maurizio salaris & santi cassisi & fabio pasian ari – liverpool john moores...

EGEE-II INFSO-RI-031688

Enabling Grids for E-sciencE

www.eu-egee.org

EGEE and gLite are registered trademarks

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



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



• 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



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



Why, What, .... ?

• Evolutionary tracks

• Isochrones

• Luminosity Functions

• Synthetic Colour – Magnitude Diagrams

• Tables with relevant data



Evolutionary tracks & isochrones: some examples



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



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



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



Determination of Star Formation Histories



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



Initial-Final mass relation



Future developmentsFuture developments

• more models…

• more chemical compositions…

• more photometric filters…

• integrated colours, mass-to-light-ratios

• theoretical high resolution Spectral Energy Distributions…



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



Integrated properties of extragalactic Stellar Systems



Why, What, Where ?

A Bag of Stellar Tracks and Isochrones



A WEB interface allows the user to compute Evolutionary Tracks/Isochrones/Luminosity

Functions/Synthetic CMDs



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



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



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



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



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.



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(?)



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.



Expected implementation



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;

maurizio salaris & santi cassisi & fabio pasian ari – liverpool john moores...

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