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AGN jet truncation
We study the 3D interaction of stellar winds from red giant (RG) stars and AGN jets. We're based on
1http://adsabs.harvard.edu/abs/2006MNRAS.371.1717H
Note this blog is in chronological order.
6 june '12
Latest sim http://www.pas.rochester.edu/~martinhe/2011/agn/hd-strongJet-edge2.gif shows that the red giant's (RG) wind, which crosses the edge of the jet's beam, strongly affects the collimation of the AGN jet. Note that in the previous sim ( http://www.pas.rochester.edu/~martinhe/2011/agn-6apr-dens2.gif) the RG's orbital path intersected the jet's axis, affecting the jet's beam more drastically.
9 Apr '12
| Run 4 | AGN jet (base) | RG wind | ambient medium |
|---|---|---|---|
| resolution [cells; 1=9.6x1018 cm] | 32 cells | 6 cells | 643 * 23 |
The other parameters are as in Run 3 (below) except for:
- the jet is launched earlier
- the RG's initial position is farther form the jet's axis
No. density movie: http://www.pas.rochester.edu/~martinhe/2011/agn-6apr-dens2.gif
I see that a reconfinement shock forms in the jet, the height of which increases in time and, at this point, is at a height close to the RG path. These shocks are expected+ and seen in many other agn jet sims. This process enhances the jet's kinetic energy flux at that height, hence affecting the winds' interaction.
+http://adsabs.harvard.edu/abs/1991MNRAS.250..581F
2 Apr '12
| Run 3 | AGN jet (base) | RG wind | ambient medium |
|---|---|---|---|
| density [part./cc] | .01 | 50 | 1 |
| vel [km/s] | 1.5e5 (~c/2) | 200 | 0 |
| Lkinetic [erg s-1] | 1.9x1045 | … | N/A |
| Orbital velocity [km/s] | N/A | 600 | N/A |
| pressure [cu] | consistent with an opening angle of 5o | ←same | ←/4 |
| temperature [K] | 1.25x1010 | 2.5x106 | 3.1x107 |
| radius | 200pc | 10AU (large?) | … |
| mass-loss [Msun yr-1] | 4.8x10-2 | 1.9x10-3 | 0 |
| resolution [cells; 1=4.8x1018 cm] | 64 cells | 8 cells | 643 * 24 |
Because of the opening angle of 5o , the jet has a density contrast of 0.0001 with respect to the ambient medium at the position of the RG, 1100pc from the origin
No. density movie: http://www.pas.rochester.edu/~martinhe/2011/agn-dens-2apr.gif
14 March '12
| Run 2 | AGN jet (base) | RG wind | ambient medium |
|---|---|---|---|
| density [part./cc] | 1* | 107 | 1 |
| vel [km/s] | 1.5e5 (~c/2) | 200 | 0 |
| Lkinetic [erg s-1] | 4.7x1046 | … | N/A |
| Orbital velocity [km/s] | N/A | 600 | N/A |
| pressure [cu] | consistent with an opening angle of 5o | ←same | ←half |
| temperature [K] | 1010 | 1.3x103 | 3.1x109 |
| mass-loss [Msun yr-1] | 1.1x10-2 | 1.5x10-6 | 0 |
| resolution [cells; 1=4.8x1019 cm] | 64 cells | 8 cells | 643 * 24 |
* Because of the opening angle of 5o , the jet has a density contrast of 0.001 with respect to the ambient medium at the position of the RG.
The jet will be launched once the star has reached the middle of the grid in the horizontal direction, not the other way around.
| Log No. density movie (still running): http://www.pas.rochester.edu/~martinhe/2011/agn-dens-20mar.gif |
13 March '12
Meeting with Eric and Martín. We found, by taking the momentum ratio of the jet over the star on the interception surface, that the back force of the jet upon the star is very weak; several orders of magnitude. The passage of the star though the jet beam is ~ 105 yr.
New runs:
- Run 2: as Run 1 (below) but (i) 8 times more resolution by a combination of grid size, jet radius and refinement level. (ii) The jet will be launched once the star has reached the middle of the grid, not the other way around.
- Run 3: as Run 2 but with Ljet-kinetic=1045 erg/s and the corresponding jet density for veljet=.5c,
- Run 2.1: as Run 2 but with a magnetized jet with beta=1, the geometry of which will be decided later.
- Run 3.1: as Run 3 but with the magnetized jet of Run 2.1.
3 March '12
| Run 1 | AGN jet (base) | RG wind | ambient medium |
|---|---|---|---|
| density [part./cc] | .1* | 1 | .1 |
| vel [km/s] | 1.5e5 (~c/2) | 200 | 0 |
| Lkinetic [erg s-1] | 4.2x1042 | … | N/A |
| Orbital velocity [km/s] | N/A | 600 | N/A |
| pressure [cu] | consistent with an opening angle of 5o | ←same | ←half |
| mass-loss [Msun yr-1] | 1.1x10-2 | 10-4 | 0 |
| resolution [cells; 1=62.5pc] | 16 (4 ref. levels) | 4 (ditto) | 323 |
* Because of the opening angle of 5o , the jet has a density contrast of 0.001 with respect to the ambient medium at the position of the RG.
The sRG enters the edge of the grid with a horizontal velocity of 200km/s once the jet's head has reached a third of the grid along the vertical direction.
Run time=2.3days, 24procs, afrank, bluehive
Log No. density movie. The jet's bow shock quickly leaves the grid and affects the RG's wind spherical structure (bright small structure on the left). The simulation takes place inside the cocoon then. The jet is not truncated; it's quite strong relative to the wind, in agreement with1. The interaction of the wind and the jet's beam edge affects the structure of the cocoon asymmetrically. A boundary effect rises affecting the jet beam structure near the base. It relates to the grid structure, easy to solve.
http://www.pas.rochester.edu/~martinhe/2011/agn6mar.gif
Mach No. The shape of the RG wind is amorphous, not spherical, despite that fact that I do inject a spherical wind, for it is subsonic in relation to the cocoon material.
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