Modelling results

From Tauwiki

1 Current IR Modelling results
2 UV Scattering output
- 2.1 With curve fitting
- 2.2 Without curve fitting
3 Dust file Modification results:
4 Results from the IR Model:

[edit] Current IR Modelling results

Plot of IRAS and IR Model for the 35 locations of FUSE Observations:

Plot of Two rations :

[edit] UV Scattering output

Following graph shows the UV flux obtained from the model with smoothened dust distribution, with a uniform dust sheet at 110pc, and FUSE observations with its errors:

Next graph shows the error between previous and latest model, as compared to observational error:

Finally, a ratio of previous model's error and current model's error to the observational error:

[edit] With curve fitting

The min_curve_surf function in IDL was used to fit the min-chi-square distances with four corner boundary conditions, to get the smooth distribution of dust. The dust file using this smoothened dust distribution was used to get the UV scattering output. Following are the plots of it:

Linear Plot:

Logarithmic Plot:

[edit] Without curve fitting

Using the min-chi-square distances(without curve fitting) in the dust file, following UV scattering simulation output was generated for 10^7 photons:

Linear Plot:

Logarithmic Plot:

As can be seen in this visual, there are discontinuous spots in the UV output. The scattering layer at 110 pc gets broken at the 25 points where optimized distances are used. Blinking the UV output graph with an image of 25 points showed closeness in location to the discontinuties and changed dust locations.

[edit] Dust file Modification results:

The dust file is modified using the Min-chi-square distances given by Sujatha et al. The min_curve_surf function from IDL is used to fit a surface through these 25 data points. The original spiked distribution and the smooth fit of the curved surface are shown below:

The MIN_CURVE_SURF function interpolates a regularly- or irregularly-gridded set of points, over either a plane or a sphere, with either a minimum curvature surface or a thin-plate-spline surface.

As seen in the image, the minimum surface shoots up on boundaries, in upward or downward directions.

This surface was tested for fit between minimum and maximum variations in the min-chi-square distances given by Sujtha, and it was found that the surface was out of these bounds at four points.

To fit the surface better, 4 extra boundary points at the corner were introduced as shown below:

The resulting surface is was within the bounds and is as shown below:

A dust file using this Min-curve-surface with boundary conditions is written while keeping the column density same, by sweeping the dust densities in uniform sheet at 110 to these new dust locations.

A 2D projected image comparison of these surfaces is shown below:

I had also checked smoothing out the dust distribution procedure, using Median and Mean smoothing. Median smoothing flattens the surface totally, as can be expected. Mean smoothing gave following results for 3 and 5 as size for smoothing neighbourhood:

[edit] Results from the IR Model:

The Ratio of IRAS to Model is plotted in the two dimentional grid for visual inspection below:

1. Logarithmic Plot of Ratios:

2. Linear Plot of ratios:

Following image is created by Aladin using logarithmic scale for both IRAS and Model. IRAS is in background with red color and Model is in blue color.