Title  Structure of the Molecular Gas Shocked by Supernova Remnatns
Pi     K. Tatematsu 
Time   206 hrs

  1. Name: Structure of the Molecular Gas
           Shocked by Supernova Remnatns
     Authors: K. Tatematsu, ....


  2. The interation of supernova remnants with molecular clouds
is one of the most important phenomena in astrophysics,
because it control local energetics in the interstellar medium and
the evolution of the global interstellar matter.  It is also suggested
that SNR-cloud interaction may trigger the next-generation star formation.
Furthermore, it will serve as a laboratory to test the theoretical studies
of interstellar shocks.

It becomes clear that intense syncrotron radiation, intense far infrared
emission, 1720-MHz OH maser emission, and some X-ray feature
are the indication of the interaction.
Arikawa, Tatematsu, et al. (1999, PASJ 51, L7) has shown that there is
shocked molecular gas in the supernova remnant W28, and its distribution is
correlated with 1720-MHz OH maser, radio synchrotron, and far infrared
emission.  Structure of unshocked and shocked gas has been observed.
However, we need higher angular resolution to
study the structure of the interstellar shock due to the supernova remnant.
By carrying out multi-J CO observations, 
we will be able to derive
the variation of the gas properties across the shock front precisely.
Multi-J CO observations will provide us with detailed kinetic temperature
and density information across the shock front.

We plan to observe regions near OH masers and other regions to
study the physics of the SNR-cloud shock.  From detailed observations,
we will make clear the physical condition for 1720-MHz OH maser emission.

3. Number of sources: 3


4. Coordinates:


   4.1. 3 sources distributed at l = 330 to 30 degrees
        which are known to interact with molecular clouds


   4.2. Moving target: no


   4.3. Time critical: no



5.  Spatial scales:


   5.1. Angular resolution: 0.15"

   5.2. Range of spatial scales/FOV: 50"
        We need mosaic observation with B6 and B7.


   5.3. Single dish: yes

   5.4. ACA: yes


   5.5. Subarrays: no



6. Frequencies:


   6.1. Receiver band: Band 3 Band 6 Band 7 Band 8


   6.2. Line: CO 1-0, 2-1, 3-2, 4-3
        Frequency: 115, 230, 345, and 460 GHz


   6.3. Spectral resolution (km/s): 1 km/s

   6.4. Spectral coverage (km/s or GHz): 100 km/s



7. Continuum flux density:


   7.1. Typical value: N/A


   7.2. Continuum peak value: N/A


   7.3. Required continuum rms: N/A


   7.4. Dynamic range in image: N/A



8. Line intensity:


   8.1. Typical value: 6-20 K (B3) 10-30 K (B6)  20-40 K (B7)  10-20K (B8)


   8.2. Required rms per channel: 1.2 K (B3,6,7, 8)

   8.3. Spectral dynamic range: >5



9. Polarization: no



10. Integration time per setting:

                             3 sources x 1 field  x 20 hrs (B3)
                             3 sources x 5 fields x 1.5 hrs (B6)
                             3 sources x 13 fields x 0.7 hrs (B7)
                             3 sources x 16 fields x 2 hrs (B8)


11. Total integration time for program: 206 hr

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Review Leonardo Testi: Sounds good. Maybe there is no need to have all
of the sources in the first three years. One or two well selected
candidates can already give important answers.
--------------------------------------------------
Review v2.0:
 
3.5.1 rev	Structure of the Molecular Gas shocked by SNR 	Tatematsu	

Shocked gas in W28 was described twenty years before the reference
given.  This proposal targets all low order CO transitions--do we
really need every transition?  This is a shock, and the energies of
the relevant levels are only a few K separated.  Suggest CO2-1, 4-3
and perhaps 6-5; I suspect even here 4-3 might be overkill and the
essential science would be contained in say 3-2 and 6-5.  1-0 perhaps;
it would show the lay of the molecular gas which had not been
disturbed.  No other lines (than OH) are mentioned, though HCO+ was
also shown to be interesting more than 20 years ago.


Answer: The pair of CO 1-0 and 2-1 will provide the physical properties
of the unshocked gas and the pair of CO 3-2 and 4-3 will provide
those of the shocked gas.
This program is aimed at very high angular resolution of 0.15"
of the thermal gas, which is not possible with existing
radio telescope, to see the detailed structure over the shock front.

I made LVG calculations for CO and HCN for relevant parameter space.
CO 6-5 intensity is 4-40 K and HCN intensity is of order 1 K at most.
Then, the total observation time becomes huge.
We can reduce the angular resolution, but it will change the scope
of the program.  Here we like to stick to very high
angular resolution.