788 research outputs found
The Distance of the SNR Kes 75 and PWN PSR J1846-0258 System
The supernova remnant (SNR) Kes 75/PSR J1846-0258 association can be regarded
as certain due to the accurate location of young PSR J1846-0258 at the center
of Kes 75 and the detected bright radio/X-ray synchrotron nebula surrounding
the pulsar. We provide a new distance estimate to the SNR/pulsar system by
analyzing the HI and CO maps, the HI emission and absorption spectra,
and the CO emission spectrum of Kes 75. No absorption features at
negative velocities strongly argue against the widely-used large distance of 19
to 21 kpc for Kes 75, and show that Kes 75 is within the Solar circle, i.e. a
distance 13.2 kpc. Kes 75 is likely at distance of 5.1 to 7.5 kpc because
the highest HI absorption velocity is at 95 km/s and no absorption is
associated with a nearby HI emission peak at 102 km/s in the direction of Kes
75. This distance to Kes 75 gives a reasonable luminosity of PSR J1846-0258 and
its PWN, and also leads to a much smaller radius for Kes 75. So the age of the
SNR is consistent with the spin-down age of PSR J1846-0258, confirming this
pulsar as the second-youngest in the Galaxy.Comment: 5 pages, two pictures, A&A letter
The Euclid Archive Processing and Data Distribution Systems: A Distributed Infrastructure for Euclid and Associated Data
The Euclid Archive System is an ambitious information system, which sits at the heart of the Euclid Science Ground Segment. It is a joint development between the Euclid Consortium and the ESAC Science Data Centre. It encompases both Euclid data and the large volume of associated ground based data (e.g. KiDS, DES and LSST). The Euclid Science Ground Segment consists of the Euclid Science Operations Centre and ten national Science Data Centres. The large data volumes demand that data transfer is minimized and that the processing is taken to the data. This is supported by the Euclid Archive Data Processing System and the Euclid Archive Distributed Data System. The Data Processing System consists of a central metadata repository, which contains the information necessary to process any data item and full data lineage of any data product created. The Distributed Data System provides a cloud solution with a node at each of the national Science Data Centres, which controls data storage and transfer. It supports a large number of storage types, including POSIX, iRODS, gridftp and Xrootd. No limitations are placed on the storage implemented at an individual SDC. Further more, the user of the system needs no knowledge of where data is located. Jobs will be started at the most appropriate locations, or data transferred as necessary
The Role of the Euclid Archive System in the Processing of Euclid and External Data
Euclid is an ESA M2 mission which will create a 15,000 square degrees space-based survey: the Euclid Archive System (EAS) is a core element of the Science Ground Segment (SGS) of Euclid. The EAS follows a data-centric approach to data processing, whereby the Data Processing System (DPS) is responsible for the centralized metadata storage and the Distributed Storage System (DSS) supports the distributed storage of data files. The EAS-DPS implements the Euclid Common Data model and along with the EAS-DSS provides numerous services for Euclid Consortium users and SGS subsystems. In addition, the EAS-DPS assists in the preparation of Euclid data releases which are copied to the third EAS subsystem, the ESA developed Science Archive System (SAS) where they become available to the wider astronomical community. The EAS-DPS implements the object-oriented Euclid Common Data Model using a relational DBMS for the storage. The EAS-DPS supports the tracing of the lineage of any data item in the system, provides services for the data quality assessment and the data processing orchestration. The EAS-DSS is a distributed storage system which is based on a set of storage nodes located in each of the ten Science Data Centers of the Euclid SGS. The storage nodes supports a wide range of solutions from local disk, using a unix filesystem, to iRODS nodes or Grid storage elements. In this paper the architectural design of EAS-DPS and EAS-DSS are reviewed: the interaction between them and tests of the already implemented components are described
The Euclid Archive Processing and Data Distribution Systems: A Distributed Infrastructure for Euclid and Associated Data
The Euclid Archive System is an ambitious information system, which sits at the heart of the Euclid Science Ground Segment. It is a joint development between the Euclid Consortium and the ESAC Science Data Centre. It encompases both Euclid data and the large volume of associated ground based data (e.g. KiDS, DES and LSST). The Euclid Science Ground Segment consists of the Euclid Science Operations Centre and ten national Science Data Centres. The large data volumes demand that data transfer is minimized and that the processing is taken to the data. This is supported by the Euclid Archive Data Processing System and the Euclid Archive Distributed Data System. The Data Processing System consists of a central metadata repository, which contains the information necessary to process any data item and full data lineage of any data product created. The Distributed Data System provides a cloud solution with a node at each of the national Science Data Centres, which controls data storage and transfer. It supports a large number of storage types, including POSIX, iRODS, gridftp and Xrootd. No limitations are placed on the storage implemented at an individual SDC. Further more, the user of the system needs no knowledge of where data is located. Jobs will be started at the most appropriate locations, or data transferred as necessary
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