Title  Kinetics, density and temperature profile in pre-stellar cores 
Pi     A. Bacmann
Time   125 hrs
Name: Kinetics, density and temperature profile in pre-stellar cores
A. Bacmann, A. Dutrey, ...

2. Science goal: to map the inner part (inner ~ 15", not resolved by
single dish telescopes) of pre-stellar cores. This program samples
both isolated star formation (taurus) and clustered star formation
(rho oph).  The density profile will be derived from the continuum
observations. For the temperature profile, various CO isotopes can be
used to probe different optical depths within the core. Other possible
strategy: with H2CO observations (but high energy transitions not
excited in 10 K objects, line often self-absorbed - maybe better for
high-mass star forming regions). Need to have a strong line because of
high expected molecular depletion in the centre.

The inner core dynamics will be investigated using the 372.4 GHz
transition of H2D+. H2D+ is abundant in pre-stellar objects, and is
one of the few species not affected by depletion at the high densities
and low temperatures characterising the inner parts of pre-stellar
cores. This ion makes it possible to map the velocity field (and
possible infall / rotation motions) in the cores. Additionally, the
abundance of H2D+ is of chemical interest in deuteration processes.


3. Number of sources: 10 sources in ophiucus, 10 in taurus, + 5 other
                      cores scattered in RA, DEC for CO/Band 6

                      10 sources total for H2D+/Band 7


4. Coordinates

4.1. RA & DEC
Taurus: RA=04 DEC=+25
Oph: RA=16:30 DEC=-24
4.2. moving target: no
4.3. Time critical: no

5. Spatial scales
5.1 angular resolution: 1" 
5.2 FOV: ~ 20" x 20" (small mosaic) for CO; single field in H2D+ at center 
5.3 total power: yes
5.4 ACA: yes
5.5 subarrays: no

6. Frequencies
6.1 Frequency band:                   Band 6                  Band 7
6.2 Line and Frequencies (GHz)
                           12CO(2-1) 230.5 GHz,             H2D+ 1-0 372.4 GHz
               13CO(2-1) 220.4 GHz, C18O(2-1) 219.6 GHz
            (strong, thermalised transitions, optically thick)
6.3 Spectral resolution: 0.1 km/s 
6.4 Bandwidth/Spectral coverage: 30 km/s

7. Continuum flux density
7.1 Typical value (Jy)  0.05 Jy
7.2 Required rms 0.005 Jy
7.3 Dynamic range within image

8. Line intensity
8.1 typical value: 3 K in C18O(2-1), 5 K in 13CO(2-1), 0.1-1 K in H2D+
8.2 required rms per channel: 0.3 K (10 sigma) for CO; 0.05 K for H2D+
8.3 spectral dynamic range: 20 for H2D+

9. polarisation: no

10. integration time per setting
CO: 7 minutes per field, mosaic 3x3, ie ~ 1h per source
(center field in C18O and 13CO, outer fields in 12CO and 13CO)

H2D+: 10 hr per source


11. total integration time for program: 25 hr: CO     Band 6
                                        100 hr: H2D+  Band 7


Notes: H2D+ 372.4 GHz falls just outside the official frequency range
of Band 7, but may be obtained with reduced sensitivity. Current
integration times are for 370 GHz. Extension of Band 7 to 372 GHz is
part of a change request.

*************************************************************************

Review John Richer: See program 2.1.1.

Comment Ewine: H2D+ has been added










--------------------------------------------------
Review v2.0:
 
init_2 = 2.1.2
Name: Kinetics, density and temperature profile in pre-stellar cores
A. Bacmann, A. Dutrey, ...

Program remains unchanged w.r.t. DRSP 1.1. THe H2D+ observations are
the most informative, and take up most time of this project. The
observational setup for the CO (+isotopes) and/or H2CO part could use
some more details on how exactly the temperature information will be
extracted independent of chemistry.