THEORETICAL ASTROPHYSICS
AND
THE US-NVO INITIATIVE
D. S. De Young
National Optical Astronomy Observatory
Theory Then

Exact Solutions (rare)
 Analytic Approximations (enable rapid
progress in new areas – but…)
 Limited Numerical Simulations (sometimes
misleading)

E/O Relevance – None (Maclaurin
spheroids??)
Theory Then

Comparison with Observations
– Very Difficult

Idealized geometries, initial and boundary
conditions

Many important processes omitted

No radiative signatures produced
Theory Now

Exact Solutions (rare)

Analytic Approximations (still useful)

Large Scale, Sophisticated Numerical
Simulations
–
Three dimensional, high resolution
– Gravitation, radiation processes
– Special and general relativity
Theory Now

E/O Connection – Highly Relevant
–
Dramatic visualizations
– Graphics, animations reveal physical processes

Comparison with Observations
–
Realistic geometries, initial conditions
– Inclusion of relevant physics
– Calculation of observed signatures
Wave of the Future:
The Confrontation of Theory
and Observations

Truly Significant Test of Models

Guide New Observations

New Paradigm for Scientific Inquiry
– Data mining in a truly virtual sky

Enabled by the Virtual Observatory
Three Dimensional MHD Jet
Propagation

I. The Calculations
–
(Tregillis, Jones, & Ryu 2001)
Includes
 Radiation losses, power law initial spectrum
 Particle reacceleration at shocks
3-D Jet Propagation

II. The Radiative Signatures
SSC
5.4 GHz synchrotron
IC-CMB
3-D Jet Propagation

III. The Observations
5.4 GHz Synch
VLA 1.5 sec
IC-CMB
1.2 KeV Chandra
The Evolution of
Globular Clusters

I. The Calculation
(McMillan & Portegies Zwart 2002)
– Orbit calculations for cluster of 65000 stars
– Scalo mass function: 0.3 – 100 solar masses
– Collisions, coalescence, binaries, stellar evolution
The Evolution of
Globular Clusters

The Formation and Growth of Black Holes
Mining
Globular Cluster Simulation
Datasets

Observational Parameters Available
– Collision vs. coalescence
– Formation of binary systems
– Evolution of stellar populations
– Role of dark matter
– Evolution of cluster morphology
– Contributions to galactic metallicities
The Evolution of Barred
Spiral Galaxies
P. Teuben, J. Barnes (2002)
Barred Spirals:
Theory and Observation

Evolution of Barred Spirals
CO Data
CO + Simulation
v
Theory
(Piner, Stone & Teuben)
The Role of Datasets from
Theoretical Astrophysics

Direct Comparisons with Observations
–

Verification (or not) of Models
Data Mining for Both Observations and
Theory
–
New Applications
– Buried Physics

Resource for Education and Outreach
Theory and the Virtual
Observatory

Size of Datasets Appropriate to VO
–
Large Scale Simulations, Parameter Space
Libraries Imply 10GB – 10 TB Datasets

Rich Complement to Observational Side

Same/Similar Tools as for Obs. Datasets

Use of VO Infrastructure
–
Grid Technology, Portals, etc.
Theory and the US-NVO

Early discussions among subset of US
theorists

Formation of an interim “TVO” site

Inclusion of theory group on NVO SWG

Representation on US-NVO Exec
The US TVO Site
Sample NVO-TVO Capability

Galaxy Cluster Evolution
– Correlations of x-ray and optical properties
– Access all available catalog data
 Correlate optical and x-ray morphologies, fluxes
 Correlate with associated radio emission
 Bin by redshift
 Form new catalogs
– Access libraries of numerical simulations
– Find correlations
Conclusions

Theoretical Astrophysics an Essential Part
of the Virtual Observatory Concept
–
Provides Benefits to Theorists
– Provides Benefits to Observers
– Provides Benefits to Education/Outreach

Drives New Science