Asteroseismic Modeling Portal (AMP) Development Haiying Xu, Travis Metcalfe (PI) NCAR, Space Science Institute

Asteroseismology Asteroseismology is a powerful technique to determine the ages and other properties of field stars. Ricker et al. (2014)

Echelle diagram for star KIC 8379927 Echelle diagrams for typical examples of the star type KIC 8379927. The plot shows the match to the frequencies after the scaled solar surface correction of CD has been applied to the raw model frequencies Different symbols are used to indicate the radial, dipole and quadrupole and octupole oscillation modes.

H-R diagram for star KIC 8379927 Spectroscopic H-R diagram for the star type KIC 8379927. Solar –composition evolution tracks from ASTEC for masses between 0.75 and 1.75 Mass in solar units are shown as dotted lines. H-R means Hertzsprung-Russell Y axis is optimal luminosity (in solar units) X axis is optimal effective temperature

Precise stellar properties 42 selected for seismology (blue), 34 selected for exoplanets (red) Some disagreement for most massive and youngest (F-like) stars Fitting frequencies improves precision of properties by 2 times or better Comparison of the asteroseismic radii, masses and ages derived from grid-modeling (GM, Chaplin) with the AMP, including the simple (black), F-like(red) and mixed-mode starts. It compares the values and uncertainties. Chaplin et al: 2.1% radius, 5.5% mass, 20% age AMP precision: 1.2% radius, 2.8% mass, 8% age Huber et al: 2.2% radius, 6.0% mass, 28% age AMP precision: 1.0% radius, 2.6% mass, 13% age Metcalfe et al. (2014); Silva Aguirre et al. (in prep)

Asteroseismic Modeling Portal A parallel genetic algrorithm Aarhus stellar evolution code Adiabatic pulsation code ASTEC-the Aarhus Stellar Evolution Code ADIPLS- the Aarhus adiabatic oscillation package MPIKAIA- Stellar Structure Modeling using a parallel Genetic Algorithm for Objective Global Optimization The Asteroseismic Modeling Portal is a web-based interface to the stellar model-fitting pipeline. The underlying science code uses a parallel genetic algorithm on XSEDE supercomputing resources to optimize the match between asteroseismic models produced by the Aarhus stellar evolution code and adiabatic pulsation code and a given set of observational constraints.

Asteroseismology – Forward Model Start with a forward stellar simulator: the Aarhus Stellar Evolution Code (ASTEC) Stellar Parameters Forward Simulation Observables M/M⊙ Mass Z Initial heavy element mass fraction Y Initial helium mass fraction α Mixing-length (convective efficiency) τ Stellar age Direct ASTEC model evaluation. In a direct model run, a scientist specifies a star’s parameters, and a model is generated using ASTEC. Data about the hypothetical star, including Echelle and HR diagram are procuded for inspection.

Asteroseismology – Genetic Algorithm Find a model that fits the observations Computationally cost Forward Simulation Stellar Parameters Observables Create population of candidate stars Choose best stars Adjust population Model Model-Fitting Genetic Algorithm (Properties from Observations) Asteroseimology allows astronomers to determine the properties of sun-like stars by analysis of their oscillation periods Observable parameter optimization. In an optimization run, a scientist specifies observable properties, such as Pulsation frequencies and a genetic algorithm is used to identify the stellar model that best fits the observed data. System GA SUs Frost (BG/L) 23,231 Kraken 16356 Big Red 38,194 Stampede 9,659 Lonestar 22,858

AMP Portal workflow AMP workflow Moved to Aarhus in 2013 Frost Kraken Users interact with a web server Grid processing on a daemon server Only communication through a SQL database Web interface attribute preparation Where a user logs in, record the authentication instant, IP When a simulation is submitted, associate with the authentication record Append-only DB tables and backup log files Gridamp daemon attribute processing When processing a job, the recorded authentication instant is tied with it Cache the generated certificate(lifetime limited by the community account certificate lifetime) Every simulation uses the same community account certificate proxy Gridamp accounting data retrieval Uses returned grid job id to get job status information Gateway Interface DB GridAMP Daemon Stampede Grid Resources Virtual Servers

Input Parameter Interface

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A successful portal for 8 years Since 2007, NCAR developed and maintained AMP. Developed by Matthew 110 astronomers, 18,795,892 SUs and 30424 jobs Stampede Kraken AMP Frost 2007 2008 2009 2010 2011 2012 2013 2014 2015 GT 4 GT 5 GT 6

Relocation and Upgrade Recently activities: In FY2013, virtual server relocated from NCAR to Aarhus, Denmark In FY2014, resources changed from Kraken to Stampede In FY2015, OS and software upgrade Recently activities: In FY2013, NCAR worked closely with system admins at Aarhus Univ at Denmark to move the servers of AMP from NCAR to Aarhus University. In FY2014, NCAR worked with TACC staffs to change the computing resources from Kraken to Stampede In FY2015, NCAR replaced the virtual server GridAMP daemon with a new OS, and upgraded GRAM, openssl, and myproxy etc.

Future Replace GRAM Optimize the scientific codes by TACC staff Upgrade more servers Replace GRAM with Gsissh for job submission Optimize the scientific codes to make best use of the computing resources Change the current OS of web server and database server to a newer one