Plan for Teresa's Orion paper

Stuff to remove from Teresa's draft (26 Jan 2005):

• Figure 2, comparison of SII ratio with literature values
• Figure 3, comparison with horizontal slits, except for maybe leave the electron density comparison but need to fo it better.

These bits are better off just being in the thesis.

How to do the Figures

RGB Color images of 4km/s bands, making 12km/s per image, plus grayscale of electron density. Arranged left-to-right: OI, SII, SIII, ne.

There will be either 5 or 6 velocity bands, going down the page. Hence it will be split into two separate figures with 3 (or 2) rows and 4 columns each.

Probably best to do it in PyX to include the axes.

(11 Apr 2005) Description of ratio maps

General statements

The OI emission seems to trace the electron density in many cases. This could be because of the lack of collisional deexcitation for OI.

The strongest global trend is that the E is higher ionization than the W on the red side of the line, whereas the W is the higher ionization on the blue side of the line.

HH objects

Electron density is high in all these objects.

We see an outer bow of the HH203/204 system, which is visible around -10km/s in SII only. This has a lowish density.

There is also of course the inner bow of this system but that is better seen in the OIII data and can't really be discerened from our lines.

HH203/204 has densities that peak in the very noses (~1.e4) but also in the jet part (?). We should really look at the higher velocity images as well. HH 202 has even higher densities in the tip.

The red apron

This is the name I give to the region behind just to the WSW of the trapezium, which is completely lacking in blue-shifted emission but does show redshifted high-ionization emission. Could this be a thin bit of the molecular cloud that is being pushed back by the ionized flow? Probably not since the biggest velocity deviation is in the highly ionized lines - so maybe it is the action of the stellar wind on the ionized gas.

More things to do (12 Apr 2005)

Calibration

Add a bit to isomaps2.py in order to write out a latex table of the maximum intensities for each image, taking into account the absolute calibration of each line. Need to check that Teresa has got these right. They should be in units of phots cm^-2 s^-1 sr^-1 (km/s)^-1

Cloudy models

We should run some Cloudy models using the Orion ionizing radiation and different densities in order to get graphs of, for example, the line ratio [SIII]/[SII] as a function of the ionization fraction S++/S. Also [OI]/[SII] as a function of H+/H.

This would also allow the absolute-calibrated line maps to be used to get the thickness of the emitting regions (so long as we assume that we know the elemental abundances).

We actually want to run 3 sets of models:

1. Similar to the ones I already ran: one-zone models for opitically thin conditions with a fine grid in density and flux (solve consistently for the temperature).
2. Complete models that run from the illuminated face to the i-front (say x = 0.01 so they are fastish) for a much coarser and more restrictive grid of density and flux. We could do most of these as constant-pressure but maybe run a single dynamics one too.
3. The first two would be with a stellar radiation field (as for theta 1 C) but we could also run some models as in 2 except with the illuminating field being the diffuse field emitted by the first models.