Query : 2003A&A...403..135D

2003A&A...403..135D - Astronomy and Astrophysics, volume 403, 135-140 (2003/5-3)

The mass-velocity and intensity-velocity relations in jet-driven molecular outflows.


Abstract (from CDS):

We use numerical simulations to examine the mass-velocity and intensity-velocity relations in the CO J=2-1 and H2 S(1)1-0 lines for jet-driven molecular outflows. Contrary to previous expectations, we find that the mass-velocity relation for the swept-up gas is a single power-law, with a shallow slope ≃-1.5 and no break to a steeper slope at high velocities. An analytic bowshock model with no post-shock mixing is shown to reproduce this behaviour very well. We show that molecular dissociation and the temperature dependence of the line emissivity are both critical in defining the shape of the line profiles at velocities above ∼20km/s. In particular, the simulated CO J=2-1 intensity-velocity relation does show a break in slope, even though the underlying mass distribution does not. These predicted CO profiles are found to compare remarkably well with observations of molecular outflows, both in terms of the slopes at low and high velocities and in terms of the range of break velocities at which the change in slope occurs. Shallower slopes are predicted at high velocity in higher excitation lines, such as H2 S(1)1-0. This work indicates that, in jet-driven outflows, the CO J=2-1 intensity profile reflects the slope of the underlying mass-velocity distribution only at velocities ≤20km/s, and that higher temperature tracers are required to probe the mass distribution at higher speed.

Abstract Copyright:

Journal keyword(s): hydrodynamics - shock waves - ISM: jets and outflows - ISM: molecules

Simbad objects: 6

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Number of rows : 6
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 LDN 1448 DNe 03 22.5 +30 35           ~ 502 0
2 LDN 1551 DNe 04 31 30.0 +18 12 30           ~ 794 1
3 M 42 OpC 05 35 17 -05 23.4           ~ 3970 0
4 NAME Ori A MoC 05 38 -07.1           ~ 2896 0
5 NGC 2071 RNe 05 47 10 +00 18.0           ~ 630 1
6 NAME Mon R2 HII 06 07 47.58 -06 22 42.6           ~ 711 2

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