Title  Inner kinematics in pre-stellar cores with H2D+
Pi     A. Bacmann
Time   360 hrs

1. Name of program and authors

Inner kinematics in pre-stellar cores with H2D+
A. Bacmann


2. One short paragraph with science goal(s)

Determining the kinematics in pre-stellar cores is essential to constrain
the initial conditions of gravitational collapse, especially in the centers
where the collapse is supposed to start.
In the cold and dense interiors of pre-stellar cores, heavy molecules have been
shown to be depleted, so that only light species may be used to trace the
kinematics. H2D+ is abundant in pre-stellar objects, and one of the few
species not affected by depletion. This project proposes to map the
velocity field of a sample of pre-stellar cores in the ortho H2D+
line at 372.4 GHz. Modelling of the line profiles over the cores will make
it possible to determine whether infall has already started and to
determine the nature of the motions (infall/rotation).



3. Number of sources 
   

~10

The sources should span a range of evolution stages (e.g. various 
central densities)

   (e.g., 1 deep field of 4'x4', 50 YSO's, 300 T Tauri stars with
   disks, ...; do NOT list individual sources or your "pet object",
   except in special cases like LMC, Cen A, HDFS)


4. Coordinates:

4.1. Rough RA and DEC 

~ 4 in Taurus (isolated star formation), 
~ 4 in Ophiuchus (clustered star formation)
+ 2-3 cores scattered in RA, DEC

     (e.g., 30 sources in Taurus, 30 in Oph, 20 in Cha, 30 in Lupus)
     Indicate if there is significant clustering in a particular
     RA/DEC range (e.g., if objects in one particular RA range take
     90% of the time)

4.2. Moving target: yes/no (e.g. comet, planet, ...)

no

4.3. Time critical: yes/no (e.g. SN, GRB, ...)

no

4.4. Scheduling constraints: (optional)


5. Spatial scales:

5.1. Angular resolution (arcsec):

0.5"

5.2. Range of spatial scales/FOV (arcsec):

extended sources (larger than primary beam)

     (optional: indicate whether single-field, small mosaic,
     wide-field mosaic...)

small mosaic
the mosaic should cover the inner 30" of the cores, ie around 9 fields

5.3. Required pointing accuracy: (arcsec)

1"

6. Observational setup

6.1. Single dish total power data: no/beneficial/required

required (extended sources)

     Observing modes for single dish total power: 

     (e.g., nutator switch; frequency switch; position switch;
     on-the-fly mapping; and combinations of the above)

6.2. Stand-alone ACA: no/beneficial/required

6.3. Cross-correlation of 7m ACA and 12m baseline-ALMA antennas: 
     no/beneficial/required

6.4. Subarrays of 12m baseline-ALMA antennas: yes/no

no

7. Frequencies:

7.1. Receiver band: Band 3, 4, 5, 6, 7, 8, or 9

Band 7

7.2. Lines and Frequencies (GHz): 

single line, 372.4 GHz

     (approximate; do _not_ go into detail of correlator set-up but
     indicate whether multi-line or single line; apply redshift
     correction yourself; for multi-line observations in a single band
     requiring different frequency settings, indicate e.g. "3
     frequency settings in Band 7" without specifying each frequency
     (or give dummies: 340., 350., 360. GHz). For projects of high-z
     sources with a range of redshifts, specify, e.g., "6 frequency
     settings in Band 3". Apply redshift correction yourself.)

7.3. Spectral resolution (km/s):

0.1 km/s

7.4. Bandwidth or spectral coverage (km/s or GHz):

30 km/s


8. Continuum flux density:

8.1. Typical value (Jy):

     (take average value of set of objects)
     (optional: provide range of fluxes for set of objects)

8.2. Required continuum rms (Jy or K):

8.3. Dynamic range within image:

     (from 7.1 and 7.2, but also indicate whether, e.g., weak objects
     next to bright objects)

8.4. Calibration requirements: absolute      ( 1-3% / 5% / 10% / n/a )
                               repeatability ( 1-3% / 5% / 10% / n/a )
                               relative      ( 1-3% / 5% / 10% / n/a )


9. Line intensity:

9.1. Typical value (K or Jy):

0.4 K (between 0.1 and 1 K)

     (take average value of set of objects)
     (optional: provide range of values for set of objects)

9.2. Required rms per channel (K or Jy):


rms 40 mK

in this project, it is required to fit the line profile, therefore 10 sigma
detections should be achieved.


9.3. Spectral dynamic range:

9.4. Calibration requirements: absolute      ( 1-3% / 5% / 10% / n/a )
                               repeatability ( 1-3% / 5% / 10% / n/a )
                               relative      ( 1-3% / 5% / 10% / n/a )

absolute: 10%
repeatability: 5%
relative: 5%


10. Polarization: yes/no (optional)

no

10.1. Required Stokes parameters:

10.2. Total polarized flux density (Jy):

10.3. Required polarization rms and/or dynamic range:

10.4. Polarization fidelity:

10.5. Required calibration accuracy:


11. Integration time for each observing mode/receiver setting (hr):

4 hours per field
ie 36 hours per source
(this takes the overlap of the mosaic fields into account).

The time estimator does not accept the frequency of the line, though the
receivers will be tunable at 372.4 GHz. Therefore the time estimation was
carried out at 370 GHz.


12. Total integration time for program (hr):

360 hrs

13. Comments on observing strategy : (optional)

    (e.g. line surveys, Target of Opportunity, Sun, ...):
--------------------------------------------------
Review v2.0:
 
2.2.11 Bacmann Inner kinematics in pre-stellar cores with H2D+

This project shows that some extremely important observations by ALMA
will take considerable time! I am trying to figure out with Aurore
whether there is any errors in the integration times as I get
different results than her - stay tuned.