formation using Fermi extragalactic diffuse gamma-ray background data

    International Nuclear Information System (INIS)

    Yuan, Qiang; Yue, Bin; Chen, Xuelei; Zhang, Bing

    2011-01-01

    It has been proposed that during the formation of the first generation stars there might be a ''dark star'' phase in which the power of the star comes from dark matter annihilation. The adiabatic contraction process to form the dark star would result in a highly concentrated density profile of the host halo at the same time, which may give enhanced indirect detection signals of dark matter. In this work we investigate the extragalactic γ-ray background from dark matter annihilation with such a dark star formation scenario, and employ the isotropic γ-ray data from Fermi-LAT to constrain the model parameters of dark matter. The results suffer from large uncertainties of both the formation rate of the first generation stars and the subsequent evolution effects of the host halos of the dark stars. We find, in the most optimistic case for γ-ray production via dark matter annihilation, the expected extragalactic γ-ray flux will be enhanced by 1-2 orders of magnitude. In such a case, the annihilation cross section of the supersymmetric dark matter can be constrained to the thermal production level, and the leptonic dark matter model which is proposed to explain the positron/electron excesses can be well excluded. Conversely, if the positron/electron excesses are of a dark matter annihilation origin, then the early Universe environment is such that no dark star can form

  10. Datça-Bozburun Yarımadası (Ege Denizi Kıyı Balıkçılığı ve Sorunları Üzerine Bir Araştırma.

    Directory of Open Access Journals (Sweden)

    Okan Akyol

    2015-12-01

    Full Text Available Bu çalışmada, Datça-Bozburun Yarımadası’nın kıyı balıkçılık aktiviteleri, hedef balık türleri, balıkçılık sorunları, balıkçı kooperatiflerinin özellikleri, balıkçı tekneleri ve barınakları araştırılmıştır. Örneklemeler iki balıkçı kooperatifi (Datça ve Karaköy ve 8 balıkçılık barınağında 2005-2006 yılları arasında yürütülmüştür. Bölgede toplam 32 kooperatif üyesi ile yaklaşık 170 balıkçı teknesi kaydedilmiştir. Üye sayılarına göre en büyük balıkçı kooperatifi Datça’dır. Bölgede kıyı balıkçılığı yoğun olarak paragat, sade ve fanyalı uzatma ağlarıyla yürütülmektedir. Uzatma ağı ve paragat balıkçılığında yakalanan balık ve omurgasızlar Ege ve Akdeniz’in yerleşik tipik balıklarıdır. Mullus barbatus, Sphyraena sphyraena, Seriola dumerilii, Pagellus erythrinus, Dentex dentex, Mullus surmuletus, Sarda sarda, Xiphias gladius, Epinephelus aeneus, Loligo vulgaris, Octopus vulgaris vb. ticari avdaki hedef türlerdir. Fakat bölgedeki balıkçılık aktiviteleri kısa balıkçılık sezonu, düşük balıkçılık kapasitesi ve az sayıdaki balıkçı nedeniyle göreceli olarak oldukça zayıf bulunmuştur

  11. Characterizing Extragalactic Star Formation with GALEX Legacy Photometric Analysis of UV-Bright Stellar Complexes

    Science.gov (United States)

    Thilker, David

    -driven galaxy evolution using both existing NASA databases and operating instruments, in addition to upcoming space telescopes. While a legacy of our project will be the hierarchical photometric database (disseminated via MAST and NED) which supports extragalactic community science, our own goals from the proposed comprehensive measurements address some vital issues: (i) Currently there is controversy regarding the power-law slope of the empirical star formation law (SFL). Is there constant star formation efficiency above the HI-to-H_2 transition gas surface density (implying ~unity slope, see papers by Bigiel et al. and Leroy et al.), or is the SFL relation a stronger function of gas density with a super-linear form (as observed by Kennicutt et al. 2007)? Liu et al. (2011) have shown that the answer may depend critically on whether or not diffuse emission underlying star-forming substructures is removed. Our analysis will allow firm resolution of this issue, as we will also apply our photometry algorithm to Spitzer imaging for a subset of our sample galaxies, thus providing background-subtracted L(UV) and L(IR) measurements for substructures which can then be compared to existing and forthcoming (ALMA) CO imaging. (ii) We will also verify/calibrate our SED-fit based determination of age, extinction, and mass for UV-bright structures via direct comparison to the ground-truth stemming from resolved stellar populations (e.g. in ANGST galaxies) and also high-resolution HST UV-optical star cluster surveys (further out in the Local Volume). (iii) Finally, we will measure the diffuse UV fraction in a few hundred of the nearest galaxies (accounting for variation tied only to spatial resolution), trying to ascertain the characteristic fraction in galaxies of different Hubble type and dust-to-gas ratio. Systematic local variations in diffuse fraction and color will also be quantified as a function of environment.

  12. Zoology Department, University Col/ege, Nairobi

    African Journals Online (AJOL)

    has frequently been detected in this way inside holes in the wild. Confirmation that .... and is also occasionally seen outside on the rocks in the cold of the early morning (Fig. J). The latter fact ..... be a group exercise (Sale 1965c). Evidence that ...

  13. Virtuaalne keeleõpe / Ege Meister

    Index Scriptorium Estoniae

    Meister, Ege

    2004-01-01

    Leonardi da Vinci programmi raames toimuvast rahvusvahelisest koostööst tehniliste erialade õpilastele inglise keele õpetamiseks. Projektist LENTEC, mille raames eri riikide õpilased õppisid virtuaalselt inglise keelt ning lahendasid ühiselt tehnikateemalisi ülesandeid

  14. Legacy ExtraGalactic UV Survey with The Hubble Space Telescope: Stellar Cluster Catalogs and First Insights Into Cluster Formation and Evolution in NGC 628

    NARCIS (Netherlands)

    Adamo, A.; Ryon, J.E.; Messa, M.; Kim, H.; Grasha, K.; Cook, D.O.; Calzetti, D.; Lee, J.C.; Whitmore, B.C.; Elmegreen, B.G.; Ubeda, L.; Smith, L.J.; Bright, S.N.; Runnholm, A.; Andrews, J.E.; Fumagalli, M.; Gouliermis, D.A.; Kahre, L.; Nair, P.; Thilker, D.; Walterbos, R.; Wofford, A.; Aloisi, A.; Ashworth, G.; Brown, T.M.; Chandar, R.; Christian, C.; Cignoni, M.; Clayton, G.C.; Dale, D.A.; de Mink, S.E.; Dobbs, C.; Elmegreen, D.M.; Evans, A.S.; Gallagher III, J.S.; Grebel, E.K.; Herrero, A.; Hunter, D.A.; Johnson, K.E.; Kennicutt, R.C.; Krumholz, M.R.; Lennon, D.; Levay, K.; Martin, C.; Nota, A.; Östlin, G.; Pellerin, A.; Prieto, J.; Regan, M.W.; Sabbi, E.; Sacchi, E.; Schaerer, D.; Schiminovich, D.; Shabani, F.; Tosi, M.; Van Dyk, S.D.; Zackrisson, E.

    2017-01-01

    We report the large effort that is producing comprehensive high-level young star cluster (YSC) catalogs for a significant fraction of galaxies observed with the Legacy ExtraGalactic UV Survey (LEGUS) Hubble treasury program. We present the methodology developed to extract cluster positions, verify

  15. CANDELS : THE COSMIC ASSEMBLY NEAR-INFRARED DEEP EXTRAGALACTIC LEGACY SURVEY-THE HUBBLE SPACE TELESCOPE OBSERVATIONS, IMAGING DATA PRODUCTS, AND MOSAICS

    NARCIS (Netherlands)

    Koekemoer, Anton M.; Faber, S. M.; Ferguson, Henry C.; Grogin, Norman A.; Kocevski, Dale D.; Koo, David C.; Lai, Kamson; Lotz, Jennifer M.; Lucas, Ray A.; McGrath, Elizabeth J.; Ogaz, Sara; Rajan, Abhijith; Riess, Adam G.; Rodney, Steve A.; Strolger, Louis; Casertano, Stefano; Castellano, Marco; Dahlen, Tomas; Dickinson, Mark; Dolch, Timothy; Fontana, Adriano; Giavalisco, Mauro; Grazian, Andrea; Guo, Yicheng; Hathi, Nimish P.; Huang, Kuang-Han; van der Wel, Arjen; Yan, Hao-Jing; Acquaviva, Viviana; Alexander, David M.; Almaini, Omar; Ashby, Matthew L. N.; Barden, Marco; Bell, Eric F.; Bournaud, Frederic; Brown, Thomas M.; Caputi, Karina I.; Cassata, Paolo; Challis, Peter J.; Chary, Ranga-Ram; Cheung, Edmond; Cirasuolo, Michele; Conselice, Christopher J.; Cooray, Asantha Roshan; Croton, Darren J.; Daddi, Emanuele; Dave, Romeel; de Mello, Duilia F.; de Ravel, Loic; Dekel, Avishai; Donley, Jennifer L.; Dunlop, James S.; Dutton, Aaron A.; Elbaz, David; Fazio, Giovanni G.; Filippenko, Alexei V.; Finkelstein, Steven L.; Frazer, Chris; Gardner, Jonathan P.; Garnavich, Peter M.; Gawiser, Eric; Gruetzbauch, Ruth; Hartley, Will G.; Haeussler, Boris; Herrington, Jessica; Hopkins, Philip F.; Huang, Jia-Sheng; Jha, Saurabh W.; Johnson, Andrew; Kartaltepe, Jeyhan S.; Khostovan, Ali A.; Kirshner, Robert P.; Lani, Caterina; Lee, Kyoung-Soo; Li, Weidong; Madau, Piero; McCarthy, Patrick J.; McIntosh, Daniel H.; McLure, Ross J.; McPartland, Conor; Mobasher, Bahram; Moreira, Heidi; Mortlock, Alice; Moustakas, Leonidas A.; Mozena, Mark; Nandra, Kirpal; Newman, Jeffrey A.; Nielsen, Jennifer L.; Niemi, Sami; Noeske, Kai G.; Papovich, Casey J.; Pentericci, Laura; Pope, Alexandra; Primack, Joel R.; Ravindranath, Swara; Reddy, Naveen A.; Renzini, Alvio; Rix, Hans-Walter; Robaina, Aday R.; Rosario, David J.; Rosati, Piero; Salimbeni, Sara; Scarlata, Claudia; Siana, Brian; Simard, Luc; Smidt, Joseph; Snyder, Diana; Somerville, Rachel S.; Spinrad, Hyron; Straughn, Amber N.; Telford, Olivia; Teplitz, Harry I.; Trump, Jonathan R.; Vargas, Carlos; Villforth, Carolin; Wagner, Cory R.; Wandro, Pat; Wechsler, Risa H.; Weiner, Benjamin J.; Wiklind, Tommy; Wild, Vivienne; Wilson, Grant; Wuyts, Stijn; Yun, Min S.

    2011-01-01

    This paper describes the Hubble Space Telescope imaging data products and data reduction procedures for the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS). This survey is designed to document the evolution of galaxies and black holes at z approximate to 1.5-8, and to study

  16. The AGN fraction of submm-selected galaxies and contributions to the submm/mm-wave extragalactic background light

    Science.gov (United States)

    Serjeant, S.; Negrello, M.; Pearson, C.; Mortier, A.; Austermann, J.; Aretxaga, I.; Clements, D.; Chapman, S.; Dye, S.; Dunlop, J.; Dunne, L.; Farrah, D.; Hughes, D.; Lee, H.-M.; Matsuhara, H.; Ibar, E.; Im, M.; Jeong, W.-S.; Kim, S.; Oyabu, S.; Takagi, T.; Wada, T.; Wilson, G.; Vaccari, M.; Yun, M.

    2010-05-01

    We present a comparison of the SCUBA half degree extragalactic survey (SHADES) at 450 μm, 850 μm and 1100 μm with deep guaranteed time 15 μm AKARI FU-HYU survey data and Spitzer guaranteed time data at 3.6-24 μm in the Lockman hole east. The AKARI data was analysed using bespoke software based in part on the drizzling and minimum-variance matched filtering developed for SHADES, and was cross-calibrated against ISO fluxes. Our stacking analyses find AKARI 15 μm galaxies with ⪆200 μJy contribute >10% of the 450 μm background, but only 0.3.

  17. Observations of three bright extragalactic radiosources at the 1.38 cm wavelength with the resolution up to 8''

    International Nuclear Information System (INIS)

    Berlin, A.B.; Korenev, Yu.V.; Lesovoj, V.Yu.; Parijskij, Yu.N.; Smirnov, V.I.; Soboleva, N.S.

    1980-01-01

    New observations of radiogalaxies in the shortest wavelength region of the RATAN-600 radiotelescope were performed using the 1.38-cm radiometer. One-dimentional radiobrightness distribution of 3C 405 (Cyg A) and Cen A as well as instantaneous spectra of the nuclear sources in 3C 111, 3C 405 and Cen A are presented. Spectra of nuclear components in radiosources 3C 111 and Cen A show marked variations at the time scale of the order of three years. Fluxes for the nuclear component of Cyg A at the wavelengths greater than 3.9 cm have decreased during the last 5 years. Wavelength independence is pointed out for brightness distribution in the main components of all sources. This contradicts to some extragalactic radiosources models in which radiation losses of relativistic electrons when moving from the hot ''spots'' to ''tails'' are suggested

  18. The PMA Catalogue as a realization of the extragalactic reference system in optical and near infrared wavelengths

    Science.gov (United States)

    Akhmetov, Volodymyr S.; Fedorov, Peter N.; Velichko, Anna B.

    2018-04-01

    We combined the data from the Gaia DR1 and Two-Micron All Sky Survey (2MASS) catalogues in order to derive the absolute proper motions more than 420 million stars distributed all over the sky in the stellar magnitude range 8 mag 2MASS catalogue objects, the 2-dimensional median filter was used. The PMA system of proper motion has been obtained by direct link to 1.6 millions extragalactic sources. The short analysis of the absolute proper motion of the PMA stars Catalogue is presented in this work. From a comparison of this data with same stars from the TGAS, UCAC4 and PPMXL catalogues, the equatorial components of the mutual rotation vector of these coordinate systems are determined.

  19. The NuSTAR Extragalactic Surveys: Initial Results and Catalog from the Extended Chandra Deep Field South

    DEFF Research Database (Denmark)

    Mullaney, J. R.; Del-Moro, A.; Aird, J.

    2015-01-01

    We present the initial results and the source catalog from the Nuclear Spectroscopic Telescope Array (NuSTAR) survey of the Extended Chandra Deep Field South (hereafter, ECDFS)—currently the deepest contiguous component of the NuSTAR extragalactic survey program. The survey covers the full ≈30......V fluxes) span the range L10 40 keV (0.7 300) 10 erg s» - ´ 43 1 -- ,sampling below the “knee” of the X-ray luminosity function out to z ~ 0.8-1. Finally, we identify oneNuSTAR source that has neither a Chandra nor an XMM-Newton counterpart, but that shows evidence of nuclearactivity at infrared...

  20. CLUES on Fermi-LAT prospects for the extragalactic detection of μνSSM gravitino dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Gómez-Vargas, G.A.; Muñoz, C.; Yepes, G. [Departamento de Física Teórica, Universidad Autónoma de Madrid, Cantoblanco, E-28049, Madrid (Spain); Fornasa, M.; Zandanel, F.; Prada, F. [Instituto de Astrofísica de Andalucía (CSIC), E-18008, Granada (Spain); Cuesta, A.J., E-mail: germanarturo.gomez@uam.es, E-mail: mattia@iaa.es, E-mail: fabio@iaa.es, E-mail: antonio.cuesta@yale.edu, E-mail: carlos.munnoz@uam.es, E-mail: fprada@iaa.es, E-mail: gustavo.yepes@uam.es [Yale Center for Astronomy and Astrophysics, Yale University, CT 06511, New Haven (United States)

    2012-02-01

    The μνSSM is a supersymmetric model that has been proposed to solve the problems generated by other supersymmetric extensions of the standard model of particle physics. Given that R-parity is broken in the μνSSM, the gravitino is a natural candidate for decaying dark matter since its lifetime becomes much longer than the age of the Universe. In this model, gravitino dark matter could be detectable through the emission of a monochromatic gamma ray in a two-body decay. We study the prospects of the Fermi-LAT telescope to detect such monochromatic lines in 5 years of observations of the most massive nearby extragalactic objects. The dark matter halo around the Virgo galaxy cluster is selected as a reference case, since it is associated to a particularly high signal-to-noise ratio and is located in a region scarcely affected by the astrophysical diffuse emission from the galactic plane. The simulation of both signal and background gamma-ray events is carried out with the Fermi Science Tools, and the dark matter distribution around Virgo is taken from a N-body simulation of the nearby extragalactic Universe, with constrained initial conditions provided by the CLUES project. We find that a gravitino with a mass range of 0.6–2 GeV, and with a lifetime range of about 3 × 10{sup 27}–2 × 10{sup 28} s would be detectable by the Fermi-LAT with a signal-to-noise ratio larger than 3. We also obtain that gravitino masses larger than about 4 GeV are already excluded in the μνSSM by Fermi-LAT data of the galactic halo.

  1. Ege bölgesi standart süreli yıllık maksimum yağışları için en uygun dağılımlar

    Directory of Open Access Journals (Sweden)

    Halil Karahan

    2013-03-01

    Full Text Available Su kaynaklarının temel girdisi olan yağışların; miktarı, süresi, şiddeti, alansal ve zamansal değişimi v.b. özelliklerinin bilinmesi; su kaynakları, tarım, kentleşme, drenaj, taşkın kontrolü ve ulaşım gibi farklı sektörlere ait planlama, tasarım, inşaat ve işletme çalışmaları için gereklidir. Belirtilen faaliyetlerin gerçekleştirilebilmesi için; mevcut gözlemlere dayalı, güvenilir ve gerçekçi tahminlerin yapılması gerekir. Güvenilir tahmin yapabilmenin ilk aşaması ise mevcut gözlemlerin güvenirliğinin test edilmesidir. Bu çalışmada; DMİ Genel Müdürlüğü tarafından işletilen Ege Bölgesi il ve ilçe merkezlerinde yer alan meteoroloji istasyonlarında (1929-2005 yıllarında ölçülen standart süreli maksimum yağış değerlerinin hangi dağılıma uyduklarını belirlemek için; Kolmogorov-Smirnov, Anderson-Darling ve Ki-Kare dağılım uygunluk testleri uygulanmıştır. Anderson-Darling testine göre gözlemlerin tümüne yakını GEV dağılımına uyum gösterirken, Kolmogorov-Smirnov ve Ki-Kare testlerine göre kısa, orta ve uzun süreli yağış gözlemleri için genellikle GEV, Gamma ve Log-Normal dağılımın uygun olduğu görülmüştür. Seçilen olasılık dağılımının parametrelerini belirlemek için farklı dağılımlara göre maksimum olabilirlik (LN2, LN3, EXP2, Gamma3, olasılık-ağırlıklı momentler (LP3,Gamma2, L-momentler (GEV ve en küçük kareler (Weibull2 yöntemleri kullanılmıştır.

  2. Understanding (Galactic) Foreground Emission: A Road To Success For The LOFAR-EoR Experiment

    NARCIS (Netherlands)

    Jelic, Vibor; Lofar Eor Team, [Unknown

    The LOFAR-EoR experiment will use the innovative technology and capabilities of the radio telescope LOFAR to study the Epoch of Reionization (EoR). However, feeble cosmological radiation is swamped by the prominent foreground emission of our Galaxy and other extragalactic radio sources. This

  3. The TopHat experiment: A balloon-borne instrument for mapping millimeter and submillimeter emission

    DEFF Research Database (Denmark)

    Silverberg, R.F.; Cheng, E.S.; Aguirre, J.E.

    2005-01-01

    The TopHat experiment was designed to measure the anisotropy in the cosmic microwave background radiation on angular scales from 0.degrees 3 to 30 degrees and the thermal emission from both Galactic and extragalactic dust. The balloon-borne instrument had five spectral bands spanning frequencies ...

  4. The JWST Extragalactic Mock Catalog: Modeling Galaxy Populations from the UV through the Near-IR over 13 Billion Years of Cosmic History

    Science.gov (United States)

    Williams, Christina C.; Curtis-Lake, Emma; Hainline, Kevin N.; Chevallard, Jacopo; Robertson, Brant E.; Charlot, Stephane; Endsley, Ryan; Stark, Daniel P.; Willmer, Christopher N. A.; Alberts, Stacey; Amorin, Ricardo; Arribas, Santiago; Baum, Stefi; Bunker, Andrew; Carniani, Stefano; Crandall, Sara; Egami, Eiichi; Eisenstein, Daniel J.; Ferruit, Pierre; Husemann, Bernd; Maseda, Michael V.; Maiolino, Roberto; Rawle, Timothy D.; Rieke, Marcia; Smit, Renske; Tacchella, Sandro; Willott, Chris J.

    2018-06-01

    We present an original phenomenological model to describe the evolution of galaxy number counts, morphologies, and spectral energy distributions across a wide range of redshifts (0.2colors, sizes, star formation, and chemical properties of the observed galaxy population. Unlike other existing approaches, our model includes a self-consistent treatment of stellar and photoionized gas emission and dust attenuation based on the BEAGLE tool. The mock galaxy catalogs generated with our new model can be used to simulate and optimize extragalactic surveys with future facilities such as the James Webb Space Telescope (JWST), and to enable critical assessments of analysis procedures, interpretation tools, and measurement systematics for both photometric and spectroscopic data. As a first application of this work, we make predictions for the upcoming JWST Advanced Deep Extragalactic Survey (JADES), a joint program of the JWST/NIRCam and NIRSpec Guaranteed Time Observations teams. We show that JADES will detect, with NIRCam imaging, 1000s of galaxies at z ≳ 6, and 10s at z ≳ 10 at {m}{AB}≲ 30 (5σ) within the 236 arcmin2 of the survey. The JADES data will enable accurate constraints on the evolution of the UV luminosity function at z > 8, and resolve the current debate about the rate of evolution of galaxies at z ≳ 8. Ready-to-use mock catalogs and software to generate new realizations are publicly available as the JAdes extraGalactic Ultradeep Artificial Realizations (JAGUAR) package.

  5. NEW CONSTRAINTS ON THE GALACTIC HALO MAGNETIC FIELD USING ROTATION MEASURES OF EXTRAGALACTIC SOURCES TOWARD THE OUTER GALAXY

    International Nuclear Information System (INIS)

    Mao, S. A.; McClure-Griffiths, N. M.; Gaensler, B. M.; Brown, J. C.; Van Eck, C. L.; Stil, J. M.; Taylor, A. R.; Haverkorn, M.; Kronberg, P. P.; Shukurov, A.

    2012-01-01

    We present a study of the Milky Way disk and halo magnetic field, determined from observations of Faraday rotation measure (RM) toward 641 polarized extragalactic radio sources in the Galactic longitude range 100°-117°, within 30° of the Galactic plane. For |b| –2 and –62 ± 5 rad m –2 in the northern and southern Galactic hemispheres, respectively. If the RM distribution is a signature of the large-scale field parallel to the Galactic plane, then this suggests that the halo magnetic field toward the outer Galaxy does not reverse direction across the mid-plane. The variation of RM as a function of Galactic latitude in this longitude range is such that RMs become more negative at larger |b|. This is consistent with an azimuthal magnetic field of strength 2 μG (7 μG) at a height 0.8-2 kpc above (below) the Galactic plane between the local and the Perseus spiral arm. We propose that the Milky Way could possess spiral-like halo magnetic fields similar to those observed in M51.

  6. Confusion-limited extragalactic source survey at 4.755 GHz. I. Source list and areal distributions

    International Nuclear Information System (INIS)

    Ledden, J.E.; Broderick, J.J.; Condon, J.J.; Brown, R.L.

    1980-01-01

    A confusion-limited 4.755-GHz survey covering 0.00 956 sr between right ascensions 07/sup h/05/sup m/ and 18/sup h/ near declination +35 0 has been made with the NRAO 91-m telescope. The survey found 237 sources and is complete above 15 mJy. Source counts between 15 and 100 mJy were obtained directly. The P(D) distribution was used to determine the number counts between 0.5 and 13.2 mJy, to search for anisotropy in the density of faint extragalactic sources, and to set a 99%-confidence upper limit of 1.83 mK to the rms temperature fluctuation of the 2.7-K cosmic microwave background on angular scales smaller than 7.3 arcmin. The discrete-source density, normalized to the static Euclidean slope, falls off sufficiently rapidly below 100 mJy that no new population of faint flat-spectrum sources is required to explain the 4.755-GHz source counts

  7. Bulk Comptonization of the Cosmic Microwave Background by Extragalactic Jets as a Probe of their Matter Content

    Science.gov (United States)

    Georganopoulos, Markos; Kazanas, Demosthenes; Perlman, Eric; Stecker, Floyd W.

    2004-01-01

    We propose a method for estimating the composition, i.e. the relative amounts of leptons and protons, of extragalactic jets which exhibit Chandra - detected knots in their kpc scale jets. The method relies on measuring, or setting upper limits on, the component of the Cosmic Microwave Background (CMB) radiation that is bulk-Comptonized by the cold electrons in the relativistically flowing jet. These measurements, along with modeling of the broadband knot emission that constrain the bulk Lorentz factor GAMMA of the jets, can yield estimates of the jet power carried by protons and leptons. We provide an explicit calculation of the spectrum of the bulk-Comptonized (BC) CMB component and apply these results to PKS 0637 - 752 and 3C 273, two superluminal quasars with Chandra - detected large scale jets. What makes these sources particularly suited for such a procedure is the absence of significant non-thermal jet emission in the 'bridge', the region between the core and the first bright jet knot, which guarantees that most of the electrons are cold there, leaving the BC scattered CMB radiation as the only significant source of photons in this region. At lambda = 3.6 - 8.0 microns, the most likely band to observe the BC scattered CMB emission, the Spitzer angular resolution (approximately 1" - 3") is considerably smaller than the the 'bridges' of these jets (approximately 10"), making it possible to both measure and resolve this emission.

  8. Study feature of variability extragalactic radio sources 3C 446 and BL Lac in the centimeter wavelength range

    International Nuclear Information System (INIS)

    Sukharev, A.L.

    2015-01-01

    This work presents the results of the analysis of long-term monitoring (over 40 years) changes in radio fluxes of the two extragalactic sources - 3C 446, and BL Lac. Observations at frequencies of 14.5, 8, 4.8 GHz were obtained in the Michigan Radio Astronomy Observatory (UMRAO). With using Fourier filtering were selected 0- C (short-period), and the trend component of flux variations that were analyzed separately with using the wavelet-analysis method. Each of these components is associated with certain physical processes in the 'core-accretion disk-jet' system. Were constructed time-frequency wavelet-spectra showing the changes of the frequency composition of the investigated data over time. For the trend component values of the main periods of -4-9 years (3C 446) and -8 years (BL Lac), for 0- C component -0.8-3 years (3C 446) and -0.6-4 years (BL Lac) and they appear in the temporal and structural changes of the jet. On the basis of calculating the global wavelet-spectra in the frequency range identified main phases activity of radio sources. Obtained comparison between the dynamics of jets (Mojave VLBI images), and change the frequency spectral structure of the studied data. With bandpass wavelet filtering, flux components corresponding to the main periods in the spectra, were identified and also found the delay between the observation frequencies in spectral bands of these periods

  9. The optical, infrared and radio properties of extragalactic sources observed by SDSS, 2mass and first surveys

    International Nuclear Information System (INIS)

    Z. Ivezic et al.

    2002-01-01

    We positionally match sources observed by the Sloan Digital Sky Survey (SDSS), the Two Micron All Sky Survey (2MASS), and the Faint Images of the Radio Sky at Twenty-cm (FIRST) survey. Practically all 2MASS sources are matched to an SDSS source within 2 arcsec; ∼ 11% of them are optically resolved galaxies and the rest are dominated by stars. About 1/3 of FIRST sources are matched to an SDSS source within 2 arcsec; ∼ 80% of these are galaxies and the rest are dominated by quasars. Based on these results, we project that by the completion of these surveys the matched samples will include about 10 7 and 10 6 galaxies observed by both SDSS and 2MASS, and about 250,000 galaxies and 50,000 quasars observed by both SDSS and FIRST. Here we present a preliminary analysis of the optical, infrared and radio properties for the extragalactic sources from the matched samples. In particular, we find that the fraction of quasars with stellar colors missed by the SDSS spectroscopic survey is probably not larger than ∼ 10%, and that the optical colors of radio-loud quasars are ∼ 0.05 mag. redder (with 4σ significance) than the colors of radio-quiet quasars

  10. THE SPITZER EXTRAGALACTIC REPRESENTATIVE VOLUME SURVEY: THE ENVIRONMENTS OF HIGH-z SDSS QUASI-STELLAR OBJECTS

    International Nuclear Information System (INIS)

    Falder, J. T.; Stevens, J. A.; Jarvis, Matt J.; Bonfield, D. G.; Lacy, M.; Farrah, D.; Oliver, S.; Surace, J.; Mauduit, J.-C.; Vaccari, M.; Marchetti, L.; Gonzalez-Solares, E.; Afonso, J.; Cava, A.; Seymour, N.

    2011-01-01

    This paper presents a study of the environments of SDSS quasi-stellar objects (QSOs) in the Spitzer Extragalactic Representative Volume Survey (SERVS). We concentrate on the high-redshift QSOs as these have not been studied in large numbers with data of this depth before. We use the IRAC 3.6-4.5 μm color of objects and ancillary r-band data to filter out as much foreground contamination as possible. This technique allows us to find a significant (>4σ) overdensity of galaxies around QSOs in a redshift bin centered on z ∼ 2.0 and an (>2σ) overdensity of galaxies around QSOs in a redshift bin centered on z ∼ 3.3. We compare our findings to the predictions of a semi-analytic galaxy formation model, based on the ΛCDM MILLENNIUM simulation, and find for both redshift bins that the model predictions match well the source density we have measured from the SERVS data.

  11. The TA and TALE Experiments

    International Nuclear Information System (INIS)

    Thomson, Gordon

    2006-01-01

    The TA/TALE experiment is under construction, and is being deployed in Millard County, Utah. It will consist of a suite of detectors covering four orders of magnitude in energy, from 10 16.5 to 10 20.5 eV, and will observe cosmic ray showers with fluorescence detectors and arrays of scintillation counters. Events will be seen by multiple detectors and cross calibration of detectors' energy scales will be possible. TA/TALE will observe all three features of the spectrum of ultrahigh energy cosmic rays, observe the galactic/extragalactic transition, study the cosmology of cosmic ray sources, and perform anisotropy studies with unprecedented accuracy

  12. Frequent VLBI Monitoring on Parsec-Scales of 450+ Extragalactic FERMI Sources at 8 and 32 GHz

    Science.gov (United States)

    Jacobs, Christopher S.; Majid, W. A.; Romero-Wolf, A.; García-Mirí, C.; Horiuchi, S.; Snedeker, L. G.; Sotuela, I.

    2012-10-01

    Executive Summary: An existing Ka-band (32 GHz, 9mm) catalog of 450+ sources is being monitored every 6-10 weeks on Giga-lambda baselines. These observations are sensitive to parsec scale activity in the AGN cores providing unique tests of gamma ray emission models. Abstract: The Fermi Large Area Telescope (LAT) has now released the 2nd catalog of high-energy gamma-ray sources (2FGL) derived from the first 24 months of mission science data with 1873 sources detected and characterized in the 100 MeV to 100 GeV range. 1017 of 1873 sources at high Galactic latitude (abs(b) > 10 degrees) are associated statistically with active galactic nuclei (AGNs). Parsec-scale VLBI measurements play an important role in characterizing the nature of the candidate AGNs by providing crucial extra information to improve the probability of correct identification - VLBI filters out objects which do not host strong compact jets at parsec scale. We are carrying out regular VLBI monitoring of 450+ compact extragalactic sources using Deep Space Network (DSN) 34-meter antennas over intercontinental baselines simultaneously at 8 and 32 GHz. In addition to precision astrometric measurements of AGN compact cores used to maintain the JPL extragalactic reference frame, this program has the potential to provide regular simultaneous flux density measurements at 8 and 32 GHz with precision level of ~20%. By providing measurements on both East-West and North-South baselines with large antennas and Gbit/s recording capability, our program can probe sources down to a flux limit of 30 mJy (10-sigma), potentially increasing the sample to a fainter population of sources. In these regards, our program complements well existing northern and southern hemisphere VLBI monitoring programs, by providing flux measurements at 32 GHz, covering a fainter population sample, and by filling the gap for sources in the -20 to -45 degree declination range. Further, our program also provides additional flexibility for

  13. CLUES on Fermi-LAT prospects for the extragalactic detection of {mu}{nu}SSM gravitino dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Vargas, G.A., E-mail: germanarturo.gomez@uam.es [Departamento de Fisica Teorica, Universidad Autonoma de Madrid, Cantoblanco, E-28049 Madrid (Spain); Instituto de Fisica Teorica IFT-UAM/CSIC, Universidad Autonoma de Madrid, Cantoblanco, E-28049 Madrid (Spain); Istituto Nazionale di Fisica Nucleare, Sez. Roma Tor Vergata, Roma (Italy)

    2012-11-11

    The {mu}{nu}SSM is a supersymmetric model that has been proposed to solve the problems generated by other supersymmetric extensions of the standard model of particle physics. Given that R-parity is broken in the {mu}{nu}SSM, the gravitino is a natural candidate for decaying dark matter since its lifetime becomes much longer than the age of the Universe. In this model, gravitino dark matter could be detectable through the emission of a monochromatic gamma ray in a two-body decay. We study the prospects of the Fermi-LAT telescope to detect such monochromatic lines in 5 years of observations of the most massive nearby extragalactic objects. We focus on the Virgo galaxy cluster, since it is associated to a particularly high signal-to-noise ratio and is located at high Galactic latitude. The simulation of both signal and background gamma-ray events is carried out with the Fermi Science Tools, and the dark matter distribution around Virgo is taken from an N-body simulation, with constrained initial conditions provided by the CLUES project. We find that a gravitino with a mass range of 0.6-2 GeV, and with a lifetime range of about 3 Multiplication-Sign 10{sup 27}-2 Multiplication-Sign 10{sup 28}s would be detectable by the Fermi-LAT with a signal-to-noise ratio larger than 3. We also obtain that gravitino masses larger than about 4 GeV are already excluded in the {mu}{nu}SSM by Fermi-LAT data of the galactic halo. These proceedings are based on Ref. [1].

  14. DECIPHERING CONTRIBUTIONS TO THE EXTRAGALACTIC GAMMA-RAY BACKGROUND FROM 2 GeV TO 2 TeV

    International Nuclear Information System (INIS)

    Lisanti, Mariangela; Mishra-Sharma, Siddharth; Necib, Lina; Safdi, Benjamin R.

    2016-01-01

    Astrophysical sources outside the Milky Way, such as active galactic nuclei and star-forming galaxies, leave their imprint on the gamma-ray sky as nearly isotropic emission referred to as the extragalactic gamma-ray background (EGB). While the brightest of these sources may be individually resolved, their fainter counterparts contribute diffusely. In this work, we use a recently developed analysis method, called the Non-Poissonian Template Fit, on up to 93 months of publicly available data from the Fermi Large Area Telescope to determine the properties of the point sources (PSs) that comprise the EGB. This analysis takes advantage of photon-count statistics to probe the aggregate properties of these source populations below the sensitivity threshold of published catalogs. We measure the source-count distributions and PS intensities, as a function of energy, from ∼2 GeV to 2 TeV. We find that the EGB is dominated by PSs, likely blazars, in all seven energy sub-bins considered. These results have implications for the interpretation of IceCube’s PeV neutrinos, which may originate from sources that contribute to the non-blazar component of the EGB. Additionally, we comment on implications for future TeV observatories such as the Cherenkov Telescope Array. We provide sky maps showing locations most likely to contain these new sources at both low (≲50 GeV) and high (≳50 GeV) energies for use in future observations and cross-correlation studies.

  15. Extragalactic gamma-ray background from AGN winds and star-forming galaxies in cosmological galaxy-formation models

    Science.gov (United States)

    Lamastra, A.; Menci, N.; Fiore, F.; Antonelli, L. A.; Colafrancesco, S.; Guetta, D.; Stamerra, A.

    2017-10-01

    We derive the contribution to the extragalactic gamma-ray background (EGB) from active galactic nuclei (AGN) winds and star-forming galaxies by including a physical model for the γ-ray emission produced by relativistic protons accelerated by AGN-driven and supernova-driven shocks into a state-of-the-art semi-analytic model of galaxy formation. This is based on galaxy interactions as triggers of AGN accretion and starburst activity and on expanding blast waves as the mechanism to communicate outwards the energy injected into the interstellar medium by the active nucleus. We compare the model predictions with the latest measurement of the EGB spectrum performed by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope (Fermi) in the range between 100 MeV and 820 GeV. We find that AGN winds can provide 35 ± 15% of the observed EGB in the energy interval Eγ = 0.1-1 GeV, for 73 ± 15% at Eγ = 1-10 GeV, and for 60 ± 20% at Eγ ≳10 GeV. The AGN wind contribution to the EGB is predicted to be larger by a factor of 3-5 than that provided by star-forming galaxies (quiescent plus starburst) in the hierarchical clustering scenario. The cumulative γ-ray emission from AGN winds and blazars can account for the amplitude and spectral shape of the EGB, assuming the standard acceleration theory, and AGN wind parameters that agree with observations. We also compare the model prediction for the cumulative neutrino background from AGN winds with the most recent IceCube data. We find that for AGN winds with accelerated proton spectral index p = 2.2-2.3, and taking into account internal absorption of γ-rays, the Fermi-LAT and IceCube data could be reproduced simultaneously.

  16. DARK MATTER SEARCHES IN THE GAMMA-RAY EXTRAGALACTIC BACKGROUND VIA CROSS-CORRELATIONS WITH GALAXY CATALOGS

    International Nuclear Information System (INIS)

    Cuoco, Alessandro; Regis, Marco; Fornengo, Nicolao; Xia, Jun-Qing; Branchini, Enzo; Viel, Matteo

    2015-01-01

    We compare the measured angular cross-correlation between the Fermi-Large Area Telescope γ-ray sky and catalogs of extragalactic objects with the expected signal induced by weakly interacting massive particle (WIMP) dark matter (DM). We include a detailed description of the contribution of astrophysical γ-ray emitters such as blazars, misaligned active galactic nucleus (AGN), and star-forming galaxies, and perform a global fit to the measured cross-correlation. Five catalogs are considered: Sloan Digital Sky Survey (SDSS)-DR6 quasars, Two Micron All Sky Survey galaxies, NRAO VLA Sky Survey radio galaxies, SDSS-DR8 Luminous Red Galaxies, and the SDSS-DR8 main galaxy sample. To model the cross-correlation signal, we use the halo occupation distribution formalism to estimate the number of galaxies of a given catalog in DM halos and their spatial correlation properties. We discuss uncertainties in the predicted cross-correlation signal arising from the DM clustering and WIMP microscopic properties, which set the DM γ-ray emission. The use of different catalogs probing objects at different redshifts significantly reduces, though not completely, the degeneracy among the different γ-ray components. We find that the presence of a significant WIMP DM signal is allowed by the data but not significantly preferred by the fit, although this is mainly due to a degeneracy with the misaligned AGN component. With modest substructure boost, the sensitivity of this method excludes thermal annihilation cross sections at 95% level for WIMP masses up to few tens of GeV. Constraining the low-redshift properties of astrophysical populations with future data will further improve the sensitivity to DM

  17. Dark Matter Searches in the Gamma-ray Extragalactic Background via Cross-correlations with Galaxy Catalogs

    Science.gov (United States)

    Cuoco, Alessandro; Xia, Jun-Qing; Regis, Marco; Branchini, Enzo; Fornengo, Nicolao; Viel, Matteo

    2015-12-01

    We compare the measured angular cross-correlation between the Fermi-Large Area Telescope γ-ray sky and catalogs of extragalactic objects with the expected signal induced by weakly interacting massive particle (WIMP) dark matter (DM). We include a detailed description of the contribution of astrophysical γ-ray emitters such as blazars, misaligned active galactic nucleus (AGN), and star-forming galaxies, and perform a global fit to the measured cross-correlation. Five catalogs are considered: Sloan Digital Sky Survey (SDSS)-DR6 quasars, Two Micron All Sky Survey galaxies, NRAO VLA Sky Survey radio galaxies, SDSS-DR8 Luminous Red Galaxies, and the SDSS-DR8 main galaxy sample. To model the cross-correlation signal, we use the halo occupation distribution formalism to estimate the number of galaxies of a given catalog in DM halos and their spatial correlation properties. We discuss uncertainties in the predicted cross-correlation signal arising from the DM clustering and WIMP microscopic properties, which set the DM γ-ray emission. The use of different catalogs probing objects at different redshifts significantly reduces, though not completely, the degeneracy among the different γ-ray components. We find that the presence of a significant WIMP DM signal is allowed by the data but not significantly preferred by the fit, although this is mainly due to a degeneracy with the misaligned AGN component. With modest substructure boost, the sensitivity of this method excludes thermal annihilation cross sections at 95% level for WIMP masses up to few tens of GeV. Constraining the low-redshift properties of astrophysical populations with future data will further improve the sensitivity to DM.

  18. DARK MATTER SEARCHES IN THE GAMMA-RAY EXTRAGALACTIC BACKGROUND VIA CROSS-CORRELATIONS WITH GALAXY CATALOGS

    Energy Technology Data Exchange (ETDEWEB)

    Cuoco, Alessandro; Regis, Marco; Fornengo, Nicolao [Dipartimento di Fisica, Università di Torino, via P. Giuria 1, I-10125 Torino (Italy); Xia, Jun-Qing [Department of Astronomy, Beijing Normal University, Beijing 100875 (China); Branchini, Enzo [Dipartimento di Matematica e Fisica, Università degli Studi “Roma Tre,” via della Vasca Navale 84, I-00146 Roma (Italy); Viel, Matteo, E-mail: cuoco@to.infn.it, E-mail: regis@to.infn.it, E-mail: fornengo@to.infn.it, E-mail: xiajq@bnu.edu.cn, E-mail: branchin@fis.uniroma3.it, E-mail: viel@oats.inaf.it [INAF Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, I-34141, Trieste (Italy)

    2015-12-15

    We compare the measured angular cross-correlation between the Fermi-Large Area Telescope γ-ray sky and catalogs of extragalactic objects with the expected signal induced by weakly interacting massive particle (WIMP) dark matter (DM). We include a detailed description of the contribution of astrophysical γ-ray emitters such as blazars, misaligned active galactic nucleus (AGN), and star-forming galaxies, and perform a global fit to the measured cross-correlation. Five catalogs are considered: Sloan Digital Sky Survey (SDSS)-DR6 quasars, Two Micron All Sky Survey galaxies, NRAO VLA Sky Survey radio galaxies, SDSS-DR8 Luminous Red Galaxies, and the SDSS-DR8 main galaxy sample. To model the cross-correlation signal, we use the halo occupation distribution formalism to estimate the number of galaxies of a given catalog in DM halos and their spatial correlation properties. We discuss uncertainties in the predicted cross-correlation signal arising from the DM clustering and WIMP microscopic properties, which set the DM γ-ray emission. The use of different catalogs probing objects at different redshifts significantly reduces, though not completely, the degeneracy among the different γ-ray components. We find that the presence of a significant WIMP DM signal is allowed by the data but not significantly preferred by the fit, although this is mainly due to a degeneracy with the misaligned AGN component. With modest substructure boost, the sensitivity of this method excludes thermal annihilation cross sections at 95% level for WIMP masses up to few tens of GeV. Constraining the low-redshift properties of astrophysical populations with future data will further improve the sensitivity to DM.

  19. The NuSTAR  Extragalactic Surveys: X-Ray Spectroscopic Analysis of the Bright Hard-band Selected Sample

    Science.gov (United States)

    Zappacosta, L.; Comastri, A.; Civano, F.; Puccetti, S.; Fiore, F.; Aird, J.; Del Moro, A.; Lansbury, G. B.; Lanzuisi, G.; Goulding, A.; Mullaney, J. R.; Stern, D.; Ajello, M.; Alexander, D. M.; Ballantyne, D. R.; Bauer, F. E.; Brandt, W. N.; Chen, C.-T. J.; Farrah, D.; Harrison, F. A.; Gandhi, P.; Lanz, L.; Masini, A.; Marchesi, S.; Ricci, C.; Treister, E.

    2018-02-01

    We discuss the spectral analysis of a sample of 63 active galactic nuclei (AGN) detected above a limiting flux of S(8{--}24 {keV})=7× {10}-14 {erg} {{{s}}}-1 {{cm}}-2 in the multi-tiered NuSTAR extragalactic survey program. The sources span a redshift range z=0{--}2.1 (median =0.58). The spectral analysis is performed over the broad 0.5–24 keV energy range, combining NuSTAR with Chandra and/or XMM-Newton data and employing empirical and physically motivated models. This constitutes the largest sample of AGN selected at > 10 {keV} to be homogeneously spectrally analyzed at these flux levels. We study the distribution of spectral parameters such as photon index, column density ({N}{{H}}), reflection parameter ({\\boldsymbol{R}}), and 10–40 keV luminosity ({L}{{X}}). Heavily obscured ({log}[{N}{{H}}/{{cm}}-2]≥slant 23) and Compton-thick (CT; {log}[{N}{{H}}/{{cm}}-2]≥slant 24) AGN constitute ∼25% (15–17 sources) and ∼2–3% (1–2 sources) of the sample, respectively. The observed {N}{{H}} distribution agrees fairly well with predictions of cosmic X-ray background population-synthesis models (CXBPSM). We estimate the intrinsic fraction of AGN as a function of {N}{{H}}, accounting for the bias against obscured AGN in a flux-selected sample. The fraction of CT AGN relative to {log}[{N}{{H}}/{{cm}}-2]=20{--}24 AGN is poorly constrained, formally in the range 2–56% (90% upper limit of 66%). We derived a fraction (f abs) of obscured AGN ({log}[{N}{{H}}/{{cm}}-2]=22{--}24) as a function of {L}{{X}} in agreement with CXBPSM and previous zvalues.

  20. DECIPHERING CONTRIBUTIONS TO THE EXTRAGALACTIC GAMMA-RAY BACKGROUND FROM 2 GeV TO 2 TeV

    Energy Technology Data Exchange (ETDEWEB)

    Lisanti, Mariangela; Mishra-Sharma, Siddharth [Department of Physics, Princeton University, Princeton, NJ 08544 (United States); Necib, Lina; Safdi, Benjamin R. [Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2016-12-01

    Astrophysical sources outside the Milky Way, such as active galactic nuclei and star-forming galaxies, leave their imprint on the gamma-ray sky as nearly isotropic emission referred to as the extragalactic gamma-ray background (EGB). While the brightest of these sources may be individually resolved, their fainter counterparts contribute diffusely. In this work, we use a recently developed analysis method, called the Non-Poissonian Template Fit, on up to 93 months of publicly available data from the Fermi Large Area Telescope to determine the properties of the point sources (PSs) that comprise the EGB. This analysis takes advantage of photon-count statistics to probe the aggregate properties of these source populations below the sensitivity threshold of published catalogs. We measure the source-count distributions and PS intensities, as a function of energy, from ∼2 GeV to 2 TeV. We find that the EGB is dominated by PSs, likely blazars, in all seven energy sub-bins considered. These results have implications for the interpretation of IceCube’s PeV neutrinos, which may originate from sources that contribute to the non-blazar component of the EGB. Additionally, we comment on implications for future TeV observatories such as the Cherenkov Telescope Array. We provide sky maps showing locations most likely to contain these new sources at both low (≲50 GeV) and high (≳50 GeV) energies for use in future observations and cross-correlation studies.

  1. The NSF Undergraduate ALFALFA Team: Partnering with Arecibo Observatory to Offer Undergraduate and Faculty Extragalactic Radio Astronomy Research Opportunities

    Science.gov (United States)

    Ribaudo, Joseph; Koopmann, Rebecca A.; Haynes, Martha P.; Balonek, Thomas J.; Cannon, John M.; Coble, Kimberly A.; Craig, David W.; Denn, Grant R.; Durbala, Adriana; Finn, Rose; Hallenbeck, Gregory L.; Hoffman, G. Lyle; Lebron, Mayra E.; Miller, Brendan P.; Crone-Odekon, Mary; O'Donoghue, Aileen A.; Olowin, Ronald Paul; Pantoja, Carmen; Pisano, Daniel J.; Rosenberg, Jessica L.; Troischt, Parker; Venkatesan, Aparna; Wilcots, Eric M.; ALFALFA Team

    2017-01-01

    The NSF-sponsored Undergraduate ALFALFA (Arecibo Legacy Fast ALFA) Team (UAT) is a consortium of 20 institutions across the US and Puerto Rico, founded to promote undergraduate research and faculty development within the extragalactic ALFALFA HI blind survey project and follow-up programs. The objective of the UAT is to provide opportunities for its members to develop expertise in the technical aspects of observational radio spectroscopy, its associated data analysis, and the motivating science. Partnering with Arecibo Observatory, the UAT has worked with more than 280 undergraduates and 26 faculty to date, offering 8 workshops onsite at Arecibo (148 undergraduates), observing runs at Arecibo (69 undergraduates), remote observing runs on campus, undergraduate research projects based on Arecibo science (120 academic year and 185 summer projects), and presentation of results at national meetings such as the AAS (at AAS229: Ball et al., Collova et al., Davis et al., Miazzo et al., Ruvolo et al, Singer et al., Cannon et al., Craig et al., Koopmann et al., O'Donoghue et al.). 40% of the students and 45% of the faculty participants have been women and members of underrepresented groups. More than 90% of student alumni are attending graduate school and/or pursuing a career in STEM. 42% of those pursuing graduate degrees in Physics or Astronomy are women.In this presentation, we summarize the UAT program and the current research efforts of UAT members based on Arecibo science, including multiwavelength followup observations of ALFALFA sources, the UAT Collaborative Groups Project, the Survey of HI in Extremely Low-mass Dwarfs (SHIELD), and the Arecibo Pisces-Perseus Supercluster Survey (APPSS). This work has been supported by NSF grants AST-0724918/0902211, AST-075267/0903394, AST-0725380, AST-121105, and AST-1637339.

  2. Can Winds Driven by Active Galactic Nuclei Account for the Extragalactic Gamma-Ray and Neutrino Backgrounds?

    Science.gov (United States)

    Liu, Ruo-Yu; Murase, Kohta; Inoue, Susumu; Ge, Chong; Wang, Xiang-Yu

    2018-05-01

    Various observations are revealing the widespread occurrence of fast and powerful winds in active galactic nuclei (AGNs) that are distinct from relativistic jets, likely launched from accretion disks and interacting strongly with the gas of their host galaxies. During the interaction, strong shocks are expected to form that can accelerate nonthermal particles to high energies. Such winds have been suggested to be responsible for a large fraction of the observed extragalactic gamma-ray background (EGB) and the diffuse neutrino background, via the decay of neutral and charged pions generated in inelastic pp collisions between protons accelerated by the forward shock and the ambient gas. However, previous studies did not properly account for processes such as adiabatic losses that may reduce the gamma-ray and neutrino fluxes significantly. We evaluate the production of gamma rays and neutrinos by AGN-driven winds in detail by modeling their hydrodynamic and thermal evolution, including the effects of their two-temperature structure. We find that they can only account for less than ∼30% of the EGB flux, as otherwise the model would violate the independent upper limit derived from the diffuse isotropic gamma-ray background. If the neutrino spectral index is steep with Γ ≳ 2.2, a severe tension with the isotropic gamma-ray background would arise as long as the winds contribute more than 20% of the IceCube neutrino flux in the 10–100 TeV range. At energies ≳ 100 TeV, we find that the IceCube neutrino flux may still be accountable by AGN-driven winds if the spectral index is as small as Γ ∼ 2.0–2.1.

  3. Detection of variable VHE γ-ray emission from the extra-galactic γ-ray binary LMC P3

    Science.gov (United States)

    HESS Collaboration; Abdalla, H.; Abramowski, A.; Aharonian, F.; Ait Benkhali, F.; Angüner, E. O.; Arakawa, M.; Armand, C.; Arrieta, M.; Backes, M.; Balzer, A.; Barnard, M.; Becherini, Y.; Becker Tjus, J.; Berge, D.; Bernhard, S.; Bernlöhr, K.; Blackwell, R.; Böttcher, M.; Boisson, C.; Bolmont, J.; Bonnefoy, S.; Bordas, P.; Bregeon, J.; Brun, F.; Brun, P.; Bryan, M.; Büchele, M.; Bulik, T.; Capasso, M.; Caroff, S.; Carosi, A.; Casanova, S.; Cerruti, M.; Chakraborty, N.; Chaves, R. C. G.; Chen, A.; Chevalier, J.; Colafrancesco, S.; Condon, B.; Conrad, J.; Davids, I. D.; Decock, J.; Deil, C.; Devin, J.; deWilt, P.; Dirson, L.; Djannati-Ataï, A.; Donath, A.; Drury, L. O.'C.; Dyks, J.; Edwards, T.; Egberts, K.; Emery, G.; Ernenwein, J.-P.; Eschbach, S.; Farnier, C.; Fegan, S.; Fernandes, M. V.; Fiasson, A.; Fontaine, G.; Funk, S.; Füßling, M.; Gabici, S.; Gallant, Y. A.; Garrigoux, T.; Gaté, F.; Giavitto, G.; Glawion, D.; Glicenstein, J. F.; Gottschall, D.; Grondin, M.-H.; Hahn, J.; Haupt, M.; Hawkes, J.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hinton, J. A.; Hofmann, W.; Hoischen, C.; Holch, T. L.; Holler, M.; Horns, D.; Ivascenko, A.; Iwasaki, H.; Jacholkowska, A.; Jamrozy, M.; Jankowsky, D.; Jankowsky, F.; Jingo, M.; Jouvin, L.; Jung-Richardt, I.; Kastendieck, M. A.; Katarzyński, K.; Katsuragawa, M.; Katz, U.; Kerszberg, D.; Khangulyan, D.; Khélifi, B.; King, J.; Klepser, S.; Klochkov, D.; Kluźniak, W.; Komin, Nu.; Kosack, K.; Krakau, S.; Kraus, M.; Krüger, P. P.; Laffon, H.; Lamanna, G.; Lau, J.; Lefaucheur, J.; Lemière, A.; Lemoine-Goumard, M.; Lenain, J.-P.; Leser, E.; Lohse, T.; Lorentz, M.; Liu, R.; López-Coto, R.; Lypova, I.; Malyshev, D.; Marandon, V.; Marcowith, A.; Mariaud, C.; Marx, R.; Maurin, G.; Maxted, N.; Mayer, M.; Meintjes, P. J.; Meyer, M.; Mitchell, A. M. W.; Moderski, R.; Mohamed, M.; Mohrmann, L.; Morå, K.; Moulin, E.; Murach, T.; Nakashima, S.; de Naurois, M.; Ndiyavala, H.; Niederwanger, F.; Niemiec, J.; Oakes, L.; O'Brien, P.; Odaka, H.; Ohm, S.; Ostrowski, M.; Oya, I.; Padovani, M.; Panter, M.; Parsons, R. D.; Pekeur, N. W.; Pelletier, G.; Perennes, C.; Petrucci, P.-O.; Peyaud, B.; Piel, Q.; Pita, S.; Poireau, V.; Prokhorov, D. A.; Prokoph, H.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raab, S.; Rauth, R.; Reimer, A.; Reimer, O.; Renaud, M.; de los Reyes, R.; Rieger, F.; Rinchiuso, L.; Romoli, C.; Rowell, G.; Rudak, B.; Rulten, C. B.; Sahakian, V.; Saito, S.; Sanchez, D. A.; Santangelo, A.; Sasaki, M.; Schlickeiser, R.; Schüssler, F.; Schulz, A.; Schwanke, U.; Schwemmer, S.; Seglar-Arroyo, M.; Seyffert, A. S.; Shafi, N.; Shilon, I.; Shiningayamwe, K.; Simoni, R.; Sol, H.; Spanier, F.; Spir-Jacob, M.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Steppa, C.; Sushch, I.; Takahashi, T.; Tavernet, J.-P.; Tavernier, T.; Taylor, A. M.; Terrier, R.; Tibaldo, L.; Tiziani, D.; Tluczykont, M.; Trichard, C.; Tsirou, M.; Tsuji, N.; Tuffs, R.; Uchiyama, Y.; van der Walt, D. J.; van Eldik, C.; van Rensburg, C.; van Soelen, B.; Vasileiadis, G.; Veh, J.; Venter, C.; Viana, A.; Vincent, P.; Vink, J.; Voisin, F.; Völk, H. J.; Vuillaume, T.; Wadiasingh, Z.; Wagner, S. J.; Wagner, P.; Wagner, R. M.; White, R.; Wierzcholska, A.; Willmann, P.; Wörnlein, A.; Wouters, D.; Yang, R.; Zaborov, D.; Zacharias, M.; Zanin, R.; Zdziarski, A. A.; Zech, A.; Zefi, F.; Ziegler, A.; Zorn, J.; Żywucka, N.

    2018-03-01

    Context. Recently, the high-energy (HE, 0.1-100 GeV) γ-ray emission from the object LMC P3 in the Large Magellanic Cloud (LMC) has been discovered to be modulated with a 10.3-day period, making it the first extra-galactic γ-ray binary. Aim. This work aims at the detection of very-high-energy (VHE, >100 GeV) γ-ray emission and the search for modulation of the VHE signal with the orbital period of the binary system. Methods: LMC P3 has been observed with the High Energy Stereoscopic System (H.E.S.S.); the acceptance-corrected exposure time is 100 h. The data set has been folded with the known orbital period of the system in order to test for variability of the emission. Results: VHE γ-ray emission is detected with a statistical significance of 6.4 σ. The data clearly show variability which is phase-locked to the orbital period of the system. Periodicity cannot be deduced from the H.E.S.S. data set alone. The orbit-averaged luminosity in the 1-10 TeV energy range is (1.4 ± 0.2) × 1035 erg s-1. A luminosity of (5 ± 1) × 1035 erg s-1 is reached during 20% of the orbit. HE and VHE γ-ray emissions are anti-correlated. LMC P3 is the most luminous γ-ray binary known so far.

  4. The SUrvey for Pulsars and Extragalactic Radio Bursts - II. New FRB discoveries and their follow-up

    Science.gov (United States)

    Bhandari, S.; Keane, E. F.; Barr, E. D.; Jameson, A.; Petroff, E.; Johnston, S.; Bailes, M.; Bhat, N. D. R.; Burgay, M.; Burke-Spolaor, S.; Caleb, M.; Eatough, R. P.; Flynn, C.; Green, J. A.; Jankowski, F.; Kramer, M.; Krishnan, V. Venkatraman; Morello, V.; Possenti, A.; Stappers, B.; Tiburzi, C.; van Straten, W.; Andreoni, I.; Butterley, T.; Chandra, P.; Cooke, J.; Corongiu, A.; Coward, D. M.; Dhillon, V. S.; Dodson, R.; Hardy, L. K.; Howell, E. J.; Jaroenjittichai, P.; Klotz, A.; Littlefair, S. P.; Marsh, T. R.; Mickaliger, M.; Muxlow, T.; Perrodin, D.; Pritchard, T.; Sawangwit, U.; Terai, T.; Tominaga, N.; Torne, P.; Totani, T.; Trois, A.; Turpin, D.; Niino, Y.; Wilson, R. W.; Albert, A.; André, M.; Anghinolfi, M.; Anton, G.; Ardid, M.; Aubert, J.-J.; Avgitas, T.; Baret, B.; Barrios-Martí, J.; Basa, S.; Belhorma, B.; Bertin, V.; Biagi, S.; Bormuth, R.; Bourret, S.; Bouwhuis, M. C.; Brânzaş, H.; Bruijn, R.; Brunner, J.; Busto, J.; Capone, A.; Caramete, L.; Carr, J.; Celli, S.; Moursli, R. Cherkaoui El; Chiarusi, T.; Circella, M.; Coelho, J. A. B.; Coleiro, A.; Coniglione, R.; Costantini, H.; Coyle, P.; Creusot, A.; Díaz, A. F.; Deschamps, A.; De Bonis, G.; Distefano, C.; Palma, I. Di; Domi, A.; Donzaud, C.; Dornic, D.; Drouhin, D.; Eberl, T.; Bojaddaini, I. El; Khayati, N. El; Elsässer, D.; Enzenhöfer, A.; Ettahiri, A.; Fassi, F.; Felis, I.; Fusco, L. A.; Gay, P.; Giordano, V.; Glotin, H.; Gregoire, T.; Gracia-Ruiz, R.; Graf, K.; Hallmann, S.; van Haren, H.; Heijboer, A. J.; Hello, Y.; Hernández-Rey, J. J.; Hößl, J.; Hofestädt, J.; Hugon, C.; Illuminati, G.; James, C. W.; de Jong, M.; Jongen, M.; Kadler, M.; Kalekin, O.; Katz, U.; Kießling, D.; Kouchner, A.; Kreter, M.; Kreykenbohm, I.; Kulikovskiy, V.; Lachaud, C.; Lahmann, R.; Lefèvre, D.; Leonora, E.; Loucatos, S.; Marcelin, M.; Margiotta, A.; Marinelli, A.; Martínez-Mora, J. A.; Mele, R.; Melis, K.; Michael, T.; Migliozzi, P.; Moussa, A.; Navas, S.; Nezri, E.; Organokov, M.; Pǎvǎlaş, G. E.; Pellegrino, C.; Perrina, C.; Piattelli, P.; Popa, V.; Pradier, T.; Quinn, L.; Racca, C.; Riccobene, G.; Sánchez-Losa, A.; Saldaña, M.; Salvadori, I.; Samtleben, D. F. E.; Sanguineti, M.; Sapienza, P.; Schüssler, F.; Sieger, C.; Spurio, M.; Stolarczyk, Th; Taiuti, M.; Tayalati, Y.; Trovato, A.; Turpin, D.; Tönnis, C.; Vallage, B.; Van Elewyck, V.; Versari, F.; Vivolo, D.; Vizzocca, A.; Wilms, J.; Zornoza, J. D.; Zúñiga, J.

    2018-04-01

    We report the discovery of four Fast Radio Bursts (FRBs) in the ongoing SUrvey for Pulsars and Extragalactic Radio Bursts at the Parkes Radio Telescope: FRBs 150610, 151206, 151230 and 160102. Our real-time discoveries have enabled us to conduct extensive, rapid multimessenger follow-up at 12 major facilities sensitive to radio, optical, X-ray, gamma-ray photons and neutrinos on time-scales ranging from an hour to a few months post-burst. No counterparts to the FRBs were found and we provide upper limits on afterglow luminosities. None of the FRBs were seen to repeat. Formal fits to all FRBs show hints of scattering while their intrinsic widths are unresolved in time. FRB 151206 is at low Galactic latitude, FRB 151230 shows a sharp spectral cut-off, and FRB 160102 has the highest dispersion measure (DM = 2596.1 ± 0.3 pc cm-3) detected to date. Three of the FRBs have high dispersion measures (DM > 1500 pc cm-3), favouring a scenario where the DM is dominated by contributions from the intergalactic medium. The slope of the Parkes FRB source counts distribution with fluences >2 Jy ms is α =-2.2^{+0.6}_{-1.2} and still consistent with a Euclidean distribution (α = -3/2). We also find that the all-sky rate is 1.7^{+1.5}_{-0.9}× 10^3FRBs/(4π sr)/day above {˜ }2{ }{Jy}{ }{ms} and there is currently no strong evidence for a latitude-dependent FRB sky rate.

  5. Evolution of the plasma universe: I. Double radio galaxies, quasars, and extragalactic jets

    International Nuclear Information System (INIS)

    Peratt, A.L.

    1986-01-01

    Cosmic plasma physics and our concept of the universe is in a state of rapid revision. This change started with in-situ measurements of plasmas in Earth's ionosphere, cometary atmospheres, and planetary magnetospheres; the translation of knowledge from laboratory experiments to astrophysical phenomena; discoveries of helical and filamentary plasma structures in the Galaxy and double radio sources; and the particle simulation of plasmas not accessible to in-situ measurement. Because of these, Birkeland (field-aligned) currents, double layers, and magnetic-field-aligned electric fields are now known to be far more important to the evolution of space plasma, including the acceleration of charged particles to high energies, than previously thought. This paper and its sequel investigate the observational evidence for a plasma universe threaded by Birkeland currents or filaments. This model of the universe was inspired by the advent of three-dimensional fully electromagnetic particle simulations and their application to the study of laboratory z pinches. This study resulted in totally unexpected phenomena in the data post-processed from the simulation particle, field, and history dumps. In particular, when the simulation parameters were scaled to galactic dimensions, the interaction between pinched filaments led to synchrotron radiation whose emission properties were found to share the following characteristics with double radio galaxies and quasars: power magnitude, isophotal morphology, spectra, brightness along source, polarization, and jets. The evolution of these pinched synchrotron emitting plasmas to elliptical, peculiar, and spiral galaxies by continuing the simulation run is addressed in a sequel paper

  6. The Cosmic Infrared Background Experiment

    Science.gov (United States)

    Bock, James; Battle, J.; Cooray, A.; Hristov, V.; Kawada, M.; Keating, B.; Lee, D.; Matsumoto, T.; Matsuura, S.; Nam, U.; Renbarger, T.; Sullivan, I.; Tsumura, K.; Wada, T.; Zemcov, M.

    2009-01-01

    We are developing the Cosmic Infrared Background ExpeRiment (CIBER) to search for signatures of first-light galaxy emission in the extragalactic background. The first generation of stars produce characteristic signatures in the near-infrared extragalactic background, including a redshifted Ly-cutoff feature and a characteristic fluctuation power spectrum, that may be detectable with a specialized instrument. CIBER consists of two wide-field cameras to measure the fluctuation power spectrum, and a low-resolution and a narrow-band spectrometer to measure the absolute background. The cameras will search for fluctuations on angular scales from 7 arcseconds to 2 degrees, where the first-light galaxy spatial power spectrum peaks. The cameras have the necessary combination of sensitivity, wide field of view, spatial resolution, and multiple bands to make a definitive measurement. CIBER will determine if the fluctuations reported by Spitzer arise from first-light galaxies. The cameras observe in a single wide field of view, eliminating systematic errors associated with mosaicing. Two bands are chosen to maximize the first-light signal contrast, at 1.6 um near the expected spectral maximum, and at 1.0 um; the combination is a powerful discriminant against fluctuations arising from local sources. We will observe regions of the sky surveyed by Spitzer and Akari. The low-resolution spectrometer will search for the redshifted Lyman cutoff feature in the 0.7 - 1.8 um spectral region. The narrow-band spectrometer will measure the absolute Zodiacal brightness using the scattered 854.2 nm Ca II Fraunhofer line. The spectrometers will test if reports of a diffuse extragalactic background in the 1 - 2 um band continues into the optical, or is caused by an under estimation of the Zodiacal foreground. We report performance of the assembled and tested instrument as we prepare for a first sounding rocket flight in early 2009. CIBER is funded by the NASA/APRA sub-orbital program.

  7. THE COSMOLOGICAL IMPACT OF LUMINOUS TeV BLAZARS. I. IMPLICATIONS OF PLASMA INSTABILITIES FOR THE INTERGALACTIC MAGNETIC FIELD AND EXTRAGALACTIC GAMMA-RAY BACKGROUND

    Energy Technology Data Exchange (ETDEWEB)

    Broderick, Avery E; Chang, Philip; Pfrommer, Christoph [Canadian Institute for Theoretical Astrophysics, 60 St. George Street, Toronto, ON M5S 3H8 (Canada)

    2012-06-10

    Inverse Compton cascades (ICCs) initiated by energetic gamma rays (E {approx}> 100 GeV) enhance the GeV emission from bright, extragalactic TeV sources. The absence of this emission from bright TeV blazars has been used to constrain the intergalactic magnetic field (IGMF), and the stringent limits placed on the unresolved extragalactic gamma-ray background (EGRB) by Fermi have been used to argue against a large number of such objects at high redshifts. However, these are predicated on the assumption that inverse Compton scattering is the primary energy-loss mechanism for the ultrarelativistic pairs produced by the annihilation of the energetic gamma rays on extragalactic background light photons. Here, we show that for sufficiently bright TeV sources (isotropic-equivalent luminosities {approx}> 10{sup 42} erg s{sup -1}) plasma beam instabilities, specifically the 'oblique' instability, present a plausible mechanism by which the energy of these pairs can be dissipated locally, heating the intergalactic medium. Since these instabilities typically grow on timescales short in comparison to the inverse Compton cooling rate, they necessarily suppress the ICCs. As a consequence, this places a severe constraint on efforts to limit the IGMF from the lack of a discernible GeV bump in TeV sources. Similarly, it considerably weakens the Fermi limits on the evolution of blazar populations. Specifically, we construct a TeV-blazar luminosity function from those objects currently observed and find that it is very well described by the quasar luminosity function at z {approx} 0.1, shifted to lower luminosities and number densities, suggesting that both classes of sources are regulated by similar processes. Extending this relationship to higher redshifts, we show that the magnitude and shape of the EGRB above {approx}10 GeV are naturally reproduced with this particular example of a rapidly evolving TeV-blazar luminosity function.

  8. The Extragalactic Lens VLBI Imaging Survey (ELVIS): Investigating galaxy cores and black holes with gravitational lens central images

    Science.gov (United States)

    Boyce, Edward R.

    This thesis describes the Extragalactic Lens VLBI Imaging Survey (ELVIS), a search for central images in gravitational lenses. We present the first four ELVIS targets, for which we have radio VLBI observations with resolutions of a few milli-arcseconds and sensitivities of 15 - 38mJy. For PMN J1838-3427, CLASS B0739+366 and CLASS B0445+123 we have not detected any central images, but have set stringent upper limits on their flux densities. For CLASS B2319+051 we have made a tentative detection of a third radio source, which may be either a central image or radio emission from the lens galaxy. Using the upper limits on the central image flux densities, we gain new information about the matter distributions in the lens galaxies of these systems. We fit a broken power law model for the matter profile, and constrain the allowed break radii and inner index of this model. To demagnify the central images to the observed level the matter profiles must be slightly shallower than or steeper than isothermal, which is consistent with previous studies of early type galaxy profiles. The presence of a super-massive black hole weakens the constraints somewhat, but the profiles are still close to isothermal. Relative to previous work, we reduce the maximum sizes of shallow cores by factors of 2 to 3, and raise the indices of r 0( r -g central cusps by g = 0.05 - 0.35. If we take the source in B2319+051 to be a central image, then we select a narrow band of allowed break radii and inner indices, finding that a constant density core has size 150--380 pc, and a pure power law has index g = 1.5 - 1.67. Our constraints still allow sufficiently shallow profiles that some super-massive black holes may form central image pairs rather than eliminating the central image, and these image pairs may be detected with future instruments. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)

  9. Variability of extragalactic sources: its contribution to the link between ICRF and the future Gaia Celestial Reference Frame

    Science.gov (United States)

    Taris, F.; Damljanovic, G.; Andrei, A.; Souchay, J.; Klotz, A.; Vachier, F.

    2018-03-01

    Context. The first release of the Gaia catalog is available since 14 September 2016. It is a first step in the realization of the future Gaia reference frame. This reference frame will be materialized by the optical positions of the sources and will be compared with and linked to the International Celestial Reference Frame, materialized by the radio position of extragalactic sources. Aim. As in the radio domain, it can be reasonably postulated that quasar optical flux variations can alert us to potential changes in the source structure. These changes could have important implications for the position of the target photocenters (together with the evolution in time of these centers) and in parallel have consequences for the link of the reference systems. Methods: A set of nine optical telescopes was used to monitor the magnitude variations, often at the same time as Gaia, thanks to the Gaia Observation Forecast Tool. The Allan variances, which are statistical tools widely used in the atomic time and frequency community, are introduced. Results: This work describes the magnitude variations of 47 targets that are suitable for the link between reference systems. We also report on some implications for the Gaia catalog. For 95% of the observed targets, new information about their variability is reported. In the case of some targets that are well observed by the TAROT telescopes, the Allan time variance shows that the longest averaging period of the magnitudes is in the range 20-70 d. The observation period by Gaia for a single target largely exceeds these values, which might be a problem when the magnitude variations exhibit flicker or random walk noises. Preliminary computations show that if the coordinates of the targets studied in this paper were affected by a white-phase noise with a formal uncertainty of about 1 mas (due to astrophysical processes that are put in evidence by the magnitude variations of the sources), it would affect the precision of the link at the

  10. THE EXTRAGALACTIC DISTANCE DATABASE

    International Nuclear Information System (INIS)

    Tully, R. Brent; Courtois, Helene M.; Jacobs, Bradley A.; Rizzi, Luca; Shaya, Edward J.; Makarov, Dmitry I.

    2009-01-01

    A database can be accessed on the Web at http://edd.ifa.hawaii.edu that was developed to promote access to information related to galaxy distances. The database has three functional components. First, tables from many literature sources have been gathered and enhanced with links through a distinct galaxy naming convention. Second, comparisons of results both at the levels of parameters and of techniques have begun and are continuing, leading to increasing homogeneity and consistency of distance measurements. Third, new material is presented arising from ongoing observational programs at the University of Hawaii 2.2 m telescope, radio telescopes at Green Bank, Arecibo, and Parkes and with the Hubble Space Telescope. This new observational material is made available in tandem with related material drawn from archives and passed through common analysis pipelines.

  11. Detection of ultra-high-energy cosmic radiation at the Pierre Auger Observatory, theoretical study of its propagation through extragalactic space

    International Nuclear Information System (INIS)

    Allard, D.

    2004-10-01

    The Pierre Auger observatory's main aim is to observe the ultra-energetic cosmic ray spectrum with high statistics. Indeed, the spectrum around 10 20 eV is so far only poorly known, due to low statistics and the expected GZK (Gneisen-Zatsepin-Kuzmin) cut-off is for the time being not clearly observed. The first part will deal with propagation of charged (protons and nuclei) ultra-energetic cosmic rays in the extragalactic medium. We will investigate the influence of physical parameters, such as the composition of cosmic ray fluxes, on the highest energy spectrum shape. The influence of the turbulent extragalactic magnetic fields on the spectrum of the clusters will also be studied. We will also investigate the possibility to observe gamma ray bursts with the Pierre Auger Observatory by using the single particle technique. We will show how galactic gamma ray bursts could become a persistent and quasi-isotropic source due to the 'Compton trail' induced by Compton scattering of the primary photon beam in the interstellar medium. In the section devoted to simulations, we will develop methods to reconstruct air showers and identify primary cosmic rays. We will also study the aperture of the Surface Detector of the Pierre Auger observatory. Finally, we will use the methods developed in the previous chapters to analyze the data of the year 2004 and will give preliminary results. (author)

  12. Extragalactic Background Light expected from photon-photon absorption on spectra of Active Galactic Nuclei at distances from z=0.018 to z=1.375

    International Nuclear Information System (INIS)

    Sinitsyna, V Y; Sinitsyna, V G

    2013-01-01

    Extragalactic background radiation blocks the propagation of TeV gamma-ray over large distances by producing e + e − pairs. As a result, primary spectrum of gamma-source is changed, depending on spectrum of background light. So, hard spectra of Active Galactic Nuclei with high red shifts allow the determination of a EBL spectrum. The redshifts of SHALON TeV gamma-ray sources range from 0.018 to 1.375 those spectra are resolved at the energies from 800 GeV to about 50 TeV. Spectral energy distribution of EBL constrained from observations of Mkn421, Mkn501, Mkn180, OJ287, 3c454.3 and 1739+522 together with models and measurements are presented.

  13. THE CHANDRA SURVEY OF EXTRAGALACTIC SOURCES IN THE 3CR CATALOG: X-RAY EMISSION FROM NUCLEI, JETS, AND HOTSPOTS IN THE CHANDRA ARCHIVAL OBSERVATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Massaro, F. [Dipartimento di Fisica, Università degli Studi di Torino, via Pietro Giuria 1, I-10125 Torino (Italy); Harris, D. E.; Paggi, A.; Wilkes, B. J.; Kuraszkiewicz, J. [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Liuzzo, E.; Orienti, M.; Paladino, R. [Istituto di Radioastronomia, INAF, via Gobetti 101, I-40129, Bologna (Italy); Tremblay, G. R. [Yale Center for Astronomy and Astrophysics, Physics Department, Yale University, P.O. Box 208120, New Haven, CT 06520-8120 (United States); Baum, S. A.; O’Dea, C. P. [University of Manitoba, Dept of Physics and Astronomy, Winnipeg, MB R3T 2N2 (Canada)

    2015-09-15

    As part of our program to build a complete radio and X-ray database of all Third Cambridge catalog extragalactic radio sources, we present an analysis of 93 sources for which Chandra archival data are available. Most of these sources have already been published. Here we provide a uniform re-analysis and present nuclear X-ray fluxes and X-ray emission associated with radio jet knots and hotspots using both publicly available radio images and new radio images that have been constructed from data available in the Very Large Array archive. For about 1/3 of the sources in the selected sample, a comparison between the Chandra and radio observations was not reported in the literature: we find X-ray detections of 2 new radio jet knots and 17 hotspots. We also report the X-ray detection of extended emission from the intergalactic medium for 15 galaxy clusters.

  14. An Indication of Anisotropy in Arrival Directions of Ultra-high-energy Cosmic Rays through Comparison to the Flux Pattern of Extragalactic Gamma-Ray Sources

    Energy Technology Data Exchange (ETDEWEB)

    Aab, A.; Abreu, P.; Aglietta, M.; Albuquerque, I. F. M.; Allekotte, I.; Almela, A.; Castillo, J. Alvarez; Alvarez-Muñiz, J.; Anastasi, G. A.; Anchordoqui, L.; Andrada, B.; Andringa, S.; Aramo, C.; Arsene, N.; Asorey, H.; Assis, P.; Avila, G.; Badescu, A. M.; Balaceanu, A.; Barbato, F.; Luz, R. J. Barreira; Beatty, J. J.; Becker, K. H.; Bellido, J. A.; Berat, C.; Bertaina, M. E.; Bertou, X.; Biermann, P. L.; Biteau, J.; Blaess, S. G.; Blanco, A.; Blazek, J.; Bleve, C.; Boháčová, M.; Bonifazi, C.; Borodai, N.; Botti, A. M.; Brack, J.; Brancus, I.; Bretz, T.; Bridgeman, A.; Briechle, F. L.; Buchholz, P.; Bueno, A.; Buitink, S.; Buscemi, M.; Caballero-Mora, K. S.; Caccianiga, L.; Cancio, A.; Canfora, F.; Caruso, R.; Castellina, A.; Catalani, F.; Cataldi, G.; Cazon, L.; Chavez, A. G.; Chinellato, J. A.; Chudoba, J.; Clay, R. W.; Cerutti, A. C. Cobos; Colalillo, R.; Coleman, A.; Collica, L.; Coluccia, M. R.; Conceição, R.; Consolati, G.; Contreras, F.; Cooper, M. J.; Coutu, S.; Covault, C. E.; Cronin, J.; D’Amico, S.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; Almeida, R. M. de; Jong, S. J. de; Mauro, G. De; de Mello Neto, J. R. T.; Mitri, I. De; Oliveira, J. de; Souza, V. de; Debatin, J.; Deligny, O.; Castro, M. L. Díaz; Diogo, F.; Dobrigkeit, C.; D’Olivo, J. C.; Dorosti, Q.; Anjos, R. C. dos; Dova, M. T.; Dundovic, A.; Ebr, J.; Engel, R.; Erdmann, M.; Erfani, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Falcke, H.; Farmer, J.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Fenu, F.; Fick, B.; Figueira, J. M.; Filipčič, A.; Freire, M. M.; Fujii, T.; Fuster, A.; Gaïor, R.; García, B.; Gaté, F.; Gemmeke, H.; Gherghel-Lascu, A.; Ghia, P. L.; Giaccari, U.; Giammarchi, M.; Giller, M.; Głas, D.; Glaser, C.; Golup, G.; Berisso, M. Gómez; Vitale, P. F. Gómez; González, N.; Gorgi, A.; Grillo, A. F.; Grubb, T. D.; Guarino, F.; Guedes, G. P.; Halliday, R.; Hampel, M. R.; Hansen, P.; Harari, D.; Harrison, T. A.; Haungs, A.; Hebbeker, T.; Heck, D.; Heimann, P.; Herve, A. E.; Hill, G. C.; Hojvat, C.; Holt, E.; Homola, P.; Hörandel, J. R.; Horvath, P.; Hrabovský, M.; Huege, T.; Hulsman, J.; Insolia, A.; Isar, P. G.; Jandt, I.; Johnsen, J. A.; Josebachuili, M.; Jurysek, J.; Kääpä, A.; Kambeitz, O.; Kampert, K. H.; Keilhauer, B.; Kemmerich, N.; Kemp, E.; Kemp, J.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Krause, R.; Krohm, N.; Kuempel, D.; Mezek, G. Kukec; Kunka, N.; Awad, A. Kuotb; Lago, B. L.; LaHurd, D.; Lang, R. G.; Lauscher, M.; Legumina, R.; Oliveira, M. A. Leigui de; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; Presti, D. Lo; Lopes, L.; López, R.; Casado, A. López; Lorek, R.; Luce, Q.; Lucero, A.; Malacari, M.; Mallamaci, M.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Mariş, I. C.; Marsella, G.; Martello, D.; Martinez, H.; Bravo, O. Martínez; Meza, J. J. Masías; Mathes, H. J.; Mathys, S.; Matthews, J.; Matthiae, G.; Mayotte, E.; Mazur, P. O.; Medina, C.; Medina-Tanco, G.; Melo, D.; Menshikov, A.; Merenda, K. -D.; Michal, S.; Micheletti, M. I.; Middendorf, L.; Miramonti, L.; Mitrica, B.; Mockler, D.; Mollerach, S.; Montanet, F.; Morello, C.; Morlino, G.; Mostafá, M.; Müller, A. L.; Müller, G.; Muller, M. A.; Müller, S.; Mussa, R.; Naranjo, I.; Nellen, L.; Nguyen, P. H.; Niculescu-Oglinzanu, M.; Niechciol, M.; Niemietz, L.; Niggemann, T.; Nitz, D.; Nosek, D.; Novotny, V.; Nožka, L.; Núñez, L. A.; Oikonomou, F.; Olinto, A.; Palatka, M.; Pallotta, J.; Papenbreer, P.; Parente, G.; Parra, A.; Paul, T.; Pech, M.; Pedreira, F.; Pȩkala, J.; Pelayo, R.; Peña-Rodriguez, J.; Pereira, L. A. S.; Perlin, M.; Perrone, L.; Peters, C.; Petrera, S.; Phuntsok, J.; Pierog, T.; Pimenta, M.; Pirronello, V.; Platino, M.; Plum, M.; Poh, J.; Porowski, C.; Prado, R. R.; Privitera, P.; Prouza, M.; Quel, E. J.; Querchfeld, S.; Quinn, S.; Ramos-Pollan, R.; Rautenberg, J.; Ravignani, D.; Ridky, J.; Riehn, F.; Risse, M.; Ristori, P.; Rizi, V.; Rodrigues de Carvalho, W.; Rodriguez Fernandez, G.; Rodriguez Rojo, J.; Roncoroni, M. J.; Roth, M.; Roulet, E.; Rovero, A. C.; Ruehl, P.; Saffi, S. J.; Saftoiu, A.; Salamida, F.; Salazar, H.; Saleh, A.; Salina, G.; Sánchez, F.; Sanchez-Lucas, P.; Santos, E. M.; Santos, E.; Sarazin, F.; Sarmento, R.; Sarmiento-Cano, C.; Sato, R.; Schauer, M.; Scherini, V.; Schieler, H.; Schimp, M.; Schmidt, D.; Scholten, O.; Schovánek, P.; Schröder, F. G.; Schröder, S.; Schulz, A.; Schumacher, J.; Sciutto, S. J.; Segreto, A.; Shadkam, A.; Shellard, R. C.; Sigl, G.; Silli, G.; Šmída, R.; Snow, G. R.; Sommers, P.; Sonntag, S.; Soriano, J. F.; Squartini, R.; Stanca, D.; Stanič, S.; Stasielak, J.; Stassi, P.; Stolpovskiy, M.; Strafella, F.; Streich, A.; Suarez, F.; Durán, M. Suarez; Sudholz, T.; Suomijärvi, T.; Supanitsky, A. D.; Šupík, J.; Swain, J.; Szadkowski, Z.; Taboada, A.; Taborda, O. A.; Theodoro, V. M.; Timmermans, C.; Peixoto, C. J. Todero; Tomankova, L.; Tomé, B.; Elipe, G. Torralba; Travnicek, P.; Trini, M.; Ulrich, R.; Unger, M.; Urban, M.; Galicia, J. F. Valdés; Valiño, I.; Valore, L.; van Aar, G.; van Bodegom, P.; Berg, A. M. van den; Vliet, A. van; Varela, E.; Cárdenas, B. Vargas; Vázquez, R. A.; Veberič, D.; Ventura, C.; Quispe, I. D. Vergara; Verzi, V.; Vicha, J.; Villaseñor, L.; Vorobiov, S.; Wahlberg, H.; Wainberg, O.; Walz, D.; Watson, A. A.; Weber, M.; Weindl, A.; Wiedeński, M.; Wiencke, L.; Wilczyński, H.; Wirtz, M.; Wittkowski, D.; Wundheiler, B.; Yang, L.; Yushkov, A.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zepeda, A.; Zimmermann, B.; Ziolkowski, M.; Zong, Z.; Zuccarello, F.

    2018-02-01

    A new analysis of the dataset from the Pierre Auger Observatory provides evidence for anisotropy in the arrival directions of ultra-high-energy cosmic rays on an intermediate angular scale, which is indicative of excess arrivals from strong, nearby sources. The data consist of 5514 events above 20 EeV with zenith angles up to 80 deg recorded before 2017 April 30. Sky models have been created for two distinct populations of extragalactic gamma-ray emitters: active galactic nuclei from the second catalog of hard Fermi-LAT sources (2FHL) and starburst galaxies from a sample that was examined with Fermi-LAT. Flux-limited samples, which include all types of galaxies from the Swift-BAT and 2MASS surveys, have been investigated for comparison. The sky model of cosmic-ray density constructed using each catalog has two free parameters, the fraction of events correlating with astrophysical objects and an angular scale characterizing the clustering of cosmic rays around extragalactic sources. A maximum-likelihood ratio test is used to evaluate the best values of these parameters and to quantify the strength of each model by contrast with isotropy. It is found that the starburst model fits the data better than the hypothesis of isotropy with a statistical significance of 4.0 sigma, the highest value of the test statistic being for energies above 39 EeV. The three alternative models are favored against isotropy with 2.7-3.2 sigma significance. The origin of the indicated deviation from isotropy is examined and prospects for more sensitive future studies are discussed.

  15. An Indication of Anisotropy in Arrival Directions of Ultra-high-energy Cosmic Rays through Comparison to the Flux Pattern of Extragalactic Gamma-Ray Sources

    Science.gov (United States)

    Aab, A.; Abreu, P.; Aglietta, M.; Albuquerque, I. F. M.; Allekotte, I.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Anastasi, G. A.; Anchordoqui, L.; Andrada, B.; Andringa, S.; Aramo, C.; Arsene, N.; Asorey, H.; Assis, P.; Avila, G.; Badescu, A. M.; Balaceanu, A.; Barbato, F.; Barreira Luz, R. J.; Beatty, J. J.; Becker, K. H.; Bellido, J. A.; Berat, C.; Bertaina, M. E.; Bertou, X.; Biermann, P. L.; Biteau, J.; Blaess, S. G.; Blanco, A.; Blazek, J.; Bleve, C.; Boháčová, M.; Bonifazi, C.; Borodai, N.; Botti, A. M.; Brack, J.; Brancus, I.; Bretz, T.; Bridgeman, A.; Briechle, F. L.; Buchholz, P.; Bueno, A.; Buitink, S.; Buscemi, M.; Caballero-Mora, K. S.; Caccianiga, L.; Cancio, A.; Canfora, F.; Caruso, R.; Castellina, A.; Catalani, F.; Cataldi, G.; Cazon, L.; Chavez, A. G.; Chinellato, J. A.; Chudoba, J.; Clay, R. W.; Cobos Cerutti, A. C.; Colalillo, R.; Coleman, A.; Collica, L.; Coluccia, M. R.; Conceição, R.; Consolati, G.; Contreras, F.; Cooper, M. J.; Coutu, S.; Covault, C. E.; Cronin, J.; D’Amico, S.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; de Jong, S. J.; De Mauro, G.; de Mello Neto, J. R. T.; De Mitri, I.; de Oliveira, J.; de Souza, V.; Debatin, J.; Deligny, O.; Díaz Castro, M. L.; Diogo, F.; Dobrigkeit, C.; D’Olivo, J. C.; Dorosti, Q.; dos Anjos, R. C.; Dova, M. T.; Dundovic, A.; Ebr, J.; Engel, R.; Erdmann, M.; Erfani, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Falcke, H.; Farmer, J.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Fenu, F.; Fick, B.; Figueira, J. M.; Filipčič, A.; Freire, M. M.; Fujii, T.; Fuster, A.; Gaïor, R.; García, B.; Gaté, F.; Gemmeke, H.; Gherghel-Lascu, A.; Ghia, P. L.; Giaccari, U.; Giammarchi, M.; Giller, M.; Głas, D.; Glaser, C.; Golup, G.; Gómez Berisso, M.; Gómez Vitale, P. F.; González, N.; Gorgi, A.; Grillo, A. F.; Grubb, T. D.; Guarino, F.; Guedes, G. P.; Halliday, R.; Hampel, M. R.; Hansen, P.; Harari, D.; Harrison, T. A.; Haungs, A.; Hebbeker, T.; Heck, D.; Heimann, P.; Herve, A. E.; Hill, G. C.; Hojvat, C.; Holt, E.; Homola, P.; Hörandel, J. R.; Horvath, P.; Hrabovský, M.; Huege, T.; Hulsman, J.; Insolia, A.; Isar, P. G.; Jandt, I.; Johnsen, J. A.; Josebachuili, M.; Jurysek, J.; Kääpä, A.; Kambeitz, O.; Kampert, K. H.; Keilhauer, B.; Kemmerich, N.; Kemp, E.; Kemp, J.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Krause, R.; Krohm, N.; Kuempel, D.; Kukec Mezek, G.; Kunka, N.; Kuotb Awad, A.; Lago, B. L.; LaHurd, D.; Lang, R. G.; Lauscher, M.; Legumina, R.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; Lo Presti, D.; Lopes, L.; López, R.; López Casado, A.; Lorek, R.; Luce, Q.; Lucero, A.; Malacari, M.; Mallamaci, M.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Mariş, I. C.; Marsella, G.; Martello, D.; Martinez, H.; Martínez Bravo, O.; Masías Meza, J. J.; Mathes, H. J.; Mathys, S.; Matthews, J.; Matthiae, G.; Mayotte, E.; Mazur, P. O.; Medina, C.; Medina-Tanco, G.; Melo, D.; Menshikov, A.; Merenda, K.-D.; Michal, S.; Micheletti, M. I.; Middendorf, L.; Miramonti, L.; Mitrica, B.; Mockler, D.; Mollerach, S.; Montanet, F.; Morello, C.; Morlino, G.; Mostafá, M.; Müller, A. L.; Müller, G.; Muller, M. A.; Müller, S.; Mussa, R.; Naranjo, I.; Nellen, L.; Nguyen, P. H.; Niculescu-Oglinzanu, M.; Niechciol, M.; Niemietz, L.; Niggemann, T.; Nitz, D.; Nosek, D.; Novotny, V.; Nožka, L.; Núñez, L. A.; Oikonomou, F.; Olinto, A.; Palatka, M.; Pallotta, J.; Papenbreer, P.; Parente, G.; Parra, A.; Paul, T.; Pech, M.; Pedreira, F.; Pȩkala, J.; Pelayo, R.; Peña-Rodriguez, J.; Pereira, L. A. S.; Perlin, M.; Perrone, L.; Peters, C.; Petrera, S.; Phuntsok, J.; Pierog, T.; Pimenta, M.; Pirronello, V.; Platino, M.; Plum, M.; Poh, J.; Porowski, C.; Prado, R. R.; Privitera, P.; Prouza, M.; Quel, E. J.; Querchfeld, S.; Quinn, S.; Ramos-Pollan, R.; Rautenberg, J.; Ravignani, D.; Ridky, J.; Riehn, F.; Risse, M.; Ristori, P.; Rizi, V.; Rodrigues de Carvalho, W.; Rodriguez Fernandez, G.; Rodriguez Rojo, J.; Roncoroni, M. J.; Roth, M.; Roulet, E.; Rovero, A. C.; Ruehl, P.; Saffi, S. J.; Saftoiu, A.; Salamida, F.; Salazar, H.; Saleh, A.; Salina, G.; Sánchez, F.; Sanchez-Lucas, P.; Santos, E. M.; Santos, E.; Sarazin, F.; Sarmento, R.; Sarmiento-Cano, C.; Sato, R.; Schauer, M.; Scherini, V.; Schieler, H.; Schimp, M.; Schmidt, D.; Scholten, O.; Schovánek, P.; Schröder, F. G.; Schröder, S.; Schulz, A.; Schumacher, J.; Sciutto, S. J.; Segreto, A.; Shadkam, A.; Shellard, R. C.; Sigl, G.; Silli, G.; Šmída, R.; Snow, G. R.; Sommers, P.; Sonntag, S.; Soriano, J. F.; Squartini, R.; Stanca, D.; Stanič, S.; Stasielak, J.; Stassi, P.; Stolpovskiy, M.; Strafella, F.; Streich, A.; Suarez, F.; Suarez Durán, M.; Sudholz, T.; Suomijärvi, T.; Supanitsky, A. D.; Šupík, J.; Swain, J.; Szadkowski, Z.; Taboada, A.; Taborda, O. A.; Theodoro, V. M.; Timmermans, C.; Todero Peixoto, C. J.; Tomankova, L.; Tomé, B.; Torralba Elipe, G.; Travnicek, P.; Trini, M.; Ulrich, R.; Unger, M.; Urban, M.; Valdés Galicia, J. F.; Valiño, I.; Valore, L.; van Aar, G.; van Bodegom, P.; van den Berg, A. M.; van Vliet, A.; Varela, E.; Vargas Cárdenas, B.; Vázquez, R. A.; Veberič, D.; Ventura, C.; Vergara Quispe, I. D.; Verzi, V.; Vicha, J.; Villaseñor, L.; Vorobiov, S.; Wahlberg, H.; Wainberg, O.; Walz, D.; Watson, A. A.; Weber, M.; Weindl, A.; Wiedeński, M.; Wiencke, L.; Wilczyński, H.; Wirtz, M.; Wittkowski, D.; Wundheiler, B.; Yang, L.; Yushkov, A.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zepeda, A.; Zimmermann, B.; Ziolkowski, M.; Zong, Z.; Zuccarello, F.; The Pierre Auger Collaboration

    2018-02-01

    A new analysis of the data set from the Pierre Auger Observatory provides evidence for anisotropy in the arrival directions of ultra-high-energy cosmic rays on an intermediate angular scale, which is indicative of excess arrivals from strong, nearby sources. The data consist of 5514 events above 20 {EeV} with zenith angles up to 80° recorded before 2017 April 30. Sky models have been created for two distinct populations of extragalactic gamma-ray emitters: active galactic nuclei from the second catalog of hard Fermi-LAT sources (2FHL) and starburst galaxies from a sample that was examined with Fermi-LAT. Flux-limited samples, which include all types of galaxies from the Swift-BAT and 2MASS surveys, have been investigated for comparison. The sky model of cosmic-ray density constructed using each catalog has two free parameters, the fraction of events correlating with astrophysical objects, and an angular scale characterizing the clustering of cosmic rays around extragalactic sources. A maximum-likelihood ratio test is used to evaluate the best values of these parameters and to quantify the strength of each model by contrast with isotropy. It is found that the starburst model fits the data better than the hypothesis of isotropy with a statistical significance of 4.0σ, the highest value of the test statistic being for energies above 39 {EeV}. The three alternative models are favored against isotropy with 2.7σ–3.2σ significance. The origin of the indicated deviation from isotropy is examined and prospects for more sensitive future studies are discussed. Any correspondence should be addressed to .

  16. The origin and development of extragalactic radio astronomy: the role of CSIRO's Division of Radiophysics Dover Heights Field Station in Sydney

    Science.gov (United States)

    Orchiston, Wayne; Robertson, Peter

    2017-12-01

    Initial post-war developments in non-solar radio astronomy were inspired by Hey, Phillips and Parson’s report in 1946 of an intense source of radio emission in Cygnus. This so-called ‘radio star’ was unique, and questions immediately were raised about its true nature. But it did not remain unique for long. Observing from Sydney, John Bolton, Gordon Stanley and Bruce Slee followed up the Cygnus discovery with more radio star detections, beginning what would evolve into a long-term multi-faceted research program and one of the mainstays of the CSIRO’s Division of Radiophysics. But more than this, these early discoveries in England and in Sydney opened up a whole new field of investigation, extragalactic radio astronomy, which has remained a major area of investigation through to the present day. This paper focusses on the early years of this program when the observations were carried out at Dover Heights Field Station in Sydney, and the ways in which new developments in instrumentation that allowed a major expansion of the program eventually led to the closure of Dover Heights and the founding of the Fleurs Field Station.

  17. Strominge in die vrouebew eging: 'n voorlopige raamwerk

    Directory of Open Access Journals (Sweden)

    M. van Niekerk

    1988-03-01

    Full Text Available The Biblical principle of reformation challenges the Christian to question the traditional position of women and if necessary to change it, as well as to critically evaluate the various trends within the women's movement. It is stated that the generalizing use of the term feminism has become outdated, and should be replaced by differentiated terminology. The latter should be based on critical nuancing, with due regard to the view of history, the approach to sexuality/sex and the religious directedness of each specific trend or school of thought. Against the background of the sexism and traditionalism of male chauvinism , this article offers a prelim inary framework from which a number of fem inist and moderate trends within the women's movement can be identified. Within feminism a distinction is drawn between egalitarian and gynaecentric (neo-sexist trends. The moderate wing of the women's movement includes a humanist and a Christian approach, with androgynous and holistic views respectively as examples of these. Finally the author points out that the use of the Bible by feminist theologians and other representatives of the women's movement offers no guarantee for Scriptural viewpoints, and warns against generalizing judgments about proponents of women's rights.

  18. Strominge in die vrouebew eging: 'n voorlopige raamwerk

    OpenAIRE

    M. van Niekerk

    1988-01-01

    The Biblical principle of reformation challenges the Christian to question the traditional position of women and if necessary to change it, as well as to critically evaluate the various trends within the women's movement. It is stated that the generalizing use of the term feminism has become outdated, and should be replaced by differentiated terminology. The latter should be based on critical nuancing, with due regard to the view of history, the approach to sexuality/sex and the religious dir...

  19. FermiGrid—experience and future plans

    Science.gov (United States)

    Chadwick, K.; Berman, E.; Canal, P.; Hesselroth, T.; Garzoglio, G.; Levshina, T.; Sergeev, V.; Sfiligoi, I.; Sharma, N.; Timm, S.; Yocum, D. R.

    2008-07-01

    Fermilab supports a scientific program that includes experiments and scientists located across the globe. In order to better serve this community, Fermilab has placed its production computer resources in a Campus Grid infrastructure called 'FermiGrid'. The FermiGrid infrastructure allows the large experiments at Fermilab to have priority access to their own resources, enables sharing of these resources in an opportunistic fashion, and movement of work (jobs, data) between the Campus Grid and National Grids such as Open Science Grid (OSG) and the Worldwide LHC Computing Grid Collaboration (WLCG). FermiGrid resources support multiple Virtual Organizations (VOs), including VOs from the OSG, EGEE, and the WLCG. Fermilab also makes leading contributions to the Open Science Grid in the areas of accounting, batch computing, grid security, job management, resource selection, site infrastructure, storage management, and VO services. Through the FermiGrid interfaces, authenticated and authorized VOs and individuals may access our core grid services, the 10,000+ Fermilab resident CPUs, near-petabyte (including CMS) online disk pools and the multi-petabyte Fermilab Mass Storage System. These core grid services include a site wide Globus gatekeeper, VO management services for several VOs, Fermilab site authorization services, grid user mapping services, as well as job accounting and monitoring, resource selection and data movement services. Access to these services is via standard and well-supported grid interfaces. We will report on the user experience of using the FermiGrid campus infrastructure interfaced to a national cyberinfrastructure - the successes and the problems.

  20. FermiGrid - experience and future plans

    International Nuclear Information System (INIS)

    Chadwick, K.; Berman, E.; Canal, P.; Hesselroth, T.; Garzoglio, G.; Levshina, T.; Sergeev, V.; Sfiligoi, I.; Timm, S.; Yocum, D.

    2007-01-01

    Fermilab supports a scientific program that includes experiments and scientists located across the globe. In order to better serve this community, Fermilab has placed its production computer resources in a Campus Grid infrastructure called 'FermiGrid'. The FermiGrid infrastructure allows the large experiments at Fermilab to have priority access to their own resources, enables sharing of these resources in an opportunistic fashion, and movement of work (jobs, data) between the Campus Grid and National Grids such as Open Science Grid and the WLCG. FermiGrid resources support multiple Virtual Organizations (VOs), including VOs from the Open Science Grid (OSG), EGEE and the Worldwide LHC Computing Grid Collaboration (WLCG). Fermilab also makes leading contributions to the Open Science Grid in the areas of accounting, batch computing, grid security, job management, resource selection, site infrastructure, storage management, and VO services. Through the FermiGrid interfaces, authenticated and authorized VOs and individuals may access our core grid services, the 10,000+ Fermilab resident CPUs, near-petabyte (including CMS) online disk pools and the multi-petabyte Fermilab Mass Storage System. These core grid services include a site wide Globus gatekeeper, VO management services for several VOs, Fermilab site authorization services, grid user mapping services, as well as job accounting and monitoring, resource selection and data movement services. Access to these services is via standard and well-supported grid interfaces. We will report on the user experience of using the FermiGrid campus infrastructure interfaced to a national cyberinfrastructure--the successes and the problems

  1. FermiGrid-experience and future plans

    International Nuclear Information System (INIS)

    Chadwick, K; Berman, E; Canal, P; Hesselroth, T; Garzoglio, G; Levshina, T; Sergeev, V; Sfiligoi, I; Sharma, N; Timm, S; Yocum, D R

    2008-01-01

    Fermilab supports a scientific program that includes experiments and scientists located across the globe. In order to better serve this community, Fermilab has placed its production computer resources in a Campus Grid infrastructure called 'FermiGrid'. The FermiGrid infrastructure allows the large experiments at Fermilab to have priority access to their own resources, enables sharing of these resources in an opportunistic fashion, and movement of work (jobs, data) between the Campus Grid and National Grids such as Open Science Grid (OSG) and the Worldwide LHC Computing Grid Collaboration (WLCG). FermiGrid resources support multiple Virtual Organizations (VOs), including VOs from the OSG, EGEE, and the WLCG. Fermilab also makes leading contributions to the Open Science Grid in the areas of accounting, batch computing, grid security, job management, resource selection, site infrastructure, storage management, and VO services. Through the FermiGrid interfaces, authenticated and authorized VOs and individuals may access our core grid services, the 10,000+ Fermilab resident CPUs, near-petabyte (including CMS) online disk pools and the multi-petabyte Fermilab Mass Storage System. These core grid services include a site wide Globus gatekeeper, VO management services for several VOs, Fermilab site authorization services, grid user mapping services, as well as job accounting and monitoring, resource selection and data movement services. Access to these services is via standard and well-supported grid interfaces. We will report on the user experience of using the FermiGrid campus infrastructure interfaced to a national cyberinfrastructure - the successes and the problems

  2. Müzik Eğitimi Anabilim Dalı 3. ve 4. Sınıf öğrencilerinin Piyano Performansı Özyeterlik Algıları ile Piyano Öğretim Elemanlarının Öğrencilerin Piyano Performansı Hakkındaki Görüşleri (Ege Bölgesi Örneği)

    OpenAIRE

    Pirlibeylioğlu, Bilge

    2015-01-01

    Piyano, müzik eğitimi veren tüm kurumlarda, özellikle Müzik Eğitimi Anabilim Dalları’nda zorunlu ders olarak yer almaktadır. Dolayısıyla müzik öğretmeni adaylarının piyano performansı sergilemesi kaçınılmazdır. Piyano performansı topluluk önünde sergilenmek zorunda olan bir olgu olduğundan; sahne kaygısı, özgüven, özyeterlik gibi duyuşsal özelliklerden büyük ölçüde etkilenmektedir. Bu araştırmada, piyano performansına ilişkin özyeterlik algısı üzerinde durulmuştur. Araştırmanın amacı, Ege Böl...

  3. Cosmological constraints on dark matter annihilation and decay. Cross-correlation analysis of the extragalactic γ-ray background and cosmic shear

    Energy Technology Data Exchange (ETDEWEB)

    Shirasaki, Masato [National Astronomical Observatory of Japan, Mitaka, Tokyo (Japan); Macias, Oscar; Horiuchi, Shunsaku [Virginia Tech, Blacksburg, VA (United States). Center for Neutrino Physics; Shirai, Satoshi [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Yoshida, Naoki [Tokyo Univ. (Japan). Dept. of Physics; Tokyo Univ., Chiba (Japan). Kavli Inst. for the Physics and Mathematics of the Universe (WPI); Japan Science and Technology Agency, Saitama (Japan). CREST

    2016-07-15

    We derive constraints on dark matter (DM) annihilation cross section and decay lifetime from cross-correlation analyses of the data from Fermi-LAT and weak lensing surveys that cover a wide area of ∝660 squared degrees in total. We improve upon our previous analyses by using an updated extragalactic γ-ray background data reprocessed with the Fermi Pass 8 pipeline, and by using well-calibrated shape measurements of about twelve million galaxies in the Canada-France-Hawaii Lensing Survey (CFHTLenS) and Red-Cluster-Sequence Lensing Survey (RCSLenS). We generate a large set of full-sky mock catalogs from cosmological N-body simulations and use them to estimate statistical errors accurately. The measured cross correlation is consistent with null detection, which is then used to place strong cosmological constraints on annihilating and decaying DM. For leptophilic DM, the constraints are improved by a factor of ∝ 100 in the mass range of O(1) TeV when including contributions from secondary γ rays due to the inverse-Compton upscattering of background photons. Annihilation cross-sections of left angle σν right angle ∝ 10{sup -23} cm{sup 3}/s are excluded for TeV-scale DM depending on channel. Lifetimes of ∝10{sup 25} sec are also excluded for the decaying TeV-scale DM. Finally, we apply this analysis to wino DM and exclude the wino mass around 200 GeV. These constraints will be further tightened, and all the interesting wino DM parameter region can be tested, by using data from future wide-field cosmology surveys.

  4. Legacy ExtraGalactic UV Survey with The Hubble Space Telescope: Stellar Cluster Catalogs and First Insights Into Cluster Formation and Evolution in NGC 628

    Science.gov (United States)

    Adamo, A.; Ryon, J. E.; Messa, M.; Kim, H.; Grasha, K.; Cook, D. O.; Calzetti, D.; Lee, J. C.; Whitmore, B. C.; Elmegreen, B. G.; Ubeda, L.; Smith, L. J.; Bright, S. N.; Runnholm, A.; Andrews, J. E.; Fumagalli, M.; Gouliermis, D. A.; Kahre, L.; Nair, P.; Thilker, D.; Walterbos, R.; Wofford, A.; Aloisi, A.; Ashworth, G.; Brown, T. M.; Chandar, R.; Christian, C.; Cignoni, M.; Clayton, G. C.; Dale, D. A.; de Mink, S. E.; Dobbs, C.; Elmegreen, D. M.; Evans, A. S.; Gallagher, J. S., III; Grebel, E. K.; Herrero, A.; Hunter, D. A.; Johnson, K. E.; Kennicutt, R. C.; Krumholz, M. R.; Lennon, D.; Levay, K.; Martin, C.; Nota, A.; Östlin, G.; Pellerin, A.; Prieto, J.; Regan, M. W.; Sabbi, E.; Sacchi, E.; Schaerer, D.; Schiminovich, D.; Shabani, F.; Tosi, M.; Van Dyk, S. D.; Zackrisson, E.

    2017-06-01

    We report the large effort that is producing comprehensive high-level young star cluster (YSC) catalogs for a significant fraction of galaxies observed with the Legacy ExtraGalactic UV Survey (LEGUS) Hubble treasury program. We present the methodology developed to extract cluster positions, verify their genuine nature, produce multiband photometry (from NUV to NIR), and derive their physical properties via spectral energy distribution fitting analyses. We use the nearby spiral galaxy NGC 628 as a test case for demonstrating the impact that LEGUS will have on our understanding of the formation and evolution of YSCs and compact stellar associations within their host galaxy. Our analysis of the cluster luminosity function from the UV to the NIR finds a steepening at the bright end and at all wavelengths suggesting a dearth of luminous clusters. The cluster mass function of NGC 628 is consistent with a power-law distribution of slopes ˜ -2 and a truncation of a few times 105 {M}⊙ . After their formation, YSCs and compact associations follow different evolutionary paths. YSCs survive for a longer time frame, confirming their being potentially bound systems. Associations disappear on timescales comparable to hierarchically organized star-forming regions, suggesting that they are expanding systems. We find mass-independent cluster disruption in the inner region of NGC 628, while in the outer part of the galaxy there is little or no disruption. We observe faster disruption rates for low mass (≤104 {M}⊙ ) clusters, suggesting that a mass-dependent component is necessary to fully describe the YSC disruption process in NGC 628. Based on observations obtained with the NASA/ESA Hubble Space Telescope, at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

  5. Extragalactic background light from hierarchical galaxy formation. Gamma-ray attenuation up to the epoch of cosmic reionization and the first stars

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Yoshiyuki [Stanford Univ., CA (United States). Kavli Inst. for Particle Astrophysics and Cosmology; Inoue, Susumu [Max Planck Inst. for Nuclear Physics, Heidelberg (Germany); Univ. of Tokyo (Japan). Inst. for Cosmic Ray Research; Kobayashi, Masakazu A. R. [Ehime Univ., Matsuyama (Japan). Research Center for Space and Cosmic Evolution; Makiya, Ryu [Kyoto Univ. (Japan). Dept. of Astronomy; Niino, Yuu [National Astronomical Observatory of Japan, Mitaka (Tokyo). Optical and Infrared Astronomy Division; Totani, Tomonori [Kyoto Univ. (Japan). Dept. of Astronomy

    2013-04-26

    Here, we present a new model of the extragalactic background light (EBL) and corresponding γγ opacity for intergalactic gamma-ray absorption from z = 0 up to z = 10, based on a semi-analytical model of hierarchical galaxy formation that reproduces key observed properties of galaxies at various redshifts. Including the potential contribution from Population III stars and following the cosmic reionization history in a simplified way, the model is also broadly consistent with available data concerning reionization, particularly the Thomson scattering optical depth constraints from Wilkinson Microwave Anisotropy Probe (WMAP). In comparison with previous EBL studies up to z ~ 3-5, our predicted γγ opacity is in general agreement for observed gamma-ray energy below 400/(1 + z) GeV, whereas it is a factor of ~2 lower above this energy because of a correspondingly lower cosmic star formation rate, even though the observed ultraviolet (UV) luminosity is well reproduced by virtue of our improved treatment of dust obscuration and direct estimation of star formation rate. Moreover, the horizon energy at which the gamma-ray opacity is unity does not evolve strongly beyond z ~ 4 and approaches ~20 GeV. The contribution of Population III stars is a minor fraction of the EBL at z = 0, and is also difficult to distinguish through gamma-ray absorption in high-z objects, even at the highest levels allowed by the WMAP constraints. Nevertheless, the attenuation due to Population II stars should be observable in high-z gamma-ray sources by telescopes such as Fermi or the Cherenkov Telescope Array and provide a valuable probe of the evolving EBL in the rest-frame UV. Our detailed results of our model are publicly available in numerical form at http://www.slac.stanford.edu/~yinoue/Download.html.

  6. CANDELS: THE COSMIC ASSEMBLY NEAR-INFRARED DEEP EXTRAGALACTIC LEGACY SURVEY—THE HUBBLE SPACE TELESCOPE OBSERVATIONS, IMAGING DATA PRODUCTS, AND MOSAICS

    International Nuclear Information System (INIS)

    Koekemoer, Anton M.; Ferguson, Henry C.; Grogin, Norman A.; Lotz, Jennifer M.; Lucas, Ray A.; Ogaz, Sara; Rajan, Abhijith; Casertano, Stefano; Dahlen, Tomas; Faber, S. M.; Kocevski, Dale D.; Koo, David C.; Lai, Kamson; McGrath, Elizabeth J.; Riess, Adam G.; Rodney, Steve A.; Dolch, Timothy; Strolger, Louis; Castellano, Marco; Dickinson, Mark

    2011-01-01

    This paper describes the Hubble Space Telescope imaging data products and data reduction procedures for the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS). This survey is designed to document the evolution of galaxies and black holes at z ≈ 1.5-8, and to study Type Ia supernovae at z > 1.5. Five premier multi-wavelength sky regions are selected, each with extensive multi-wavelength observations. The primary CANDELS data consist of imaging obtained in the Wide Field Camera 3 infrared channel (WFC3/IR) and the WFC3 ultraviolet/optical channel, along with the Advanced Camera for Surveys (ACS). The CANDELS/Deep survey covers ∼125 arcmin 2 within GOODS-N and GOODS-S, while the remainder consists of the CANDELS/Wide survey, achieving a total of ∼800 arcmin 2 across GOODS and three additional fields (Extended Groth Strip, COSMOS, and Ultra-Deep Survey). We summarize the observational aspects of the survey as motivated by the scientific goals and present a detailed description of the data reduction procedures and products from the survey. Our data reduction methods utilize the most up-to-date calibration files and image combination procedures. We have paid special attention to correcting a range of instrumental effects, including charge transfer efficiency degradation for ACS, removal of electronic bias-striping present in ACS data after Servicing Mission 4, and persistence effects and other artifacts in WFC3/IR. For each field, we release mosaics for individual epochs and eventual mosaics containing data from all epochs combined, to facilitate photometric variability studies and the deepest possible photometry. A more detailed overview of the science goals and observational design of the survey are presented in a companion paper.

  7. LUMINOUS AND HIGH STELLAR MASS CANDIDATE GALAXIES AT z ≈ 8 DISCOVERED IN THE COSMIC ASSEMBLY NEAR-INFRARED DEEP EXTRAGALACTIC LEGACY SURVEY

    International Nuclear Information System (INIS)

    Yan Haojing; Finkelstein, Steven L.; Huang, Kuang-Han; Ryan, Russell E.; Ferguson, Henry C.; Koekemoer, Anton M.; Grogin, Norman A.; Dickinson, Mark; Newman, Jeffrey A.; Somerville, Rachel S.; Davé, Romeel; Faber, S. M.; Papovich, Casey; Guo Yicheng; Giavalisco, Mauro; Lee, Kyoung-soo; Reddy, Naveen; Siana, Brian D.; Cooray, Asantha R.; Hathi, Nimish P.

    2012-01-01

    One key goal of the Hubble Space Telescope Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey is to track galaxy evolution back to z ≈ 8. Its two-tiered ''wide and deep'' strategy bridges significant gaps in existing near-infrared surveys. Here we report on z ≈ 8 galaxy candidates selected as F105W-band dropouts in one of its deep fields, which covers 50.1 arcmin 2 to 4 ks depth in each of three near-infrared bands in the Great Observatories Origins Deep Survey southern field. Two of our candidates have J 1 mag brighter than any previously known F105W-dropouts. We derive constraints on the bright end of the rest-frame ultraviolet luminosity function of galaxies at z ≈ 8, and show that the number density of such very bright objects is higher than expected from the previous Schechter luminosity function estimates at this redshift. Another two candidates are securely detected in Spitzer Infrared Array Camera images, which are the first such individual detections at z ≈ 8. Their derived stellar masses are on the order of a few × 10 9 M ☉ , from which we obtain the first measurement of the high-mass end of the galaxy stellar mass function at z ≈ 8. The high number density of very luminous and very massive galaxies at z ≈ 8, if real, could imply a large stellar-to-halo mass ratio and an efficient conversion of baryons to stars at such an early time.

  8. Cosmological constraints on dark matter annihilation and decay. Cross-correlation analysis of the extragalactic γ-ray background and cosmic shear

    International Nuclear Information System (INIS)

    Shirasaki, Masato; Macias, Oscar; Horiuchi, Shunsaku; Yoshida, Naoki; Tokyo Univ., Chiba; Japan Science and Technology Agency, Saitama

    2016-07-01

    We derive constraints on dark matter (DM) annihilation cross section and decay lifetime from cross-correlation analyses of the data from Fermi-LAT and weak lensing surveys that cover a wide area of ∝660 squared degrees in total. We improve upon our previous analyses by using an updated extragalactic γ-ray background data reprocessed with the Fermi Pass 8 pipeline, and by using well-calibrated shape measurements of about twelve million galaxies in the Canada-France-Hawaii Lensing Survey (CFHTLenS) and Red-Cluster-Sequence Lensing Survey (RCSLenS). We generate a large set of full-sky mock catalogs from cosmological N-body simulations and use them to estimate statistical errors accurately. The measured cross correlation is consistent with null detection, which is then used to place strong cosmological constraints on annihilating and decaying DM. For leptophilic DM, the constraints are improved by a factor of ∝ 100 in the mass range of O(1) TeV when including contributions from secondary γ rays due to the inverse-Compton upscattering of background photons. Annihilation cross-sections of left angle σν right angle ∝ 10"-"2"3 cm"3/s are excluded for TeV-scale DM depending on channel. Lifetimes of ∝10"2"5 sec are also excluded for the decaying TeV-scale DM. Finally, we apply this analysis to wino DM and exclude the wino mass around 200 GeV. These constraints will be further tightened, and all the interesting wino DM parameter region can be tested, by using data from future wide-field cosmology surveys.

  9. The VIMOS Public Extragalactic Redshift Survey (VIPERS). An unprecedented view of galaxies and large-scale structure at 0.5 < z < 1.2

    Science.gov (United States)

    Guzzo, L.; Scodeggio, M.; Garilli, B.; Granett, B. R.; Fritz, A.; Abbas, U.; Adami, C.; Arnouts, S.; Bel, J.; Bolzonella, M.; Bottini, D.; Branchini, E.; Cappi, A.; Coupon, J.; Cucciati, O.; Davidzon, I.; De Lucia, G.; de la Torre, S.; Franzetti, P.; Fumana, M.; Hudelot, P.; Ilbert, O.; Iovino, A.; Krywult, J.; Le Brun, V.; Le Fèvre, O.; Maccagni, D.; Małek, K.; Marulli, F.; McCracken, H. J.; Paioro, L.; Peacock, J. A.; Polletta, M.; Pollo, A.; Schlagenhaufer, H.; Tasca, L. A. M.; Tojeiro, R.; Vergani, D.; Zamorani, G.; Zanichelli, A.; Burden, A.; Di Porto, C.; Marchetti, A.; Marinoni, C.; Mellier, Y.; Moscardini, L.; Nichol, R. C.; Percival, W. J.; Phleps, S.; Wolk, M.

    2014-06-01

    We describe the construction and general features of VIPERS, the VIMOS Public Extragalactic Redshift Survey. This ESO Large Programme is using the Very Large Telescope with the aim of building a spectroscopic sample of ~ 100 000 galaxies with iABcontamination is found to be only 3.2%, endorsing the quality of the star-galaxy separation process and fully confirming the original estimates based on the VVDS data, which also indicate a galaxy incompleteness from this process of only 1.4%. Using a set of 1215 repeated observations, we estimate an rms redshift error σz/ (1 + z) = 4.7 × 10-4 and calibrate the internal spectral quality grading. Benefiting from the combination of size and detailed sampling of this dataset, we conclude by presenting a map showing in unprecedented detail the large-scale distribution of galaxies between 5 and 8 billion years ago. Based on observations collected at the European Southern Observatory, Cerro Paranal, Chile, using the Very Large Telescope under programmes 182.A-0886 and partly 070.A-9007. Also based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. This work is based in part on data products produced at TERAPIX and the Canadian Astronomy Data Centre as part of the Canada-France-Hawaii Telescope Legacy Survey, a collaborative project of NRC and CNRS. The VIPERS website is http://www.vipers.inaf.it/

  10. Robust Foregrounds Removal for 21-cm Experiments

    Science.gov (United States)

    Mertens, F.; Ghosh, A.; Koopmans, L. V. E.

    2018-05-01

    Direct detection of the Epoch of Reionization via the redshifted 21-cm line will have unprecedented implications on the study of structure formation in the early Universe. To fulfill this promise current and future 21-cm experiments will need to detect the weak 21-cm signal over foregrounds several order of magnitude greater. This requires accurate modeling of the galactic and extragalactic emission and of its contaminants due to instrument chromaticity, ionosphere and imperfect calibration. To solve for this complex modeling, we propose a new method based on Gaussian Process Regression (GPR) which is able to cleanly separate the cosmological signal from most of the foregrounds contaminants. We also propose a new imaging method based on a maximum likelihood framework which solves for the interferometric equation directly on the sphere. Using this method, chromatic effects causing the so-called ``wedge'' are effectively eliminated (i.e. deconvolved) in the cylindrical (k⊥, k∥) power spectrum.

  11. Galaxy as fundamental calibrator of the extragalactic distance scale. I. The basic scale factors of the galaxy and two kinematic tests of the long and short distance scales

    International Nuclear Information System (INIS)

    de Vaucouleurs, G.

    1983-01-01

    A new version of the oldest approach to estimating the distances of galaxies (direct comparison with our Galaxy) is proposed to relate the extragalactic distance scale to the basic metric, photometric, and kinematic scale factors of the Galaxy. These include the galactocentric distance of the Sun, R/sub sun/, the total magnitude of the Galaxy, M 0 /sub T/, and its spheroidal component, M 0 /sub I/, the galactic rotation velocity of the local standard of rest, V(R/sub sun/), the central velocity dispersion sigma/sub ν/(0) of the spheroidal component, and related parameters. The following ''most probable'' values and their mean errors are adopted from a variety of recent determinations: morphological type of galaxy, SABX(rXs)bc(T = 4 +- 0.5), R/sub sun/ = 8.5 +- 0.5 kpc, M 0 /sub T/(B) = -20.2 +- 0.15, (B-V) 0 /sub T/ = 0.53 +- 0.04, M 0 /sub I/(B) = -18.2 +- 0.3, (B-V) 0 /sub I/ = 0.65 +- 0.05, V(R/sub sun/) = 220 +- 15 km s -1 , sigma/sub ν/(0) = 130 +- 7 km s -1 . 1. The zero points of the Tully-Fisher (T-F) relations, -M 0 /sub T/(B) = a(B)+5(log V/sub M/ -2.2), in the B/sub T/ system, and -M/sup c/(H) = a(H)+10(log W 20 -2.5), in the H/sub -0.5/ system, are determined in terms of the galactocentric distance of the Sun R/sub sun/, and the galactic rotation velocity of the local standard of rest, V(R/sub sun/)equivalentV 0 roughly-equalV/sub M/, or the corresponding line width W 20 . The galactic zero point a(B) agrees within 0.1 mag with that (19.4 +- 0.15) previously derived on the short scale from 11 nearby calibrating galaxies

  12. Extragalactic Gamma-Ray Astrophysics

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    During the last decades, various classes of radio-loud active galactic nuclei have been established as sources of high-energy radiation extending over a very broad range from soft gamma-rays (photon energies E~MeV) up to very-high-energy gamma-rays (E>100 GeV). These include blazars of different types, as well as young and evolved radio galaxies. The observed gamma-ray emission from such implies efficient particle acceleration processes taking place in highly magnetized and relativistic jets produced by supermassive black holes, processes that have yet to be identified and properly understood. In addition, nearby starforming and starburst galaxies, some of which host radio-quiet Seyfert-type nuclei, have been detected in the gamma-ray range as well. In their cases, the observed gamma-ray emission is due to non-thermal activity in the interstellar medium, possibly including also a contribution from accretion disks and nuclear outflows. Finally, the high-energy emission from clusters of galaxies remains elusive...

  13. Infrared emission and extragalactic starbursts

    International Nuclear Information System (INIS)

    Telesco, C.M.

    1985-01-01

    The paper examines the belief that recent star formation plays a significant role in determining many of the infrared properties of galaxies. Pertinent types of infrared observations and the infrared properties of starbursts are briefly summarized. Recently developed models which describe the evolution of starbursts are also considered. (U.K.)

  14. Planck intermediate results. VII. Statistical properties of infrared and radio extragalactic sources from the Planck Early Release Compact Source Catalogue at frequencies between 100 and 857 GHz

    Science.gov (United States)

    Planck Collaboration; Ade, P. A. R.; Aghanim, N.; Argüeso, F.; Arnaud, M.; Ashdown, M.; Atrio-Barandela, F.; Aumont, J.; Baccigalupi, C.; Balbi, A.; Banday, A. J.; Barreiro, R. B.; Battaner, E.; Benabed, K.; Benoît, A.; Bernard, J.-P.; Bersanelli, M.; Bethermin, M.; Bhatia, R.; Bonaldi, A.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Burigana, C.; Cabella, P.; Cardoso, J.-F.; Catalano, A.; Cayón, L.; Chamballu, A.; Chary, R.-R.; Chen, X.; Chiang, L.-Y.; Christensen, P. R.; Clements, D. L.; Colafrancesco, S.; Colombi, S.; Colombo, L. P. L.; Coulais, A.; Crill, B. P.; Cuttaia, F.; Danese, L.; Davis, R. J.; de Bernardis, P.; de Gasperis, G.; de Zotti, G.; Delabrouille, J.; Dickinson, C.; Diego, J. M.; Dole, H.; Donzelli, S.; Doré, O.; Dörl, U.; Douspis, M.; Dupac, X.; Efstathiou, G.; Enßlin, T. A.; Eriksen, H. K.; Finelli, F.; Forni, O.; Fosalba, P.; Frailis, M.; Franceschi, E.; Galeotta, S.; Ganga, K.; Giard, M.; Giardino, G.; Giraud-Héraud, Y.; González-Nuevo, J.; Górski, K. M.; Gregorio, A.; Gruppuso, A.; Hansen, F. K.; Harrison, D.; Henrot-Versillé, S.; Hernández-Monteagudo, C.; Herranz, D.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Holmes, W. A.; Jaffe, T. R.; Jaffe, A. H.; Jagemann, T.; Jones, W. C.; Juvela, M.; Keihänen, E.; Kisner, T. S.; Kneissl, R.; Knoche, J.; Knox, L.; Kunz, M.; Kurinsky, N.; Kurki-Suonio, H.; Lagache, G.; Lähteenmäki, A.; Lamarre, J.-M.; Lasenby, A.; Lawrence, C. R.; Leonardi, R.; Lilje, P. B.; López-Caniego, M.; Macías-Pérez, J. F.; Maino, D.; Mandolesi, N.; Maris, M.; Marshall, D. J.; Martínez-González, E.; Masi, S.; Massardi, M.; Matarrese, S.; Mazzotta, P.; Melchiorri, A.; Mendes, L.; Mennella, A.; Mitra, S.; Miville-Deschènes, M.-A.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Munshi, D.; Murphy, J. A.; Naselsky, P.; Nati, F.; Natoli, P.; Nørgaard-Nielsen, H. U.; Noviello, F.; Novikov, D.; Novikov, I.; Osborne, S.; Pajot, F.; Paladini, R.; Paoletti, D.; Partridge, B.; Pasian, F.; Patanchon, G.; Perdereau, O.; Perotto, L.; Perrotta, F.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Popa, L.; Poutanen, T.; Pratt, G. W.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Reach, W. T.; Rebolo, R.; Reinecke, M.; Renault, C.; Ricciardi, S.; Riller, T.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Rowan-Robinson, M.; Rubiño-Martín, J. A.; Rusholme, B.; Sajina, A.; Sandri, M.; Savini, G.; Scott, D.; Smoot, G. F.; Starck, J.-L.; Sudiwala, R.; Suur-Uski, A.-S.; Sygnet, J.-F.; Tauber, J. A.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Türler, M.; Valenziano, L.; Van Tent, B.; Vielva, P.; Villa, F.; Vittorio, N.; Wade, L. A.; Wandelt, B. D.; White, M.; Yvon, D.; Zacchei, A.; Zonca, A.

    2013-02-01

    We make use of the Planck all-sky survey to derive number counts and spectral indices of extragalactic sources - infrared and radio sources - from the Planck Early Release Compact Source Catalogue (ERCSC) at 100 to 857 GHz (3 mm to 350 μm). Three zones (deep, medium and shallow) of approximately homogeneous coverage are used to permit a clean and controlled correction for incompleteness, which was explicitly not done for the ERCSC, as it was aimed at providing lists of sources to be followed up. Our sample, prior to the 80% completeness cut, contains between 217 sources at 100 GHz and 1058 sources at 857 GHz over about 12 800 to 16 550 deg2 (31 to 40% of the sky). After the 80% completeness cut, between 122 and 452 and sources remain, with flux densities above 0.3 and 1.9 Jy at 100 and 857 GHz. The sample so defined can be used for statistical analysis. Using the multi-frequency coverage of the Planck High Frequency Instrument, all the sources have been classified as either dust-dominated (infrared galaxies) or synchrotron-dominated (radio galaxies) on the basis of their spectral energy distributions (SED). Our sample is thus complete, flux-limited and color-selected to differentiate between the two populations. We find an approximately equal number of synchrotron and dusty sources between 217 and 353 GHz; at 353 GHz or higher (or 217 GHz and lower) frequencies, the number is dominated by dusty (synchrotron) sources, as expected. For most of the sources, the spectral indices are also derived. We provide for the first time counts of bright sources from 353 to 857 GHz and the contributions from dusty and synchrotron sources at all HFI frequencies in the key spectral range where these spectra are crossing. The observed counts are in the Euclidean regime. The number counts are compared to previously published data (from earlier Planck results, Herschel, BLAST, SCUBA, LABOCA, SPT, and ACT) and models taking into account both radio or infrared galaxies, and covering a

  15. THE COSMIC INFRARED BACKGROUND EXPERIMENT (CIBER): THE WIDE-FIELD IMAGERS

    Energy Technology Data Exchange (ETDEWEB)

    Bock, J.; Battle, J. [Jet Propulsion Laboratory (JPL), National Aeronautics and Space Administration (NASA), Pasadena, CA 91109 (United States); Sullivan, I. [Department of Physics, University of Washington, Seattle, WA 98195 (United States); Arai, T.; Matsumoto, T.; Matsuura, S.; Tsumura, K. [Department of Space Astronomy and Astrophysics, Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara, Kanagawa 252-5210 (Japan); Cooray, A.; Mitchell-Wynne, K.; Smidt, J. [Center for Cosmology, University of California, Irvine, CA 92697 (United States); Hristov, V.; Lam, A. C.; Levenson, L. R.; Mason, P. [Department of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Keating, B.; Renbarger, T. [Department of Physics, University of California, San Diego, San Diego, CA 92093 (United States); Kim, M. G. [Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); Lee, D. H. [Institute of Astronomy and Astrophysics, Academia Sinica, National Taiwan University, Taipei 10617, Taiwan (China); Nam, U. W. [Korea Astronomy and Space Science Institute (KASI), Daejeon 305-348 (Korea, Republic of); Suzuki, K. [Instrument Development Group of Technical Center, Nagoya University, Nagoya, Aichi 464-8602 (Japan); and others

    2013-08-15

    We have developed and characterized an imaging instrument to measure the spatial properties of the diffuse near-infrared extragalactic background light (EBL) in a search for fluctuations from z > 6 galaxies during the epoch of reionization. The instrument is part of the Cosmic Infrared Background Experiment (CIBER), designed to observe the EBL above Earth's atmosphere during a suborbital sounding rocket flight. The imaging instrument incorporates a 2 Degree-Sign Multiplication-Sign 2 Degree-Sign field of view to measure fluctuations over the predicted peak of the spatial power spectrum at 10 arcmin, and 7'' Multiplication-Sign 7'' pixels, to remove lower redshift galaxies to a depth sufficient to reduce the low-redshift galaxy clustering foreground below instrumental sensitivity. The imaging instrument employs two cameras with {Delta}{lambda}/{lambda} {approx} 0.5 bandpasses centered at 1.1 {mu}m and 1.6 {mu}m to spectrally discriminate reionization extragalactic background fluctuations from local foreground fluctuations. CIBER operates at wavelengths where the electromagnetic spectrum of the reionization extragalactic background is thought to peak, and complements fluctuation measurements by AKARI and Spitzer at longer wavelengths. We have characterized the instrument in the laboratory, including measurements of the sensitivity, flat-field response, stray light performance, and noise properties. Several modifications were made to the instrument following a first flight in 2009 February. The instrument performed to specifications in three subsequent flights, and the scientific data are now being analyzed.

  16. New Theoretical Estimates of the Contribution of Unresolved Star-Forming Galaxies to the Extragalactic Gamma-Ray Background (EGB) as Measured by EGRET and the Fermi-LAT

    Science.gov (United States)

    Venters, Tonia M.

    2011-01-01

    We present new theoretical estimates of the contribution of unresolved star-forming galaxies to the extragalactic gamma-ray background (EGB) as measured by EGRET and the Fermi-LAT. We employ several methods for determining the star-forming galaxy contribution the the EGB, including a method positing a correlation between the gamma-ray luminosity of a galaxy and its rate of star formation as calculated from the total infrared luminosity, and a method that makes use of a model of the evolution of the galaxy gas mass with cosmic time. We find that depending on the model, unresolved star-forming galaxies could contribute significantly to the EGB as measured by the Fermi-LAT at energies between approx. 300 MeV and approx. few GeV. However, the overall spectrum of unresolved star-forming galaxies can explain neither the EGRET EGB spectrum at energies between 50 and 200 MeV nor the Fermi-LAT EGB spectrum at energies above approx. few GeV.

  17. Real-Time Cosmology with Gaia: Developing the Theory to Use Extragalactic Proper Motions to Make Dynamical Cosmological Tests, to Measure Geometric Distances, and to Detect Primordial Gravitational Waves

    Science.gov (United States)

    Darling, Jeremy

    A new field of study, "real-time cosmology," is now possible. This involves observing a dynamic universe that can be seen to change over human timescales. Most cosmological observations are geometrical, using standard candles or rulers to measure the expansion history and curvature as light propagates through the universe. Real-time cosmological measurements are dynamical, revealing the changing geometry of the universe - thus often providing geometrical distances independent of the canonical cosmological distance ladder - and are typically orthogonal to customary cosmological tests. This field of inquiry is no longer far-fetched, and this proposal demonstrates using extant data that many types of measurement are now within a factor of a few of being detectable, but the theory will very soon lag the observational capabilities. The Gaia mission will provide astrometry and proper motions of roughly 100 microarcseconds per year for half a million quasars by the end of its 5-year mission, but the theory for how to employ these data for cosmological tests has not been established. This project will develop the theory, models, and methods needed to make optimal use of the Gaia extragalactic proper motion measurements and to make significant new cosmological tests, distance measurements, and mass measurements. Gaia data can provide rich cosmological tests that are nearly model-independent. This work will build the theoretical framework enabling Gaia to measure or constrain: (1) The real-time growth and recession of structures, providing mass and distance measurements, (2) Extragalactic parallax for a statistical sample and individual galaxies, thus providing geometric distances, (3) The primordial stochastic long-period gravitational wave background, which deflects quasar light in a quadrupolar proper motion pattern, and (4) Cosmic shear, rotation, bulk motion, and local voids that may manifest as an apparent acceleration attributed to dark energy. One can also test the

  18. Deriving the Contribution of Blazars to the Fermi-LAT Extragalactic γ-ray Background at E > 10 GeV with Efficiency Corrections and Photon Statistics

    Science.gov (United States)

    Di Mauro, M.; Manconi, S.; Zechlin, H.-S.; Ajello, M.; Charles, E.; Donato, F.

    2018-04-01

    The Fermi Large Area Telescope (LAT) Collaboration has recently released the Third Catalog of Hard Fermi-LAT Sources (3FHL), which contains 1556 sources detected above 10 GeV with seven years of Pass 8 data. Building upon the 3FHL results, we investigate the flux distribution of sources at high Galactic latitudes (| b| > 20^\\circ ), which are mostly blazars. We use two complementary techniques: (1) a source-detection efficiency correction method and (2) an analysis of pixel photon count statistics with the one-point probability distribution function (1pPDF). With the first method, using realistic Monte Carlo simulations of the γ-ray sky, we calculate the efficiency of the LAT to detect point sources. This enables us to find the intrinsic source-count distribution at photon fluxes down to 7.5 × 10‑12 ph cm‑2 s‑1. With this method, we detect a flux break at (3.5 ± 0.4) × 10‑11 ph cm‑2 s‑1 with a significance of at least 5.4σ. The power-law indexes of the source-count distribution above and below the break are 2.09 ± 0.04 and 1.07 ± 0.27, respectively. This result is confirmed with the 1pPDF method, which has a sensitivity reach of ∼10‑11 ph cm‑2 s‑1. Integrating the derived source-count distribution above the sensitivity of our analysis, we find that (42 ± 8)% of the extragalactic γ-ray background originates from blazars.

  19. The Herschel–ATLAS Data Release 2, Paper I. Submillimeter and Far-infrared Images of the South and North Galactic Poles: The Largest Herschel Survey of the Extragalactic Sky

    Science.gov (United States)

    Smith, Matthew W. L.; Ibar, Edo; Maddox, Steve J.; Valiante, Elisabetta; Dunne, Loretta; Eales, Stephen; Dye, Simon; Furlanetto, Christina; Bourne, Nathan; Cigan, Phil; Ivison, Rob J.; Gomez, Haley; Smith, Daniel J. B.; Viaene, Sébastien

    2017-12-01

    We present the largest submillimeter images that have been made of the extragalactic sky. The Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) is a survey of 660 deg2 with the PACS and SPIRE cameras in five photometric bands: 100, 160, 250, 350, and 500 μm. In this paper we present the images from our two largest fields, which account for ∼75% of the survey. The first field is 180.1 deg2 in size, centered on the north Galactic pole (NGP), and the second is 317.6 deg2 in size, centered on the south Galactic pole. The NGP field serendipitously contains the Coma cluster. Over most (∼80%) of the images, the pixel noise, including both instrumental noise and confusion noise, is approximately 3.6, and 3.5 mJy pix‑1 at 100 and 160 μm, and 11.0, 11.1 and 12.3 mJy beam‑1 at 250, 350 and 500 μm, respectively, but reaches lower values in some parts of the images. If a matched filter is applied to optimize point-source detection, our total 1σ map sensitivity is 5.7, 6.0, and 7.3 mJy at 250, 350, and 500 μm, respectively. We describe the results of an investigation of the noise properties of the images. We make the most precise estimate of confusion in SPIRE maps to date, finding values of 3.12 ± 0.07, 4.13 ± 0.02, and 4.45 ± 0.04 mJy beam‑1 at 250, 350, and 500 μm in our un-convolved maps. For PACS we find an estimate of the confusion noise in our fast-parallel observations of 4.23 and 4.62 mJy beam‑1 at 100 and 160 μm. Finally, we give recipes for using these images to carry out photometry, both for unresolved and extended sources.

  20. Extragalactic globular clusters. I. The metallicity calibration

    International Nuclear Information System (INIS)

    Brodie, J.P.; Huchra, J.P.

    1990-01-01

    The ability of absorption-line strength indices, measured from integrated globular cluster spectra, to predict mean cluster metallicity is explored. Statistical criteria, are used to identify the six best indices out of about 20 measured in a large sample of Galactic and M31 cluster spectra. Linear relations between index and metallicity have been derived along with new calibrations of infrared colors (V - K, J - K, and CO) versus Fe/H. Estimates of metallicity from the six spectroscopic index-metallicity relations have been combined in three different ways to identify the most efficient estimator and the minimum bias estimator of Fe/H - the weighted mean. This provides an estimate of Fe/H accurate to about 15 percent. 37 refs

  1. Extragalactic Fields Optimized for Adaptive Optics

    Science.gov (United States)

    2011-03-01

    4Gemini Observatory, Southern Operations Center, c/o AURA, Casilla 603,La Serena, Chile . sObservatories of the Carnegie Institution of Washington...unsuitable anyway. Any such fields would be inaccessible from Chile and be at quite high air mass most of the time for major northem hemisphere...drawback of such a star is not the vertical blooming , which affects a small fraction of the imaging area, but the halos due to internal reflections

  2. Collimation of extragalactic jets: evidence from hotspots

    International Nuclear Information System (INIS)

    Banhatti, D.G.

    1984-01-01

    A linear relation with slope near unity is found between the logarithms of the hotspot size perpendicular to the source major axis and the distance from the core for 14 compact and/ or intense hotspots selected from a sample of 31 quasars having the largest angular sizes at various redshifts, as observed at 4.87 GHz with sub-arcsec resolution. A slope significantly less than 1 implies that the jet feeding the hotspot is laterally confined by the intergalactic medium, whereas a slope of 1 does not distinguish between a laterally confined jet and a free jet. The relation is found to have a slope near 1 implying a 0deg.1 jet confined within a cone of half-angle 15deg to 20deg or a 1deg-wide free jet. (author)

  3. Gamma ray bursts from extragalactic sources

    Science.gov (United States)

    Hoyle, Fred; Burbidge, Geoffrey

    1992-01-01

    The properties of gamma ray bursts of classical type are found to be explicable in terms of high speed collisions between stars. A model is proposed in which the frequency of such collisions can be calculated. The model is then applied to the nuclei of galaxies in general on the basis that galaxies, or at least some fraction of them, originate in the expulsion of stars from creation centers. Evidence that low level activity of this kind is also taking place at the center of our own Galaxy is discussed. The implications for galactic evolution are discussed and a negative view of black holes is taken.

  4. Extragalactic observations with the MAGIC telescopes

    International Nuclear Information System (INIS)

    Shore, S.N.

    2014-01-01

    The MAGIC imaging atmospheric Cherenkov telescopes, both as a single detector and now used in stereo mode, have been observing a variety of active galaxies and galactic clusters for almost a decade. This review provides a brief summary of some of the most recent results for blazars observed in the energy range > 50 GeV to tens of TeV. The very high energy emission observed with MAGIC is essential for disentangling the various contributions and timescales to the observed spectra and variability. (author)

  5. On the origin of extragalactic infrared radiation

    International Nuclear Information System (INIS)

    Yorke, H.W.; Kollatschny, W.

    1985-01-01

    The paper concerns the infrared radiation flux of galaxies in terms of star formation processes and stellar evolution. Phase transitions in the interstellar medium are discussed, as well as stellar evolution and the time dependent appearance of a galaxy. (U.K.)

  6. Observation of extragalactic X-ray sources

    International Nuclear Information System (INIS)

    Bui-Van, Andre.

    1973-01-01

    A narrow angular resolution detection apparatus using a high performance collimator has proved particularly well suited for the programs of observation of X ray sources. The experimental set-up and its performance are described. One chapter deals with the particular problems involved in the observation of X ray sources with the aid of sounding balloons. The absorption of extraterrestrial photons by the earth atmosphere is taken into account in the procesing of the observation data using two methods of calculation: digital and with simulation techniques. The results of three balloon flights are then presented with the interpretation of the observations carried out using both thermal and non thermal emission models. This analysis leads to some possible characteristics of structure of the Perseus galaxy cluster [fr

  7. Physical processes in extragalactic radio sources

    NARCIS (Netherlands)

    Carilli, CL; Perley, R; Harris, DE; Barthel, PD

    This paper summarizes extensive observational studies of the closest ultraluminous radio galaxy Cygnus A. These data are used to test jet theory for powering the double-lobed radio emitting structures. Issues addressed include: (i) jet stability, confinement, composition, and velocity, (ii) the

  8. The extragalactic Universe: an alternative view

    International Nuclear Information System (INIS)

    Arp, H.C.

    1990-01-01

    This article challenges the generally accepted Big Bang model for the origin of the Universe as much observational data does not fit the model, and non-thermal objects with large redshifts such as quasi stellar objects (QSOs) seem to have these values intrinsically and to be closer than was originally postulated. Each of these difficulties is examined in detail. The authors offer several alternative theories which may be moulded into future cosmological models. (UK)

  9. Multivariate Approaches to Classification in Extragalactic Astronomy

    Directory of Open Access Journals (Sweden)

    Didier eFraix-Burnet

    2015-08-01

    Full Text Available Clustering objects into synthetic groups is a natural activity of any science. Astrophysics is not an exception and is now facing a deluge of data. For galaxies, the one-century old Hubble classification and the Hubble tuning fork are still largely in use, together with numerous mono- or bivariate classifications most often made by eye. However, a classification must be driven by the data, and sophisticated multivariate statistical tools are used more and more often. In this paper we review these different approaches in order to situate them in the general context of unsupervised and supervised learning. We insist on the astrophysical outcomes of these studies to show that multivariate analyses provide an obvious path toward a renewal of our classification of galaxies and are invaluable tools to investigate the physics and evolution of galaxies.

  10. FROM GALACTIC TO EXTRAGALACTIC JETS: A REVIEW

    Directory of Open Access Journals (Sweden)

    James H. Beall

    2013-12-01

    Full Text Available An analysis of the data that have recently become available from observing campaigns, including VLA, VLBA, and satellite instruments, shows some remarkable similarities and significant differences in the data from some epochs of galactic microquasars, including GRS 1915+105, the concurrent radio and X-ray data [3] on Centaurus A (NGC 5128, 3C120 [35], and 3C454.3 as reported by Bonning et al. [16], which showed the first results from the Fermi Space Telescope for the concurrent variability at optical, UV, IR, and g-ray variability of that source. In combination with observations from microquasars and quasars from the MOJAVE Collaboration [32], these data provide time-dependent evolutions of radio data at mas (i.e., parsec for AGNs, and Astronomical Unit scales for microquasars. These sources all show a remarkable richness of patterns of variability for astrophysical jets across the entire electromagnetic spectrum. It is likely that these patterns of variability arise from the complex structures through which the jets propagate, but it is also possible that the jets constitution, initial energy, and collimation have significant observational consequences. On the other hand, Ulrich et al. [42] suggest that this picture is complicated for radio-quiet AGN by the presence of significant emission from accretion disks in those sources. Consistent with the jet-ambient-medium hypothesis, the observed concurrent radio and X-ray variability of Centaurus A [3] could have been caused by the launch of a jet element from Cen A’s central source and that jet’s interaction with the interstellar medium in the core region of that galaxy.

  11. The Chemistry of Extragalactic Carbon Stars

    Science.gov (United States)

    Woods, Paul; Walsh, C.; Cordiner, M. A.; Kemper, F.

    2013-01-01

    Prompted by the ongoing interest in Spitzer Infrared Spectrometer spectra of carbon stars in the Large Magellanic Cloud, we have investigated the circumstellar chemistry of carbon stars in low-metallicity environments. Consistent with observations, our models show that acetylene is particularly abundant in the inner regions of low metallicity carbon-rich asymptotic giant branch stars - more abundant than carbon monoxide. As a consequence, larger hydrocarbons have higher abundances at the metallicities of the Magellanic Clouds than in stars with solar metallicity. We also find that the oxygen and nitrogen chemistry is suppressed at lower metallicity, as expected. Finally, we calculate molecular line emission from carbon stars in the Large and Small Magellanic Cloud and find that several molecules should be readily detectable with the Atacama Large Millimeter Array at Full Science operations.

  12. Detection of ultra-high-energy cosmic radiation at the Pierre Auger Observatory, theoretical study of its propagation through extragalactic space; Detection des rayons cosmiques ultra-energetiques avec l'observatoire Pierre Auger et etude theorique de leur propagation dans le milieu extragalactique

    Energy Technology Data Exchange (ETDEWEB)

    Allard, D

    2004-10-01

    The Pierre Auger observatory's main aim is to observe the ultra-energetic cosmic ray spectrum with high statistics. Indeed, the spectrum around 10{sup 20} eV is so far only poorly known, due to low statistics and the expected GZK (Gneisen-Zatsepin-Kuzmin) cut-off is for the time being not clearly observed. The first part will deal with propagation of charged (protons and nuclei) ultra-energetic cosmic rays in the extragalactic medium. We will investigate the influence of physical parameters, such as the composition of cosmic ray fluxes, on the highest energy spectrum shape. The influence of the turbulent extragalactic magnetic fields on the spectrum of the clusters will also be studied. We will also investigate the possibility to observe gamma ray bursts with the Pierre Auger Observatory by using the single particle technique. We will show how galactic gamma ray bursts could become a persistent and quasi-isotropic source due to the 'Compton trail' induced by Compton scattering of the primary photon beam in the interstellar medium. In the section devoted to simulations, we will develop methods to reconstruct air showers and identify primary cosmic rays. We will also study the aperture of the Surface Detector of the Pierre Auger observatory. Finally, we will use the methods developed in the previous chapters to analyze the data of the year 2004 and will give preliminary results. (author)

  13. Advantages of pre-production WLCG/EGEE services for VOs and users

    CERN Document Server

    Thackray, N; Fernandez Sanchez, C; Freire Garcia, E; Simon Garcia, A; Lopez Cacheiro, J

    2008-01-01

    The benefits that the Pre-Production Service (PPS) can offer to VOs and new users will be shown. Current PPS processes will be described so they have a better understanding of the PPS environment. PPS offers a proper place where VOs can test their applications and check their compatibility with upcoming middleware releases. PPS could help VOs improve their applications and at the same time, VOs would be helping PPS to produce better tested middleware releases that would go into Production (PROD) Currently a well-defined set of procedures is followed in PPS, beginning with the pre-deployment activity and finishing with the approval of a new middleware release that can go into PROD. The PPS Coordination Team takes care of supervising all these steps, mainly trying to spot possible bugs in the middleware before it goes into PROD. Unfortunately, VO contribution in this part of the deployment is currently very limited and the PPS team does not have a full feedback from these important groups. One of the problems i...

  14. The VIMOS Public Extragalactic Redshift Survey (VIPERS). An unbiased estimate of the growth rate of structure at ⟨z⟩ = 0.85 using the clustering of luminous blue galaxies

    Science.gov (United States)

    Mohammad, F. G.; Granett, B. R.; Guzzo, L.; Bel, J.; Branchini, E.; de la Torre, S.; Moscardini, L.; Peacock, J. A.; Bolzonella, M.; Garilli, B.; Scodeggio, M.; Abbas, U.; Adami, C.; Bottini, D.; Cappi, A.; Cucciati, O.; Davidzon, I.; Franzetti, P.; Fritz, A.; Iovino, A.; Krywult, J.; Le Brun, V.; Le Fèvre, O.; Maccagni, D.; Małek, K.; Marulli, F.; Polletta, M.; Pollo, A.; Tasca, L. A. M.; Tojeiro, R.; Vergani, D.; Zanichelli, A.; Arnouts, S.; Coupon, J.; De Lucia, G.; Ilbert, O.; Moutard, T.

    2018-02-01

    We used the VIMOS Public Extragalactic Redshift Survey (VIPERS) final data release (PDR-2) to investigate the performance of colour-selected populations of galaxies as tracers of linear large-scale motions. We empirically selected volume-limited samples of blue and red galaxies as to minimise the systematic error on the estimate of the growth rate of structure fσ8 from the anisotropy of the two-point correlation function. To this end, rather than rigidly splitting the sample into two colour classes we defined the red or blue fractional contribution of each object through a weight based on the (U - V ) colour distribution. Using mock surveys that are designed to reproduce the observed properties of VIPERS galaxies, we find the systematic error in recovering the fiducial value of fσ8 to be minimised when using a volume-limited sample of luminous blue galaxies. We modelled non-linear corrections via the Scoccimarro extension of the Kaiser model (with updated fitting formulae for the velocity power spectra), finding systematic errors on fσ8 of below 1-2%, using scales as small as 5 h-1 Mpc. We interpret this result as indicating that selection of luminous blue galaxies maximises the fraction that are central objects in their dark matter haloes; this in turn minimises the contribution to the measured ξ(rp,π) from the 1-halo term, which is dominated by non-linear motions. The gain is inferior if one uses the full magnitude-limited sample of blue objects, consistent with the presence of a significant fraction of blue, fainter satellites dominated by non-streaming, orbital velocities. We measured a value of fσ8 = 0.45 ± 0.11 over the single redshift range 0.6 ≤ z ≤ 1.0, corresponding to an effective redshift for the blue galaxies ⟨z⟩=0.85. Including in the likelihood the potential extra information contained in the blue-red galaxy cross-correlation function does not lead to an appreciable improvement in the error bars, while it increases the systematic error

  15. Customer experience

    OpenAIRE

    Koperdáková, Zuzana

    2016-01-01

    Bachelor thesis deals with the theme of customer experience and terms related to this topic. The thesis consists of three parts. The first part explains the terms generally, as the experience or customer loyalty. The second part is dedicated to medotology used for Customer Experience Management. In the third part is described application of Customer Experience Management in practice, particularly in the context Touch Point Analyses in GE Money Bank.

  16. Intercropping of corn with cowpea and bean: Biomass yield and ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-11-19

    Nov 19, 2008 ... An experiment was carried out at the Bornova experimental fields of Field Crops Department of Agriculture. Faculty., Ege Univ. .... design with three replicates. ... Corn plant height increased in the mixture with legumes and the ...

  17. Key European Grid event to take place in Geneva

    CERN Multimedia

    2006-01-01

    EGEE'06 is the main conference of the EGEE project, which is co-funded by the European Union and hosted by CERN. More than 90 partners all over Europe and beyond are working together in EGEE to provide researchers in both academia and industry with access to major computing resources, independent of their geographic location. The largest user community of the EGEE Grid is the High-Energy Physics community and in particular the LHC experiments, which are already making heavy use of the infrastructure to prepare for data taking. However, with the many new challenges faced by EGEE in its second phase that started in April this year, an even broader audience than at previous EGEE conferences is expected. In particular, a large number of related Grid projects will feature prominently in both plenary and parallel sessions during the 5 days of this event. Industry will also be well represented, highlighting the EGEE project's commitment to technology transfer to industry. CERN is the host of the conference, which i...

  18. THE COSMIC INFRARED BACKGROUND EXPERIMENT (CIBER): THE LOW RESOLUTION SPECTROMETER

    Energy Technology Data Exchange (ETDEWEB)

    Tsumura, K.; Arai, T.; Matsumoto, T.; Matsuura, S.; Murata, K. [Department of Space Astronomy and Astrophysics, Institute of Space and Astronoutical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara, Kanagawa 252-5210 (Japan); Battle, J.; Bock, J. [Jet Propulsion Laboratory (JPL), National Aeronautics and Space Administration (NASA), Pasadena, CA 91109 (United States); Brown, S.; Lykke, K.; Smith, A. [Optical Technology Division, National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899 (United States); Cooray, A. [Center for Cosmology, University of California, Irvine, Irvine, CA 92697 (United States); Hristov, V.; Levenson, L. R.; Mason, P. [Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Keating, B.; Renbarger, T. [Department of Physics, University of California, San Diego, San Diego, CA 92093 (United States); Kim, M. G. [Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); Lee, D. H.; Nam, U. W. [Korea Astronomy and Space Science Institute (KASI), Daejeon 305-348 (Korea, Republic of); Sullivan, I., E-mail: tsumura@ir.isas.jaxa.jp [Department of Physics, The University of Washington, Seattle, WA 98195 (United States); and others

    2013-08-15

    Absolute spectrophotometric measurements of diffuse radiation at 1 {mu}m to 2 {mu}m are crucial to our understanding of the radiative content of the universe from nucleosynthesis since the epoch of reionization, the composition and structure of the zodiacal dust cloud in our solar system, and the diffuse galactic light arising from starlight scattered by interstellar dust. The Low Resolution Spectrometer (LRS) on the rocket-borne Cosmic Infrared Background Experiment is a {lambda}/{Delta}{lambda} {approx} 15-30 absolute spectrophotometer designed to make precision measurements of the absolute near-infrared sky brightness between 0.75 {mu}m <{lambda} < 2.1 {mu}m. This paper presents the optical, mechanical, and electronic design of the LRS, as well as the ground testing, characterization, and calibration measurements undertaken before flight to verify its performance. The LRS is shown to work to specifications, achieving the necessary optical and sensitivity performance. We describe our understanding and control of sources of systematic error for absolute photometry of the near-infrared extragalactic background light.

  19. Pixel Experiments

    DEFF Research Database (Denmark)

    Petersen, Kjell Yngve; Søndergaard, Karin; Augustesen, Christina

    2015-01-01

    Pixel Experiments The term pixel is traditionally defined as any of the minute elements that together constitute a larger context or image. A pixel has its own form and is the smallest unit seen within a larger structure. In working with the potentials of LED technology in architectural lighting...... for using LED lighting in lighting design practice. The speculative experiments that have been set-up have aimed to clarify the variables that can be used as parameters in the design of lighting applications; including, for example, the structuring and software control of light. The experiments also...... elucidate and exemplify already well-known problems in relation to the experience of vertical and horizontal lighting. Pixel Experiments exist as a synergy between speculative test setups and lighting design in practice. This book is one of four books that is published in connection with the research...

  20. TRIO experiment

    International Nuclear Information System (INIS)

    Clemmer, R.G.; Finn, P.A.; Malecha, R.F.

    1984-09-01

    The TRIO experiment is a test of in-situ tritium recovery and heat transfer performance of a miniaturized solid breeder blanket assembly. The assembly (capsule) was monitored for temperature and neutron flux profiles during irradiation and a sweep gas flowed through the capsule to an anaytical train wherein the amounts of tritium in its various chemical forms were determined. The capsule was designed to operate at different temperatures and sweep gas conditions. At the end of the experiment the amount of tritium retained in the solid was at a concentration of less than 0.1 wppM. More than 99.9% of tritium generated during the experiment was successfully recovered. The results of the experiment showed that the tritium inventories at the beginning and at the end of the experiment follow a relationship which appears to be characteristic of intragranular diffusion

  1. Classic experiments

    CERN Multimedia

    CERN. Geneva; Franklin, M

    2001-01-01

    These will be a set of lectures on classic particle physics experiments, with emphasis on how the emasurements are made. I will discuss experiments made to measure the electric charge distribution of particles, to measure the symmetries of the weak decays, to measure the magnetic moment of the muon. As well as experiments performed which discovered new particles or resonances, like the tAU2and the J/Psi. The coverage will be general and should be understandable to someone knowing little particle physics.

  2. Simulated experiments

    International Nuclear Information System (INIS)

    Bjerknes, R.

    1977-01-01

    A cybernetic model has been developed to elucidate some of the main principles of the growth regulation system in the epidermis of the hairless mouse. A number of actual and theoretical biological experiments have been simulated on the model. These included simulating the cell kinetics as measured by pulse labelling with tritiated thymidine and by continuous labelling with tritiated thymidine. Other simulated experiments included steady state, wear and tear, painting with a carcinogen, heredity and heredity and tumour. Numerous diagrams illustrate the results of these simulated experiments. (JIW)

  3. Researching experiences

    DEFF Research Database (Denmark)

    Gjedde, Lisa; Ingemann, Bruno

    In the beginning was - not the word - but the experience. This phenomenological approach provides the basis for this book, which focuses on how a person-in-situation experiences and constructs meaning from a variety of cultural visual events. This book presents video-based processual methods......, dialogue, moods, values and narratives have been investigated qualitatively with more than sixty informants in a range of projects. The processual methodological insights are put into a theoretical perspective and also presented as pragmatic dilemmas. Researching Experiences is relevant not only...

  4. Antimatter Experiments

    CERN Multimedia

    2004-01-01

    Antimatter should behave in identical fashion to matter if a form of spacetime symmetry called CPT invariance holds. Two experiments at CERN near Geneva are testing this hypothesis using antihydrogen atoms

  5. Pixel Experiments

    DEFF Research Database (Denmark)

    Petersen, Kjell Yngve; Søndergaard, Karin; Augustesen, Christina

    2015-01-01

    Pixel Experiments The term pixel is traditionally defined as any of the minute elements that together constitute a larger context or image. A pixel has its own form and is the smallest unit seen within a larger structure. In working with the potentials of LED technology in architectural lighting...... lighting design in practice, one quickly experiences and realises that there are untapped potentials in the attributes of LED technology. In this research, speculative studies have been made working with the attributes of LEDs in architectural contexts, with the ambition to ascertain new strategies...... for using LED lighting in lighting design practice. The speculative experiments that have been set-up have aimed to clarify the variables that can be used as parameters in the design of lighting applications; including, for example, the structuring and software control of light. The experiments also...

  6. Experiment Databases

    Science.gov (United States)

    Vanschoren, Joaquin; Blockeel, Hendrik

    Next to running machine learning algorithms based on inductive queries, much can be learned by immediately querying the combined results of many prior studies. Indeed, all around the globe, thousands of machine learning experiments are being executed on a daily basis, generating a constant stream of empirical information on machine learning techniques. While the information contained in these experiments might have many uses beyond their original intent, results are typically described very concisely in papers and discarded afterwards. If we properly store and organize these results in central databases, they can be immediately reused for further analysis, thus boosting future research. In this chapter, we propose the use of experiment databases: databases designed to collect all the necessary details of these experiments, and to intelligently organize them in online repositories to enable fast and thorough analysis of a myriad of collected results. They constitute an additional, queriable source of empirical meta-data based on principled descriptions of algorithm executions, without reimplementing the algorithms in an inductive database. As such, they engender a very dynamic, collaborative approach to experimentation, in which experiments can be freely shared, linked together, and immediately reused by researchers all over the world. They can be set up for personal use, to share results within a lab or to create open, community-wide repositories. Here, we provide a high-level overview of their design, and use an existing experiment database to answer various interesting research questions about machine learning algorithms and to verify a number of recent studies.

  7. The Experiment

    Science.gov (United States)

    Mariana Nicoara, Floare

    2016-04-01

    My name is Nicoara Floarea and I am teacher at Secondary School Calatele and I teach students from preparatory class and the second grade . They are six-eight years old. In my activity, for introducing scientific concepts to my students, I use various and active methods or traditional methods including experiments. The experiment stimulates students' curiosity, their creativity, the understanding and knowledge taught accessibility. I propose you two such experiments: The life cycle of the plants (long-term experiment, with rigorous observation time):We use beans, wheat or other; They are grown in pots and on the cotton soaked with water,keeping under students' observation protecting them ( just soak them regularly) and we waiting the plants rise. For discussions and comments of plant embryo development we use the plants which rose on the cotton soaked with water plants at the end of the first week. Last school year we had in the pot climbing beans which in May made pods. They were not too great but our experiment was a success. The students could deduce that there will develop those big beans which after drying will be planted again. The influence of light on plants (average duration experiment with the necessary observation time): We use two pots in which plants are of the same type (two geraniums), one of them is situated so as to get direct sunlight and other plant we put in a closed box. Although we wet both plants after a week we see that the plant that benefited from sunlight has turned strain in direct sunlight, developing normally in return the plant out of the box I have yellowed leaves, photosynthesis does not She has occurred . Students will understand the vital role of the Sun in plants' life, both in the classroom and in nature. The experiment is a method of teaching students extremely pleasant, with a remarkable percentage of acquiring more knowledge.

  8. Collaborative experience

    DEFF Research Database (Denmark)

    Mortensen, Thomas Bøtker

    -Doerr, 1996) and has been shown to have a positive effect to the outcome of collaborative R&D (Sampson, 2005). Anand & Khanna (2000), furthermore, hypothesized that research joint ventures are more ambiguous than marketing joint ventures and even more the licensing and showed that the effect of collaborative......Literature review: Collaborative experience has been shown to have a positive effect on the collaborative outcome in general (Anand & Khanna, 2000; Kale, Dyer & Singh, 2002). Furthermore, it has been linked to the ability to exploit the network of the firm for learning (Powell, Koput and Smith...... experience was largest the higher the hypothesized ambiguity. Theoretically contribution: This research project aims at contributing to existing literature by arguing, that collaborative experience is a moderating variable which moderates the effects on collaborative outcome from the level of complexity...

  9. Channeling experiment

    International Nuclear Information System (INIS)

    Abelin, H.; Birgersson, L.; Widen, H.; Aagren, T.; Moreno, L.; Neretnieks, I.

    1990-07-01

    Channeling of water flow and tracer transport in real fractures in a granite body at Stripa have been investigated experimentally. The experimental site was located 360 m below the ground level. Two kinds of experiments were performed. In the single hole experiments, 20 cm diameter holes were drilled about 2.5 m into the rock in the plane of the fracture. Specially designed packers were used to inject water into the fracture in 5 cm intervals all along the fracture trace in the hole. The variation of the injection flowrates along the fracture were used to determine the transmissivity variations in the fracture plane. Detailed photographs were taken from inside the hole and the visual fracture aperture was compared with the injection flowrates in the same locations. Geostatistical methods were used to evaluate the results. Five holes were measured in great detail. In addition 7 holes were drilled and scanned by simpler packer systems. A double hole experiment was performed where two parallel holes were drilled in the same fracture plane at nearly 2 m distance. Pressure pulse tests were made between the holes in both directions. Tracers were injected in 5 locations in one hole and monitored for in many locations in the other hole. The single hole experiment and the double hole experiment show that most of the fracture planes are tight but that there are open sections which form connected channels over distances of at least 2 meters. It was also found in the double hole experiment that the investigated fracture was intersected by at least one fracture between the two holes which diverted a large amount of the injected tracers to several distant locations at the tunnel wall. (authours)

  10. Poetic Experience

    Directory of Open Access Journals (Sweden)

    Shahab Yar Khan

    2014-01-01

    Full Text Available Nature of poetic experience is hereby redefined. The present article initially deals with the perennial nature of true poetic experience and its essential relevance to the world. It attempts to elaborate the process through which a poet is uplifted in a creative moment beyond terrestrial boundaries and is aligned with the ‘state of Perfection'. The role of successive generations of audiences in rediscovering the meaning of a poetic image is defined as life principle of all great poetry. Shakespeare is discussed as the ultimate example of this principle since his popularity remains an irreversible phenomenon

  11. EXPERIENCE WITH

    African Journals Online (AJOL)

    SURGERY DEPT

    Abstract. Background:Island flap techniques currently used in urethroplasty utilize the prepuce and the dorsal penile skin. Our experience with a one-stage island flap urethroplasty for urethral strictures utilizing the ventral penile skin is described. Patients and Method: This is a longitudinal study of seventy six consecutive ...

  12. Impact on Health-Related Quality of Life in Adults with Eosinophilic Gastritis and Gastroenteritis: A Qualitative Assessment.

    Science.gov (United States)

    Bedell, Alyse; Taft, Tiffany; Craven, Meredith R; Guadagnoli, Livia; Hirano, Ikuo; Gonsalves, Nirmala

    2018-05-01

    Eosinophilic gastritis (EG) and eosinophilic gastroenteritis (EGE) are chronic immune-mediated conditions of the digestive tract, which affect the stomach only, or the stomach and small intestines, respectively. Though these disorders are uncommon, they are being increasingly recognized and diagnosed. While health-related quality of life (HRQOL) has been evaluated in other eosinophilic gastrointestinal diseases, this study is the first to describe HRQOL impacts unique to EG/EGE. This study aims to qualitatively describe experiences of adults diagnosed with EG and EGE. We aim to identify impacts on HRQOL in this population in order to inform clinical care and assessment. Seven patients diagnosed with EG or EGE participated in semi-structured interviews assessing common domains of HRQOL. Four distinct themes emerged from qualitative analyses, which represent impacts to HRQOL: the psychological impact of the diagnosis, impact on social relationships, financial impact, and impact on the body. These generally improved over time and with effective treatment. This study demonstrated that patients with EG/EGE experience impacts to HRQOL, some of which differ from HRQOL of other eosinophilic gastrointestinal diseases. These results support the development of a disease-specific measure, or adaptation of an existing measure, to assess HRQOL in EG/EGE.

  13. Authoring experience

    DEFF Research Database (Denmark)

    Knox, Jeanette Bresson Ladegaard; Svendsen, Mette Nordahl

    2015-01-01

    This article examines the storytelling aspect inphilosophizing with rehabilitating cancer patients in small Socratic dialogue groups (SDG). Recounting an experienceto illustrate a philosophical question chosen by the participantsis the traditional point of departure for the dialogicalexchange....... However, narrating is much more than abeginning point or the skeletal framework of events and itdeserves more scholarly attention than hitherto given. Storytelling pervades the whole Socratic process and impactsthe conceptual analysis in a SDG. In this article weshow how the narrative aspect became a rich...... an experiencethrough a collaborative effort, most participants hadtheir initial experience existentially refined and the chosenconcept of which the experience served as an illustrationtransformed into a moral compass to be used in self-orientationpost cancer....

  14. Dirac experiment

    International Nuclear Information System (INIS)

    Gomez, F.; Adeva, B.; Afanasev, L.; Benayoun, M.; Brekhovskikh, V.; Caragheorgheopol, G.; Cechak, T.; Chiba, M.; Constantinescu, S.; Doudarev, A.; Dreossi, D.; Drijard, D.; Ferro-Luzzi, M.; Gallas, M.V.; Gerndt, J.; Giacomich, R.; Gianotti, P.; Goldin, D.; Gorin, A.; Gortchakov, O.; Guaraldo, C.; Hansroul, M.; Hosek, R.; Iliescu, M.; Jabitski, M.; Kalinina, N.; Karpoukhine, V.; Kluson, J.; Kobayashi, M.; Kokkas, P.; Komarov, V.; Koulikov, A.; Kouptsov, A.; Krouglov, V.; Krouglova, L.; Kuroda, K.-I.; Lanaro, A.; Lapshine, V.; Lednicky, R.; Leruste, P.; Levisandri, P.; Lopez Aguera, A.; Lucherini, V.; Maki, T.; Manuilov, I.; Montanet, L.; Narjoux, J.-L.; Nemenov, L.; Nikitin, M.; Nunez Pardo, T.; Okada, K.; Olchevskii, V.; Pazos, A.; Pentia, M.; Penzo, A.; Perreau, J.-M.; Petrascu, C.; Plo, M.; Ponta, T.; Pop, D.; Riazantsev, A.; Rodriguez, J.M.; Rodriguez Fernandez, A.; Rykaline, V.; Santamarina, C.; Saborido, J.; Schacher, J.; Sidorov, A.; Smolik, J.; Takeutchi, F.; Tarasov, A.; Tauscher, L.; Tobar, M.J.; Trusov, S.; Vazquez, P.; Vlachos, S.; Yazkov, V.; Yoshimura, Y.; Zrelov, P.

    2001-01-01

    The main objective of DIRAC experiment is the measurement of the lifetime τ of the exotic hadronic atom consisting of π + and π - mesons. The lifetime of this atom is determined by the decay mode π + π - → π 0 π 0 due to the strong interaction. Through the precise relationship between the lifetime and the S-wave pion-pion scattering length difference |a 0 - a 2 | for isospin 0 and 2 (respectively), a measurement of τ with an accuracy of 10% will allow a determination of |a 0 - a 2 | at a 5% precision level. Pion-pion scattering lengths have been calculated in the framework of chiral perturbation theory with an accuracy below 5%. In this way DIRAC experiment will provide a crucial test of the chiral symmetry breaking scheme in QCD effective theories at low energies

  15. Dirac experiment

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, F.; Adeva, B.; Afanasev, L.; Benayoun, M.; Brekhovskikh, V.; Caragheorgheopol, G.; Cechak, T.; Chiba, M.; Constantinescu, S.; Doudarev, A.; Dreossi, D.; Drijard, D.; Ferro-Luzzi, M.; Gallas, M.V.; Gerndt, J.; Giacomich, R.; Gianotti, P.; Goldin, D.; Gorin, A.; Gortchakov, O.; Guaraldo, C.; Hansroul, M.; Hosek, R.; Iliescu, M.; Jabitski, M.; Kalinina, N.; Karpoukhine, V.; Kluson, J.; Kobayashi, M.; Kokkas, P.; Komarov, V.; Koulikov, A.; Kouptsov, A.; Krouglov, V.; Krouglova, L.; Kuroda, K.-I.; Lanaro, A.; Lapshine, V.; Lednicky, R.; Leruste, P.; Levisandri, P.; Lopez Aguera, A.; Lucherini, V.; Maki, T.; Manuilov, I.; Montanet, L.; Narjoux, J.-L.; Nemenov, L.; Nikitin, M.; Nunez Pardo, T.; Okada, K.; Olchevskii, V.; Pazos, A.; Pentia, M.; Penzo, A.; Perreau, J.-M.; Petrascu, C.; Plo, M.; Ponta, T.; Pop, D.; Riazantsev, A.; Rodriguez, J.M.; Rodriguez Fernandez, A.; Rykaline, V.; Santamarina, C.; Saborido, J.; Schacher, J.; Sidorov, A.; Smolik, J.; Takeutchi, F.; Tarasov, A.; Tauscher, L.; Tobar, M.J.; Trusov, S.; Vazquez, P.; Vlachos, S.; Yazkov, V.; Yoshimura, Y.; Zrelov, P

    2001-04-01

    The main objective of DIRAC experiment is the measurement of the lifetime {tau} of the exotic hadronic atom consisting of {pi}{sup +} and {pi}{sup -} mesons. The lifetime of this atom is determined by the decay mode {pi}{sup +} {pi}{sup -} {yields} {pi}{sup 0} {pi}{sup 0} due to the strong interaction. Through the precise relationship between the lifetime and the S-wave pion-pion scattering length difference |a{sub 0} - a{sub 2}| for isospin 0 and 2 (respectively), a measurement of {tau} with an accuracy of 10% will allow a determination of |a{sub 0} - a{sub 2}| at a 5% precision level. Pion-pion scattering lengths have been calculated in the framework of chiral perturbation theory with an accuracy below 5%. In this way DIRAC experiment will provide a crucial test of the chiral symmetry breaking scheme in QCD effective theories at low energies.

  16. Russian experience

    International Nuclear Information System (INIS)

    Trabalka, J.R.

    1981-01-01

    Soviet research in terrestrial decontamination appears to have paralleled that of the US in many respects. However, the probability exists that long-term evaluations of decontamination techniques (over 10 to 20 years) have been carried out at one nuclear accident site (a marked divergence from US experience). The area of aquatic decontamination seems to offer the most intriguing possibilities for new information acquisition from the USSR; at this point only its potential importance can be speculated upon

  17. Polarization experiments

    International Nuclear Information System (INIS)

    Halzen, F.

    1977-02-01

    In a theoretical review of polarization experiments two important points are emphasized: (a) their versatility and their relevance to a large variety of aspects of hadron physics (tests of basic symmetries; a probe of strong interaction dynamics; a tool for hadron spectroscopy); (b) the wealth of experimental data on polarization parameters in pp and np scattering in the Regge language and in the diffraction language. (author)

  18. Experiments expectations

    OpenAIRE

    Gorini, B; Meschi, E

    2014-01-01

    This paper presents the expectations and the constraints of the experiments relatively to the commissioning procedure and the running conditions for the 2015 data taking period. The views about the various beam parameters for the p-p period, like beam energy, maximum pileup, bunch spacing and luminosity limitation in IP2 and IP8, are discussed. The goals and the constraints of the 2015 physics program are also presented, including the heavy ions period as well as the special...

  19. Media experiences

    DEFF Research Database (Denmark)

    Buhl, Mie

    2010-01-01

    The paper discusses mediated experiences from the perspective of the visual modality in combination with the multimodal interaction. ICT-studies has a rapid influx of new words and concepts. Digital technology led to a need to describe the convergence of images, text and sound has taken various w...... to educational practices as still more advanced technology emerge and intertwine the scientific areas in new and cross-disciplinary frameworks....

  20. TRISTAN experiment

    International Nuclear Information System (INIS)

    Iwata, Seigi

    1994-01-01

    Any successor to PETRA and PEP colliders was expected to extend the energy range to the region where the weak interaction effect becomes sizable in annihilation process. The aim was to reach the level, at which the all round study of the standard model can be performed in a clean system of e + e - collision. Also it was aimed to explore the energy region where top quark pair production is likely. Considering the available site for accelerator construction and the expected size of the electroweak interference effect, the target energy was set at 60 GeV at the lowest. TRISTAN-1 experiment is a big initial step in the long range physics program. The laboratory established the plan to move on to TRISTAN-2 (B Factory) project. The TRISTAN accelerator including the main storage ring, the time sequence of storage ring operation, three experimental groups of AMY, TOPAZ and VENUS, and so on are explained. The experiments on basic annihilation process, the search for new particles, the electroweak interaction, QCD studies and so on are reported. The optimum TRISTAN ring was estimated as 3 km in diameter, but the largest possible size in the site was 1/3 of that. Hard decision was made to equip the ring with unusually many accelerating RF cavities and to apply superconducting technology. (K.I.)

  1. Experimenting with a design experiment

    Directory of Open Access Journals (Sweden)

    Bakker, Judith

    2012-12-01

    Full Text Available The design experiment is an experimental research method that aims to help design and further develop new (policy instruments. For the development of a set of guidelines for the facilitation of citizens’ initiatives by local governments, we are experimenting with this method. It offers good opportunities for modeling interventions by testing their instrumental validity –the usefulness for the intended practical purposes. At the same time design experiments are also useful for evaluating the empirical validity of theoretical arguments and the further development of these arguments in the light of empirical evidence (by using e.g. the technique of pattern matching. We describe how we have applied this methodology in two cases and discuss our research approach. We encountered some unexpected difficulties, especially in the cooperation with professionals and citizens. These difficulties complicate the valid attribution of causal effects to the use of the new instrument. However, our preliminary conclusion is that design experiments are useful in our field of study

    El experimento de diseño es un método de investigación experimental que tiene como objetivo diseñar y desarrollar posteriormente nuevas herramientas (políticas. En este artículo experimentamos con este método para desarrollar un conjunto de directrices que permitan a los gobiernos locales facilitar las iniciativas ciudadanas. El método ofrece la oportunidad de modelar las intervenciones poniendo a prueba su validez instrumental (su utilidad para el fin práctico que se proponen. Al mismo tiempo, los experimentos de diseño son útiles también para evaluar la validez empírica de las discusiones teóricas y el posterior desarrollo de esas discusiones a la luz de la evidencia empírica (usando, por ejemplo, técnicas de concordancia de patrones. En este trabajo describimos cómo hemos aplicado este método a dos casos y discutimos nuestro enfoque de

  2. Operating experience

    International Nuclear Information System (INIS)

    McRae, L.P.; Six, D.E.

    1991-01-01

    In 1987, Westinghouse Hanford Company began operating a first-generation integrated safeguards system in the Plutonium Finishing Plant storage vaults. This Vault Safety and Inventory System is designed to integrate data into a computer-based nuclear material inventory monitoring system. The system gathers, in real time, measured physical parameters that generate nuclear material inventory status data for thousands of stored items and sends tailored report to the appropriate users. These data include canister temperature an bulge data reported to Plant Operations and Material Control and Accountability personnel, item presence and identification data reported to Material Control and Accountability personnel, and unauthorized item movement data reported to Security response forces and Material Control and Accountability personnel. The Westinghouse Hanford Company's experience and operational benefits in using this system for reduce radiation exposure, increase protection against insider threat, and real-time inventory control are discussed in this paper

  3. Management Experiences

    Directory of Open Access Journals (Sweden)

    Gheorghe Popovici

    2016-12-01

    Full Text Available The paper presents the results of the survey about the changes in modern management, identified from the experience of Romanian managers. By this online study one presents both the obstacles encountered and the recommendations for such a type of management that the present and future mangers must take into account. What motivated the respondent Romanian managers most to open their own business is the independence it offered them. They work in the field they have liked since they were young. The second reason was the perspective to have an additional income from the business development. The third argument in favour of opening a business is the possibility to assure the balance between personal life and career.

  4. The HXR80M-balloon experiment: a microprocessor-controlled transatlantic payload

    International Nuclear Information System (INIS)

    Ubertini, P.; Bazzano, A.; Boccaccini, L.

    1980-01-01

    Following the results obtained from the succesful transatlantic flight launched during the summer 1976 from the CNR Milo Base, Sicily, the Laboratorio di Astrofisica Spaziale has started a new program in the hard X-ray astronomy field. It basically consists in the development of high resolution large area Multiwire Proportional Chambers to be employed in long duration balloon flights to study and monitor galactic and extragalactic sources. This note will describe the flight configuration and performances of the HXR80M payload. The experiment is expected to fly during July 1980 from the Milo Base in the framework of the CNR experimental balloon campaign. The note will analyze the main characteristics of the detectors employed, of the data handling electronics and in particular of the hardware and the software of the on-board microprocessor controlled multichannel analyzer. In fact the limitation due to the low bit rate HF link (1.2kbit/s) and the long flight duration (about one week) make imperative the use of an on-board microprocessor system to handle and select in real time the scientific data and to control the housekeeping and the telecommand systems

  5. The Simultaneous Medicina-Planck Experiment: data acquisition, reduction and first results

    Science.gov (United States)

    Procopio, P.; Massardi, M.; Righini, S.; Zanichelli, A.; Ricciardi, S.; Libardi, P.; Burigana, C.; Cuttaia, F.; Mack, K.-H.; Terenzi, L.; Villa, F.; Bonavera, L.; Morgante, G.; Trigilio, C.; Trombetti, T.; Umana, G.

    2011-10-01

    The Simultaneous Medicina-Planck Experiment (SiMPlE) is aimed at observing a selected sample of 263 extragalactic and Galactic sources with the Medicina 32-m single-dish radio telescope in the same epoch as the Planck satellite observations. The data, acquired with a frequency coverage down to 5 GHz and combined with Planck at frequencies above 30 GHz, will constitute a useful reference catalogue of bright sources over the whole Northern hemisphere. Furthermore, source observations performed in different epochs and comparisons with other catalogues will allow the investigation of source variabilities on different time-scales. In this work, we describe the sample selection, the ongoing data acquisition campaign, the data reduction procedures, the developed tools and the comparison with other data sets. We present 5 and 8.3 GHz data for the SiMPlE Northern sample, consisting of 79 sources with δ≥ 45° selected from our catalogue and observed during the first 6 months of the project. A first analysis of their spectral behaviour and long-term variability is also presented.

  6. The HiSCORE experiment and its potential for gamma-ray astronomy

    International Nuclear Information System (INIS)

    Tluczykont, M; Hampf, D; Einhaus, U; Horns, D; Büker, M; Epimakhov, S; Kunnas, M; Maurer, A; Brückner, M; Budnev, N; Chvalaev, O; Dyachok, A; Gress, O; Ivanova, A; Konstantinov, E; Mirgazov, R; Korosteleva, E; Kuzmichev, L; Lubsandorzhiev, B K; Lubsandorzhiev, N B

    2013-01-01

    The HiSCORE (Hundred*i Square-km Cosmic ORigin Explorer) detector aims at the exploration of the accelerator sky, using indirect air-shower observations of cosmic rays from 100 TeV to 1 EeV and gamma rays in the last remaining observation window of gamma-ray astronomy from 10 TeV to several PeV. The main questions addressed by HiSCORE are cosmic ray composition and spectral measurements in the Galactic/extragalactic transition range, and the origin of cosmic rays via the search for gamma rays from Galactic PeV accelerators, the pevatrons. HiSCORE is based on non-imaging Cherenkov light-front sampling with sensitive large-area detector modules of the order of 0.5 m 2 . A prototype station was deployed on the Tunka cosmic ray experiment site in Siberia, where an engineering array of up to 1km 2 is planned for deployment in 2012/2013. Here, we address the expected physics potential of HiSCORE, the status of the project, and further plans.

  7. Gravitational lensing effect and polarization of the cosmic microwave background in the PLANCK Experiment and post-planckian projects; Effet de lentilles gravitationnelles et polarisation du fond diffus cosmologique dans le cadre de l'experience PLANCK et de projets post-planckiens

    Energy Technology Data Exchange (ETDEWEB)

    Perotto, Laurence [Universite Paris 7 - Denis Diderot, UFR de Physique, 75205 Paris Cedex 13 (France)

    2006-01-15

    This thesis is motivated by the upcoming high-resolution, high-sensitivity microwave background experiments, which should be sensitive to the CMB polarization and lensing. The first chapter provides a review of the CMB polarization with emphasis on future related experiments. The PLANCK experiment is described in a second chapter, where I develop a fast simulation code of PLANCK time-ordered data optimized to ease elaboration and test of data analysis methods. The two last chapters deal with gravitational lensing of the cosmic background radiation. First, I evaluate the capability of the upcoming experiments mentioned above to measure the power spectrum of Large Scale Structure by means of the extraction of weak lensing. Then I derive their sensitivity to the total neutrino mass, using the suppression of power due to free-streaming of massive neutrinos. Finally, I develop a method to estimate the foreground effects in the gravitational lensing extraction process. This method uses the best linear estimator available in the literature and is validated by numerical simulations that include non-Gaussian CMB lensed maps and extra-galactic radio sources maps. I find that sources emission reduces the sensitivity of future experiments to the weak lensing and leads to an overestimate of the convergence power spectrum. (author)

  8. Gravitational lensing effect and polarization of the cosmic microwave background in the PLANCK Experiment and post-planckian projects; Effet de lentilles gravitationnelles et polarisation du fond diffus cosmologique dans le cadre de l'experience PLANCK et de projets post-planckiens

    Energy Technology Data Exchange (ETDEWEB)

    Perotto, Laurence [Universite Paris 7 - Denis Diderot, UFR de Physique, 75205 Paris Cedex 13 (France)

    2006-01-15

    This thesis is motivated by the upcoming high-resolution, high-sensitivity microwave background experiments, which should be sensitive to the CMB polarization and lensing. The first chapter provides a review of the CMB polarization with emphasis on future related experiments. The PLANCK experiment is described in a second chapter, where I develop a fast simulation code of PLANCK time-ordered data optimized to ease elaboration and test of data analysis methods. The two last chapters deal with gravitational lensing of the cosmic background radiation. First, I evaluate the capability of the upcoming experiments mentioned above to measure the power spectrum of Large Scale Structure by means of the extraction of weak lensing. Then I derive their sensitivity to the total neutrino mass, using the suppression of power due to free-streaming of massive neutrinos. Finally, I develop a method to estimate the foreground effects in the gravitational lensing extraction process. This method uses the best linear estimator available in the literature and is validated by numerical simulations that include non-Gaussian CMB lensed maps and extra-galactic radio sources maps. I find that sources emission reduces the sensitivity of future experiments to the weak lensing and leads to an overestimate of the convergence power spectrum. (author)

  9. Particle physics experiments 1983

    International Nuclear Information System (INIS)

    Stuart, G.W.

    1983-01-01

    The report describes work carried out in 1983 on experiments approved by the Particle Physics Experiments Selection Panel. The contents consist of unedited contributions from each experiment. (author)

  10. Design of modern experiments

    International Nuclear Information System (INIS)

    Park, Sung Hweon

    1984-03-01

    This book is for researchers and engineers, which is written to focus on practical design of experiments. It gives descriptions of conception of design of experiments, basic statistics theory, one way design of experiment, two-way layout without repetition, two-way layout with repetition, partition, a correlation analysis and regression analysis, latin squares, factorial design, design of experiment by table of orthogonal arrays, design of experiment of response surface, design of experiment on compound, Evop, and design of experiment of taguchi.

  11. THE UNUSUALLY LUMINOUS EXTRAGALACTIC NOVA SN 2010U

    International Nuclear Information System (INIS)

    Czekala, Ian; Berger, E.; Chornock, R.; Marion, G. H.; Margutti, R.; Challis, P.; Pastorello, A.; Botticella, M. T.; Ergon, M.; Sollerman, J.; Smartt, S.; Vinkó, J.; Wheeler, J. C.

    2013-01-01

    We present observations of the unusual optical transient SN 2010U, including spectra taken 1.03 days to 15.3 days after maximum light that identify it as a fast and luminous Fe II type nova. Our multi-band light curve traces the fast decline (t 2 = 3.5 ± 0.3 days) from maximum light (M V = –10.2 ± 0.1 mag), placing SN 2010U in the top 0.5% of the most luminous novae ever observed. We find typical ejecta velocities of ≈1100 km s –1 and that SN 2010U shares many spectral and photometric characteristics with two other fast and luminous Fe II type novae, including Nova LMC 1991 and M31N-2007-11d. For the extreme luminosity of this nova, the maximum magnitude versus rate of decline relationship indicates a massive white dwarf (WD) progenitor with a low pre-outburst accretion rate. However, this prediction is in conflict with emerging theories of nova populations, which predict that luminous novae from massive WDs should preferentially exhibit an alternate spectral type (He/N) near maximum light.

  12. Extragalactic Gamma Ray Excess from Coma Supercluster Direction

    Indian Academy of Sciences (India)

    More precise analysis of EGRET data however, makes it possible to estimate the diffuse gamma ray in Coma supercluster (i.e., Coma\\A1367 supercluster) direction with a value of ( > 30MeV) ≃ 1.9 × 10-6 cm-2 s-1, which is considered to be an upper limit for the diffuse gamma ray due to Coma supercluster. The related ...

  13. PROBING EXTRAGALACTIC DUST THROUGH NEARBY GAMMA-RAY BURST AFTERGLOWS

    International Nuclear Information System (INIS)

    Liang, S. L.; Li Aigen

    2010-01-01

    The quantities and wavelength dependencies of the dust extinction along the lines of sight toward 33 nearby gamma-ray bursts (GRBs) with redshifts z V derived from the Drude approach is generally larger by a factor of ∼2-5 than that inferred by assuming a SMC-type template extinction law. Consistent with previous studies, the extinction-to-gas ratio is mostly smaller than that of the MW, and does not seem to correlate with the shape of the extinction curve. It is shown that the standard silicate-graphite interstellar grain model closely reproduces the extinction curves of all 33 GRBs host galaxies. For these 33 bursts at z < 2, we find no evidence for the evolution of the dust extinction, dust sizes, and relative abundances of silicate to graphite on redshifts.

  14. Relativistic parametric instabilities in extended extragalactic radio sources

    Energy Technology Data Exchange (ETDEWEB)

    Ferrari, A [Consiglio Nazionale delle Ricerche, Turin (Italy). Lab. di Cosmo-Geofisica; Trussoni, E; Zaninetti, L

    1978-01-01

    A general discussion is presented of parametric instabilities of electromagnetic waves in cold plasmas. Previous results for f = eE/msub(e)c..omega../sub 0/ >> 1 and << 1 are extended and the intermediate range f approximately 1, which could be relevant in some astrophysical applications, is analysed by numerical techniques. In the final section a model for particle acceleration and radiation emission by turbulent plasma modes excited in extended radiosources by parametric absorption of strong electromagnetic waves is tentatively discussed.

  15. GALACTIC AND EXTRAGALACTIC SUPERNOVA REMNANTS AS SITES OF PARTICLE ACCELERATION

    Directory of Open Access Journals (Sweden)

    Manami Sasaki

    2013-12-01

    Full Text Available Supernova remnants, owing to their strong shock waves, are likely sources of Galactic cosmic rays. Studies of supernova remnants in X-rays and gamma rays provide us with new insights into the acceleration of particles to high energies. This paper reviews the basic physics of supernova remnant shocks and associated particle acceleration and radiation processes. In addition, the study of supernova remnant populations in nearby galaxies and the implications for Galactic cosmic ray distribution are discussed.

  16. Turblence-related morphology in extragalactic radio sources

    International Nuclear Information System (INIS)

    Benford, G.; Ferrari, A.; Trussoni, E.

    1980-01-01

    As particle beams propagate through the intergalactic medium, unavoidable instabilities from shear flows produce turbulent magnetic waves. Rather than disrupting beams, this wave energy may enhance luminosity and alter morphology. For reasonable parameters the dominant nonlinear process is an energy cascade from long wavelengths ( 21 cm) to short wavelengths ( 14 cm), where particles are reaccelerated in quasi-linear fachion. We construct a phenomenological turbulence theory to describe this. In an ambient magnetic field, wave-particle scatterings which cause reacceleration can also lead to spatial cross-field diffusion, broadening the beam. Thus beams can flare rapidly as they propagate. This relates luminosity to morphology in a new way. The broadening is wholly intrinsic, unrelated to the beam environment. A variety of radio source types may be related to his effect. Protons do not scatter strongly, remaining collimated and depositing most of the beam energy in hot spots, which are generally weak in the radio but strong in the X-ray

  17. The morphology and surface brightness of extragalactic jets

    International Nuclear Information System (INIS)

    Bicknell, G.V.

    1983-01-01

    The problems associated with laminar flow models are reviewed, and an analogy between laboratory jets and astrophysical jets is given. The relationship between surface brightness and the jet full width half maximum is not in general as predicted by simple magnetohydrodynamic models. An alternative turbulent model is presented

  18. Egret observations of the extragalactic gamma-ray emission

    DEFF Research Database (Denmark)

    Sreekumar, P.; Bertsch, D.L.; Dingus, B.L.

    1998-01-01

    The all-sky survey in high-energy gamma rays (E > 30 MeV) carried out by EGRET aboard the Compton Gamma Ray Observatory provides a unique opportunity to examine in detail the diffuse gamma-ray emission. The observed diffuse emission has a Galactic component arising from cosmic-ray interactions wi...

  19. Observational constraints on the cosmological evolution of extragalactic radio sources

    International Nuclear Information System (INIS)

    Perryman, M.A.C.

    1979-11-01

    The thesis discusses statistical studies of the remote radio sources, taking into account the various parameters for such sources, based on data from the various Cambridge Catalogues. Some of the sources have optical counterparts which yield distances from their redshifts. Combining optical and radio observations, an attempt is made to investigate whether large-scale evolution of galaxies occurs as one looks backwards in time to early epochs. Special attention is paid to ensuring that the optical identifications of the selected radio sources are sound and that the selection procedures do not distort the inferences obtained. (U.K.)

  20. Balloon observations of galactic and extragalactic objects at 100 microns.

    Science.gov (United States)

    Hoffmann, W. F.

    1972-01-01

    Recent far-infrared balloon-borne instruments have yielded observations of a number of bright sources at 100 microns. Many of these coincide with HII regions where molecular line emision has been detected. There is some indication of 100 micron emission which does not coincide with radio measurements.

  1. Extragalactic interstellar extinction curves: Indicators of local physical conditions

    Energy Technology Data Exchange (ETDEWEB)

    Cecchi-Pestellini, Cesare [INAF-Osservatorio Astronomico di Palermo, P.zza Parlamento 1, I-90134 Palermo (Italy); Viti, Serena; Williams, David A., E-mail: cecchi-pestellini@astropa.unipa.it, E-mail: sv@star.ucl.ac.uk, E-mail: daw@star.ucl.ac.uk [Department of Physics and Astronomy, University College London Gower Street, London WC1E 6BT (United Kingdom)

    2014-06-20

    Normalized interstellar extinction curves (ISECs) in the Milky Way and other galaxies show a variety of shapes. This variety is attributed to differences along different sight lines in the abundances of the several dust and gas components contributing to extinction. In this paper we propose that these abundance differences are not arbitrary but are a specific consequence of the physical conditions on those sight lines. If this proposal is correct, then it implies that ISECs contain information about physical conditions in the regions generating extinction. This may be particularly important for high redshift galaxies where information on the conditions may be difficult to obtain. We adopt a model of extinction carriers in which the solid and gaseous components are not immutable but respond time-dependently to the local physics. We validate this model by fitting extinction curves measured on sight lines in the Magellanic Clouds and obtained for the gamma-ray burst afterglow GRB 080605. We present results for this model as follows: (1) we show that computed ISECs are controlled by a small number of physical parameters, (2) we demonstrate the sensitivity of computed ISECs to these parameters, (3) we compute as examples ISECs for particular galaxy types, and (4) we note that different galaxy types have different shapes of ISEC.

  2. Variability of Extragalactic Objects in Relation to Redshift, Color ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    properties of the objects, viz., redshift, color indices, radio spectral index ... properties of different types of closely related objects are expected to throw light on the ...... z = 3.0, OVV objects are concentrated at the lower range of the scale, mostly at ..... from the practical point of view in the sense that redshifts can be predicted ...

  3. Giant Rapid X-ray Flares in Extragalactic Globular Clusters

    Science.gov (United States)

    Irwin, Jimmy

    2018-01-01

    There is only one known class of non-destructive, highly energetic astrophysical object in the Universe whose energy emission varies by more than a factor of 100 on time scales of less than a minute -- soft gamma repeaters/anomalous X-ray pulsars, whose flares are believed to be caused by the energy release from the cracking of a neutron star's surface by very strong magnetic fields. All other known violent, rapid explosions, including gamma-ray bursts and supernovae, are believed to destroy the object in the process. Here, we report the discovery of a second class of non-destructive, highly energetic rapidly flaring X-ray object located within two nearby galaxies with fundamentally different properties than soft gamma repeaters/anomalous X-ray pulsars. One source is located within a suspected globular cluster of the host galaxy and flared one time, while the other source is located in either a globular cluster of the host galaxy or the core of a stripped dwarf companion galaxy that flared on six occasions over a seven year time span. When not flaring, the sources appear as normal accreting neutron star or black hole X-ray binaries, indicating that the flare event does not significantly disrupt the host system. While the nature of these sources is still unclear, the discovery of these sources in decade-old archival Chandra X-ray Observatory data illustrates the under-utilization of X-ray timing as a means to discover new classes of explosive events in the Universe.

  4. Galactic and extragalactic searches for pulsars and radio transients

    NARCIS (Netherlands)

    Rubio Herrera, E.A.

    2010-01-01

    Eduardo Rubio Herrera presenteert resultaten en methoden die gerelateerd zijn aan de zoektocht naar radiopulsars. Deze objecten zijn te vinden door te speuren naar periodieke signalen, of door de helderste individuele pulsen die ze uitzenden op te sporen. Hij beschrijft de implementatie van een

  5. The psisub(IPS)-LAS relation for extragalactic radio sources

    International Nuclear Information System (INIS)

    Banhatti, D.G.

    1984-01-01

    Metre-wavelength interplanetary scintillation (IPS) observations give the overall angular sizes psi of scintillating compact structures in radio sources. From 326.5-MHz IPS data for a sample of faint (Ooty) radio sources, log psi versus log (largest angular size) is seen, on average, to have a slope 0.2, significantly less than one. A similar trend is seen from 81.5-MHz IPS data for a sample of strong, powerful (3CR) double sources, although the slope is 0.4 and the mean psi about four times larger. The difference in slopes is due mainly to the large spread in the redshifts of the 3CR sources compared to the expected narrow range for the Ooty sources, while the difference in mean psi values is due to the different methods of determining psi for the two samples, the different frequencies used for the IPS observations and the different mean LAS values. (author)

  6. Data acquisition. GRAAL experiment. Hybrid reactor experiment. AMS experiment

    International Nuclear Information System (INIS)

    Barancourt, D.; Barbier, G.; Bosson, G.; Bouvier, J.; Gallin-Martel, L.; Meillon, B.; Stassi, P.; Tournier, M.

    1997-01-01

    The main activity of the data acquisition team has consisted in hardware and software developments for the GRAAL experiment with the trigger board, for the 'Reacteurs Hybrides' group with an acquisition board ADCVME8V and for the AMS experiment with the monitoring of the aerogel detector. (authors)

  7. Particle physics experiments 1989

    International Nuclear Information System (INIS)

    Bairstow, R.

    1990-01-01

    This report describes work carried out in 1989 on experiments approved by the Particle Physics Experiments Selection Panel of Rutherford Appleton Laboratory. The contents consist of unedited contributions from each experiment. (author)

  8. Particle physics experiments 1987

    International Nuclear Information System (INIS)

    Stuart, G.W.

    1988-01-01

    This report describes work carried out in 1987 on experiments approved by the Particle Physics Experiments Selection Panel (United Kingdom). The contents consist of unedited contributions from each experiment. (author)

  9. Particle physics experiments

    International Nuclear Information System (INIS)

    Stuart, G.W.

    1986-01-01

    The report of the Rutherford Appleton Laboratory describes the work carried out in 1985 on experiments approved by the Particle Physics Experiments Selection Panel. The contents consist of unedited contributions from each experiment. (author)

  10. Particle physics experiments 1986

    International Nuclear Information System (INIS)

    Stuart, G.W.

    1987-01-01

    The paper presents research work carried out in 1986 on 52 elementary particle experiments approved by the Particle Physics Experiments Selection Panel. Most of the experiments were collaborative and involved research groups from different countries. About half of the experiments were conducted at CERN, the remaining experiments employed the accelerators: LAMPT, LEP, PETRA, SLAC, and HERA. The contents consist of unedited contributions from each experiment. (U.K.)

  11. A Messaging Infrastructure for WLCG

    International Nuclear Information System (INIS)

    Casey, James; Cons, Lionel; Lapka, Wojciech; Paladin, Massimo; Skaburskas, Konstantin

    2011-01-01

    During the EGEE-III project operational tools such as SAM, Nagios, Gridview, the regional Dashboard and GGUS moved to a communication architecture based on ActiveMQ, an open-source enterprise messaging solution. LHC experiments, in particular ATLAS, developed prototypes of systems using the same messaging infrastructure, validating the system for their use-cases. In this paper we describe the WLCG messaging use cases and outline an improved messaging architecture based on the experience gained during the EGEE-III period. We show how this provides a solid basis for many applications, including the grid middleware, to improve their resilience and reliability.

  12. Particle physics experiments 1982

    International Nuclear Information System (INIS)

    Rousseau, M.D.; Stuart, G.

    1983-01-01

    Work carried out in 1982 on 52 experiments approved by the Particle Physics Experiments Selection Panel is described. Each experiment is listed under title, collaboration, technique, accelerator, year of running, status and spokesman. Unedited contributions are given from each experiment. (U.K.)

  13. Framework of product experience

    NARCIS (Netherlands)

    Desmet, P.; Hekkert, P.

    2007-01-01

    In this paper, we introduce a general framework for product experience that applies to all affective responses that can be experienced in human-product interaction. Three distinct components or levels of product experiences are discussed: aesthetic experience, experience of meaning, and emotional

  14. Adaptive structures flight experiments

    Science.gov (United States)

    Martin, Maurice

    The topics are presented in viewgraph form and include the following: adaptive structures flight experiments; enhanced resolution using active vibration suppression; Advanced Controls Technology Experiment (ACTEX); ACTEX program status; ACTEX-2; ACTEX-2 program status; modular control patch; STRV-1b Cryocooler Vibration Suppression Experiment; STRV-1b program status; Precision Optical Bench Experiment (PROBE); Clementine Spacecraft Configuration; TECHSAT all-composite spacecraft; Inexpensive Structures and Materials Flight Experiment (INFLEX); and INFLEX program status.

  15. THE Q/U IMAGING EXPERIMENT: POLARIZATION MEASUREMENTS OF RADIO SOURCES AT 43 AND 95 GHz

    Energy Technology Data Exchange (ETDEWEB)

    Huffenberger, K. M. [Department of Physics, Florida State University, P.O. Box 3064350, Tallahassee, FL 32306-4350 (United States); Araujo, D.; Zwart, J. T. L. [Department of Physics and Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Bischoff, C.; Buder, I. [Kavli Institute for Cosmological Physics, Department of Physics, Enrico Fermi Institute, The University of Chicago, Chicago, IL 60637 (United States); Chinone, Y.; Hasegawa, M. [High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Cleary, K. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 E. California Blvd M/C 249-17, Pasadena, CA 91125 (United States); Kusaka, A. [Physics Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Monsalve, R. [School of Earth and Space Exploration, Arizona State University, 781 E. Terrace Road, Tempe, AZ 85287 (United States); Næss, S. K. [Department of Astrophysics, University of Oxford, Keble Road, Oxford, OX1 3RH (United Kingdom); Newburgh, L. B. [Dunlap Institute, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada); Reeves, R. [CePIA, Departamento de Astronomía, Universidad de Concepción (Chile); Ruud, T. M.; Eriksen, H. K. [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, NO-0315 Oslo (Norway); Wehus, I. K.; Gaier, T. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Dickinson, C. [Jodrell Bank Centre for Astrophysics, Alan Turing Building, School of Physics and Astronomy, The University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Gundersen, J. O., E-mail: huffenbe@physics.fsu.edu [Department of Physics, University of Miami, 1320 Campo Sano Drive, Coral Gables, FL 33146 (United States); Collaboration: QUIET Collaboration; and others

    2015-06-10

    We present polarization measurements of extragalactic radio sources observed during the cosmic microwave background polarization survey of the Q/U Imaging Experiment (QUIET), operating at 43 GHz (Q-band) and 95 GHz (W-band). We examine sources selected at 20 GHz from the public, >40 mJy catalog of the Australia Telescope (AT20G) survey. There are ∼480 such sources within QUIET’s four low-foreground survey patches, including the nearby radio galaxies Centaurus A and Pictor A. The median error on our polarized flux density measurements is 30–40 mJy per Stokes parameter. At signal-to-noise ratio > 3 significance, we detect linear polarization for seven sources in Q-band and six in W-band; only 1.3 ± 1.1 detections per frequency band are expected by chance. For sources without a detection of polarized emission, we find that half of the sources have polarization amplitudes below 90 mJy (Q-band) and 106 mJy (W-band), at 95% confidence. Finally, we compare our polarization measurements to intensity and polarization measurements of the same sources from the literature. For the four sources with WMAP and Planck intensity measurements >1 Jy, the polarization fractions are above 1% in both QUIET bands. At high significance, we compute polarization fractions as much as 10%–20% for some sources, but the effects of source variability may cut that level in half for contemporaneous comparisons. Our results indicate that simple models—ones that scale a fixed polarization fraction with frequency—are inadequate to model the behavior of these sources and their contributions to polarization maps.

  16. The ERASMUS experiment archive

    Science.gov (United States)

    Isakeit, Dieter; Sabbatini, Massimo; Carey, William

    2005-08-01

    The Erasmus Experiment Archive is an electronic database, accessible through the Internet, that collects in a single reference repository scientific, technical and operational information regarding the experiments performed in the experiment facilities which fall under the responsibility of the ESA Directorate of Human Spaceflight, Microgravity and Exploration. The archive is operated, filled with content and kept up-to-date by the Erasmus User Centre. which forms part of the Directorate. The archive shares its records and is interoperable with similar experiment archives of the partner agencies NASA USA) and JAXA (Japan) through a mutually agreed standard for experiment records called the International Distributed Experiment Archive (IDEA).

  17. Experiment WA1 (CDHS Neutrino Experiment)

    CERN Multimedia

    CERN PhotoLab

    1977-01-01

    Experiment WA1, also known under CDHS (CERN, Dortmund, Heidelberg, Saclay; spokesman Jack Steinberger), was the first neutrino experiment on the SPS, in its West Area. Magnetized iron (with a toroidal field) forms the core of the detector. On its outside we see drift chambers and photomultipliers (detecting the light from the plastic scintillators further in). Peter Schilly is wearing a white coat. See also CERN Annual Report 1976, p.57.

  18. Neutron delayed choice experiments

    International Nuclear Information System (INIS)

    Bernstein, H.J.

    1986-01-01

    Delayed choice experiments for neutrons can help extend the interpretation of quantum mechanical phenomena. They may also rule out alternative explanations which static interference experiments allow. A simple example of a feasible neutron test is presented and discussed. (orig.)

  19. Particle physics experiments 1984

    International Nuclear Information System (INIS)

    Stuart, G.

    1985-01-01

    The Rutherford Appleton laboratory report describes work carried out in 1984 on experiments approved by the Particle Physics selection panel. The contents consist of unedited contributions from each experiment. (author)

  20. GARP Atlantic Tropical Experiment

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The GARP Atlantic Tropical Experiment (GATE) was the first major international experiment of the Global Atmospheric Research Program (GARP). It was conducted over...

  1. Double beta decay: experiments

    International Nuclear Information System (INIS)

    Fiorini, Ettore

    2006-01-01

    The results obtained so far and those of the running experiments on neutrinoless double beta decay are reviewed. The plans for second generation experiments, the techniques to be adopted and the expected sensitivities are compared and discussed

  2. Organic chemistry experiment

    International Nuclear Information System (INIS)

    Mun, Seok Sik

    2005-02-01

    This book deals with organic chemistry experiments, it is divided five chapters, which have introduction, the way to write the experiment report and safety in the laboratory, basic experiment technic like recrystallization and extraction, a lot of organic chemistry experiments such as fischer esterification, ester hydrolysis, electrophilic aromatic substitution, aldol reaction, benzoin condensation, wittig reaction grignard reaction, epoxidation reaction and selective reduction. The last chapter introduces chemistry site on the internet and way to find out reference on chemistry.

  3. The Experiment Factory: standardizing behavioral experiments

    Directory of Open Access Journals (Sweden)

    Vanessa V Sochat

    2016-04-01

    Full Text Available The administration of behavioral and experimental paradigms for psychology research is hindered by lack of a coordinated effort to develop and deploy standardized paradigms. While several frameworks (de Leeuw (2015; McDonnell et al. (2012; Mason and Suri (2011; Lange et al. (2015 have provided infrastructure and methods for individual research groups to develop paradigms, missing is a coordinated effort to develop paradigms linked with a system to easily deploy them. This disorganization leads to redundancy in development, divergent implementations of conceptually identical tasks, disorganized and error-prone code lacking documentation, and difficulty in replication. The ongoing reproducibility crisis in psychology and neuroscience research (Baker (2015; Open Science Collaboration (2015 highlights the urgency of this challenge: reproducible research in behavioral psychology is conditional on deployment of equivalent experiments. A large, accessible repository of experiments for researchers to develop collaboratively is most efficiently accomplished through an open source framework. Here we present the Experiment Factory, an open source framework for the development and deployment of web-based experiments. The modular infrastructure includes experiments, virtual machines for local or cloud deployment, and an application to drive these components and provide developers with functions and tools for further extension. We release this infrastructure with a deployment (http://www.expfactory.org that researchers are currently using to run a set of over 80 standardized web-based experiments on Amazon Mechanical Turk. By providing open source tools for both deployment and development, this novel infrastructure holds promise to bring reproducibility to the administration of experiments, and accelerate scientific progress by providing a shared community resource of psychological paradigms.

  4. Future of neutrino experiments

    Indian Academy of Sciences (India)

    them are under construction. The next generation double beta decay experiments are sensitive to the inverted mass hierarchy. In order to explore the normal mass hierarchy, the sensitivity of the experiments still needs to be improved substantially. For example, see [32] for more details of the double beta decay experiments.

  5. Particle physics experiments 1988

    International Nuclear Information System (INIS)

    Bairstow, R.

    1989-01-01

    This report describes work carried out in 1988 on experiments approved by the Particle Physics Experiments Selection Panel. The contents consist of unedited contributions from each experiment. More than forty projects at different accelerators (SPS, ISIS, PETRA, LAMPF, LEP, HERA, BNL, ILL, LEAR) are listed. Different organisations collaborate on different projects. A brief progress report is given. References to published articles are given. (author)

  6. The Game Experience Questionnaire

    NARCIS (Netherlands)

    IJsselsteijn, W.A.; de Kort, Y.A.W.; Poels, K.

    2013-01-01

    This document contains the English version of the Game Experience Questionnaire. The development and testing of the Game Experience Questionnaire is described in project Deliverable 3.3. The Game Experience Questionnaire has a modular structure and consists of : 1. The core questionnaire 2. The

  7. Virtual neutron scattering experiments

    DEFF Research Database (Denmark)

    Overgaard, Julie Hougaard; Bruun, Jesper; May, Michael

    2017-01-01

    . In the last week of the course, students travel to a large-scale neutron scattering facility to perform real neutron scattering experiments. Through student interviews and survey answers, we argue, that the virtual training prepares the students to engage more fruitfully with experiments by letting them focus......We describe how virtual experiments can be utilized in a learning design that prepares students for hands-on experiments at large-scale facilities. We illustrate the design by showing how virtual experiments are used at the Niels Bohr Institute in a master level course on neutron scattering...

  8. Experiments in physical chemistry

    CERN Document Server

    Wilson, J M; Denaro, A R

    1968-01-01

    Experiments in Physical Chemistry, Second Edition provides a compilation of experiments concerning physical chemistry. This book illustrates the link between the theory and practice of physical chemistry. Organized into three parts, this edition begins with an overview of those experiments that generally have a simple theoretical background. Part II contains experiments that are associated with more advanced theory or more developed techniques, or which require a greater degree of experimental skill. Part III consists of experiments that are in the nature of investigations wherein these invest

  9. Cosmic rays from 1017eV to beyond 1020eV: evidence from the fly's eye experiment and ground arrays.

    Science.gov (United States)

    Sokolsky, P.

    The study of cosmic rays with energies well above the knee (1015eV) of the spectrum has a long history. Beginning with the pioneering work of Linsley and the Volcano Ranch array, followed by the SUGAR, Haverah Park, Yakutsk, Akeno and AGASA array and the Fly's Eye detector, evidence has been steadily accumulating that the spectrum exhibits a change in slope near 10×1018eV. This flattening may indicate that the spectrum in this region is largely extragalactic in origin. If the sources of this spectrum are sufficiently distant, a cut-off due to the interaction of near 1020eV protons with black body photons should be observed. Recent data from the AGASA and Fly's Eye detectors have brought to bear information of spectral shape, composition and anisotropy to this study. In addition to clarifying the nature of the spectral structure, these new results lead to the surprising conclusion that nearby cosmic ray sources must exist that produce particles with energies well in excess of 1020eV. New experiments are being designed which will have the enormous apertures necessary for detecting these very rare events.

  10. Virtual neutron scattering experiments

    DEFF Research Database (Denmark)

    Overgaard, Julie Hougaard; Bruun, Jesper; May, Michael

    2016-01-01

    We describe how virtual experiments can be utilized in a learning design that prepares students for hands-on experiments at large-scale facilities. We illustrate the design by showing how virtual experiments are used at the Niels Bohr Institute in a master level course on neutron scattering....... In the last week of the course, students travel to a large-scale neutron scattering facility to perform real neutron scattering experiments. Through student interviews and survey answers, we argue, that the virtual training prepares the students to engage more fruitfully with experiments by letting them focus...... on physics and data rather than the overwhelming instrumentation. We argue that this is because they can transfer their virtual experimental experience to the real-life situation. However, we also find that learning is still situated in the sense that only knowledge of particular experiments is transferred...

  11. The Belle II Experiment

    CERN Document Server

    Kahn, J

    2017-01-01

    Set to begin data taking at the end of 2018, the Belle II experiment is the next-generation B-factory experiment hosted at KEK in Tsukuba, Japan. The experiment represents the cumulative effort from the collaboration of experimental and detector physics, computing, and software development. Taking everything learned from the previous Belle experiment, which ran from 1998 to 2010, Belle II aims to probe deeper than ever before into the field of heavy quark physics. By achieving an integrated luminosity of 50 ab−1 and accumulating 50 times more data than the previous experiment across its lifetime, along with a rewritten analysis framework, the Belle II experiment will push the high precision frontier of high energy physics. This paper will give an overview of the key components and development activities that make the Belle II experiment possible.

  12. Diagnostics for pellet experiments

    International Nuclear Information System (INIS)

    Johnson, R.R.

    1978-01-01

    The target diagnostics which are being used and planned in current laser driven ICF Experiments are described. Most of these diagnostics can be easily applied to future ion-beam fusion experiments. The status of laser fusion diagnostics has been much improved in the last 5 years and further improvements can be expected and should be available when the first ICF experiments using ion beams are performed. As an example, x-ray temporal and spatial resolutions are now approximately 5 psec and 3 μm, which is approximately a factor of 4 better than the resolution reported in the first implosion experiments. As one plans ahead for ion-beam fusion experiments it should be emphasized that high yield experiments are easier to diagnose provided adequate shielding is employed. However, in the event that the first high yield experiments fail it will be necessary to have diagnostics available to determine where the problems lie. In laser fusion it is interesting to note that higher laser powers are required now for breakeven experiments than first anticipated, mainly because some aspects of the laser-interaction physics were not recognized until the experiments were carefully diagnosed. Thus as has been pointed out, it may be necessary to increase the energy of the ion-beam driver to enable us to do breakeven experiments with high confidence

  13. Popper's Thought Experiment Reinvestigated

    Science.gov (United States)

    Richardson, Chris; Dowling, Jonathan

    2012-02-01

    Karl Popper posed an interesting thought experiment in 1934. With it, he meant to question the completeness of quantum mechanics. He claimed that the notion of quantum entanglement leads to absurd scenarios that cannot be true in real life and that an implementation of his thought experiment would not give the results that QM predicts. Unfortunately for Popper, it has taken until recently to perform experiments that test his claims. The results of the experiments do not refute QM as Popper predicted, but neither do they confirm what Popper claimed QM predicted. Kim and Shih implemented Popper's thought experiment in the lab. The results of the experiment are not clear and have instigated many interpretations of the results. The results show some correlation between entangled photons, but not in the way that Popper thought, nor in the way a simple application of QM might predict. A ghost-imaging experiment by Strekalov, et al. sheds light on the physics behind Popper's thought experiment, but does not try to directly test it. I will build the physics of Popper's thought experiment from the ground up and show how the results of both of these experiments agree with each other and the theory of QM, but disprove Popper.

  14. Learning and Experience

    DEFF Research Database (Denmark)

    Olesen, Henning Salling

    2017-01-01

    Abstract: This chapter introduces a psycho-societal approach to theorizing learning, combining a materialist theory of socialization with a hermeneutic interpretation methodology. The term "approach" indicates the intrinsic connection between theory, empirical research process and epistemic subject....... Learning is theorized as dynamic subjective experience of (socially situated) realities, counting on individual subjectivity as well as subjective aspects of social interaction. This psycho-societal theory of subjective experiences conceptualizes individual psychic development as interactional experience...... of societal relations, producing an inner psycho-dynamic as a conscious and unconscious individual resource in future life. The symbolization of immediate sensual experiences form an individual life experience of social integration, language use being the medium of collective, social experience (knowledge...

  15. Stimulated Brillouin scattering experiments

    International Nuclear Information System (INIS)

    Slater, D.C.; Berger, R.L.; Busch, G.; Kinzer, C.M.; Mayer, F.J.; Powers, L.V.; Tanner, D.J.

    1981-01-01

    This report describes two experiments in which SBS would be expected to play an important role. In the first experiment, we find a clear signature of the Brillouin backscatter of a short (100 psec) pulse from a long (approx. 50 μm) gradient length gas target plasma. The second experiment used much longer (approx. 1 nsec) pulses on spherical glass shell targets. These experiments were done with both narrow ( 30A) bandwidth laser light. Using one-dimensional, spherically symmetric fluid simulations, we have attempted to model many of the laser-plasma interaction processes which combine to determine the amount of absorbed energy in the long-pulse experiments. These simulations indicate that modest laser bandwidths are successful in reducing the level of SBS at the irradiances ( 15 W/cm 2 ) used in these experiments

  16. Experiment, right or wrong

    CERN Document Server

    Franklin, Allan

    2008-01-01

    In Experiment, Right or Wrong, Allan Franklin continues his investigation of the history and philosophy of experiment presented in his previous book, The Neglect of Experiment. In this new study, Franklin considers the fallibility and corrigibility of experimental results and presents detailed histories of two such episodes: 1) the experiment and the development of the theory of weak interactions from Fermi's theory in 1934 to the V-A theory of 1957 and 2) atomic parity violation experiments and the Weinberg-Salam unified theory of electroweak interactions of the 1970s and 1980s. In these episodes Franklin demonstrates not only that experimental results can be wrong, but also that theoretical calculations and the comparison between experiment and theory can also be incorrect. In the second episode, Franklin contrasts his view of an "evidence model" of science in which questions of theory choice, confirmation, and refutation are decided on the basis of reliable experimental evidence, with that proposed by the ...

  17. Linking consumer experiences

    DEFF Research Database (Denmark)

    Smed, Karina Madsen

    become part of the individual self, worldview, and behaviour. This paper seeks to explore links between consumer experiences through the exploration of narrative sequences in travel blogs. Findings indicate that non-consumption is a central element to the bloggers and also indicative of a community......Consumers consume products in various ways serving a number of purposes. Much attention has been paid to experiences attached to consumption, sometimes very explicitly, e.g. in tourism, the essence of which is experiences of various sorts, but often also implicitly as internalised experiences...

  18. Analytical chemistry experiment

    International Nuclear Information System (INIS)

    Park, Seung Jo; Paeng, Seong Gwan; Jang, Cheol Hyeon

    1992-08-01

    This book deals with analytical chemistry experiment with eight chapters. It explains general matters that require attention on experiment, handling of medicine with keep and class, the method for handling and glass devices, general control during experiment on heating, cooling, filtering, distillation and extraction and evaporation and dry, glass craft on purpose of the craft, how to cut glass tube and how to bend glass tube, volumetric analysis on neutralization titration and precipitation titration, gravimetric analysis on solubility product, filter and washing and microorganism experiment with necessary tool, sterilization disinfection incubation and appendixes.

  19. LDR structural experiment definition

    Science.gov (United States)

    Russell, R. A.

    1988-01-01

    A system study to develop the definition of a structural flight experiment for a large precision segmented reflector on the Space Station was accomplished by the Boeing Aerospace Company for NASA's Langley Research Center. The objective of the study was to use a Large Deployable Reflector (LDR) baseline configuration as the basis for focusing an experiment definition, so that the resulting accommodation requirements and interface constraints could be used as part of the mission requirements data base for Space Station. The primary objectives of the first experiment are to construct the primary mirror support truss and to determine its structural and thermal characteristics. Addition of an optical bench, thermal shield and primary mirror segments, and alignment of the optical components, would occur on a second experiment. The structure would then be moved to the payload point system for pointing, optical control, and scientific optical measurement for a third experiment. Experiment 1 will deploy the primary support truss while it is attached to the instrument module structure. The ability to adjust the mirror attachment points and to attach several dummy primary mirror segments with a robotic system will also be demonstrated. Experiment 2 will be achieved by adding new components and equipment to experiment one. Experiment 3 will demonstrate advanced control strategies, active adjustment of the primary mirror alignment, and technologies associated with optical sensing.

  20. The G0 Experiment

    International Nuclear Information System (INIS)

    Nakahara, Kazutaka

    2007-01-01

    The G0 experiment measures the parity-violating asymmetries in elastic electron-proton and quasi-elastic electron-deuteron scattering over the momentum transfers 0.12 ≤ Q2 ≤ 1.0 GeV2. These asymmetries are sensitive to the strange-quark contribution to the charge and magnetization distributions of the proton. The experiment is conducted at Jefferson Laboratory using a toroidal spectrometer designed to detect forward scattered recoil protons and backward scattered elastic and quasi-elastic electrons. The forward angle experiment was completed in 2004, and the backward angle phase of the experiment is currently taking place

  1. Real Life Experiences with Experience Design

    DEFF Research Database (Denmark)

    Dalsgård, Peter; Halskov, Kim

    2006-01-01

    technologies for knowledge dissemination and marketing, in cooperation with public institutions and businesses. We argue that collaborative formulation of core design intentions and values is a valuable instrument in guiding experience design processes, and present three cases from this project, two of which...... resulted in interactive installations. The case installations range from walk-up-and-use consoles, to immersive, responsive, environments based on bodily interaction. We compare the installations, and discuss the interrelations between the resulting interfaces and the intentions for creating...

  2. Rocket Experiment Demonstration of a Soft X-ray Polarimeter

    Science.gov (United States)

    Marshall, Herman

    This proposal is the lead proposal. Boston University will submit, via NSPIRES, a Co-I proposal, per instructions for Suborbital proposals for multiple-award. Our scientific goal of the Rocket Experiment Demonstration of a Soft X-ray Polarimeter (REDSoX Polarimeter) is to make the first measurement of the linear X-ray polarization of an extragalactic source in the 0.2-0.8 keV band. The first flight of the REDSoX Polarimeter would target Mk 421, which is commonly modeled as a highly relativistic jet aimed nearly along the line of sight. Such sources are likely to be polarized at a level of 30-60%, so the goal is to obtain a significant detection even if it is as low as 10%. Significant revisions to the models of jets emanating from black holes at the cores of active galaxies would be required if the polarization fraction lower than 10%. We employ multilayer-coated mirrors as Bragg reflectors at the Brewster angle. By matching to the dispersion of a spectrometer, one may take advantage of high multilayer reflectivities and achieve polarization modulation factors over 90%. Using replicated foil mirrors from MSFC and gratings made at MIT, we construct a spectrometer that disperses to three laterally graded multilayer mirrors (LGMLs). The lateral grading changes the wavelength of the Bragg peak for 45 degree reflections linearly across the mirror, matching the dispersion of the spectrometer. By dividing the entrance aperture into six equal sectors, pairs of blazed gratings from opposite sectors are oriented to disperse to the same LGML. The position angles for the LGMLs are 120 degrees to each other. CCD detectors then measure the intensities of the dispersed spectra after reflection and polarizing by the LGMLs, giving the three Stokes parameters needed to determine the source polarization. We will rely on components whose performance has been verified in the laboratory or in space. The CCD detectors are based on Chandra and Suzaku heritage. The mirror fabrication team

  3. Link calibrations for the TDRSS orbiting VLBI experiment

    International Nuclear Information System (INIS)

    Edwards, C.D.

    1987-01-01

    The first successful interferometric observations of extragalactic radio sources using an orbiting antenna as one of the observing stations were achieved in July and August 1986 using the TDRSS. The technical obstacles to maintaining phase coherence between the orbiting antenna and the ground stations are reviewed, with an emphasis on the effects of spacecraft motion. An analysis of the interferometric delay and phase reveals the signature of errors in the spacecraft ephemeris. Various calibration schemes are discussed, including the use of a ground beacon at White Sands to calibrate the communications link between White Sands and the TDRSE satellite. Using all available calibrations, coherence of 84 percent was achieved for 700-sec integrations

  4. Cosmic ray and gamma astrophysics with the AMS-02 experiment

    International Nuclear Information System (INIS)

    Natale, Sonia

    2006-01-01

    The Alpha Magnetic Spectrometer (AMS) is a particle physics detector designed to operate on the International Space Station (ISS) for a minimum period of three years. The aim of AMS is the direct detection of charged particles in the rigidity range from 0.5 GV to few TV to perform high statistics studies of cosmic rays in space and a search for antimatter and dark matter. AMS will provide precise gamma measurements in the GeV range. In addition, the good angular resolution and identification capabilities of the detector will allow clean studies of galactic and extra-galactic sources, the diffuse gamma background and gamma ray bursts

  5. Science Experience Unit: Conservation.

    Science.gov (United States)

    Ferguson-Florissant School District, Ferguson, MO.

    GRADES OR AGES: Intermediate grades. SUBJECT MATTER: Conservation. ORGANIZATION AND PHYSICAL APPEARANCE: The guide is divided into 24 experiments. It is mimeographed and staple-bound with a paper cover. OBJECTIVES AND ACTIVITIES: A specific skill or knowledge objective is stated at the beginning of each experiment. Detailed procedures are listed…

  6. The French experience

    CERN Document Server

    Bougard, Marie-Thérèse

    2003-01-01

    Developed for beginners, The French Experience 1 course book is designed to accompany the French Experience 1 CDs (9780563472582) but can also be used on its own to develop your reading and writing skills. You’ll gain valuable insights into French culture too.

  7. Neutrino oscillation experiments

    International Nuclear Information System (INIS)

    Camilleri, L.

    1996-01-01

    Neutrino oscillation experiments (ν μ →ν e and ν μ →ν τ ) currently being performed at accelerators are reviewed. Future plans for short and long base-line experiments are summarized. (author) 10 figs., 2 tabs., 29 refs

  8. Social experience infrastructure

    DEFF Research Database (Denmark)

    Kvistgaard, Peter

    2006-01-01

    and explorative fashion to share with others thoughts and ideas concerning the development of new ways to construct/reconstruct recreational spaces with a better coherence with regard to designing experiences. This article claims that it is possible to design recreational spaces with good social experience...

  9. Teaching Knowledge Engineering: Experiences

    DEFF Research Database (Denmark)

    Andersen, Tom; Hartvig, Susanne C

    1998-01-01

    Includes description of experiences gained by teaching KE in construction domains. It outlines good starting points and overall guidance to education in applied AI.......Includes description of experiences gained by teaching KE in construction domains. It outlines good starting points and overall guidance to education in applied AI....

  10. User Experience Dimensions

    DEFF Research Database (Denmark)

    Lykke, Marianne; Jantzen, Christian

    2016-01-01

    The present study develops a set of 10 dimensions based on a systematic understanding of the concept of experience as a holistic psychological. Seven of these are derived from a psychological conception of what experiencing and experiences are. Three supplementary dimensions spring from the obser...

  11. ATLAS Experiment Brochure - French

    CERN Multimedia

    2018-01-01

    ATLAS is one of the four major experiments at the Large Hadron Collider at CERN. It is a general-purpose particle physics experiment run by an international collaboration, and is designed to exploit the full discovery potential and the huge range of physics opportunities that the LHC provides.

  12. ATLAS Experiment Brochure - Turkish

    CERN Multimedia

    AUTHOR|(CDS)2081027

    2018-01-01

    ATLAS is one of the four major experiments at the Large Hadron Collider at CERN. It is a general-purpose particle physics experiment run by an international collaboration, and is designed to exploit the full discovery potential and the huge range of physics opportunities that the LHC provides.

  13. ATLAS Experiment Brochure - Hebrew

    CERN Multimedia

    AUTHOR|(CDS)2081027

    2018-01-01

    ATLAS is one of the four major experiments at the Large Hadron Collider at CERN. It is a general-purpose particle physics experiment run by an international collaboration, and is designed to exploit the full discovery potential and the huge range of physics opportunities that the LHC provides.

  14. ATLAS Experiment Brochure - Italian

    CERN Multimedia

    2018-01-01

    ATLAS is one of the four major experiments at the Large Hadron Collider at CERN. It is a general-purpose particle physics experiment run by an international collaboration, and is designed to exploit the full discovery potential and the huge range of physics opportunities that the LHC provides.

  15. ATLAS Experiment Brochure - German

    CERN Multimedia

    AUTHOR|(CDS)2081027

    2018-01-01

    ATLAS is one of the four major experiments at the Large Hadron Collider at CERN. It is a general-purpose particle physics experiment run by an international collaboration, and is designed to exploit the full discovery potential and the huge range of physics opportunities that the LHC provides.

  16. ATLAS Experiment Brochure - Japanese

    CERN Multimedia

    Anthony, Katarina

    2018-01-01

    ATLAS is one of the four major experiments at the Large Hadron Collider at CERN. It is a general-purpose particle physics experiment run by an international collaboration, and is designed to exploit the full discovery potential and the huge range of physics opportunities that the LHC provides.

  17. ATLAS Experiment Brochure - Portuguese

    CERN Multimedia

    AUTHOR|(CDS)2081027

    2018-01-01

    ATLAS is one of the four major experiments at the Large Hadron Collider at CERN. It is a general-purpose particle physics experiment run by an international collaboration, and is designed to exploit the full discovery potential and the huge range of physics opportunities that the LHC provides.

  18. ATLAS Experiment Brochure - Czech

    CERN Multimedia

    AUTHOR|(CDS)2081027

    2018-01-01

    ATLAS is one of the four major experiments at the Large Hadron Collider at CERN. It is a general-purpose particle physics experiment run by an international collaboration, and is designed to exploit the full discovery potential and the huge range of physics opportunities that the LHC provides.

  19. ATLAS Experiment Brochure - Dutch

    CERN Multimedia

    AUTHOR|(CDS)2081027

    2018-01-01

    ATLAS is one of the four major experiments at the Large Hadron Collider at CERN. It is a general-purpose particle physics experiment run by an international collaboration, and is designed to exploit the full discovery potential and the huge range of physics opportunities that the LHC provides.

  20. ATLAS Experiment Brochure - Romanian

    CERN Multimedia

    AUTHOR|(CDS)2081027

    2018-01-01

    ATLAS is one of the four major experiments at the Large Hadron Collider at CERN. It is a general-purpose particle physics experiment run by an international collaboration, and is designed to exploit the full discovery potential and the huge range of physics opportunities that the LHC provides.

  1. ATLAS Experiment Brochure - Serbian

    CERN Multimedia

    2018-01-01

    ATLAS is one of the four major experiments at the Large Hadron Collider at CERN. It is a general-purpose particle physics experiment run by an international collaboration, and is designed to exploit the full discovery potential and the huge range of physics opportunities that the LHC provides.

  2. ATLAS Experiment Brochure

    CERN Multimedia

    AUTHOR|(INSPIRE)INSPIRE-00085461

    2016-01-01

    ATLAS is one of the four major experiments at the Large Hadron Collider at CERN. It is a general-purpose particle physics experiment run by an international collaboration, and is designed to exploit the full discovery potential and the huge range of physics opportunities that the LHC provides.

  3. On the Poggendorff Experiment

    Science.gov (United States)

    Coelho, Ricardo Lopes; Silva, P. A. S.; Borges, Paulo de Faria

    2015-01-01

    Poggendorff showed experimentally, in the middle of the 19th century, that the weight of an Atwood machine is reduced when it is brought to motion. His experiment has been revisited from time to time, making use of instrumentation that reflects the technological development of the moment. In this paper, the evolution of the experiment is briefly…

  4. Experiments as politics

    NARCIS (Netherlands)

    Spears, R; Smith, HJ

    The purpose of this paper is to illustrate the political nature of laboratory experiments. Such experiments can be construed as paradigms of power, open to construction and debate, where different agents and interests are involved in a process of struggle over both (re)presentation and substance.

  5. Peak Experience Project

    Science.gov (United States)

    Scott, Daniel G.; Evans, Jessica

    2010-01-01

    This paper emerges from the continued analysis of data collected in a series of international studies concerning Childhood Peak Experiences (CPEs) based on developments in understanding peak experiences in Maslow's hierarchy of needs initiated by Dr Edward Hoffman. Bridging from the series of studies, Canadian researchers explore collected…

  6. Experience and Its Generation

    Science.gov (United States)

    Youqing, Chen

    2006-01-01

    Experience is an activity that arouses emotions and generates meanings based on vivid sensation and profound comprehension. It is emotional, meaningful, and personal, playing a key role in the course of forming and developing one's qualities. The psychological process of experience generation consists of such links as sensing things, arousing…

  7. Neutrino oscillation experiments

    Energy Technology Data Exchange (ETDEWEB)

    Camilleri, L [European Organization for Nuclear Research, Geneva (Switzerland)

    1996-11-01

    Neutrino oscillation experiments ({nu}{sub {mu}}{yields}{nu}{sub e} and {nu}{sub {mu}}{yields}{nu}{sub {tau}}) currently being performed at accelerators are reviewed. Future plans for short and long base-line experiments are summarized. (author) 10 figs., 2 tabs., 29 refs.

  8. Experience with MODSIM II

    International Nuclear Information System (INIS)

    Streets, J.; Berg, D.; Oleynik, G.; Pordes, R.; Slimmer, D.

    1992-02-01

    We present results of computer simulations for Data Acquisition systems for large fixed target experiments in an object oriented simulation language, MODSIM. This paper summarizes our experiences and presents preliminary results from the simulation already completed. We also indicate the resources required for this project

  9. Particle physics experiments 1992

    International Nuclear Information System (INIS)

    Roberts, B.A.

    1993-03-01

    The research programs described here were carried out in 1992 at Rutherford Appleton Laboratory and funded by the United Kingdom Science and Engineering Research Council. The area covered in these experiments is particle physics. Unedited contributions from over forty experimental programs are included. Experiments are listed according to their current status, the accelerator used and its years of operation. (UK)

  10. THX Experiment Overview

    Science.gov (United States)

    Wernet, Mark; Wroblewski, Adam; Locke, Randy; Georgiadis, Nick

    2016-01-01

    This presentation provides an overview of experiments conducted at NASA GRC to provide turbulent flow measurements needed for new turbulence model development and validation. The experiments include particle image velocimetry (PIV) and hot-wire measurements of mean flow velocity and temperature fields, as well as fluctuating components.

  11. CDF experience with monte carlo production using LCG grid

    International Nuclear Information System (INIS)

    Griso, S P; Lucchesi, D; Compostella, G; Sfiligoi, I; Cesini, D

    2008-01-01

    The upgrades of the Tevatron collider and CDF detector have considerably increased the demand on computing resources, in particular for Monte Carlo production. This has forced the collaboration to move beyond the usage of dedicated resources and start exploiting the Grid. The CDF Analysis Farm (CAF) model has been reimplemented into LcgCAF in order to access Grid resources by using the LCG/EGEE middleware. Many sites in Italy and in Europe are accessed through this portal by CDF users mainly to produce Monte Carlo data but also for other analysis jobs. We review here the setup used to submit jobs to Grid sites and retrieve the output, including CDF-specific configuration of some Grid components. We also describe the batch and interactive monitor tools developed to allow users to verify the jobs status during their lifetime in the Grid environment. Finally we analyze the efficiency and typical failure modes of the current Grid infrastructure reporting the performances of different parts of the system used

  12. Understanding patient experience

    DEFF Research Database (Denmark)

    Andersen, Tariq O.; Andersen, Pernille R. D.; Kornum, Anders C.

    2017-01-01

    , safety) arise from getting feedback on symptoms and from continuous and comforting interaction with clinicians. With this paper, we aim to sensitise UX researchers and designers of patient-centred e-health by proposing three UX dimensions: connectedness, comprehension, and compassion.......The term 'patient experience' is currently part of a global discourse on ways to improve healthcare. This study empirically explores what patient experience is in cardiac remote monitoring and considers the implications for user experience (UX). Through interviews around the deployment of a mobile...... app that enables patients to collaborate with clinicians, we unpack experiences in six themes and present narratives of patients' lifeworlds. We find that patients' emotions are grounded in negative feelings (uncertainty, anxiety, loss of hope) and that positive experiences (relief, reassurance...

  13. Radiochemical solar neutrino experiments

    International Nuclear Information System (INIS)

    Rich, R.; Spiro, M.

    1993-01-01

    This review covers the three presently running radiochemical solar neutrino experiments, namely the Chlorine, SAGE, and GALLEX experiments. The focus of the review is on a discussion of statistical consistency checks of the available data. The chlorine radiochemical experiment is conceptually simple and shows no strong indication of any statistical anomalies. It still forms the basis of the solar neutrino problem. Each of the two gallium experiments show internal statistical consistency. SAGE's recent preliminary results are consistent with the published GALLEX results. If this convergence is confirmed by a more definitive analysis, this would suggest that the combined result of the two gallium experiments, SAGE and GALLEX, be used for comparisons with theoretical expectations. 5 refs., 15 figs

  14. Undergraduate reactor control experiment

    International Nuclear Information System (INIS)

    Edwards, R.M.; Power, M.A.; Bryan, M.

    1992-01-01

    A sequence of reactor and related experiments has been a central element of a senior-level laboratory course at Pennsylvania State University (Penn State) for more than 20 yr. A new experiment has been developed where the students program and operate a computer controller that manipulates the speed of a secondary control rod to regulate TRIGA reactor power. Elementary feedback control theory is introduced to explain the experiment, which emphasizes the nonlinear aspect of reactor control where power level changes are equivalent to a change in control loop gain. Digital control of nuclear reactors has become more visible at Penn State with the replacement of the original analog-based TRIGA reactor control console with a modern computer-based digital control console. Several TRIGA reactor dynamics experiments, which comprise half of the three-credit laboratory course, lead to the control experiment finale: (a) digital simulation, (b) control rod calibration, (c) reactor pulsing, (d) reactivity oscillator, and (e) reactor noise

  15. Molybdenum solar neutrino experiment

    International Nuclear Information System (INIS)

    Wolfsberg, K.; Cowan, G.A.; Bryant, E.A.

    1984-01-01

    The goal of the molybdenum solar neutrino experiment is to deduce the 8 B solar neutrino flux, averaged over the past several million years, from the concentration of 98 Tc in a deeply buried molybdenum deposit. The experiment is important to an understanding of stellar processes because it will shed light on the reason for the discrepancy between theory and observation of the chlorine solar neutrino experiment. Possible reasons for the discrepancy may lie in the properties of neutrinos (neutrino oscillations or massive neutrinos) or in deficiencies of the standard solar model. The chlorine experiment only measures the 8 B neutrino flux in current times and does not address possible temporal variations in the interior of the sun, which are also not considered in the standard model. In the molybdenum experiment, we plan to measure 98 Tc (4.2 Myr), also produced by 8 B neutrinos, and possibly 97 Tc (2.6 Myr), produced by lower energy neutrinos

  16. Cryogenics for LHC experiments

    CERN Multimedia

    2001-01-01

    Cryogenic systems will be used by LHC experiments to maximize their performance. Institutes around the world are collaborating with CERN in the construction of these very low temperature systems. The cryogenic test facility in hall 180 for ATLAS magnets. High Energy Physics experiments have frequently adopted cryogenic versions of their apparatus to achieve optimal performance, and those for the LHC will be no exception. The two largest experiments for CERN's new flagship accelerator, ATLAS and CMS, will both use large superconducting magnets operated at 4.5 Kelvin - almost 270 degrees below the freezing point of water. ATLAS also includes calorimeters filled with liquid argon at 87 Kelvin. For the magnets, the choice of a cryogenic version was dictated by a combination economy and transparency to emerging particles. For the calorimeters, liquid argon was selected as the fluid best suited to the experiment's physics requirements. High Energy Physics experiments are the result of worldwide collaborations and...

  17. Space Experiment Module (SEM)

    Science.gov (United States)

    Brodell, Charles L.

    1999-01-01

    The Space Experiment Module (SEM) Program is an education initiative sponsored by the National Aeronautics and Space Administration (NASA) Shuttle Small Payloads Project. The program provides nationwide educational access to space for Kindergarten through University level students. The SEM program focuses on the science of zero-gravity and microgravity. Within the program, NASA provides small containers or "modules" for students to fly experiments on the Space Shuttle. The experiments are created, designed, built, and implemented by students with teacher and/or mentor guidance. Student experiment modules are flown in a "carrier" which resides in the cargo bay of the Space Shuttle. The carrier supplies power to, and the means to control and collect data from each experiment.

  18. Simulation - modeling - experiment; Simulation - modelisation - experience

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    After two workshops held in 2001 on the same topics, and in order to make a status of the advances in the domain of simulation and measurements, the main goals proposed for this workshop are: the presentation of the state-of-the-art of tools, methods and experiments in the domains of interest of the Gedepeon research group, the exchange of information about the possibilities of use of computer codes and facilities, about the understanding of physical and chemical phenomena, and about development and experiment needs. This document gathers 18 presentations (slides) among the 19 given at this workshop and dealing with: the deterministic and stochastic codes in reactor physics (Rimpault G.); MURE: an evolution code coupled with MCNP (Meplan O.); neutronic calculation of future reactors at EdF (Lecarpentier D.); advance status of the MCNP/TRIO-U neutronic/thermal-hydraulics coupling (Nuttin A.); the FLICA4/TRIPOLI4 thermal-hydraulics/neutronics coupling (Aniel S.); methods of disturbances and sensitivity analysis of nuclear data in reactor physics, application to VENUS-2 experimental reactor (Bidaud A.); modeling for the reliability improvement of an ADS accelerator (Biarotte J.L.); residual gas compensation of the space charge of intense beams (Ben Ismail A.); experimental determination and numerical modeling of phase equilibrium diagrams of interest in nuclear applications (Gachon J.C.); modeling of irradiation effects (Barbu A.); elastic limit and irradiation damage in Fe-Cr alloys: simulation and experiment (Pontikis V.); experimental measurements of spallation residues, comparison with Monte-Carlo simulation codes (Fallot M.); the spallation target-reactor coupling (Rimpault G.); tools and data (Grouiller J.P.); models in high energy transport codes: status and perspective (Leray S.); other ways of investigation for spallation (Audoin L.); neutrons and light particles production at intermediate energies (20-200 MeV) with iron, lead and uranium targets (Le Colley F

  19. Understanding customer experience.

    Science.gov (United States)

    Meyer, Christopher; Schwager, Andre

    2007-02-01

    Anyone who has signed up for cell phone service, attempted to claim a rebate, or navigated a call center has probably suffered from a company's apparent indifference to what should be its first concern: the customer experiences that culminate in either satisfaction or disappointment and defection. Customer experience is the subjective response customers have to direct or indirect contact with a company. It encompasses every aspect of an offering: customer care, advertising, packaging, features, ease of use, reliability. Customer experience is shaped by customers' expectations, which largely reflect previous experiences. Few CEOs would argue against the significance of customer experience or against measuring and analyzing it. But many don't appreciate how those activities differ from CRM or just how illuminating the data can be. For instance, the majority of the companies in a recent survey believed they have been providing "superior" experiences to customers, but most customers disagreed. The authors describe a customer experience management (CEM) process that involves three kinds of monitoring: past patterns (evaluating completed transactions), present patterns (tracking current relationships), and potential patterns (conducting inquiries in the hope of unveiling future opportunities). Data are collected at or about touch points through such methods as surveys, interviews, focus groups, and online forums. Companies need to involve every function in the effort, not just a single customer-facing group. The authors go on to illustrate how a cross-functional CEM system is created. With such a system, companies can discover which customers are prospects for growth and which require immediate intervention.

  20. Conducting interactive experiments online.

    Science.gov (United States)

    Arechar, Antonio A; Gächter, Simon; Molleman, Lucas

    2018-01-01

    Online labor markets provide new opportunities for behavioral research, but conducting economic experiments online raises important methodological challenges. This particularly holds for interactive designs. In this paper, we provide a methodological discussion of the similarities and differences between interactive experiments conducted in the laboratory and online. To this end, we conduct a repeated public goods experiment with and without punishment using samples from the laboratory and the online platform Amazon Mechanical Turk. We chose to replicate this experiment because it is long and logistically complex. It therefore provides a good case study for discussing the methodological and practical challenges of online interactive experimentation. We find that basic behavioral patterns of cooperation and punishment in the laboratory are replicable online. The most important challenge of online interactive experiments is participant dropout. We discuss measures for reducing dropout and show that, for our case study, dropouts are exogenous to the experiment. We conclude that data quality for interactive experiments via the Internet is adequate and reliable, making online interactive experimentation a potentially valuable complement to laboratory studies.

  1. LDR structural experiment definition

    Science.gov (United States)

    Russell, Richard A.; Gates, Richard M.

    1988-01-01

    A study was performed to develop the definition of a structural flight experiment for a large precision segmented reflector that would utilize the Space Station. The objective of the study was to use the Large Deployable Reflector (LDR) baseline configuration for focusing on experiment definition activity which would identify the Space Station accommodation requirements and interface constraints. Results of the study defined three Space Station based experiments to demonstrate the technologies needed for an LDR type structure. The basic experiment configurations are the same as the JPL baseline except that the primary mirror truss is 10 meters in diameter instead of 20. The primary objectives of the first experiment are to construct the primary mirror support truss and to determine its structural and thermal characteristics. Addition of the optical bench, thermal shield and primary mirror segments and alignment of the optical components occur on the second experiment. The structure will then be moved to the payload pointing system for pointing, optical control and scientific optical measurement for the third experiment.

  2. Thermogravimetric experiments with titanium

    International Nuclear Information System (INIS)

    Porter, L.J.; Longhurst, G.R.

    1991-02-01

    In the process of preparing for pyrophoricity experiments involving uranium, we conducted hydriding and air-exposure experiments on titanium. In these experiments the hydriding reactions and response to air-exposure was generally within the range expected based on work reported by others. One aberrant behavior was a sudden weight gain followed by a significant weight loss. We speculate that loss may be due to hydrogen evolution from the TiH 2 resulting from local heating by oxidation reactions. We verified that titanium is not pyrophoric at temperatures less than 750 degree C. 18 refs. 1 fig

  3. Game user experience evaluation

    CERN Document Server

    Bernhaupt, Regina

    2015-01-01

    Evaluating interactive systems for their user experience (UX) is a standard approach in industry and research today. This book explores the areas of game design and development and Human Computer Interaction (HCI) as ways to understand the various contributing aspects of the overall gaming experience. Fully updated, extended and revised this book is based upon the original publication Evaluating User Experience in Games, and provides updated methods and approaches ranging from user- orientated methods to game specific approaches. New and emerging methods and areas explored include physiologi

  4. Results from neutrino experiments

    International Nuclear Information System (INIS)

    Smirnov, A.Yu.

    1993-11-01

    Recent (first or/and the best) results from the neutrino experiments are reviewed and their implications for the theory are discussed. The sense of the experiments is the searching for neutrino masses, mixing and interactions beyond the standard model. Present laboratory experiments give upper bounds on the masses and the mixing which are at the level of predictions of the ''electroweak see-saw''. Positive indications of nonzero lepton mixing follow from studies of the solar and atmospheric neutrinos. (author). 95 refs, 11 figs

  5. CANDU operating experience

    International Nuclear Information System (INIS)

    McConnell, L.G.; Woodhead, L.W.; Fanjoy, G.R.; Thurygill, E.W.

    1980-05-01

    The CANDU-PHW program is based upon 38 years of heavy water reactor experience with 35 years of operating experience. Canada has had 72 reactor years of nuclear-electric operations experience with 10 nuclear units in 4 generating stations during a period of 18 years. All objectives have been met with outstanding performance: worker safety, public safety, environmental emissions, reliable electricity production, and low electricity cost. The achievement has been realized through total teamwork involving all scientific disciplines and all project functions (research, design, manufacturing, construction, and operation). (auth)

  6. Experience as Excursion

    DEFF Research Database (Denmark)

    Svabo, Connie; Shanks, Michael

    2014-01-01

    researchers and practitioners to travel – making it possible to follow experiences as they are enacted across and between places, modes of transportation, mobile mediation and assemblages of things. Drawing on the nomadic metaphysics of philosopher Michel Serres, the journeying, shifting and propagating...... qualities of experience are highlighted as part of a suggestion that design may indeed relate as much to metaphysics as to mechanics, materials science, and the psychology of the consumer and user. An Experience Design is sketched out as the choreography of temporary and shifting engagements across...

  7. Nightshade Prototype Experiments (Silverleaf)

    Energy Technology Data Exchange (ETDEWEB)

    Danielson, Jeremy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bauer, Amy L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-12-23

    The Red Sage campaign is a series of subcritical dynamic plutonium experiments designed to measure ejecta. Nightshade, the first experiments in Red Sage scheduled for fiscal year 2019, will measure the amount of ejecta emission into vacuum from a double-­shocked plutonium surface. To address the major technical risks in Nightshade, a Level 2 milestone was developed for fiscal year 2016. Silverleaf, a series of four experiments, was executed at the Los Alamos National Laboratory in July and August 2016 to demonstrate a prototype of the Nightshade package and to satisfy this Level 2 milestone. This report is documentation that Red Sage Level 2 milestone requirements were successfully met.

  8. The Experiment as Act

    DEFF Research Database (Denmark)

    Søndergaard, Morten

    In December 1965, an experiment took place at The Independent Art Space in Copenhagen (Den Frie Kunstbygning). Short named POEX65, it was looking to create and activate POetry EXperiments across artistic genres and formats (thus, in essence, making a POetry EXposition). The POEX65 event framed many...... to be able to analyse the phenomena found at POEX65. Here I will use the notion of the ‘ontological theatre’ (Pickering), which, according to Pickering, is acted out in experimental art productions. The experiment could thus be seen as an ‘agency-realism’ – as an ‘act’ of relations across the aesthetics...

  9. Velocity Feedback Experiments

    Directory of Open Access Journals (Sweden)

    Chiu Choi

    2017-02-01

    Full Text Available Transient response such as ringing in a control system can be reduced or removed by velocity feedback. It is a useful control technique that should be covered in the relevant engineering laboratory courses. We developed velocity feedback experiments using two different low cost technologies, viz., operational amplifiers and microcontrollers. These experiments can be easily integrated into laboratory courses on feedback control systems or microcontroller applications. The intent of developing these experiments was to illustrate the ringing problem and to offer effective, low cost solutions for removing such problem. In this paper the pedagogical approach for these velocity feedback experiments was described. The advantages and disadvantages of the two different implementation of velocity feedback were discussed also.

  10. Future neutrino experiments

    CERN Document Server

    Di Lella, L

    2001-01-01

    Future experiments to search for neutrino oscillations using neutrinos from the Sun, from reactors and accelerators are reviewed. Possible long-term developments based on neutrino factories are also described. (29 refs).

  11. LADEE LUNAR DUST EXPERIMENT

    Data.gov (United States)

    National Aeronautics and Space Administration — This archive bundle includes data taken by the Lunar Dust Experiment (LDEX) instrument aboard the Lunar Atmosphere and Dust Environment Explorer (LADEE) spacecraft....

  12. Experience and Its Generation

    Institute of Scientific and Technical Information of China (English)

    Chen Youqing

    2006-01-01

    Experience iS an activity that arouses emotions and generates meanings based on vivid sensation and profound compreh ension.It iS emotional,meaningful,and personal,playing a key role in the course of forming and developing one'S qualities.The psychological process of experience generation consists of such links as sensing things,arousing emotions,promoting comprehension and association,generating insights and meanings,and deepening emotional responses.Undergoing things personally by means of direct sensation,taking part in activities,and living life are the most important preconditions of experience generation.Emotional influence,situational edification,and arts edification ale extemal factors that induce experience generation.

  13. Muon ionization cooling experiment

    CERN Multimedia

    CERN. Geneva

    2003-01-01

    A neutrino factory based on a muon storage ring is the ultimate tool for studies of neutrino oscillations, including possibly leptonic CP violation. It is also the first step towards muon colliders. The performance of this new and promising line of accelerators relies heavily on the concept of ionisation cooling of minimum ionising muons, for which much R&D is required. The concept of a muon ionisation cooling experiment has been extensively studied and first steps are now being taken towards its realisation by a joint international team of accelerator and particle physicists. The aim of the workshop is to to explore at least two versions of an experiment based on existing cooling channel designs. If such an experiment is feasible, one shall then select, on the basis of effectiveness, simplicity, availability of components and overall cost, a design for the proposed experiment, and assemble the elements necessary to the presentation of a proposal. Please see workshop website.

  14. Experience Communication and Aesthetics

    DEFF Research Database (Denmark)

    Thorlacius, Lisbeth

    to user aspect (web 2.0), the personal engagement or the community spirit. This increasing demand of experiences reflects the postmodern cultural trends where rules for how to think and behave no longer exist. This results in individualism, where the identity of the human being has changed from something......-actualization. The individualization of the human being can lead to loneliness and a need of participating in communities as a replacement of an overall fixed point in one's life. (Anthony Giddens, 1990, 1991; Zygmunt Bauman, 1997; Carsten René Jørgensen, 2002). The field of communication is consequently experiencing a great......In this article the term "experience communication" will be introduced and discussed. It will be illustrated how different concepts of aesthetical experiences are an integrated part of experience communication and how these concepts are produced within the industries of consumerism, branding...

  15. The experiments ALICE

    CERN Document Server

    Fabjan, Christian

    2009-01-01

    This article documents the main design choices and the close to 20 years of preparation, detector R&D, construction and installation of ALICE, the dedicated heavy ion experiment at the CERN LHC accelerator.

  16. General relativity and experiment

    OpenAIRE

    Damour, T.

    1994-01-01

    The confrontation between Einstein's theory of gravitation and experiment is summarized. Although all current experimental data are compatible with general relativity, the importance of pursuing the quest for possible deviations from Einstein's theory is emphasized.

  17. Nova target experiments

    International Nuclear Information System (INIS)

    Drake, R.P.

    1985-11-01

    The Nova laser, at the Lawrence Livermore National Laboratory, provides unique opportunities for target experiments. It has unprecedented energy on target and significant flexibility. The paper presented by John Hunt described the capabilities and the status of Nova. This paper discusses plans for future experiments using Nova, and the present status of target experiments. We plan to perform high-quality physics experiments that exploit the unique capabilities of Nova. Because this is our goal, we are fielding an extensive array of well-characterized target diagnostics to measure the emissions from the target. The first section of this paper discusses the basic target diagnostics. We are also taking care to quantify the performance of the laser

  18. Rationality, Experience and Theory.

    Science.gov (United States)

    Shaw, K. E.

    1983-01-01

    A discussion of the usefulness of reasoning, as compared to experience, in three levels of decision making in school management informs this critique of the state of educational management theory and research. (MJL)

  19. German and French experiences

    International Nuclear Information System (INIS)

    Engl, G.

    1999-01-01

    In this lecture author presents experience in-service inspection programme of primary circuit components at home and abroad, implementation into WWER (world methodology and equipment) as well as system qualification. Objectives European network for inspection qualification (ENIQ) are presented

  20. International experience of microcredit

    OpenAIRE

    Nazarenko, M.; Nazarenko, O.

    2014-01-01

    The authors analyze international experience of microcredit development and made appropriate conclusions about the advantages and disadvantages of microcredit organization. Microcredit organizations are self-sufficient and stable institutions which are regulated by bank and state legislation.

  1. Experiments in Animal Behavior

    Science.gov (United States)

    Polt, James M.

    1971-01-01

    Describes experiments in conditioning, sensory processes, social behavior, imprinting, innate preferences for color and form, and discrimination learning suitable for secondary school students. Mealworms, crickets, and chicks are used as subjects. (AL)

  2. The world's biggest experiment

    CERN Multimedia

    Gregson, Liz

    2008-01-01

    According to CERN, our understanding of the Universe is about the change. Meet the Imperial alumni and staff who are involved in CERN's Large Hadron Collider, the world's biggest experiment. (3 pages)

  3. Water Flow Experiments

    Indian Academy of Sciences (India)

    year undergraduate student at Ashoka University,. Sonipat, Haryana. This article studies how the height of water varies with time when water ... Experiment using a one-bottle system with a small bore tube at- tached to .... restricting free flow.

  4. Experiment-o-mania

    Science.gov (United States)

    Drndarski, Marina

    2015-04-01

    Every 21st century student is expected to develop science literacy skills. As this is not part of Serbian national curriculum yet, we decided to introduce it with this project. Experiment-o-mania provides students to experience science in different and exciting way. It makes opportunity for personalized learning offering space and time to ask (why, where, how, what if) and to try. Therefore, we empower young people with skills of experimenting, and they love science back. They ask questions, make hypothesis, make problems and solve them, make mistakes, discuss about the results. Subsequently this raises the students' interest for school curriculum. This vision of science teaching is associated with inquiry-based learning. Experiment-o-mania is the unique and recognizable teaching methodology for the elementary school Drinka Pavlović, Belgrade, Serbia. Experiment-o-mania implies activities throughout the school year. They are held on extra class sessions, through science experiments, science projects or preparations for School's Days of science. Students learn to ask questions, make observations, classify data, communicate ideas, conduct experiments, analyse results and make conclusions. All science teachers participate in designing activities and experiments for students in Experiment-o-mania teaching method. But they are not alone. Teacher of fine arts, English teachers and others also take part. Students have their representatives in this team, too. This is a good way to blend knowledge among different school subject and popularize science in general. All the experiments are age appropriate and related to real life situations, local community, society and the world. We explore Fibonacci's arrays, saving energy, solar power, climate change, environmental problems, pollution, daily life situations in the country or worldwide. We introduce great scientists as Nikola Tesla, Milutin Milanković and sir Isaac Newton. We celebrate all relevant international days, weeks

  5. The CLOUD experiment

    CERN Multimedia

    Maximilien Brice

    2006-01-01

    The Cosmics Leaving Outdoor Droplets (CLOUD) experiment as shown by Jasper Kirkby (spokesperson). Kirkby shows a sketch to illustrate the possible link between galactic cosmic rays and cloud formations. The CLOUD experiment uses beams from the PS accelerator at CERN to simulate the effect of cosmic rays on cloud formations in the Earth's atmosphere. It is thought that cosmic ray intensity is linked to the amount of low cloud cover due to the formation of aerosols, which induce condensation.

  6. Towards LHC experiments

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    As plans for the LHC proton collider to be built in CERN's 27-kilometre LEP tunnel take shape, interest widens to bring in the experiments exploiting the big machine. The first public presentations of 'expressions of interest' for LHC experiments featured from 5-8 March at Evian-les-Bains on the shore of Lake Geneva, some 50 kilometres from CERN, at the special Towards the LHC Experimental Programme' meeting

  7. The MAJORANA Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Aguayo Navarrete, Estanislao; Avignone, F. T.; Back, Henning O.; Barabash, Alexander S.; Bergevin, M.; Bertrand, F.; Boswell, M.; Brudanin, V.; Busch, Matthew; Chan, Yuen-Dat; Christofferson, Cabot-Ann; Collar, J. I.; Combs, Dustin C.; Cooper, R. J.; Detwiler, Jason A.; Doe, Peter J.; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H.; Elliott, Steven R.; Esterline, James H.; Fast, James E.; Fields, N.; Finnerty, P.; Fraenkle, Florian; Gehman, Victor M.; Giovanetti, G. K.; Green, Matthew P.; Guiseppe, Vincente; Gusey, K.; Hallin, A. L.; Hazama, R.; Henning, R.; Hime, Andrew; Hoppe, Eric W.; Horton, Mark; Howard, Stanley; Howe, M. A.; Johnson, R. A.; Keeter, K.; Keillor, Martin E.; Keller, C.; Kephart, Jeremy D.; Kidd, Mary; Knecht, A.; Kochetov, Oleg; Konovalov, S.; Kouzes, Richard T.; LaFerriere, Brian D.; LaRoque, B. H.; Leon, Jonathan D.; Leviner, L.; Loach, J. C.; MacMullin, S.; Marino, Michael G.; Martin, R. D.; Mei, Dong-Ming; Merriman, Jason H.; Miller, M. L.; Mizouni, Leila; Nomachi, Masaharu; Orrell, John L.; Overman, Nicole R.; Phillips, D.; Poon, Alan; Perumpilly, Gopakumar; Prior, Gersende; Radford, D. C.; Rielage, Keith; Robertson, R. G. H.; Ronquest, M. C.; Schubert, Alexis G.; Shima, T.; Shirchenko, M.; Snavely, Kyle J.; Sobolev, V.; Steele, David; Strain, J.; Thomas, K.; Timkin, V.; Tornow, W.; Vanyushin, I.; Varner, R. L.; Vetter, Kai; Vorren, Kris R.; Wilkerson, John; Wolfe, B. A.; Yakushev, E.; Young, A.; Yu, Chang-Hong; Yumatov, Vladimir; Zhang, C.

    2011-10-01

    The Majorana collaboration is actively pursuing research and development aimed at a tonne-scale {sup 76}Ge neutrinoless double-beta decay ({beta}{beta}(0{nu})-decay) experiment. The current, primary focus is the construction of the Majorana Demonstrator experiment, an R and D effort that will field approximately 40 kg of germanium detectors with mixed enrichment levels. This article provides a status update on the construction of the Demonstrator.

  8. Hamlet and psychoanalytic experience.

    Science.gov (United States)

    Schwaber, Paul

    2007-01-01

    Hamlet draws us into its rendered world, enabling us to experience it with depth, awareness, and resonance, in a mode we recognize as aesthetic. By way of Shakespeare's play--primarily the first act--and a detailed case study, aesthetic and psychoanalytic experience are compared, to suggest that, for our own analytic discourse, we revalue Freud's unease that his case studies read like short stories.

  9. Experiments with dipole antennas

    International Nuclear Information System (INIS)

    Kraftmakher, Yaakov

    2009-01-01

    Employment of a data-acquisition system for data collection and calculations makes experiments with antennas more convenient and less time consuming. The determined directional patterns of the dipole antennas of different lengths are in reasonable agreement with theory. The enhancement of the signal by using a reflector is demonstrated, and a variant of the Yagi-Uda antenna is explored. The experiments are suitable as laboratory works and classroom demonstrations, and are attractive for student projects.

  10. Remote earth sensing experiments

    Energy Technology Data Exchange (ETDEWEB)

    Trifonov, Yu V

    1981-01-01

    Description of data devices for deriving multi-spectral measuring television measurement data of middle and high resolution through use of second generation Meteor-type satellites. Options for developing a permanent and active remote sensing system in USSR are discussed. It is noted that the present experiment is an important step in that direction. Design and structural data for this particular device and its application in the experiment are covered.

  11. Review of experiments

    International Nuclear Information System (INIS)

    Chang, C.; Yodh, G.; Cutts, D.; Lanou, R.; Engels, E.; Kramer, M.; Danby, G.

    1977-01-01

    A study was made to examine the effects which raising the ISA from 200 x 200 GeV to 400 x 400 GeV would have on the ''canonical'' experiments. These were ''canonical'' in the sense that they span the full range of foreseeable physics and have served as topics in previous Summer Studies and Workshops which resulted in quite explicit hardware designs and experimental goals. The study results indicate that all of the ''canonical'' experiments survive. Some are actually improved, some are unaffected, and some require changes which are suggested. In general, the 90 0 experiments are relatively unaffected. The single arm small angle spectrometer, the wide aperture (FATS-WASP) spectrometer and the Coulomb interference experiment have the largest number of modifications suggested. No uniqueness to these solutions are claimed, and there may be more desirable radical approaches. It is, however, felt that the 400 x 400 GeV ISA not only permits the work on conceptual experiments from previous Summer Studies to be taken over entirely, but indicates areas of improvement in many of them. Specifics of the individual experiments are discussed

  12. Inverse Cerenkov experiment

    International Nuclear Information System (INIS)

    Kimura, W.D.

    1993-01-01

    The final report describes work performed to investigate inverse Cherenkov acceleration (ICA) as a promising method for laser particle acceleration. In particular, an improved configuration of ICA is being tested in a experiment presently underway on the Accelerator Test Facility (ATF). In the experiment, the high peak power (∼ 10 GW) linearly polarized ATF CO 2 laser beam is converted to a radially polarized beam. This is beam is focused with an axicon at the Cherenkov angle onto the ATF 50-MeV e-beam inside a hydrogen gas cell, where the gas acts as the phase matching medium of the interaction. An energy gain of ∼12 MeV is predicted assuming a delivered laser peak power of 5 GW. The experiment is divided into two phases. The Phase I experiments, which were completed in the spring of 1992, were conducted before the ATF e-beam was available and involved several successful tests of the optical systems. Phase II experiments are with the e-beam and laser beam, and are still in progress. The ATF demonstrated delivery of the e-beam to the experiment in Dec. 1992. A preliminary ''debugging'' run with the e-beam and laser beam occurred in May 1993. This revealed the need for some experimental modifications, which have been implemented. The second run is tentatively scheduled for October or November 1993. In parallel to the experimental efforts has been ongoing theoretical work to support the experiment and investigate improvement and/or offshoots. One exciting offshoot has been theoretical work showing that free-space laser acceleration of electrons is possible using a radially-polarized, axicon-focused laser beam, but without any phase-matching gas. The Monte Carlo code used to model the ICA process has been upgraded and expanded to handle different types of laser beam input profiles

  13. Experiments in computing: a survey.

    Science.gov (United States)

    Tedre, Matti; Moisseinen, Nella

    2014-01-01

    Experiments play a central role in science. The role of experiments in computing is, however, unclear. Questions about the relevance of experiments in computing attracted little attention until the 1980s. As the discipline then saw a push towards experimental computer science, a variety of technically, theoretically, and empirically oriented views on experiments emerged. As a consequence of those debates, today's computing fields use experiments and experiment terminology in a variety of ways. This paper analyzes experimentation debates in computing. It presents five ways in which debaters have conceptualized experiments in computing: feasibility experiment, trial experiment, field experiment, comparison experiment, and controlled experiment. This paper has three aims: to clarify experiment terminology in computing; to contribute to disciplinary self-understanding of computing; and, due to computing's centrality in other fields, to promote understanding of experiments in modern science in general.

  14. Staged theta pinch experiments

    International Nuclear Information System (INIS)

    Linford, R.K.; Downing, J.N.; Gribble, R.F.; Jacobson, A.R.; Platts, D.A.; Thomas, K.S.

    1976-01-01

    Two implosion heating circuits are being experimentally tested. The principal experiment in the program is the 4.5-m-long Staged Theta Pinch (STP). It uses two relatively low energy (50kJ and 100 kJ), high voltage (125 kV) capacitor banks to produce the theta pinch plasma inside the 20 cm i.d. quartz discharge tube. A lower voltage (50 kV), higher energy (750 kJ) capacitor bank is used to contain the plasma and provide a variable amount of adiabatic compression. Because the experiment produces a higher ratio of implosion heating to compressional heating than conventional theta pinches, it should be capable of producing high temperature plasmas with a much larger ratio of plasma radius to discharge tube radius than has been possible in the past. The Resonant Heating Experiment (RHX) in its initial configuration is the same as a 0.9-m-long section of the high voltage part of the STP experiment and all the plasma results here were obtained with the experiment in that configuration. Part of the implosion bank will be removed and a low inductance crowbar added to convert it to the resonant heating configuration. (U.K.)

  15. An MHD Dynamo Experiment.

    Science.gov (United States)

    O'Connell, R.; Forest, C. B.; Plard, F.; Kendrick, R.; Lovell, T.; Thomas, M.; Bonazza, R.; Jensen, T.; Politzer, P.; Gerritsen, W.; McDowell, M.

    1997-11-01

    A MHD experiment is being constructed which will have the possibility of showing dynamo action: the self--generation of currents from fluid motion. The design allows sufficient experimental flexibility and diagnostic access to study a variety of issues central to dynamo theory, including mean--field electrodynamics and saturation (backreaction physics). Initially, helical flows required for dynamo action will be driven by propellers embedded in liquid sodium. The flow fields will first be measured using laser doppler velocimetry in a water experiment with an identical fluid Reynolds number. The magnetic field evolution will then be predicted using a MHD code, replacing the water with sodium; if growing magnetic fields are found, the experiment will be repeated with sodium.

  16. Thought experiment with tritium

    International Nuclear Information System (INIS)

    Anderson, H.F.; Everhart, J.L.; Hobrock, D.L.; Seabaugh, P.W.

    1995-01-01

    An experiment is proposed in which a minimum of thirty (30) grams of tritium is packaged as lithium tritide in a steel container weighing several kilograms. After decontamination of the outside surface, calorimetry measurements would be made, and the unit would be weighed very accurately. After several decades, the calorimeter and weight measurements would be repeated. If the weight measurements could be made with the required accuracy, it would be possible to correlate the observed change in mass with the total energy emitted (calculated from the mean energy measured by calorimetry) over the time interval. If successful, this experiment would, in the opinion of the authors, be the first laboratory experiment to directly verify the equivalency of mass and energy. 4 refs., 2 figs., 3 tabs

  17. Nuclear power experience

    International Nuclear Information System (INIS)

    1983-01-01

    The International Conference on Nuclear Power Experience, organized by the International Atomic Energy Agency, was held at the Hofburg Conference Center, Vienna, Austria, from 13 to 17 September 1982. Almost 1200 participants and observers from 63 countries and 20 organizations attended the conference. The 239 papers presented were grouped under the following seven main topics: planning and development of nuclear power programmes; technical and economic experience of nuclear power production; the nuclear fuel cycle; nuclear safety experience; advanced systems; international safeguards; international co-operation. The proceedings are published in six volumes. The sixth volume contains a complete Contents of Volume 1 to 5, a List of Participants, Authors and Transliteration Indexes, a Subject Index and an Index of Papers by Number

  18. ATLAS IBL operational experience

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00237659; The ATLAS collaboration

    2017-01-01

    The Insertable B-Layer (IBL) is the inner most pixel layer in the ATLAS experiment, which was installed at 3.3 cm radius from the beam axis in 2014 to improve the tracking performance. To cope with the high radiation and hit occupancy due to proximity to the interaction point, a new read-out chip and two different silicon sensor technologies (planar and 3D) have been developed for the IBL. After the long shut-down period over 2013 and 2014, the ATLAS experiment started data-taking in May 2015 for Run-2 of the Large Hadron Collider (LHC). The IBL has been operated successfully since the beginning of Run-2 and shows excellent performance with the low dead module fraction, high data-taking efficiency and improved tracking capability. The experience and challenges in the operation of the IBL is described as well as its performance.

  19. Operating experience feedback

    International Nuclear Information System (INIS)

    Cimesa, S.

    2007-01-01

    Slovenian Nuclear Safety Administration (SNSA) has developed its own system for tracking, screening and evaluating the operating experiences of the nuclear installations. The SNSA staff regularly tracks the operating experiences throughout the world and screens them on the bases of applicability for the Slovenian nuclear facilities. The operating experiences, which pass the screening, are thoroughly evaluated and also recent operational events in these facilities are taken into account. If needed, more information is gathered to evaluate the conditions of the Slovenian facilities and appropriate corrective actions are considered. The result might be the identification of the need for modification at the licensee, the need for modification of internal procedures in the SNSA or even the proposal for the modification of regulations. Information system helps everybody to track the process of evaluation and proper logging of activities. (author)

  20. Qualitative experiments in psychology

    DEFF Research Database (Denmark)

    Wagoner, Brady

    2015-01-01

    In this article, I explore the meaning of experiments in early twentieth century psychology, focusing on the qualitative experimental methodology of psychologist Frederic BARTLETT. I begin by contextualizing BARTLETT's experiments within the continental research tradition of his time, which...... was in a state of transition from a focus on elements (the concern of psychophysics) to a focus on wholes (the concern of Gestalt psychology). The defining feature of BARTLETT's early experiments is his holistic treatment of human responses, in which the basic unit of analysis is the active person relating...... to some material within the constraints of a social and material context. This manifests itself in a number of methodological principles that contrast with contemporary understandings of experimentation in psychology. The contrast is further explored by reviewing the history of "replications...

  1. Experiences with treating immigrants

    DEFF Research Database (Denmark)

    Sandhu, Sima; Bjerre, Neele V; Dauvrin, Marie

    2012-01-01

    PURPOSE: While there has been systematic research on the experiences of immigrant patients in mental health services within certain European countries, little research has explored the experiences of mental health professionals in the delivery of services to immigrants across Europe. This study...... sought to explore professionals' experiences of delivering care to immigrants in districts densely populated with immigrants across Europe. METHODS: Forty-eight semi-structured interviews were conducted with mental health care professionals working in 16 European countries. Professionals in each country...... were recruited from three areas with the highest proportion of immigrants. For the purpose of this study, immigrants were defined as first-generation immigrants born outside the country of current residence, including regular immigrants, irregular immigrants, asylum seekers, refugees and victims...

  2. Experiments in mixed reality

    Science.gov (United States)

    Krum, David M.; Sadek, Ramy; Kohli, Luv; Olson, Logan; Bolas, Mark

    2010-01-01

    As part of the Institute for Creative Technologies and the School of Cinematic Arts at the University of Southern California, the Mixed Reality lab develops technologies and techniques for presenting realistic immersive training experiences. Such experiences typically place users within a complex ecology of social actors, physical objects, and collections of intents, motivations, relationships, and other psychological constructs. Currently, it remains infeasible to completely synthesize the interactivity and sensory signatures of such ecologies. For this reason, the lab advocates mixed reality methods for training and conducts experiments exploring such methods. Currently, the lab focuses on understanding and exploiting the elasticity of human perception with respect to representational differences between real and virtual environments. This paper presents an overview of three projects: techniques for redirected walking, displays for the representation of virtual humans, and audio processing to increase stress.

  3. The Experience City

    DEFF Research Database (Denmark)

    Marling, Gitte; Jensen, Ole B.; Kiib, Hans

    2009-01-01

      The article take its point of departure in the pressure of the experience economy on European cities - a pressure which in recent years has found its expression in a number of comprehensive transformations of the physical and architectural environments, and new eventscapes related to fun...... and cultural experience are emerging. In the discussion of the transformation into the ‘experience economy' relevant to cities and urban areas we rarely find an analysis of the physical and spatial implications of this transformation. However, the physical, cultural and democratic consequences...... clear goals related to the improvement of social interaction, performance and cultural exchange. The article contains three sections. in section one, we present three European cases in order to relate to the wider international debate and development. In section two we present the main theoretical...

  4. experience in school

    Directory of Open Access Journals (Sweden)

    Maria da Graça B. B. Dias

    2005-01-01

    Full Text Available An experiment investigated the effect of a make-believe fantasy mode of problem presentation on reasoning about valid conditional syllogisms in three groups of 5-year-old children: a school children from middle-class families in England; b school children from middle-class families in Brazil; and, c children from low SES families in Brazil who had never gone to school. Previous investigations had reported that the use of a fantasy context elicited significantly more logically appropriate responses from school children than did other contexts, and that children with school experiences made significantly more logically appropriate responses than did children without school experience. The present investigation extended these findings to show that the beneficial effects of a fantasy context extended to lower-class illiterate children who never had been exposed to schooling

  5. Crystal box experiments

    International Nuclear Information System (INIS)

    Hoffman, C.M.; Highland, V.L.; Hogan, G.E.; Hallin, A.

    1985-01-01

    The aim of these experiments is to search for several rare-decay modes of the muon and the pion and to study these decay modes should they be observed. In Exps. 400/445, the muon-number-nonconserving decays μ + αe + e + e - , μ + →e + γ, and μ + →e + γγ are being sought with a sensitivity to branching ratios of about 10 -11 relative to ordinary muon decay. Experiment 726 will search for the charge-conjugation-violating decay π 0 →3γ with a sensitivity to a branching ratio as small as 10 -9 relative to ordinary π 0 decay. Experiment 888 is a study of radiative pion decay π + →e + nu/sub e/γ

  6. Cooperative Prototyping Experiments

    DEFF Research Database (Denmark)

    Bødker, Susanne; Grønbæk, Kaj

    1989-01-01

    This paper describes experiments with a design technique that we denote cooperative prototyping. The experiments consider design of a patient case record system for municipal dental clinics in which we used HyperCard, an off the shelf programming environment for the Macintosh. In the ecperiments we...... tried to achieve a fluent work-like evaluation of prototypes where users envisioned future work with a computer tool, at the same time as we made on-line modifications of prototypes in cooperation with the users when breakdown occur in their work-like evaluation. The experiments showed...... that it was possible to make a number of direct manipulation changes of prototypes in cooperation with the users, in interplay with their fluent work-like evaluation of these. However, breakdown occurred in the prototyping process when we reached the limits of the direct manipulation support for modification. From...

  7. Experience Innovation in Tourism

    DEFF Research Database (Denmark)

    Jensen, Jens Friis; Sørensen, Flemming

    2017-01-01

    This paper discusses how front-line employees can play an important role in innovation processes that lead tourism companies from service production to experience creation. The increasing focus on experiential value by customers in general (Sundbo and Sørensen, 2013) puts pressure on service...... companies to move from functional service production to creating experiences (Pine and Gilmore, 2013). This is also the case in tourism companies. In tourism, most encounters between employees and tourists operate on a service logic (Sørensen and Jensen, 2015). Thus, we suggest there is a value potential...... in developing such encounters into experience encounters focusing on the co-creation of experiential value. While frontline employees are central for service quality they are mostly not included in systematised innovation processes in tourism companies. These companies are often hierarchically organised...

  8. Compact ignition experiments

    International Nuclear Information System (INIS)

    Angelini, A.; Coppi, B.; Nassi, M.

    1992-01-01

    This paper reports on high magnetic field experiments which can be designed to investigate D-T ignition conditions based on present-day experimental results and theoretical understanding of plasma phenomena. The key machine elements are: large plasma currents, compact dimensions, tight aspect ratios, moderate elongations and significant triangularities of the plasma column. High plasma densities, strong ohmic heating, the needed degree of energy confinement, good plasma purity and robust stability against ideal and resistive instabilities can be achieved simultaneously. The Ignitor design incorporates all these characteristics and involves magnet technology developments, started with the Alcator experiment, that use cryogenically cooled normal conductors

  9. Photon mass experiment

    International Nuclear Information System (INIS)

    Crandall, R.E.

    1983-01-01

    A Coulomb null experiment is described that enables physics students to obtain rigorous upper bounds on photon mass. The experimenter searches for subnanovolt signals that would escape a closed shell were photon mass to be positive. The approach can be adapted for several college levels. At the simplest level, a ''miniature'' low-cost experiment allows a student to verify the exponent ''-2'' in Coulomb's law to eight or more decimal places. An advanced student given a full-size apparatus (at greater cost) can obtain mass bounds very close to the established laboratory limit

  10. The LDMX Experiment

    OpenAIRE

    Mans Jeremiah

    2017-01-01

    The thermal-relic mechanism for the production of dark-matter in the early universe, combined with the precision measurements of the cosmic microwave background and the lack of observation of dark matter at the LHC, motivates the search for dark matter in the mass range between 1 MeV and 1 GeV. We describe the concept for the Light Dark Matter Experiment (LDMX), which could carry out such a search using the missing-momentum technique. The experiment would utilize a unique high-rate, low-curre...

  11. Experimenting with alternative economies

    DEFF Research Database (Denmark)

    Longhurst, Noel; Avelino, Flor; Wittmayer, Julia

    2016-01-01

    Neoliberalism is a powerful narrative that has shaped processes of urban economic development across the globe. This paper reports on four nascent ‘new economic’ narratives which represent fundamentally different imaginaries of the urban economy. Experiments informed by these narratives challenge...... the dominant neoliberal logic in four key dimensions: What is the purpose of economic development? What are the preferred distributive mechanisms? Who governs the economy? What is the preferred form of economic organisation? The emergence of these experiments illustrates that cities are spaces where counter...

  12. Experiments in radiochemistry

    International Nuclear Information System (INIS)

    Schwankner, R.

    1980-11-01

    Twelve experiments in radiochemistry, nuclear chemistry, radiation detection and radiation measurement are presented which have been tested in teaching practice. Criteria of selection were minimum apparative expenditure, preparation time, radiation exposure, and danger of incorporation or contamination. The experiments will teach students how to handle unsealed radioactive materials within a fraction of a permissible values and thus train them in radiochemical techniques of working. Theoretical, historical and topical aspects are mentioned in order to give the students some background. A detailed bibliography of relevant publications is given. (orig./HP) [de

  13. Lidar calibration experiments

    DEFF Research Database (Denmark)

    Ejsing Jørgensen, Hans; Mikkelsen, T.; Streicher, J.

    1997-01-01

    detection to test the reproducibility and uncertainty of lidars. Lidar data were obtained from both single-ended and double-ended Lidar configurations. A backstop was introduced in one of the experiments and a new method was developed where information obtained from the backstop can be used in the inversion...... algorithm. Independent in-situ aerosol plume concentrations were obtained from a simultaneous tracer gas experiment with SF6, and comparisons with the two lidars were made. The study shows that the reproducibility of the lidars is within 15%, including measurements from both sides of a plume...

  14. SUPERCOLLIDER: Planning for experiments

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    To push forward the necessarily lengthy preparations for experiments at the proposed US Superconducting Super Collider, a Workshop on Experiments, Detectors and Experimental Areas was held at Berkeley from 7 to 17 July. Participants looked ahead to the task of extracting physics (like the search for Higgs particles, supersymmetry or other heavy quarks and leptons) from the chaos of hadron collisions at 20 TeV beam energies with luminosities in excess of 10 32 . The door would also have to be left open for unexpected physics in these higher energy regions

  15. Accessibility and sensory experiences

    DEFF Research Database (Denmark)

    Ryhl, Camilla

    2010-01-01

    and accessibility. Sensory accessibility accommodates aspects of a sensory disability and describes architectural design requirements needed to ensure access to architectural experiences. In the context of architecture accessibility has become a design concept of its own. It is generally described as ensuring...... physical access to the built environment by accommodating physical disabilities. While the existing concept of accessibility ensures the physical access of everyone to a given space, sensory accessibility ensures the choice of everyone to stay and be able to participate and experience....

  16. Who Needs Business Experience?

    DEFF Research Database (Denmark)

    Walter, Achim; Ritter, Thomas; Coviello, Nicole

    that prior business experience does not predict very early export (within three years). Our results offer fresh insight to the international business and international entrepreneurship literatures, and implications for policy development. In particular, international R&D collaborations at public research...... the founding teams’ pre-foundation R&D and customer collaborations to early exports. We also show that pre-foundation involvement in these various forms of collaboration, as well as a diverse stock of prior technical knowledge, can compensate for a lack of business experience in the team. The results also show...

  17. Experiences of depression

    DEFF Research Database (Denmark)

    Rønberg, Mette

    In this thesis, I examine the complex experiences of what we call depression in everyday life, the multifaceted and ambiguous experiences of getting a depression diagnosis, and the in-depth processes involved in learning to live under the description of depression. The thesis is based......-and-for-all-dealt-with matters but rather messy and complicated processes, that involve several actors and multiple relations to the diagnosis. The thesis furthermore challenges the dominant diagnostic understanding depression as a neurobiological, and individual disorder in present-day diagnostic cultures, by arguing...

  18. Experiment SPHERE status 2008

    International Nuclear Information System (INIS)

    Shaulov, S.B.; Besshapov, S.P.; Kabanova, N.V.; Sysoeva, T.I.; Antonov, R.A.; Anyuhina, A.M.; Bronvech, E.A.; Chernov, D.V.; Galkin, V.I.; Tkaczyk, W.; Finger, M.; Sonsky, M.

    2009-01-01

    The expedition carried out in March, 2008 to Lake Baikal became an important stage in the development of the SPHERE experiment. During the expedition the SPHERE-2 installation was hoisted, for the first time, on a tethered balloon, APA, to a height of 700 m over the lake surface covered with ice and snow. A series of test measurements were made. Preliminary results of the data processing are presented. The next plan of the SPHERE experiment is to begin a set of statistics for constructing the CR spectrum in the energy range 10 16 -10 18 eV.

  19. Experiment SPHERE status 2008

    Energy Technology Data Exchange (ETDEWEB)

    Shaulov, S.B., E-mail: shaul@sci.lebedev.r [P.N.Lebedev Physical Institute, Russian Academy of Sciences, Leninsky prospect 53, Moscow 119991 (Russian Federation); Besshapov, S.P.; Kabanova, N.V.; Sysoeva, T.I. [P.N.Lebedev Physical Institute, Russian Academy of Sciences, Leninsky prospect 53, Moscow 119991 (Russian Federation); Antonov, R.A.; Anyuhina, A.M.; Bronvech, E.A.; Chernov, D.V.; Galkin, V.I. [Skobeltsyn Institute of Nuclear Physics, Lomonosov State University, Moscow 119992 (Russian Federation); Tkaczyk, W. [Department of Experimental Physics of University of Lodz (Poland); Finger, M. [Karlov University, Prague (Czech Republic); Sonsky, M. [COMPAS Consortium, Turnov (Czech Republic)

    2009-12-15

    The expedition carried out in March, 2008 to Lake Baikal became an important stage in the development of the SPHERE experiment. During the expedition the SPHERE-2 installation was hoisted, for the first time, on a tethered balloon, APA, to a height of 700 m over the lake surface covered with ice and snow. A series of test measurements were made. Preliminary results of the data processing are presented. The next plan of the SPHERE experiment is to begin a set of statistics for constructing the CR spectrum in the energy range 10{sup 16}-10{sup 18} eV.

  20. The OLYMPUS Experiment

    OpenAIRE

    Milner, R.; Hasell, D. K.; Kohl, M.; Schneekloth, U.; Akopov, N.; Alarcon, R.; Andreev, V. A.; Ates, O.; Avetisyan, A.; Bayadilov, D.; Beck, R.; Belostotski, S.; Bernauer, J. C.; Bessuille, J.; Brinker, F.

    2013-01-01

    The OLYMPUS experiment was designed to measure the ratio between the positron-proton and electron-proton elastic scattering cross sections, with the goal of determining the contribution of two-photon exchange to the elastic cross section. Two-photon exchange might resolve the discrepancy between measurements of the proton form factor ratio, $\\mu_p G^p_E/G^p_M$, made using polarization techniques and those made in unpolarized experiments. OLYMPUS operated on the DORIS storage ring at DESY, alt...

  1. AGS experiments---1987, 1988, 1989

    International Nuclear Information System (INIS)

    Depken, J.C.

    1989-04-01

    This report contains: Experimental Areas Layout; Table of Beam Parameters and Fluxes; Experiment Schedule ''as run''; Experiment Long Range Schedule; A listing of experiments by number; Two-page summaries of each experiment begin here, also ordered by number; Publications of AGS experiments; and List of experimenters

  2. AGS experiments: 1985, 1986, 1987

    International Nuclear Information System (INIS)

    Depken, J.C.

    1987-01-01

    This report contains: Experimental areas layout, table of beam parameters and fluxes, experiment schedule ''as run,'' experiment long range schedule, a listing of experiments by number, two-page summaries of each experiment, also ordered by number, and publications of AGS experiments, 1982-1987

  3. AGS experiments, 1988, 1989, 1990

    International Nuclear Information System (INIS)

    Depken, J.C.

    1991-04-01

    This report contains: experimental areas layout; table of beam parameters and fluxes; experiment schedule ''as run''; experiment long range schedule; a listing of experiments by number; two-page summaries of each experiment begin here, also ordered by number; publications of AGS experiments; and list of experimenters

  4. Ultrafast gas switching experiments

    International Nuclear Information System (INIS)

    Frost, C.A.; Martin, T.H.; Patterson, P.E.; Rinehart, L.F.; Rohwein, G.J.; Roose, L.D.; Aurand, J.F.; Buttram, M.T.

    1993-01-01

    We describe recent experiments which studied the physics of ultrafast gas breakdown under the extreme overvoltages which occur when a high pressure gas switch is pulse charged to hundreds of kV in 1 ns or less. The highly overvolted peaking gaps produce powerful electromagnetic pulses with risetimes Khz at > 100 kV/m E field

  5. The Mentoring Experience.

    Science.gov (United States)

    Longhurst, Mark F.

    1994-01-01

    Dialogue with Canadian family practice faculty and teachers indicates that the mentorship experience is one that cannot be assigned to a learner. Examines aspects of a mentorship that can be ascribed and explored in a family practice residency training program. (LZ)

  6. Experiments on ferrimagnetism

    International Nuclear Information System (INIS)

    Kraftmakher, Yaakov

    2013-01-01

    Ferrimagnetism undoubtedly deserves a proper place in the undergraduate laboratory on electricity and magnetism. Four student experiments on ferrimagnetism are considered: (i) the hysteresis loops and permeability of a ‘soft’ ferrite; (ii) the differential permeability versus a dc bias; (iii) the frequency dependence of the complex permeability and (iv) the electromagnetic interference suppression by ferrite chokes and beads. Two ferrite cores taken off a low-frequency choke and a power cord are used. The measurements are simple and straightforward and show the important properties of ferrites and their applications. The values of the permeability of the ferrite core determined in experiments (i)–(iii) are in reasonable agreement. The frequency dependence of the complex permeability of the ferrites is similar to that given by the manufacturers. The capability of absorbing electromagnetic waves in a definite frequency range shown in experiment (iv) demonstrates one of the principles of Stealth technology. The equipment necessary for the experiments can be found in many student laboratories. (paper)

  7. [The AMY experiment

    International Nuclear Information System (INIS)

    1989-01-01

    The AMY experiment is one of three major experiments at TRISTAN which is studying the states the matter produced in electron positron annihilations in the center of mass energy range of 50--65GeV. It provides information between the lower energy facilities such as PEP and PETRA and the new facilities SLC and LEP which are designed to operate in the region of the Z 0 mass near 90GeV. In the region of the AMY experiment, interaction cross sections are near their minimum of about 100pb, making it difficult to acquire large data samples during typical running cycles. This last year has seen an accumulation of about 10---12pb -1 of integrated luminosity in the energy range from 58 to 61.7GeV. Despite this limited data sample, the AMY experiment has been extremely active in attempting to extract the minimum amount of information from the data. Some of the most significant results are discussed in this paper. 9 refs

  8. The Transgender Military Experience

    Directory of Open Access Journals (Sweden)

    Michelle Dietert

    2015-04-01

    Full Text Available Although there have been studies that focus on the experiences of the gay and lesbian population serving in the United States military, few have focused on the experience of active duty transgender service members. Transgender individuals transgress the binary conception of gender by deviating from societal gender norms associated with assigned sex at birth. The Department of Defense has set policies and standards that reflect a binary conception of gender, with a focus on conformity. We argue that able-bodied gender variant service personnel are just as capable of serving their country as anyone else. Because of the repercussions associated with active duty transgender military personnel, our sample is small and involves nine clandestine service members and two international service members who wanted to share their stories from a different perspective. Snowball sampling was aimed at finding current active duty and reserve transgender service members. Using a combination of telephone interviews and questionnaires, data were collected from active duty transgender service personnel throughout the United States and two from international militaries that allow transgender people to serve. Data collection focused on the overall experiences of the participants along with questions regarding workplace discrimination, suggestions for policy changes, and their views about the overturn of Don’t Ask, Don’t Tell. Our findings add to a growing source of information about the transgender military experience in the U.S. armed forces and the importance of overturning discriminatory workplace policies that negatively impact transgender service members.

  9. PERICLES 2D experiment

    International Nuclear Information System (INIS)

    Morel, Christophe

    2001-01-01

    Scope of the lecture was the modelling of severe reactor accidents. The PERICLES 2D experiment was compared to CATHARE 3D simulation results considering progression of a quench front inside the reactor core, steam flow rates, heat conduction, cladding temperature. (uke)

  10. Experimenting for resilience

    DEFF Research Database (Denmark)

    Hagedorn-Rasmussen, Peter; Dupret, Katia

    Focusing on how an experimental approach to organizing may pave the way for organizational resilience, we explore opportunities and barriers of experimental organizing by following a concrete social experiment in civil society and discuss its adaptability in traditional organizations. The social ...... through balancing a strategic and anticipatory strategy with experimental setups inspired by civil society organizing initiatives....

  11. The KOSI experiments

    International Nuclear Information System (INIS)

    Huebner, W.F.

    1991-01-01

    Whipply's icy conglomerate model of the comet nucleus has enjoyed progressively increasing acceptance and success in explaining Earth-based observations of comets since its very inception (Whipple, 1950, 1951). According to this model, the nucleus is a solid body composed of frozen gases and dust. The missions to Comet Halley in 1986, in particular the Vega and the Giotto missions, have confirmed that there is a single solid nucleus that is the root of all the observed phenomena that can be associated with an active comet. Two new comet mission (CRAF and Rosetta) are planned by NASA and ESA to extract further details about the structure and composition of the nucleus. Laboratory experiments play an important role in defining and identifying the objectives of these missions. Although such experiments have been carried out in many laboratories in Europe, the Soviet Union, the USA, Israel, and Japan, the KOSI experiments are the first large-scale investigations (in spatial dimensions and duration). (KOSI is an acronym for Kometensimulation, German for comet simulation). Starting with a summary and explanation of the KOSI experiments by Grun et al. (1991) and some of the experimental limitations by Keller and Markiewicz (1991), the author reports in this special issue the progress achieved about halfway through the planned series of investigations

  12. The BLAST experiment

    NARCIS (Netherlands)

    Hasell, D.; Botto, T.; van den Brand, J.F.J.

    2009-01-01

    The Bates large acceptance spectrometer toroid (BLAST) experiment was operated at the MIT-Bates Linear Accelerator Center from 2003 until 2005. The detector and experimental program were designed to study, in a systematic manner, the spin-dependent electromagnetic interaction in few-nucleon systems.

  13. Prospects in coincidence experiments

    International Nuclear Information System (INIS)

    Laget, J.M.

    1984-01-01

    The sensitivity of virtual photons to the local variations of the charge and magnetization densities is exploited to study the short-range part of the nucleon-nucleon interaction inside the nucleus. The possibility of varying energy, squared mass and longitudinal polarization of the photons independently enables us to disentangle the mechanisms related to the internal structure of the nucleon (e.g. quark interchange) and the contribution due to meson exchange. Coincidence experiments of the type (e,e'N) and (e,e'NN) are performed to suppress the meson contribution to the longitudinal part of the quasi-elastic peak. Four typical examples of coincidence experiments induced by virtual photons are discussed: experiments (1) on the spectroscopic structure of the quasi-elastic peak and the problem of deep lying hole states; (2) on the structure of the continuum; (3) on the low energy side of the quasi-elastic peak; and finally a three-arm coincidence experiment. (Auth.)

  14. Belief Elicitation in Experiments

    DEFF Research Database (Denmark)

    Blanco, Mariana; Engelmann, Dirk; Koch, Alexander

    Belief elicitation in economics experiments usually relies on paying subjects according to the accuracy of stated beliefs in addition to payments for other decisions. Such incentives, however, allow risk-averse subjects to hedge with their stated beliefs against adverse outcomes of other decisions......-belief elicitation treatment using a financial investment frame, where hedging arguably would be most natural....

  15. Long baseline neutrino experiments

    Indian Academy of Sciences (India)

    Atmospheric neutrino experiments (IMB, Kamiokande, Super-Kamiokande (SK)) show that νµ created in cosmic ray interactions with atmospheric nuclei are being converted into ντ but νe created in such interactions are unaffected. SK measure- ment of νµ and νe event rates as functions of zenith angle is the key ...

  16. The Majorana Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Aalseth, Craig E.; Aguayo Navarrete, Estanislao; Amman, M.; Avignone, F. T.; Back, Henning O.; Bai, Xinhua; Barabash, Alexander S.; Barbeau, P. S.; Bergevin, M.; Bertrand, F.; Boswell, M.; Brudanin, V.; Bugg, William; Burritt, Tom H.; Busch, Matthew; Capps, Greg L.; Chan, Yuen-Dat; Collar, J. I.; Cooper, R. J.; Creswick, R.; Detwiler, Jason A.; Diaz, J.; Doe, Peter J.; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H.; Elliott, S. R.; Ely, James H.; Esterline, James H.; Farach, H. A.; Fast, James E.; Fields, N.; Finnerty, P.; Fraenkle, Florian; Gehman, Victor M.; Giovanetti, G. K.; Green, M.; Guiseppe, Vincente; Gusey, K.; Hallin, A. L.; Harper, Gregory; Hazama, R.; Henning, Reyco; Hime, Andrew; Hong, H.; Hoppe, Eric W.; Hossbach, Todd W.; Howard, Stanley; Howe, M. A.; Johnson, R. A.; Keeter, K.; Keillor, Martin E.; Keller, C.; Kephart, Jeremy D.; Kidd, M. F.; Knecht, A.; Kochetov, Oleg; Konovalov, S.; Kouzes, Richard T.; LaRoque, B. H.; Leviner, L.; Loach, J. C.; Luke, P.; MacMullin, S.; Marino, Michael G.; Martin, R. D.; Medlin, D.; Mei, Dong-Ming; Miley, Harry S.; Miller, M. L.; Mizouni, Leila; Myers, Allan W.; Nomachi, Masaharu; Orrell, John L.; Peterson, David; Phillips, D.; Poon, Alan; Perevozchikov, O.; Perumpilly, Gopakumar; Prior, Gersende; Radford, D. C.; Reid, Douglas J.; Rielage, Keith; Robertson, R. G. H.; Rodriguez, Larry; Ronquest, M. C.; Salazar, Harold; Schubert, Alexis G.; Shima, T.; Shirchenko, M.; Sobolev, V.; Steele, David; Strain, J.; Swift, Gary; Thomas, K.; Timkin, V.; Tornow, W.; Van Wechel, T. D.; Vanyushin, I.; Varner, R. L.; Vetter, Kai; Vorren, Kris R.; Wilkerson, J. F.; Wolfe, B. A.; Xiang, W.; Yakushev, E.; Yaver, Harold; Young, A.; Yu, Chang-Hong; Yumatov, V.; Zhang, C.

    2011-08-01

    The Majorana Collaboration is assembling an array of HPGe detectors to search for neutrinoless double-beta decay in 76Ge. Initially, Majorana aims to construct a prototype module to demonstrate the potential of a future 1-tonne experiment. The design and potential reach of this prototype Demonstrator module are presented.

  17. Experiences of Collaborative Research

    Science.gov (United States)

    Kahneman, Daniel

    2003-01-01

    The author's personal history of the research that led to his recognition in economics is described, focusing on the process of collaboration and on the experience of controversy. The author's collaboration with Amos Tversky dealt with 3 major topics: judgment under uncertainty, decision making, and framing effects. A subsequent collaboration,…

  18. Experiment CATETO II

    International Nuclear Information System (INIS)

    Hendriks, J.A.; Freudenreich, W.E.

    1994-03-01

    In the irradiation experiment CATETO II different reduced activation (RA) steels will be irradiated up to 2.5 dpa at a temperature of 300 C. The results of the calculation of the nuclear constants, the reactivity effect, and the activity of the steel samples are presented. (orig.)

  19. Olkiluoto 3 Experience

    International Nuclear Information System (INIS)

    Tiippana, Petteri

    2011-01-01

    This paper discusses the experience from the Olkiluoto 3 nuclear power plant project from regulator's point of view. There are certain factors that have affected greatly the project progress. First, Olkiluoto 3 nuclear power plant is the first European Pressurised Reactor (EPR) being constructed. Secondly, construction of the unit started after a fairly long break in nuclear power plant construction in Europe, which had resulted in loss of experienced and qualified engineering and manufacturing resources. These factors have to be kept in mind when evaluating the experience from Olkiluoto 3. Experience discussed in this paper have to do with the licensing and regulatory oversight process, completion of the design prior to construction, experience and know-how of the participating organisations, quality management in a nuclear construction project, advanced manufacturing and construction technologies, turnkey contract with regard to licensee's responsibility, safety culture aspects in a nuclear construction project, and the role and importance of regulator's oversight. (author)

  20. Magnetized gun experiments

    International Nuclear Information System (INIS)

    Jarboe, T.R.; Henins, I.; Hoida, H.W.; Marshall, J.; Sherwood, A.R.

    1981-01-01

    In the Los Alamos Magnetized Gun Experiment we are attempting to produce a compact torus in a manner similar to an earlier experiment of Alfven. In our experiment a solenoidal coil is placed inside the inner electrode of a coaxial plasma gun. This coil produces an axial magnetic field inside the inner electrode which diverges and becomes a largely radial field in front of the gun muzzle. The idea is that when the gun is fired, the plasma escaping from the gun stretches these radial fields along the axial direction away from the gun, and these field lines can reconnect behind the plasma forming the poloidal field of the compact torus. The magnetic field generated by the gun current becomes the toroidal field and the major axis of the compact torus will be the same as the axis of the coaxial gun. Recent interest in this possible method of compact torus generation was stimulated by C. Hartman, and the approach is also being pursued in the field-reversed plasma gun experiment at LLL