TheoryOutline

 

ANITA Jan 2003

Hi folks,

The ANITA workshop "Observing the Synthetic Universe" has just concluded. It was a very interesting workshop attenedd by about 30 theorists with an interest in adding theory to the VO. Twelve talks were presented, all of which will be availble at the workshop website very soon (see http://astronomy.swin.edu.au/anita/)

A workshop summary will be presented here in the next few days, so stay tuned.

Cheers, Sarah.

-- SarahMaddison - 29 Jan 2003

ANITA Nov 2003

Hi folks,

I said I'd be back in a few days and now nearly 10 months has gone by! Sorry about that (and a warning to all - don't wait 10 months to summarise a meeting as you're bound to forget a few important things...) I gave a summary presentation about the ANITA meeting at the Aus-VO 2003 meeting on Monday, so I assume David will add that somewhere to TWiki. Here's a brief summary of the ANITA workshop:

  • ANITA hosted a workshop in January 2003 on "Observing the Theoretical Universe: Theoretical Astrophysics & the VO".
  • There were 12 talks over 2 days covering:
    • background on the VO & Australia's involvement (summary of Aus-VO 2002 meeting by Anne Green),
    • VO technologies (summary of the November 2003 ADASS meeting by Vince McIntyre),
    • adding observational databases to the VO (re-analysis of the Molonglo Cross Survey by David Crawford),
    • ensuring new observing projects are VO compliant (making SKAMP VO compliant by Nyma Warr),
    • and various ideas about adding theory to the VO.
  • There was also a lot of general discussion about adding theory to the VO, whether people thought it was a good idea or not, how it could be done, who was interested in participating etc.
  • Andrew Melatos & myself gave general talks about what type of theory resources were currently on the web - including freely available code, interface to proprietary code, raw simulation output, and highly post-processed simulations in the form of animations. While there are many theory tools out there, the quality and usefulness varies greatly, there are no standards, and searching for tools is difficult unless you know exactly what you're looking for. The VO would integrate the various stand-alone theory resources into a single pipeline.
  • There seemed to be four main "themes":
    1. adding codes to the VO
    2. adding interface to codes to the VO
    3. adding simulation data to the VO
    4. building virtual telescopes for the VO
  • Alex Knebe talked about N-body cosmological codes and the problems with comparing simulation results with observational data as well as comparing results from grid and particles codes. The Santa Barbara Cluster Comparison Project (Frenk et al. 1999) was an excellent example of a coordinated approach to comparing codes. Within the VO this could be routine (or at least easier to coordinate than it is now!). Alex also offered up his code MLAPM (Knebe et al. 2001) to the VO.
  • Daisuke Kawata discussed using his galactic chemodynamical evolution code GCD+ (Kawata & Gibson 2003) to conduct multi-wavelength views of the virtual. GCD+ enables comparisons between simulation results and observational data both directly and quantitatively from the radio through to X-ray domain.
  • Randall Wayth talked about adding gravitational lensing codes to the VO which can be used to study lens galaxy mass distributions and cosmological models. Randall fully supported the idea of making codes publicly available so that others can help you debug your code (good point!) and that keen collaborators would help you improve your code. Furthermore others can do good science with your code while you're busy doing something else.
  • Mike Dopita talked about recent experience in getting their publicly available photoionisation code MAPPINGS III (Sutherland & Dopita 1993) online. The interface version is ideal for new users, though obviously various parameters are constrained. The source code is still available for expert users.
  • I gave an overview of a series of online interfaces to codes used on a computational astrophysics course at Swinburne. There were sis modules that use a variety of interfaces to public and in-house code, interfaces to simulation data, as well as interfaces to virtual telescopes. Experience in setting up this subject lends itself nicely to ideas about add theory to the VO. Better yet, the student were actually doing some really nice projects with 'real codes'.
  • Geraint Lewis talked about building virtual telescopes, whereby numerical simulations are run and theoretical spectra, brightness, colours etc are modelled from the simulation data, telescopes response functions are added and then simulated data can be easily compared with observational data. This is obviously a hop topic to people working on next generation telescopes and instruments such as the SKA, ALMA, JWST etc.
  • Joss Bland-Hawthorn discussed near-field cosmology and using the VO to search the observational stellar databases (for further mission/instruments like GAIA and Ukidna) as well as use codes to determine physical quantities to get complete phase space descriptions (metallicity, abundance, age, position and velocity) of thousands (millions?) of stars. These chemically and dynamically tagged stars provide fossil evidence to help us understand the formation of the galaxy.
  • There was a lot of discussion about how one would actually go about adding theory to the VO - what type of metadata was needed to fully describe a code? Obviously the numerical technique, the algorithms and equations would have to be described somehow. Readme files, installation instructions, and reference publications would also bee needed. Ideally a set of test cases would also be provided with appropriate initial and/or boundary conditions.
  • Overall people were mostly enthusiastic about getting involved in theory to the VO projects and prepared to offer their codes to the VO. There was some concern about who would actually do the work and where the money would come from (naturally...).

Most talks are available on the meeting website. Any errors in this summary are totally mine and not those of the speakers.

Cheers, Sarah.

-- SarahMaddison - 19 Nov 2003

Virtual Theory Strategies

Overall people were mostly enthusiastic about getting involved in theory to the VO projects and prepared to offer their codes to the VO. There was some concern about who would actually do the work and where the money would come from (naturally...).

using GPL

IMHO use of the GPL to make sure VO projects remain public and cannot be closed off might help. In particular, there are a lot of people who could help find bugs, without necessarily fixing them. This is how the whole GNU/linux system works.

many eyes make all bugs shallow

Hopefully my next few publications will have GPL distributions of the accompanying code. The initial versions are more likely to be hacker-friendly than user-friendly ;), but anyone able to make them better will be forced to release their versions also under the GPL. That's the whole idea...

Using the wikipedia

There's also a barrier to non-specialists - or undergrad students - getting to grips with a field they don't know much about. And we also all know practising astronomers who really have missed some of the basics of modern mathematics (no names will be cited ;)

An excellent way to either learn what you don't know about the theory side, or help others get to know it, is:

Some of the students in ToruĊ„ are learning from and contributing to the Polish version:

-- BoudRoukema - 08 Jan 2004 - from the snow-covered place where http://en.wikipedia.org/wiki/Nicolaus_Copernicus was born.