CASSIS -Present state of the program - LTE model

1
CASSIS -Present state of the program - LTE model
Tools Baseline gaussian fit Rotational diagram
JPL
Observed spectrum
CDMS
compare line-by-line or globally
automatic periodic update
Vary parameters
Recalculate intensities - LTE model
Single spectroscopic database
Simulated Spectrum
2
Predict overview spectra
3
Select molecules and enter parameters
4
Fit and subtract a baseline
skip rapidly from one line to the next
5
Fit a gaussian and compare with predictions from
the model
6
Show close lying components
7
Interactive creation of rotational diagrams
Choose different areas
8
Compare multi-species simulations with observed
spectra
Choose different areas
9
Comet model
10
Future Developments - done, next step, later?
Template (initial source parameters)
Statistical tools
rotational diagram
ANALYSIS
TOOLS
MODELS
Line-by-line global display
AI
Collisional databases

MODELS
LVG
comets
LTE
other
11
CASSIS - Development principles

• Specific features of HIFI/HSO
• Lots of data in a short time
• Very large spectral range (high spectral
  resolution)
• Rapid first analysis needed to define subsequent
  observations
• ESA wants a standard environment for data
  analysis before launch.
• Other instruments
• Versatility to work on data from other
  high-spectral-resolution instruments.
• A few transitions ? large spectral scans

12
CASSIS development principles

• A first spectral analysis should give rapidly a
  first overview of physical and chemical
  properties of the studied object
• Start with simple models
• Access to databases.
• As exhaustive as possible.
• The user should not have to worry about
  converting inhomogeneous units or working out
  different formats.
• Give access to the latest data
• Respect the intellectual property of database
  managers and the authors of models.
• The task of verifying data and models needs to be
  shared according to everyones personal
  competences.

13
How CASSIS can help to get the most out of models
and data already available.

• Controlling what is going on
• Faster interactive analysis the scientist can
  verify the results at each stage
• Visual display
• Modularity et homogeneity
• Separation of data and models. Free choice of
  data for each model.
• Make available the most recent data
• Compare the results of different models in a
  standard environment.
• Associate different analysis tools without
  worrying about input and output formats.

14
How CASSIS can help to get the most out of models
and data already available.

• Open project
• Available to all qualified scientists
• Few conditions on the user.
• Contents well documented and verifiable.
• User feedback
• Knowledge sharing

15
CASSIS choice of programming language

• Simple to use
• The computer tools must work in as many computer
  environments as possible (PC, Mac, workstations,
  windows, Linux,).
• Easy updating
• Compatible with Herschel Space Observatory
  computer toolboxes
• Compatibles with VO toolboxes
• Input/output VO compatible.
• VO protocols (astrogrid etc.)
• JAVA

16
Proposed spectral analysis scheme (in order)

• Simulation of spectra to prepare measurement
  campaigns
• (spectral surveys) Identification of as many
  species present as possible.
• Species by species characterization
• For the species where it is possible LVG model
  or equivalent (e.g RADEX) determination of the
  best parameters by c2 minimisation.
• If LVG not possible or ETL more appropriate ETL
  model. Determination of best parameters using a
  rotational diagram.

17
Proposed spectral analysis scheme (in order)

• Simulation of the spectrum for all identified
  species slight change in parameters where
  necessary
• Offsets observed in the spectrum. Problems with
  the theory or the data ? feedback
• Treat with more sophisticated models. Within or
  outside the CASSIS project ? For inclusion in
  CASSIS
• The model must compute spectra rapidly
• Or use a table of pre-calculated