Molecular Gas in Ara OB1: 2006 Observations

Latest Moment-0 Maps

12CO: includes data from 27 July - 5 August.
13CO: includes data from 27 July - 8 August.

C18O: includes data from 30 July - 5 August.

13CO (2005): from 2005

General Observing Info

The line list is: 12CO, 13CO, C18O, C17O, CN-1, CN-2, CH3CN, CH3OH (newvc only) and SO (newvc only).

Line	Rest Freq	Sky Freq (v=-20km/s)
12CO	115271.203	115272.220
13CO	110201.37	110202.342
C18O	109782.182	109783.150
C17O	112358.988	112359.979
CH3CN	110695.506	110696.482
CN-1	113490.982	113491.983
CN-2	113191.317	113192.135
SO	1089252.212	109253.175
CH3OH	108893.929	108894.889

We are making 5' x 5' OTF maps.

The calibrator we are using is M17-SW (once per night).

The maser we are using for pointing is IRSV 1540. Don't forget to make a beam map every few days.

All the schedule files and MOPS configuration files are stored in the ~/M160/scheds/ directory on minos. The files call the zoomcfg file m160zoomcfg. On July 29, I shifted the band centre from 112660 MHz to 111420 MHz. This made the Tsys estimate for block 4 more reliable, but I added zoom windows to observe the SO and CH3OH lines at the same time. Schedule files for vc=112660 are in ~/M160/scheds/oldvc/. Schedules files for vc=111420 are in ~/M160/scheds/newvc. In general you should use the newvc schedule files.

The schedule file for the calibrator is M160-M17SW.sch. It calls the zoomcfg file m160calzoomcfg. The schedfiles for the beam maps are WHya_RA_beam.sch and WHya_dec_beam.sch. They call the zoomcfg file whyabeamzoomcfg.

All the schedfiles have been transferred to /nfs/online/local/tcs/sched/M160/ directory on bigrock, i.e. I have already schedput them all. The directory structure is the same on bigrock and minos.

A few words about attenuators

The most 'hands-on' part of observing is checking the attenuator levels. This must be done for both the pointing and the programme observations, since there is a significant shift in frequency between SiO and 12CO. However, it is less critical that the attenuator levels are 'perfect' (i.e. GTP ~ 0.4-0.5, no attenuators saturated) than for the actual AraOB1 maps. I've found it takes about 2 scans of the pointing for the attenuators to adjust to reasonable levels, and about 4 scans of the AraOB1 map schedfiles. Also you have to wait for the Tsys scan to do its thing - this will (obviously!) make the GTP plot looks like it's gone crazy

To adjust the attenuators:

• Start the schedule file in TCS
• Type matt auto in the MOPS window to allow the attenuator levels to adjust themselves.
• When the GTPs for all the IFs are within about 0.4-0.55 for the AraOB1 maps, or between 0.2 and 0.95 for the pointing, then type matt man in the MOPS window. No lines should be coloured red in the Sampler tab. Blue means that the sampler levels are "sub-optimal", but I've often found that the IF2, Pol1 attenuator will remain blue forever, so don't worry too much if that one is blue.
• Stop the schedule file in TCS
• Start the schedule file in TCS
• Ideally, the total power plot should show the GTPs are stable, and around 0.4-0.55. Small wiggles around a mean value usually indicate cloudlets and other atmospheric buglets.

Calibration Scans

Molecular Gas in Ara OB1: 2006 Data Reduction

Molecular Gas in Ara OB1: 2006 Data Reduction