ALMA simulation library

Molecular line emission model for a proto-planetary disk 

Observing mode: C17O(3-2) line emission at 337 GHz 

Author: Itziar de Gregorio-Monsalvo  (ALMA Fellow in Santiago)

corresponding DRSP project Nb 2.4.13 "Protoplanetary disks in Orion"  

description from the authors:

These are a set of molecular line emission models calculated for various mass accretion rates, radius, viscosity and maximum dust grain distributions.

We tried to reproduce a real interferometric observation of a protoplanetary disk with different physical parameters, we integrated the radiative transfer equation and convolved each model with a beam of 0."4.

The line selected was C17O(3-2) transition at 337 GHz (high excitation transition of a CO isotope with very low abundance, less susceptible to be affected by absorption and emission from the surrounding cloud material).

Some assumptions:

- we assume disk in steady state, with constant mass accretion rate and viscosity parameter alpha

- we assume gas and dust thermally coupled and vertical hydrostatic equilibrium.

Input parameters:

We considered typical parameters of a TTauri star (Mstar=0.5 Msun, Rstar=2Rsun, Tstar=4000 K) for all the models. We assume the disks are at 140 pc of distance (the distance to the Taurus molecular cloud), and with a disk inclination angle of 60degrees.

We have considered the next set of input physical parameters:

Rd (maximum disk radius) = 50, 100, 150 AU

a_max (maximum radius of dust grains)= 1,10,100,1000,10000,100000 microns

M_p (mass accretion rate)= 10e-09, 3x10e-08, 10e-07 M_sun/year

alpha (viscosity parameter)= 0.001, 0.005, 0.01, 0.02, 0.05

And we have built models for all the combinations (physically possible) of these physical parameters.

CO(4-3) imaging of a Milky Way-type galaxy at z=3

Observing mode: CO(4-3) maps

Author: Thomas Greve (MPIA Heidelberg)

corresponding DRSP Nb 1.1.5 "Molecular line studies of submm galaxies"

description from the authors:

CO(4-3) maps (velocity-cubes)

The intensity units are simply Jy (I've multiplied with the solid angle of each pixel, so the units are Jy).

The velocity units are km/s

The pixel scale is 0.1kpc/px while the velocity resolution is 5km/s

CO imaging of comet Hale-Bobb

corresponding DRSP Nb 4.3.1 "A complete picture of Earth-grazing comet 103P/Hartley 2"

description from the authors:

a model of the CO emission of comet Hale-Bopp computed on the basis of hydrodynamical simulations. The model assumes the presence of a CO jet creating a spiral structure.

256x256 pixels (0.5x0.5'' each)

RA: 22:31:17.798, DEC: 40:49:18.55

Units: Jy

reference frequency 230538.0 in channel 20 (CO J2-1)

40 channels of 0.1 km/s

Comet geocentric distance ~1.5 AU

Comet heliocentric distance ~1 AU

Production rate of water : 1.5e31 molecules/s

Production rate of water : 1.3e30 molecules/s

Sensitivity:

The sensitivity is not a limitation by itself in the case of a comet as bright as Hale-Bopp. The spectrum peak in the brightest pixel of the map is close to 1Jy. The important point is to make an image in a short integration time (<1h) in order to have successive snapshots of the coma and study the chinematics of the gas.