README web version of /home/usg/OPS/MTS/readme_xml/readme_82052700

Principal Investigator Email Address

• tokunaga@ifa.hawaii.edu

Estimated Total Execution Time (hours, including overheads)

• 12.2

General Description

• These are observations of infrared absorption lines of H_2 and CO molecules
   in dense molecular clouds.  The approach is to observe the v=0-1 S(0) quadrople
   H_2 line at 2223.nm and the v=2-0 CO overtone lines near 2345.31nm in absorption
   against the continuum of bright sources behind dense clouds.  This provides a direct
   measurement of the CO/H_2 ratio.  The H_2 line, being a quadrople transistion is
   very weak, with an estimated absorption line depth of about 0.01 (1%) of the continuum.
    Therefore we require high S/N ~ 250.  This implies high spectral resolution (R~50,000),
   long integration times, good sky conditions, and careful calibrations with standard
   stars. The CO band is strong but suffers from interference by telluric CO.  Therefore
   CO observations must be timed when the radial velocity is > 15 km/s.

Waiver Requests

• No Waiver Request was submitted

Critical Observing Condition Constraints

• In order to achieve high S/N, the H_2 spectra of the source object and
   the calibration object SHOULD BE MEASURED ON THE SAME PIXEL ROW IF POSSIBLE.

Time-Critical Aspects

• The CO observations require radial velocities of > 15 km/s for the
   source CO lines to be Doppler shifted away from telluric CO lines.  The TIME INTERVALS
   for the CO observations have been set to meet this requirement.

Special Execution Requirements

• Because of the high S/N on the narrow H_2 line needed in these observations,
   it would be very desirable if the H2 line region (2236.1 nm) can be located on a
   part of the array where the pixel quality is high (that is where the best flat fielding
   can be achieved).

Special Calibration Information

• The calibration OBs of spectral standard stars are needed to ratio out
   Earth atmosphere spectral line structure so that 1% or less source H_2 absorptions
   can be detected.  They should be executed either immediately before or immediately
   after the source observations.  While we specify that we can tolerate thin cirrus,
   we cannot tolerate significantly variable sky conditions.

ToO Information

• ---(Empty)---

ToO Activators List

• ---(Empty)---

Do the README file and the instrument comments of the telluric stars
 OBs include the required S/N/pixel of the spectrum of the telluric star, its spectral
 type and allowed spectral range?

• YES

Do any OBs include wavelength or flatfield calibrations?

• NO

If you are observing Moving Targets, have you attached suitable ephemeris
 files to your OBs?

• N/A

If the slit viewer guide star is different from the target, are the RA
 and DEC offsets accurate to within 0.05 arcsec and do they take into account the
 relative proper motion between the two objects?

• N/A

If you have preferences which OBs should be executed first for objects
 at similar RA, did you make use of the User Priority field in the OBs?

• N/A