DATE: May 22, 2006 </br>
Subject: Procedure of data reduction for high spectral resolution in Miriad </br>
From: Jun-Hui Zhao & K. H. (Taco) Young</br>
</br>

<center><b> ABSTRACT </b></center>
This memo reports the detailed procedure 
for reducing SMA high spectral resolution data  in Miriad based on
the recent testing data observed on May 12, 2006.   
</br></br>

<b>1. Data Conversion and Reduction Script</b></br> 
The miriad program <b>smalod</b> has been
updated for converting SMA high spectral resolution data
from the Mir data format to Miriad.
Based on a testing data set taken  on May 12, 2006 by Taco using the SMA,
we made this template script for the reduction of high
spectral resolution data. The target source in this test
is the SiO maser in R-Cas at the rest frequency of 
215.59591 GHz. The chunk 16 in the lower side band 
contains the maser line. Neptune is used for bandpass.
The phase reference calibrator is 0133+476. Ceres
is used to determine the flux density scale. 
<a href="http://www.cfa.harvard.edu/sma/miriad/smaspec/highSpRe/060512.csh
">060512.csh</a> is the end-to-end reduction script. 
This script gives the details in data reduction process
in Miriad in terms of Tsys correction,  bandpass calibration
for removing antenna-based bandpass for both the high resolution 
(2048 channels per chunk) and lower resolution chunks 
(128 channels per chunk), antenna-gain calibration, flux density
scale bootstraping, and imaging the line cube.
The testing data <b>060512_18:10:36</b> can be found under
/pool/jove1/miriad in the CF system or from SMA data archive.
There is one obvious problem in the testing data that
the amplitude scale is off by a factor of 1.7 between
the lower and the higher spectral resolution chunks.
To fix the scaling problem, one must run smaflux for
the higher and lower spectral resolution data separately, as
is shown in the script (<a href="http://www.cfa.harvard.edu/sma/miriad/smaspec/highSpRe/060512.csh
">060512.csh</a>). The on-line software will fix this problem. 
</br></br>

<b>2. Plots</b></br>
We show a few plots derived from the data reduction process:
</br>
<b>2.1. High velocity resolution spectrum</b></br>
<img src="http://www.cfa.harvard.edu/sma/miriad/smaspec/highSpRe/hsrfig1.gif">
</br>
This is a very high resolution spectrum of the  SiO maser in R-Cas
obtained in the uv domain by averaging all the baselines and time; 
the channel width is 0.05 MHz or 0.07 km/s.
</br>
<b>2.2. Line cube </b></br>
<a href="http://www.cfa.harvard.edu/sma/miriad/smaspec/highSpRe/hsrfig2.pdf">
This </a> is a pdf file of the line images in the central 400 channels folded in 16 pages.
</br>
<b>2.3. Spectrum derived from the line cube </b></br>
<img src="http://www.cfa.harvard.edu/sma/miriad/smaspec/highSpRe/hsrfig3.gif"></br>
This is the spectrum derived from the line image cube in the central 2 
arcsec region.
</br>
</br>
Updated:
jhz 2006-5-25