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This README file contains a description of the Orion KL ALMA, EOC,
test mosaic data, scripts and data products. 

Spectral windows include polarized dust continuum emission. 

The observations were done using configurations C43-2 for band 3
during 2018 and in C43-3/4 for band 6 during 2019.

The approximate resolution for band 3 is  ~1.2 x 0.7 arcseconds in band 3
and ~ 0.7 x 0.5 in band 6.

The approximate RMS before selfcal, when considering the complete mosaic is:
* 0.9 mJy/beam band 3 in Stokes I
* 2.1 mJy/beam band 6 in Stokes I


Additional information can be found in the comments section
included in this README.

The Calibrated Data and Reference Images provided here were produced using
CASA version 5.4 

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OrionKL_Band3_Scripts.tgz contains the calibration and imaging scripts:

#Scripts for gain calibration
* uid___A002_Xca795f_Xd0.ms.scriptForCalibration.py
* uid___A002_Xca795f_X50f.ms.scriptForCalibration.py
* uid___A002_Xca795f_Xcbd.ms.scriptForCalibration.py
#Scripts for polarization calibration
* scriptForPolCalibration.py  
#Reference script for sample images
* scriptForImaging.py  

OrionKL_Band3_UncalibratedData.tgz contains the raw data:

Three ASDM dataset:
* uid___A002_Xca795f_X50f  
* uid___A002_Xca795f_Xcbd  
* uid___A002_Xca795f_Xd0

OrionKL_Band3_CalibratedData.tgz contains the calibrated uv-data:

#Gain calibrated MS
* uid___A002_Xca795f_X50f.ms.split.cal 
* uid___A002_Xca795f_Xcbd.ms.split.cal 
* uid___A002_Xca795f_Xd0.ms.split.cal

#Polarization calibrated MS
* concat.ms.cal

To produce this calibrated dataset you will need to execute the calibration
scripts first followed by the polarization calibration script.
The calibration scripts have to be executed in
following order:


1) execfile('uid___A002_Xca795f_Xd0.ms.scriptForCalibration.py')
2) execfile('uid___A002_Xca795f_Xcbd.ms.scriptForCalibration.py')
3) execfile('uid___A002_Xca795f_X50f.ms.scriptForCalibration.py')
4) execfile('scriptForPolCalibration.py')

OrionKL_Band3_ReferenceImages.tgz contains the continuum reference images:

* concat.ms.cal.mfs.impbcor.I.fits
* concat.ms.cal.mfs.impbcor.Q.fits
* concat.ms.cal.mfs.impbcor.U.fits


The reference images can be re-created by executing the imaging script
(scriptForImaging.py). Some bening warnings can be ignored.
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OrionKL_Band6_Scripts.tgz contains the calibration and imaging scripts:

#Scripts for gain calibration
* uid___A002_Xdab261_X13a0a.ms.scriptForCalibration.py
* uid___A002_Xdab261_X1448a.ms.scriptForCalibration.py
#Scripts for polarization calibration
* scriptForPolCalibration.py
#Reference script for sample images
* scriptForImaging.py  

OrionKL_Band3_UncalibratedData.tgz contains the raw data:

Three ASDM dataset:
* uid___A002_Xdab261_X13a0a  
* uid___A002_Xdab261_X1448a

OrionKL_Band6_CalibratedData.tgz contains the calibrated uv-data:

#Gain calibrated MS
* uid___A002_Xdab261_X13a0a.split.cal
* uid___A002_Xdab261_X1448a.split.cal

#Polarization calibrated MS
* concat.ms.cal

To produce this calibrated dataset you will need to execute the calibration
scripts first followed by the polarization calibration script. The calibration scripts have to be executed in 
following order:

1) execfile('uid___A002_Xdab261_X13a0a.ms.scriptForCalibration.py')
2) execfile('uid___A002_Xdab261_X1448a.ms.scriptForCalibration.py')
3) execfile('scriptForPolCalibration.py')

OrionKL_Band6_ReferenceImages.tgz contains the continuum reference images:

* concat.ms.cal.mfs.impbcor.I.fits
* concat.ms.cal.mfs.impbcor.Q.fits
* concat.ms.cal.mfs.impbcor.U.fits


The reference images can be re-created by executing the imaging script
(scriptForImaging.py). Some bening warnings can be ignored.



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Publications making use of these data must include the following statement 
in the acknowledgement:

"This paper makes use of the following ALMA data: ADS/JAO.ALMA#0000.0.00377.CSV. 
ALMA is a partnership of ESO (representing its member states), NSF (USA) and 
NINS (Japan), together with NRC (Canada) and NSC and ASIAA (Taiwan), and KASI (Republic of Korea), 
in cooperation with the Republic of Chile. The Joint ALMA Observatory is 
operated by ESO, AUI/NRAO and NAOJ."

In addition, publications from NA authors must include the standard NRAO 
acknowledgement:

"The National Radio Astronomy Observatory is a facility of the National 
Science Foundation operated under cooperative agreement by Associated 
Universities, Inc."

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COMMENTS:

The observations were setup to compare different mosaic patterns, which we labeled according to their
different densities: Hyper-Nyquist (separation between the pointings is ∼ 1/4 of the FWHM), Super-Nyquist
(separation of ∼ 1/3 of the FWHM), Nyquist (separation of ∼ 1/2 of the FWHM), and a single field, which
for the band 3 data corresponds to the center pointing (reference coordinates). In this way, we are able to
compare the errors introduced by the off-axis instrumental polarization in the different sampling patterns.
The objective of this investigation is to estimates the errors in the final image of an arbitrary polarization
mosaic to conclude if any of them is “sufficiently acceptable.” (see Hull et al. 2020)

Both mosaics have the same reference coordinates (α = 05:35:14.5, δ = −05:22:31.6).
The observations at 3.1 mm were performed between 17 and 18 March 2018 under marginal weather conditions;
and on 12 April 2019 for the 1.3 mm data, under regular weather conditions.
The data were calibrated using the standard procedure for processing ALMA polarization observations.
We used J0522-3627 as the polarization calibrator, J0423-0120 as the bandpass calibrator, and J0529-0519
as the phase calibrator. The same sources were used in both band 3 and 6 observations. The polarization
calibrator was interleaved every ∼ 35 minutes with only one bandpass scan in the first EB. 
Given that a session will always contain at least one scan of the polarization calibrator in each EB, we
derived both bandpass and flux scaling from the polarization calibrator for each EB independently.
The images released here are simple reference images. Thus, we recommend that for full exploitation of these 
data, self-calibration should be attempt

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HOW TO EXECUTE THE CALIBRATION SCRIPT FOR BAND 3
(same procedure for band 6)

(1) Put the ALMA raw data and the calibration scripts in the same directory

(2) In CASA 5.x

1) execfile('uid___A002_Xca795f_Xd0.ms.scriptForCalibration.py')
2) execfile('uid___A002_Xca795f_Xcbd.ms.scriptForCalibration.py')
3) execfile('uid___A002_Xca795f_X50f.ms.scriptForCalibration.py')
4) execfile('scriptForPolCalibration.py')


HOW TO EXECUTE THE IMAGING SCRIPT

(1) In CASA 5.x

execfile('scriptForImaging.py')