44 research outputs found
Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18
Combining the precise parallaxes and optical photometry delivered by Gaia’s second data release with the photometric catalogues of Pan-STARRS1, 2MASS, and AllWISE, we derived Bayesian stellar parameters, distances, and extinctions for 265 million of the 285 million objects brighter than G = 18. Because of the wide wavelength range used, our results substantially improve the accuracy and precision of previous extinction and effective temperature estimates. After cleaning our results for both unreliable input and output data, we retain 137 million stars, for which we achieve a median precision of 5% in distance, 0.20 mag in V-band extinction, and 245 K in effective temperature for G ≤ 14, degrading towards fainter magnitudes (12%, 0.20 mag, and 245 K at G = 16; 16%, 0.23 mag, and 260 K at G = 17, respectively). We find a very good agreement with the asteroseismic surface gravities and distances of 7000 stars in the Kepler, K2-C3, and K2-C6 fields, with stellar parameters from the APOGEE survey, and with distances to star clusters. Our results are available through the ADQL query interface of the Gaia mirror at the Leibniz-Institut für Astrophysik Potsdam (gaia.aip.de) and as binary tables at data.aip.de. As a first application, we provide distance- and extinction-corrected colour-magnitude diagrams, extinction maps as a function of distance, and extensive density maps. These demonstrate the potential of our value-added dataset for mapping the three-dimensional structure of our Galaxy. In particular, we see a clear manifestation of the Galactic bar in the stellar density distributions, an observation that can almost be considered direct imaging of the Galactic ba
Diversity and Interoperability of Repositories in a Grid Curation Environment
Repository-based environments are increasingly important in research. While grid technologies and its relatives used to draw most attention, the e-Infrastructure community is now often looking to the repository and preservation communities to learn from their experiences. After all, trustworthy data-management and concepts to foster the agenda for data-intensive research (Data-Intensive Research: how should we improve our ability to use data. e-Science Theme, March 2010. http://www.nesc.ac.uk/esi/events/1047/) are among the key requirements of researchers from a great variety of disciplines. The WissGrid project (WissGrid - Grid for the Sciences, a D-Grid project. Funded by the German Federal Ministry of Education and Research (BMBF). www.wissgrid.de) aims to provide cross-disciplinary data curation tools for a grid environment by adapting repository concepts and technologies to the existing D-Grid e-Infrastructure. To achieve this, it combines existing systems including Fedora, iRODS, DCache, JHove, and others. WissGrid respects diversity of systems, and aims to improve interoperability of the interfaces between those systems
Diversity and Interoperability of Repositories in a Grid Curation Environment
Repository-based environments are increasingly important in research. While grid technologies and its relatives used to draw most attention, the e-Infrastructure community is now often looking to the repository and preservation communities to learn from their experiences. After all, trustworthy data-management and concepts to foster the agenda for data-intensive research (Data-Intensive Research: how should we improve our ability to use data. e-Science Theme, March 2010. http://www.nesc.ac.uk/esi/events/1047/) are among the key requirements of researchers from a great variety of disciplines. The WissGrid project (WissGrid - Grid for the Sciences, a D-Grid project. Funded by the German Federal Ministry of Education and Research (BMBF). www.wissgrid.de) aims to provide cross-disciplinary data curation tools for a grid environment by adapting repository concepts and technologies to the existing D-Grid e-Infrastructure. To achieve this, it combines existing systems including Fedora, iRODS, DCache, JHove, and others. WissGrid respects diversity of systems, and aims to improve interoperability of the interfaces between those systems
Potsdam Library of Astronomical Photographic Plates
ACM Computing Classification System (1998): J.2.We present the Potsdam photographic plate library at the Leibniz Institute for Astrophysics Potsdam. It includes plate archives, data from
plate index catalogues and extracts from astronomical logbooks, as well as digitized plate images and interfaces for accessing all the available information. The plate index catalogues and the digitized images of the Potsdam astronomical photographic plates are prepared according to the standards of the Wide-Field Plate Database and German Astrophysical Virtual Observatory. The high-resolution digitization of the plates (in standardized FITS file format), the low-resolution plate previews (in TIFF and JPEG file format), as well as suitable digitization of the catalogues, logbooks, and relevant scientific research papers (in JPEG and TIFF) are made using commercial flatbed scanners.This work is supported by the bilateral project STE 710/6-1, 2009-11-20, between
BAS/DFG, and partially by BG NSF DO-02-273 and DO-02-275 grants
AstroGrid-D: Grid Technology for Astronomical Science
We present status and results of AstroGrid-D, a joint effort of
astrophysicists and computer scientists to employ grid technology for
scientific applications. AstroGrid-D provides access to a network of
distributed machines with a set of commands as well as software interfaces. It
allows simple use of computer and storage facilities and to schedule or monitor
compute tasks and data management. It is based on the Globus Toolkit middleware
(GT4). Chapter 1 describes the context which led to the demand for advanced
software solutions in Astrophysics, and we state the goals of the project. We
then present characteristic astrophysical applications that have been
implemented on AstroGrid-D in chapter 2. We describe simulations of different
complexity, compute-intensive calculations running on multiple sites, and
advanced applications for specific scientific purposes, such as a connection to
robotic telescopes. We can show from these examples how grid execution improves
e.g. the scientific workflow. Chapter 3 explains the software tools and
services that we adapted or newly developed. Section 3.1 is focused on the
administrative aspects of the infrastructure, to manage users and monitor
activity. Section 3.2 characterises the central components of our architecture:
The AstroGrid-D information service to collect and store metadata, a file
management system, the data management system, and a job manager for automatic
submission of compute tasks. We summarise the successfully established
infrastructure in chapter 4, concluding with our future plans to establish
AstroGrid-D as a platform of modern e-Astronomy.Comment: 14 pages, 12 figures Subjects: data analysis, image processing,
robotic telescopes, simulations, grid. Accepted for publication in New
Astronom
MultiDark-Galaxies: data release and first results
We present the public release of the MultiDark-Galaxies: three distinct galaxy catalogues derived from one of the Planck cosmology MULTIDARK simulations (i.e. MDPL2, with a volume of (1 h-1 Gpc)3 and mass resolution of 1.5 Ă— 109 h-1 M⊙) by applying the semi-analytic models GALACTICUS, SAG, and SAGE to it. We compare the three models and their conformity with observational data for a selection of fundamental properties of galaxies like stellar mass function, star formation rate, cold gas fractions, and metallicities - noting that they sometimes perform differently reflecting model designs and calibrations. We have further selected galaxy subsamples of the catalogues by number densities in stellar mass, cold gas mass, and star formation rate in order to study the clustering statistics of galaxies. We show that despite different treatment of orphan galaxies, i.e. galaxies that lost their dark-matter host halo due to the finite-mass resolution of the N-body simulation or tidal stripping, the clustering signal is comparable, and reproduces the observations in all three models - in particular when selecting samples based upon stellar mass. Our catalogues provide a powerful tool to study galaxy formation within a volume comparable to those probed by ongoing and future photometric and redshift surveys. All model data consisting of a range of galaxy properties - including broad-band SDSS magnitudes - are publicly available.Facultad de Ciencias AstronĂłmicas y GeofĂsicasInstituto de AstrofĂsica de La Plat
MultiDark-Galaxies: data release and first results
We present the public release of the MultiDark-Galaxies: three distinct galaxy catalogues derived from one of the Planck cosmology MULTIDARK simulations (i.e. MDPL2, with a volume of (1 h-1 Gpc)3 and mass resolution of 1.5 Ă— 109 h-1 M⊙) by applying the semi-analytic models GALACTICUS, SAG, and SAGE to it. We compare the three models and their conformity with observational data for a selection of fundamental properties of galaxies like stellar mass function, star formation rate, cold gas fractions, and metallicities - noting that they sometimes perform differently reflecting model designs and calibrations. We have further selected galaxy subsamples of the catalogues by number densities in stellar mass, cold gas mass, and star formation rate in order to study the clustering statistics of galaxies. We show that despite different treatment of orphan galaxies, i.e. galaxies that lost their dark-matter host halo due to the finite-mass resolution of the N-body simulation or tidal stripping, the clustering signal is comparable, and reproduces the observations in all three models - in particular when selecting samples based upon stellar mass. Our catalogues provide a powerful tool to study galaxy formation within a volume comparable to those probed by ongoing and future photometric and redshift surveys. All model data consisting of a range of galaxy properties - including broad-band SDSS magnitudes - are publicly available.Facultad de Ciencias AstronĂłmicas y GeofĂsicasInstituto de AstrofĂsica de La Plat
MultiDark-Galaxies: data release and first results
We present the public release of the MultiDark-Galaxies: three distinct galaxy catalogues derived from one of the Planck cosmology MULTIDARK simulations (i.e. MDPL2, with a volume of (1 h-1 Gpc)3 and mass resolution of 1.5 Ă— 109 h-1 M⊙) by applying the semi-analytic models GALACTICUS, SAG, and SAGE to it. We compare the three models and their conformity with observational data for a selection of fundamental properties of galaxies like stellar mass function, star formation rate, cold gas fractions, and metallicities - noting that they sometimes perform differently reflecting model designs and calibrations. We have further selected galaxy subsamples of the catalogues by number densities in stellar mass, cold gas mass, and star formation rate in order to study the clustering statistics of galaxies. We show that despite different treatment of orphan galaxies, i.e. galaxies that lost their dark-matter host halo due to the finite-mass resolution of the N-body simulation or tidal stripping, the clustering signal is comparable, and reproduces the observations in all three models - in particular when selecting samples based upon stellar mass. Our catalogues provide a powerful tool to study galaxy formation within a volume comparable to those probed by ongoing and future photometric and redshift surveys. All model data consisting of a range of galaxy properties - including broad-band SDSS magnitudes - are publicly available.Facultad de Ciencias AstronĂłmicas y GeofĂsicasInstituto de AstrofĂsica de La Plat