Nasce a Liverpool, settimo figlio di una famiglia benestante di mercanti di confessione unitariana.
Maurizio Salaris & Santi Cassisi & Fabio Pasian ARI – Liverpool John Moores University, UK
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Transcript of Maurizio Salaris & Santi Cassisi & Fabio Pasian ARI – Liverpool John Moores University, UK
EGEE-II INFSO-RI-031688
Enabling Grids for E-sciencE
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Maurizio Salaris & Santi Cassisi & Fabio Pasian
ARI – Liverpool John Moores University, UKINAF – Collurania Astronomical Observatory, IINAF – Trieste Astronomical Observatory, I
BaSTIBaSTI@VObs & @VObs & GRIDGRIDa Bag of Stellar Tracks &
Isochrones…and… much more!
In collaboration with:
A. PietrinferniF. CastelliD. CordierM. Castellani
P. Manzato R. Smareglia G. Taffoni C. Vuerli
S. Percival
Enabling Grids for E-sciencE
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Why…,Why…, ??
Stellar evolution model and isochrone archives are a fondamental working tool in modern astrophysics. Their use ranges from the study of single stellar objects, to Galactic and extragalactic stellar systems, in the near universe and at high redshift.
• Improvements in the physical inputs
• Homogeneity
• Coverage of the parameter space
• User friendly
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• Equation of State: FreeEos by A. Irwin (2005)
• Radiative opacity: high-T OPAL (Rogers et al. 2000) - low-T Alexander & Ferguson (1994) + Ferguson et al. (2005)
• Conductive opacity: Potekhin (1999)
• Nuclear cross sections: NACRE (Angulo et al. 1999) + updates (Kunz et al.
2000, Formicola et al. 2003 + …)
The most updated library of stellar evolution modelscurrently available!!!
Input physics
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The coverage
• 11 metallicities: from Very Metal-poor Stars to Very metal-rich ones
• Heavy elements mixture: scaled solar & α-enhanced
• Helium abundance: Ypr=0.245 - Y/Z~1.4
• Core convection: canonical & overshooting
• Mass loss: Reimers’ law with =0.2 and 0.4
• Extremely fine mass grid for all evolutionary stages
• From the Pre-Main Sequence to the end of the Asymptotic Giant Branch or C-ignition
• Updated Color – Teff transformations + BC scale
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Why, What, .... ?
• Evolutionary tracks
• Isochrones
• Luminosity Functions
• Synthetic Colour – Magnitude Diagrams
• Tables with relevant data
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Evolutionary tracks & isochrones: some examples
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Horizontal Branch stellar models: some examples
RR Lyraeinstability stripAccurate sampling of the different evolutionary phases
A reliable tool for population synthesis analysis
A fundamental ingredient for investigating the properties of different types of pulsating stars
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Synthetic Colour-Magnitude diagrams
~90,000 objects
SFR typical of the solar neighbourhood
Salpeter IMF
1 photometric error of 0.03 mag
20% unresolved binaries
an example!
we can account for a spread in the AMR, photometric errors, depth effects, interstellar extinction and unresolved binaries
It provides information about the number and period distribution of various types of radially pulsating stars
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Theory Observations: some scientific cases
NGC2420:•(mM)0=11.90 mag•E(BV)=0.06•[Fe/H]=0.44
solid – overshooting 3.2Gyrdashed – canonical 2Gyr
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Determination of Star Formation Histories
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The Horizontal Branch: The R parameter
RGB
HB
N
NR = NHB – number of HB stars
NRGB – number of RGB stars brighter than the HBRGB
HB
ττ
=
The mean GC He abundance is Y=0.250±0.006
Fully consistent with the primordial He abundance obtained by CMB observations coupled to primordial nucleosynthesis calculations
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Initial-Final mass relation
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Future developmentsFuture developments
• more models…
• more chemical compositions…
• more photometric filters…
• integrated colours, mass-to-light-ratios
• theoretical high resolution Spectral Energy Distributions…
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Integrated spectra
• We are at present working intensively (large part of the work is completed) on computing theoretical integrated spectra (at both low- and high resolution), integrated colours, mass-to-light ratios, for studies of extragalactic stellar populations
Low resolution theoretical spectra of a typical Galactic globular cluster and an old open cluster
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Integrated properties of extragalactic Stellar Systems
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Why, What, Where ?
A Bag of Stellar Tracks and Isochrones
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A WEB interface allows the user to compute Evolutionary Tracks/Isochrones/Luminosity
Functions/Synthetic CMDs
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Some numbers related to the BaSTI “traffic”(last update 8 May 2007)
Visits (since Feb. 2004):
• Total – about 6000
• Average per day – 9
• Average visit length – 5 min
Page views (since Feb. 2004):
• Total – about 13000
• Average per day – 19
• Average per visit – 2.1
The refereed papers introducing BaSTI have collected 138 citations in 19 months
Summary of last year’s visits and page views
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The BaSTI archive @
•To make the archive VO compliant
Standards…Query languageData access layerSemanticsData models
A pilot project for stellar astrophysics
•Re-building the database to allow ADQL access
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The BaSTI archive@
The state-of-the-art:
•Connection with three WPsWP3 – integration of DBsWP4 – theory within VOWP5 – connection with grids
Part of the EU/FP6 funded VO-DCA project
•Will participate in definition of VO Data Model for theory
•Will test integration of VO-compliant DB with EGEE
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Basti & GRID
• Finalising the ‘gridification’ of the code to allow the calculation of new models using the Grid infrastructure
State-of-the-art:
Our evolutionary code is now efficiently running within LINUX platform and we start the preliminary tests needed before a massive use of the Grid infrastructure.
Mid-term projects:We plan to compute in the next few months an extended set of
stellar models for chemical compositions and masses not yet included in the BaSTI archive. We’ll also compute a large set of integrated spectra for stellar populations with complex Star Formation Histories
Long-term project:We wish to allow an “on-line” access to our evolutionary code so
that users can compute their own evolutionary models: the computational work should be performed within a Grid infrastructure
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EGEE Added Values
• CPU power:– E-computing lab– Production burst– Efficient CPU usage/sharing
• Data storing/sharing:– Distributed data for distributed
users– Replica and security– Common interface to software and
data
FRANEC simulations are highly computing demanding and produce a huge amount of data.
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Proposed Activity
• Run simulations of the FRANEC code on the Grid• Manage Job submission from portal; • Store data on Grid environment;• Share data to Virtual Observatory Community
– Interoperability use case(?)
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Proposed Activity
• To allow users to run FRANEC simulation SW we need to create some specific services on EGEE common environment;
• They must be used to run both one or more stellar population runs;
• They are modular and easy to integrate with new code implementations: when some upgrade is needed.
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Expected implementation
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Why EGEE
EGEE infrastructure is stable and efficent;
Need to use job management + data management + metadata management services
Services are not too complicated to integrate;