Delta Quadrant Survey Homepage

This page details procedures and information for the Delta Quadrant Survey (DQS) project.
For a general overview click here.

Observing Procedure

See the observing checklists below for step-by-step observing guidelines. Tony Wong's notes on the DQS are also essential reading, covering the logging programs, Filewatch and rpflog, as well as providing an overview of the observing procedures and data reduction. Note that the handwritten paper log should also be completed by observers. The log of the observations already taken is given online here. An observing report should be written at the end of the run; those written so far are given here.

In addition to mapping the DQS, each night take a standard 12CO and 13CO spectrum on the M17 and Orion sources. Observing schedule for these (which include all frequency settings) are M17SW1-12co, M17SW1-13co, OrionKL-12co and OrionKL-13co. These contain details for two on-off pairs (1 degree away), 36x2s per position. Remember to point beforehand, to Orion SiO and VX Sgr (as appropriate). Note that the M17 standard measurements can actually be made after the DQS sets, since the RA is later.

Finally, remember to monitor the 86 GHz beam shape once per run (i.e. once per observing week). Do this by making 2 SiO observations, one on Orion and one on Mira. Use the respective schedule files Orion-siobeam and Oceti_map (?) for this. This only has to be done in polarization B (ie don't bother tuning polarization A for SiO). We are monitoring the beam on these 2 sources as they produce a different beam shape which needs investigating.

Observing Strategy

We originally planned to scan the whole region (see Figures 1 and 2) with a `first pass' in RA and then make a `second pass' (second pass grid numbers are prefixed by 2-) using dec scans with pointings offset by 1' N and 1' E. Two passes improves the snr and the use of offsets minimises the edge effects introduced by the field boundaries. The following describes what we have done and have yet to do. Note that the use of `offset' is in reference to the field pointings used in the first pass.

The current status of the observations is that we had collected maps for 13CO, C18O, CS, C34S, HCCCN (90GHz), HCO+, HCN, CCH, SiO, H13CN, CH3OH, H13CO+, N2H+, SO, OCS, C33S, 13CH3OH, CCCS and CH3CN. In 2007, we will complete the survey by mapping the region from 103 to 113 GHz.

DQS Fields

Figure 1: The 93 DQS fields that have been mapped in the first pass are shown overlaid on the MSX 8 micron image below; fields 94-96 may be added later:

The panels below give the centre positions for each field in each of the 2 passes, referenced to the plots in Figure 2.

Figure 2:The 21 micron MSX images below show the fields scanned (top) in the first (mainly RA) pass and (bottom) in the second offset (mainly Dec) pass, and their grid numbers. They are colour-coded such that coloured fields are those that have been observed already: blue fields are OK; red ones have baseline and/or noise errors; yellow fields are also problematic but not hugely so; orange ones haven't been reduced yet; green fields are the current priority. The hatched fields (top) were observed in the first pass with the original pointing centres but with scanning in dec mode. In the bottom plot the complementary second pass fields are also hatched; these will be/have been observed in RA scan mode. This figure last updated 17th September 2004.

Data & Reduction

Livedata is the ATNF package used to process the raw .rpf files into sdf files with correct position stamps on each spectrum. The sdf file is further processed by a package called Gridzilla, which regrids the sdf file and creates a FITS data cube. Notes for the operation of Livedata and Gridzilla are available here.